COORDINATION AND CONTROL

Chapter 12 

COORDINATION AND CONTROL

Q.1. What do you mean by coordination? How is it brought about?
Ans. The tissues and organs in the bodies of multicellular organisms do not work independently of each other They work together performing their many tasks as the needs of the whole body. This means that these activities are coordinated. Coordination also enables the organism to respond to happenings in the world around it.

Q.2. Explain muscle coordination with a suitable example.
Ans. Life activities are controlled and coordinated i e., body works as one unit, in which its different
Organ and cooperation and work in harmony with each other.
When a boy runs to catch a ball, he uses hundreds of muscles to move his arms, legs and back His nervous system uses information from his sense organs and coordinates these muscles Due to this coordination, the muscles contract in the correct sequence, power and length of time But that is not all Such activities involve many other kinds of coordination For example, breathing and heartbeat rates are increased, blood pressure is adjusted, and extra heat is removed at a faster rate from the body.

Q.3. Identify the types of coordination in living organisms.
Ans. There are two types of coordination systems in organisms which are related to
each other.
(i) Nervous coordination brought about by nervous system and
(ii) Chemical coordination brought about by endocrine system
Animals have both the nervous and chemical coordination systems in their bodies while plants and other organisms have only chemical coordination.

Q.4. What are the main components of coordination?
Ans. Coordination Action
A coordination action has five components;
Stimulus -> Receptors -> Coordinator -> Effecter -> Response
i) Stimuli
We can define a stimulus as any change in environment (external and internal), which can provoke a response in organism

Examples
Touch, light etc. are factors that can bring about certain responses in livin organisms. These factors are called stimuli.
More examples of stimuli are heat, cold, pressure, sound waves, presence chemicals, microbial infections etc.
ii) Receptors
Stimuli are detected- by special organs, tissues or cells of body. The organ tissue or cells which are specifically built to detect particular type of stimuli , called receptors.
Example
For example sound waves are detected by ears, light is detected by eyes, chemicals in air are detected by nose and so on.
HI) Coordinators
These are the organs that receive information from receptors and messages to particular organs for proper action.
Examples
In nervous coordination, brain and spinal cord are coordinators. They information and send messages through neurons in the form of nerve impuls
In chemical coordination, various endocrine glands play the role of coordinat< They receive information in the form of .various chemicals and send messagesj secreting particular hormones in blood.
iv) Effectors
These are the parts of body which receive messages from coordinators produce particular responses.
Examples
In nervous coordination, neurons carry messages from coordinators (brain < spinal card) to muscles and glands, which act as effectors.
In chemical coordination, particular hormones carry messages from coordin| (endocrine glands) to particular target tissues, which act as effectors. For i” hormones, nephrons act as effectors. Similarly, bones liver act as effector many hormones.
Response
On receiving the message from coordinators, the effectors perform action.] action is called response. Usually, nervous coordination produces immedi; short-living responses while chemical coordination produces slowly but living responses. –
Coordination and Control 35
Example
For example, pulling our hand away from something very hot and the movement of the flower of sunflower towards light are responses.

Q.5. Differentiate between the modes of nervous and chemical coordination.
Ans. Nervous coordination produces immediate but short-living responses, while chemical coordination produces slowly but long-living responses. Both the coordination systems act in close contact with each other. Figure 12.1
Fig 12.1 of book
Figure 12.1 Nervous and chemical coordination

Q.6. What are the major components of human nervous system?
Ans. The nervous system in man and in other higher animals is composed of two major components i.e.
i- Centra) nervous system, and, ii- Peripheral nervous system.
Central nervous system comprises of coordinators i.e. brain and spinal cord while peripheral nervous system consists of nerves that arise from central nervous system and spread in different parts of body. All these components are made of neurons.

Q.7. Define neuron and describe the structure of a general neuron. Ans. Nerve cejl or Neuron
Nerve cell or neuron is the unit of the nervous system. The human nervous system consists of billions of neurons plus supporting (neuroglial) cells.
Function
Neurons are specialized cells that are able to conduct nerve impulses from’ receptors to coordinators and from coordinators to effectors. In this way they communicate with each other and with other types of body cells.

36 Caravan’s Biology Objective

Q.8. Ans.
Structure of Neuron
Neuron consists of following major components:
Cell body, dendrites, axons, Schwann cells, myelin sheath, and nodes of Ranvier.
The nucleus and most of the cytoplasm of a neuron is located in its cell body. Different processes extend out from the cell body. These are called dendrites and axons. Dendrites conduct impulses toward cell body and axons conduct impulses away from cell body.
Schwann cells are special neuralgia cells located at regular intervals along axons. In some neurons, Schwann cells secrete a fatty layer called myelin sheath, over axons. Between the areas of myelin on an axon, there are non-militated points, called the nodes of Ranvier.
Myelin sheath is an insulator so the membrane coated with the sheath does not
conduct nerve impulse. In such a neuron, impulses ‘jump’ over the areas of myelin going from node to node. Such impulses are called saltatory (‘jumping’) impulses. This increases the speed of nerve impulse.
Cell body
Axon
Dendrites Nucleus Myelin sheath
Nodes of Ranviei Schwann cells
Directionof nerve impulse I
Nerve Growth Factor
Unlike ordinary cellsV mature neurons never divide. But a protein called nerve-growth-factor promotes the regeneration of broken nerve cells. The degenerating brain cells could be repaired, by using embryonic stem cells. Figure 12.2
. v.f .
What is nerve impulse?
A nerve impulse is a wave of electrochemical changes that travels along the length of neurons.
Model neuron (motor neuron) Figure 12.2 Structure of a typical neuron

Q.9. Enlist different types of neurons and give their functions briefly. Ans, On the basis of their functions, neurons are classified into three types:
1. Sensory neurons conduct sensory information (nerve impulse) from receptors towards the CNS. Sensory neurons have one dendrite and pne-axon.
Coordination tnd Control 37.
2. Interneurons form brain and spinal card. They receive information, interpret them and stimulate motor neurons. They have many dendrites and axons.
3. Motor neurons carry information from interneuron’s to muscle* or glands : (effectors). They have many dendrites but only one axon.

Q.10. What rs a nerve? Name their types.
Ans. A nerve means the union of several axons that are enveloped by a covering made of lipid. Based on the property of axons, the nerves are classified into three types.
1. Sensory nerves contain the axon of sensory neurons only.
2. Motor nerves contain the axons of motor neurons only.
3. Mixed nerves contain the axons of both i.e. sensory and motor neurons.

Q.11. What do you mean by ganglion?
Ans. In certain parts of body, the cell bodies of many neurons form a group enveloped by a membrane This is called ganglion.

Q.12. Explain the parts and functions of human brain. Ans. BRAIN
In animals, all life activities are under the control of brain. The structure of brain is suitable to perform these functions.
i) Cranium
Brain is situated inside a bony cranium i.e., brain box, (part of skull).
.ii) Meninges
Inside cranium, brain is covered by three layers called meninges. Meninges protect brain and also provide nutrients and oxygen to brain tissue through their capillaries.
iii) Ventricles
The brain contains fluid-filled ventricles that are continuous with the central canal of spinal cord.
iv) Cerebrospinal fluid
Fluid within ventricles and central canal is called cerebrospinal fluid (CSF)
The Divisions of Brain •
There are three major regions in the brain of human and other vertebrates. These are forebrain, midbrain and hindbrain. Important parts of each of these regions are described below.

Figure 12.3

Forebrain is the largest area of brain: It is most highly developed in humans.
38 Caravan’s Biology Objective
Parts of Forebrain
Following are the important parts of forebrain.
Thalamus
Location ,
It lies just below the cerebrum.
Functions
It serves as a relay centre between various parts of brain and spinal cord. It also receives and modifies sensory impulses (except from nose) before they travel to cerebrum, Thalamus is also involved in pain perception and consciousness (sleep and awakening)
Forebrain
Cerebrum Thalamus Hypothalamus
Frontal lobe
Parietal lobe
Occipital lobe
Midbrain
Pituitary gland
Temporal Sp|na, cord lobe
Cerebellum -i
Pons -Medulla -oblongata’
Hindbrain
Figure12.3 Structure of human brain (longitudinal section to show internal parts)
ii) Hypothalamus Location
It lies above midbrain and just below thalamus.
Size
In humans, it is roughly the size of an almond.
Functions
One of the most important-functions of hypothalamus is to link nervous system and endocrine system. It controls the secretions of pituitary gland. It also controls feelings such as rage, pain, pleasure and sorrow.
iii) Cerebrum
It is the largest part of forebrain.
Coordination and Control 39
Functions
It controls skeletal muscles, thinking, intelligence and emotions.
Division
It is divided into two cerebral hemispheres.
The anterior parts of cerebral hemispheres are called olfactory bulbs which receive impulses from olfactory nerves and create the sensation of smell.
The upper layer of cerebral hemispheres i.e. cerebral cortex consists of grey matter. The grey matter of nervous system consists of cell bodies and non-myelinated axons. Beneath this layer is present the white matter. The white matter of nervous system consists of myelinated axbns. Cerebral cortex has a large surface area and is folded in order to fit in skull. It is divided into four lobes.

Lobe
Function

Frontal
Controls motor functions, permits conscious control of skeletal muscles and Coordinates movements involved in speech

Parietal
Contains sensory areas that receive impulses from skin.

Occipital
Receives and analyzes visual information

Temporal
Concerned with hearing and smell.

2- Midbrain
Location –
Midbrain is the part between hindbrain and forebrain and connects the two. Functions
It receives sensory information and sends it to the appropriate part of forebrain. Midbrain also controls some auditory reflexes and posture.
3- Hindbrain
Hindbrain consists of three major pats:
i) Medulla Oblongata
It lies on the top of spinal cord. ‘
Functions
It controls breathing, heart rate and bold pressure. It also controls many reflexes such as vomiting, coughing, sneezing etc. Information that passes between spinal cord and the rest of brain pass through medulla.
ii) Cerebellum is behind medulla. Functions
It coordinates muscle movements.
40 Caravan’s Biology Objective
iii) Rons is present on top of medulla. -Functions
It assists medulla in controlling breathing. It also serves as a connection between oerebeHum and spinal cord.

Q.13.. What do you mean by hippocampus?
Hippocampus is a structure that is deep in the cerebrum. It functions for the ‘ formation of new memories. People with a damaged hippocampus cannot remember things that occurred after the damage but can remember things that occurred before damage.

Q.14. Describe the structure and functions of spinal cord. Spinal Cord
Spinal cord is the continuation of medulla qblongata. It is in fact a tubular bundle of nerves. It starts from brain stem and extend to lower back. Like brain, spinal cord is also covered by meninges. The vertebral column surrounds and protects spinal cord.
White matter Grey matter Sensory neuron
Dorsal ———a^^^flfe^wlill^^^L. /- Ganglion root __ _ __ _.__ _ __.
Fromfeceptor
——^^—^^^M*,••.. ,o^b^__^v Towards effector root
Spinal cord^jf
Motor neuron
Figure 12-4 (T S) SpJnal cord and spinal nerves


Size
Spinal cord is roughly 40cm long and about as wide as your thumb for most of its length.
Structure
The outer region of spinal cord is made of white matter (containing myelinated axons). The central region is butterfly shaped that surrounds the central canal. It is made of grey matter (containing neuron cell bodies).
Spinal Nerves
31 pairs of spinal nerves arise along spinal cord. These are “mixed” nerves because each contains axons of both sensory and motor neurons. At the point where a spinal nerve arises from spinal cord, there are two roots of spinal nerve. Both roots unite and form one mixed spinal nerve. Figure 12.4

Coordination and Control 41
• The dorsal root contains sensory axons and a”ganglion where cell bodies are located.
• The ventral,root contains axons of motor neurons.
Functions
Spinal cord performs two main functions:
1) It serves as a link between body parts and brain. Spinal cord transmits nerve impulses from body parts to brain and from brain to body parts.
2) Spinal cord also acts as a coordinator, responsible for some simple reflexes.

Q. 15. What is peripheral nervous system? How does it differ from central nervous system?
Ans. The
peripheral
nervous
system
(PNS) is
composed
of nerves
and ganglia.
Ganglia are
the clusters
of neuron
cell bodies
outside
CMS. On the
other hand,
central
nervous
system
consists of ‘
brain and
spinal cord. Figure 12.5

Q. 16. Differentiate between cranial and spinal nerves.
Ans. Nerves that arise or lead to brain are called cranial nerves, and the nerves that arise or lead to spinal cord are named as spinal nerves. Humans’have 12 pairs of cranial nerves and 31 pairs of spinal nerves. Some cranial nerves are sensory, some are motor and some are mixed. On the other hand, all spinal nerves are mixed nerves.

Q. 17. Differentiate between sensory pathway and motor pathway.
Ans. The cranial and spinal nerves make two pathways i.e. sensory pathway (conducting impulses from receptors to CNS) and motor pathway (conducting impulses from CNS to effectors). ‘
• Brain
and
Spinal cord
Cranial nerves
and Spinal nerves
Somatic
nervous system
(to skeletal muscles)
Autonomic
nervous system
(to smooth muscles,
heart, internal organs)
Sympathetic ne/vous system
Parasympathetlc nervous system Coordination and Control 43
Sensory neuron •
Receptors ” ^ (of temperature and pain) o
•I
Motor neuron
\ Effectors ” 3 j(Muscles of arm) —
Figure 12.6 Reflex arc in a reflex action

Q. 21. Name the receptors found in human.
Ans. The organs or parts which are specifically built to detect particular type of stimuli are called sense organs or receptors. Main receptors in man are eyes, ears, nose, taste, receptors of touch, heat and cold etc

Q. 22. Describe the structure of human eye in detail. Ans. Structure of Eye Eye Orbit
Our eyes are located in small portions of skull known as the orbits or eye .sockets.
Eyelids
Eyelids wipe eyes and prevent dehydration. They spread tears on eyes, which contains substances for fighting bacterial infections.
Eyelashes
Eyelashes prevent fine particles from entering eye.
The structure of eye can be divided into three main layers.
Outer Layer .
The outer layer of eyeball consists of sclera and cornea.
Sclera gives eye most of its white colour. It consists of dense connective tissue and protects the inner components of eye and maintains its shape. In the front, sclera forms the transparent cornea. Cornea admits light to the interior of eye and bends light rays so that they can be brought to a focus.
42 Caravan’s Biology Objective

Q. 18. How many systems motor pathway makes?
Ans. Motor pathway makes two systems; somatic nervous system and autonomic nervous system
Somatic Nervous System
It is responsible for the conscious and voluntary actions. It includes all of the motor neurons that conduct impulses from CNS to skeletal muscles.
Autonomic Nervous System
It is responsible for the activities, which are not under conscious control. It consists of motor neurons that send impulses to cardiac muscles, smooth muscle and glands. Autonomic nervous system comprises of sympathetic system and parasympathetic system.

Q.19. How sympathetic nervous system helps prepare for “fight or flighf’response?
Ans. Sympathetic nervous system prepares body to deal with emergency situations. This Is often called the “fight or flight” response. During an emergency situation, this system takes necessary actions. For example; it dilates pupils, accelerates heartbeat, increases breathing rate and inhibits digestion. When stress ends, the parasympathetic nervous system takes action and normalizes all the functions*. It causes pupils to contract, promotes digestion, and slows the rate of heartbeat and breathing rate.

Q. 20. Write an account on reflex action with a suitable example. Ans. Reflex Action
When central nervous system sends impulses to muscles and glands, two types of actions (responses) result. Figure 12.6
1. The higher centres of brain control the conscious action or voluntary actions.
2. When impulses are not passed to the higher centres of brain, it results in responses which are not under conscious control. Such responses are called involuntary actions. Sometimes, the involuntary response produced by the CNS is very quick. Such a response is called reflex action. The pathway followed by the nerve impulses for producing a reflex action, is called reflex arc.
Example
The most common example of reflex adtion is the withdrawal of hand after touching a hot object. In this reflex action, spinal cord acts as coordinator. Heat stimulates temperature and pain receptors in skin. A nerve impulse is generated which is carried by sensory neurons to the interneurons of spinal cord. From interneurons, the impulse is passed to motor neurons, which carry it to the muscles of arm. As a result, the muscles contract to withdraw hand. During it, other interneurons transmit nerve impulses up to brain so that the person becomes aware of pain and what happened.

44 Caravan’s Biology Objective
Middle Layer
The middle layer is called choroid. It contains blood vessels and gives the inner eye a dark colour. The dark colour prevents disruptive reflections within eye.
Iris and Pupil
Suspensory ligament
Aqiious humour
Sclera i Choroid Lf Vers Retina J of the eye
Blind spot
Optic nerve
Ciliary ‘ muscles
Figure 12.7 Structure of human eye
Behind cornea,
choroid bends to form
a muscular ring, called :
iris. There is round
hole, called pupil, in the centre of iris. After striking the cornea, light passes
through the pupil. The size of pupil is adjusted by the muscles of iris. Pupil
constricts in bright light when the circular muscles of iris contract. Similarly, pupil
dilates in dim light when the radial muscles of iris contract. Figure’12.7,12.8
Lens .
Behind iris, there is a convex lens, which focuses light on retina.
Ciliary muscles and suspensory ligament
Lens is attached to ciliary muscles of eye via a ring of suspensory ligaments. To clearly see an object far away, ciliary muscles are relaxed and lens becomes less convex. When ciliary muscles contract, lens becomes more convex and round.
Inner Layer e
The inner layer is sensory and is called retina.
Rods and Cones .
Retina contains the photosensitive cells called rods and cones and associated neurons.

Rods are sensitive to, dim light while cones are sensitive to bright light and so distinguish different colours.
Fovea and Optic disc
Retina has two points i.e. fovea and optic disc.
Fovea is a dip in retina, directly opposite to lens and is densely packed with cone cells. It is largely responsible for colour vision and sharpness. Optic disc is a point on retina where the optic nerve enters retina. There are no rods and cones at this point, that is why it is also referred to as the blind spot.
Coordination and Control 45
Radial muscles • Radial muscles
(contracted) . (relaxed)
Circular muscles Circular muscles
(relaxed) (contracted)
When light intensity : decreases :
j When light intensity i increases
Figure 12.8 Contraction and dilation of pupil
Aqueous humour and Vitreous humour
The iris divides the cavity of eye into two chambers. The anterior chamber is in front of iris i.e. between cornea and iris; whereas the posterior chamber is between iris and retina. The anterior chamber contains a clear fluid known as aqueous humour while the posterior chamber contains a jelly-like fluid known as vitreous humour. It helps maintain the shape of eye and suspends the delicate lens.

Q. 23. How many rods and cones are present in human eye? Ans. In human eye about 125 lac rods and 7 lac cones are present.

Q. 24. Why the eyes of cats and dogs shine in the night?
Ans. The eyes of cats and dogs shine in the night. The reason for this is the presence of tapetum behind the eye which js a layer .capable of reflecting light.

Q. 25. How image focusing takes place?
Ans. Light from objects enters eye and is refracted when it passes through cornea, aqueous humour, lens and vitreous humour. Lens also focuses light on retina. As a result, the image falls on retina. Rods and cones generate nerve impulses in the optic nerve. These impulses are carried to the brain, which makes the sensation of vision.

Q.26. How would you associate the role of vitamin A with the vision and effects of its deficiency on retina?
Ans. Rods contain a pigment called rhodopsin. When light falls on rhodopsin, it breaks for generating a nerve impulse. In the absence of light, the breakdown .products are again converted into rhodopsin. Body synthesizes rhodopsin from vitamin A and that is why the deficiency of vitamin A causes poor night vision. This problem is called night blindness.

Q. 27. What is colour blindness? What is the reason for colour blindness?
Ans. Cones also contain a pigment, known as iodopsin There are three main .types of cones and each type has a specific iodopsin. Each type of cone recognizes one of the three primary colours i.e blue, green and red. If any type of cones is not working well, it becomes difficult to recognize that colour. Such person is also not able to distinguish different colours. This disease is called colour blindness and it is a genetic problem.
46 Caravan’s Biology Objective

Q. 28. What are the short sight and long sight problems and how these can be treated?
Ans. Disorders of the Eye
The working of eye is affected by the changes in the shape of eyeball.
Myopia (Short sight)
The elongation of eyeball results in myopia. Such persons are not able to see distant objects clearly. The image of a distant object is formed in front of retina. This problem can be rectified by using concave lens.
Myopia
Hypermetropia
Concave
lens- Treatment of myopia
Convex
lens Treatment of hypermetropia
Hypermetropia (Long sight)
It happens when eyeball shortens. Such persons are not able to see near objects clearly. The image is formed behind retina . Convex lens is used to rectify this problem. Figure 12.9

Q.29. Relate the contribution of Ibn-al-Haitham and Ali-lbn-lsa about the knowledge of the structure of eye and treatment of various ophthalmic diseases.
Ans. Contributions of Ali ibn Isa
All ibn Isa (950-1012) was a famous Arab scientist. He wrote three books on ophthalmology (study of the diseases and surgery of eyes). He described 130 eye diseases and prescribed 143 drugs to, treat these diseases.
Contributions of Ibn al-Haytham
Ibn al-Haytham (965-1039), an Arab scientist made significant contributions to the principles of eye and vision. He is regarded as the father of optics (study of the behavior of light). His “Book of Optics” correctly explained and proved the modern theory of vision. He discussed the topics of medicine and dye surgery in his book. He made several improvements to .eye surgery and accurately described the process of sight, the structure of eye, image formation in eye and visual system. Ibn al-Haytham also described the principles of pinhole camera.

Coordination and Control 47
Ibn al-Haytham’s “Book of Optics” has been ranked alongside a book of Isaac Newton. It is one of the most influential books ever written in the history of physics.

Q. 30. How an owl is able to see in dark?
Ans. Owl is not able to see during day time. The reason for this is the deficiency of cones which receive and sense the bright light. But the presence of more rods gives it greater power of vision during night. AH animals that search for prey during night have this characteristic.

Q. 31. How would you describe the structure of external, middle and inner ear of man?
Ans. EAR
Hearing is as important as is vision.
Role of Ear
Our ear helps us in hearing and also to maintain the balance or equilibrium of our body.
Parts of Ear
Ear has three main parts i.e. external ear, middle ear, and internal ear.
A) External Ear
Division of External ear
External ear consists of pinna, auditory canal and ear drum (tympanum).
Pinna is the broad external part, made of cartilage and covered with skin. It helps to direct sound waves into auditory canal. There are special glands in the walls of auditory canal, which produce wax. The wax and the hairs in auditory canal protect ear from small insects, germs and dust. In additions to this, is helps to maintain the temperature and dampness of auditory canal. Auditory canal ends in ear drum. This thin membrane separates external ear from middle ear.
B) Middle Ear
Middle ear is a chamber after external ear. Three small bones, called middle ear ossicles, are present in a chain in middle ear. These movable bones include malleus, incus and stapes. Malleus is attached with ear drum, and then
Middle ear bones
————
„ lntjusj Semicircular Malleus I Stapes canals
Oval window
Pinna
.Round window
Figure 12.10 Structure of human ear
48 Caravan’s Biology Objective
Semicircular canals
comes incus and finally stapes that is connected with a membrane called oval window. Oval window separates middle ear from inner ear. Middle ear also communicates with the nasal cavity through Eustachian tube. This tube regulates the air pressure on both sides of ear drum, figure 12.10
C- Inner Ear
Division of inner ear
Inner ear consists of three parts i.e. vestibule, semicircular canals and cochlea.
Vestibule is present in the centre of inner ear.
Three canals called semicircular canals are posterior to the vestibule.
The cochlea is made of three ducts and wraps itself into a coiled tube. Sound receptor cells are present within the middle duct of cochlea. Figure 12.11

Q.32. Name the smallest bone of the human body.
Ans. Stapes is the smallest bone of the human body.

Q. 33. Describe the process of hearing in man?
Ans. The Process of Hearing _______
. . ^^^^^F^\ N——Vestibule The pinna of the external ear
focuses and directs sound waves into auditory canal. The sound waves strike ear drum and produce vibrations in it. From ear drum, the vibrations strike middle ear and produce further vibrations in malleus, incus and then stapes. From stapes, the vibrations strike .the oval window and then reach the fluid-filled middle duct of cochlea. The fluid of cochlea is moved and receptor cells are stimulated. The receptor cells generate a nerve impulse, which travels to brain and is interpreted as sound.

Q. 34. What are the reasons of deafness?
Ans. Deafness is a state in which hearing is not possible. The defect of ear drum, cochlea, middle ear ossicles, or auditory nerve may cause deafness. Infection in eustachian tube may spread to middle ear too. Ear drum may be damaged by an infection- in auditory canal. Excessive noise, strong blows on cheek, pointed objects entering auditory canal and attack from insects may also affect hearing.

Q. 35. Explain the role of ear in the maintenance of balance. Ans. Ears Maintain the Balance of Body
Semicircular canals and vestibule help to maintain the balance of body. Semicircular canals contain sensory nerves which can detect any movement of head. Vestibule can detect any changes in the posture of body. The neurons coming from these two receptors reach cerebellum through the auditory nerve.
Cochlea

Figure t2.11 Structure of inner ear


Coordination and Control 49

Q. 36. To which part of ear, the tympanum belongs?

Ans. The tympanum is a part of external ear.

Q.37. Define the terms exocrine and endocrine gland.
Ans. A gland is a cell or group of cells which secrete a substance or chemical. Many glands in our body are exocrine. Such glands have ducts for releasing their secretions e.g. digestive glands, skin glands etc. While on the other hand endocrine glands are ductless glands and release their secretions (hormones) directly into bloodstream e.g. pituitary gland, thyroid gland etc.

Q. 38. What is a hormone? What is its role in animals?
Ans. A hormone is a specific messenger molecule synthesized and secreted by an endocrine gland.’These glands are ductless and release their secretions (hormones) directly into bloodstream. Blood carries the hormones to target organs or tissues, upon which they act.
Role on hormones
The activities such as growth, reproduction, maintenance of glucose concentration in blood, reabsorption of water in kidneys etc. need to be regulated Endocrine system performs this job with the help of hormones. Other important role ofjiormones is the stepwise process of metamorphosis in many animals is controlled by hormones. Life activities such as cell division in invertebrates are also regulated by hormones. Hormones also control activities like migration in birds. Hormones have been identified even in unicellular organism.

Q.39. Enlist various endocrine glands found in human,
Ans. Some important endocrine glands of humans are: Figure 12.12
Parathyroid
glands
(in the posterior
of the thyroid)
Testes (only in males)

Figure 12.12 Endocrine glands in human body

50 Caravan’s Biology Objective
(i) Pituitary gland . * •
‘ (ii) Thyroid gland
(iii) Parathyroid gland
(iv) Adrenal gland
(v) Pancreas, and,
– • * ”
(vi) Gonads

Q. 40. Write an account on Pituitary gland. Ans. Pituitary Gland
It is a pea-shaped gland attached to the hypothalamus part of brain. Many hormones (tropic hormones) of pituitary gland influence the secretions of other endocrine glands. However some hormones of this gland act directly on various tissues of body.
Lobes of Pituitary Gland
There are two lobes of pituitary gland i.e. anterior lobe and posterior lobe.
1. Anterior Lobe
It produces many hormones.
i) One of its important hormones is somatotrophin (growth hormone). It promotes the growth of body. If the production of this hormone is diminished during growing age, the rate of growth decreases. This condition is called dwarfisni. If this hormone is excessively produced during growing age, it leads to gigantism (very tall and overweight). If somatotrophin is excessively produced after growing age, internal organs and body extremities alone grow large. This condition is known as acromegaly. Such persons will have large hands, feet and jawbones.
ii) Another important hormone secreted by the anterior lobe of pituitary gland is thyroid-stimulating-hormone (TSH). It stimulates thyroid gland to secrete its hormones. The remaining hormones of anterior lobe influence reproductive organs and also control adrenal glands.
* ‘ • 2. Posterior Lobe ,
The posterior lobe of pituitary gland stores and secretes two hormones i.e. oxytocin aad vasopressin (anti diuretic hormone, ADH). These hormones are produced by hypothalamus (a part of brain).
i) Vasopressin increases the rate of reabsorption of water from nephrons. When we have low amount of water in body fluids, pituitary gland secretes vasopressin and so more reabsorption of water occurs from nephrons into blood. In this way, body retains water and less amount of urine is produced. On the other hand, when body fluids have more than normal water, there is a decline in the secretion of this hormone. If pituitary gland does -not secrete this hormone in the required amount, less water is reabsorbed from nephrons and there is excessive loss of water through urine. This condition is known as diabetes insipidus.
Coordination and Control 51
ii) The hormone, oxytocin stimulates the contraction of uterus walls in mothers for child birth. Moreover, this hormone is necessary for the ejection of milk from breast.

Q.41. What is thyroid gland? Name its secretions and their effect on human body. Ans. This is the largest endocrine gland in human body.
Location: It is present in neck region, below larynx.
Hormones: Thyroid produces thyroxin and calcitonin.
Thyroxin: Iodine is required for the production of this hormone.
Goiter
If a person lacks iodine in diet, thyroid gland cannot make this hormone. In this condition, thyroid gland enlarges. This disorder is called goiter.
Effects of Thyroxin: Thyroxin increases the breakdown of food (oxidation) and release of energy in body. It is also responsible for the growth of body. Hypothyroidism is caused by the under-production of thyroxin. It is characterized by low energy production, in body and slowing down of heart-beat. Hyperthyroidism is caused by over production of thyroxin. Its symptoms are increase in energy production, increased heart-beat, frequent sweating and shivering of hands.
»
Calcitonin
The thyroid gland produces another hormone called calcitonin. It decreases the level of calcium ions in blood and promotes the absorption of calcium from blood into bones.
Calcitonin and parathorrhone complement each and regulate the level .of calcium ions in the blood.

Q.42. Describe briefly parathyroid glands and their functions. .
Ans. Parathyroid Glands Location
These are four glands situated on the posterior side of thyroid gland.
Hormone
Parathyroid glands produce a hormone known as parathormone.
Function
Parathormone increases the level of calcium ions in blood.
When there is increased production of parathormone, more than normal calcium salts are absorbed from the bones and added to blood, Consequently the bones become brittle. If there is deficiency in the production of parathormone, blood calcium level falls. It leads to tentany, which affects the functioning of muscles.
52 Caravan’s Biology Objective

Q. 43. What is tetany? What is the cause of tetany?
Ans. Tetany is marked by sharp flexion of the wrist and ankle joints, muscle twitching, cramps and convulsions. It is due to decreased blood calcium level which makes the nerves and muscles more excitable.

Q.44. Describe adrenal glands? Explain how adrenaline may be involved in exercise and emergency conditions.
Ans, Adrenal Glands -Location .
Two adrenal glands are situated above kidneys.
Division
Each adrenal gland consists of two parts. The outer part is cortex and the inner part is medulla.
Hormones
Adrenal medulla secretes a hormone called eplnephrlne or adrenaline in response to stress.
Role of Adrenaline
Adrenaline prepares our body to overcome emergency situations. Therefore, it is also termed as’emergency hormone”.
When a person experiences fear, anger or anxiety, the rate and intensity of heartbeat increases, blood pressure increases, blood flow to the limbs increases, blood flow to the alimentary canal and skin is reduced. Such changes prepare the body to face any emergency situation.
Role of Corticosteroids
The adrenal cortex secretes many hormones called corticosteroids which maintain the balance of salts in blood.

Q. 45. What is pancreas? Describe the secretions produced by it. Ans. Pancreas
This organ performs two functions. The major part of pancreas is a ducted (exocrine) gland. This portion secretes digestive enzymes, through a duct, into the small intestine. Some portions of pancreas serve as ductless (endocrine) gland. This Portion contains groups of endocrine cells referred to as islets of Langerhans.
Hormones
Islets of Langerhans secrete two hormones i.e. insulin and glucagon.
i) GLUCAGON influences the liver to release glucose in blood and so the blood glucose concentration rises.

Coordination and Control S3
ii) Insulin influences the liver to take excess glucose from blood and so the blood glucose concentration falls.

Q. 46. Write a brief account on diabetes mellitus. Ans. Diabetes Mellitus
The blood glucose concentration is maintained at the rate of 80 to 120 mg per 100 ml of blood.
If a person’s pancreas does not make normal quantity of insulin, the blood glucose concentration rises and we say that the person has diabetes mellitus.
Symptoms
Persons with diabetes have loss of body weight, weakening of muscles and tiredness.
Treatment .
The disease can be controlled by insulin administration. Formerly insulin extracted from animals was used for this purpose. But now human insulin produced from bacteria through genetic engineering is available.

Q.47. What is BGC test? Describe the value of blood glucose in normal and diabetic person.
Ans. Blood Glucose Concentration (BGC) Test:
The amount of glucose in blood is measured by this test. It is used to diagnose diabetes. Blood glucose may be measured on a fasting basis, (collected after an 8 to 10 hour fast), randomly (anytime) and after a meat. The results of some BGC tests are given here.

Blood Glucose After 8-10 hours fast

BGC
Diagnosis

From70to99mg/100
Normal

From 100 to 125 mg/100ml
Pre-diabetic

126 mg/100 ml and above
Diabetic

Blood Glucose 2 hours after a 75 gram Glucose drink

BGC
Diagnosis

Less than 140 mg/100ml
Normal

From 140 to 200 mg/100ml
Pre-diabetic

Over 200 mg//1 00ml
Diabetic

54 Caravan’s Biology Objective

Q.48. What are gonads? Describe the role of hormones secreted by gonads. Ans. Gonads ,
Testes (S/ngu/artestis) and ovaries are the male and female reproductive organs i.e. gonads: In addition to producing gametes, gonads also secrete hormones, called sex hormones.
Hormones
Testes secrete hormones e.g. testosterone.
Function
It is responsible for the development of male secondary, sex characters such as growth of hair on face and coarseness of voice etc.
Ovaries secrete estrogen and progesterone,
Function
. ^
It is responsible for the development of female secondary characters such as the development of breast etc.

Q. 49. What do you mean by feedback mechanism? Ans. Feedback Mechanisms
Endocrine glands do not secrete their hormones at a constant rate. The rate varies with the needs of the body. Like many other functions in body, the secretion of hormones is also regulated by feedback mechanisms. Feedback mechanism means the regulation of a process by the output of the same process. Feedback mechanisms are of two types i.e. positive and negative feedbacks.

Q. 50. Describe negative feedback with reference to insulin and glucagon.
Ans. In negative feedback, the output of a process decreases or inhibits the process. This mechanism works to return a condition towards its normal value.
Example
When the blood glucose concentration rises, pancreas secretes insulin. It decreases the blood glucose concentration. Decline in the blood glucose concentration to a normal set-point inhibits the secretion of insulin. Similarly, when blood glucose concentration drops below normal, pancreas secretes glucagon. It raises the blood glucose concentration, in this case, rise in the blood glucose concentration to a normal set-point inhibits the secretion of glucagon. In other words, the blood glucose concentration (output) controls the process i.e. the secretion of insulin and glucagon.

Q.51. What is positive feedback?
Ans. In positive feedback, the changes resulting from a process increase the rate of process. For example; suckling action of an infant stimulates the production of a

Coordination and Control 55
hormone in mother. This hormone works for the production of milk. More suckling leads to more hormone, which in turn leads to more milk production.
Q.52. What are some of the disorders of nervous system? Ans. DISORDERS OF NERVOUS SYSTEM
Disorders of nervous system can be categorized into two main types.
i) Vascular disorders e.g. paralysis and functional disorders e.g. epilepsy. Vascular disorders are due to any disturbance in the blood supply to nervous system. .
ii) Functional disorders are due to disturbance in nerve impulse generation and transmission.
i

Q. 53. Enlist the important symptoms and treatments of paralysis and epilepsy. Ans. Paralysis
Symptoms
Paralysis is the complete loss of function by one or more muscle groups.
Causes
It is most often caused by damage to the central nervous system (brain or spinal cord). The damage may be due to stroke (rupture in a blood vessel of brain or spinal cord), blood clotting in these blood vessels, or poison produced by polio viruses.
Patient may have weak paralysis throughout his/her body or have paralysis in one side of body. There may also be paralysis in the lower extremities or in all four limbs.
Epilepsy
Epilepsy is a nervous disorder in which there is abnormal and excessive discharge of nerve impulses in brain.
Causes
It causes unprovoked seizures in patient. A seizure of epilepsy is a temporary abnormal state of brain marked by convulsions. ‘
In younger people, epilepsy may be due to genetic or developmental causes. In people over age 40 years, brain tumors are more likely to cause epilepsy. Head trauma and central nervous system infections may cause epilepsy at any age.
Treatment and Preventions
There is no known cure of epilepsy but medicines can control seizures. Patients of epilepsy have to take medicines daily for the treatment as well as prevention of seizures. These are termed “anticonvulsant” or “antiepileptic” drugs.
56 Caravan’s Biology Objective
MULTIPLE CHOICE
Encircle or tick (V) the correct option for the statements from the MCQs given below:
1. The organism responds to happenings in the world around it through
(a) excretion (b) osmoregulation (c) coordination (d) locomotion
2. In animals coordination is produced by
(a) nervous system
(b) endocrine system
(c) skeleton and muscles
(d) both a and b
3. Plants have only
(a) nervous system
(b) endocrine system
(c) chemical coordination
(d) exocrine system
4. A coordinated action has ———— components (a) 3 (b) 4 (c) 5 (d) 6
5. A coordination action is brought about by
(a) stimulus and receptor
(b) coordinator
(c) effector and response
(d) all of these
6. Any change in environment which can provoke a response is called (a) stimulus (b) receptor (c) effector (d) coordinator
7. Stimuli are detected by (a) organs (b) tissues (c) cells of body (d) all of these
8. The organs, tissue or cells which are specifically built to detect particular types of stimuli are called (a) effectors
(b) receptors
(c) sensory organs
(d) coordinators
9. These are the organs that receive information from receptors and send messages to particular organs for proper action
(a) receptors (b) effectors (c) coordinators (d) stimulus
10. In nervous’ coordinators the coordinator/s is/are
(a) brain (b) spinal cord (c) sense organs (d) both a and b
11. ———— are the parts of body which receive messages from coordinators and produce particular responses (a) receptors (b) effectors (c) coordinators (d) sense organs
12. In nervous coordination, neurons carry messages to
(a) muscles
(b) glands
(c) brain and spinal cord
(d) both a and b
13. In chemical coordination, particular hormones carry messages to particular target tissues which act as (a) effectors (b) receptors (c) coordinators (d) all of these
14. Nervous coordinators produce
(a) immediate but short-living responses
(b) immediate but long-living responses
(c) slow and short-living responses
(d) slow but long-living responses
Coordination and Control 57
15. Chemical coordination produces
(a) slow but short living responses
(b) slow but long living responses
(c) immediate but short-living responses
(d) immediate but long living responses
16.
22.
is the unit of nervous
system
(a) neuron (b) brain
(c) spinal cord (d) hormone

17. The information about the stimuli is conveyed to the endocrine glands through
(a) neurons (b) muscles (c) blood (d) heart
18. Projections that carry impulses away from neuron’s cell body are called
(a) dendrites
(b) axons
(c) nudes of Ranvier
(d) Myelin sheath
19. The exposed regions of axon are called
(a) nerves
(b) dendrites
(c) nodes of Ranvier
(d) cytoplasmic processes
20. Many axons and even dendrites combine to form a single (a) neuron (b) nerve (c) effector (d) receptor
21. The neurons that carry nerve impulses from central nervous system to effectors are
(a) sensory neurons
(b) motor neurons
(c) associated neurons
(d) all of these
(b) motor neurons
(c) associated neurons
(d) all of these
23. The neurons that form CNS are
(a) sensory neurons
(b) motor neurons
(c) inter neurons
(d) all of these
24. The specialized cells that are able to conduct impulses from receptors to coordinators and from coordinators to effectors are
(a) dendrons (b) nephrons (c) neurons (d) cephalons
25. In neurons, the nucleus is located in
(a) cell body
(b) dendrites
(c) nodes of Ranvier
(d) Schwann cells
26. The parts of axon without covering are called
(a) nodes of point
(b) nodes of Ranvier
(c) anti nodes
(d) nodes of axon
27.
28.
have a long dendrite and a
The CNS is made up of
(a) sensory neurons
(b) interneurons
(c) motor neurons
(d) alia, bandc
is/are present in the cell
short axon
(a) sensory neurons
body of neuron
(a) dendrites (b) axons
(c) nucleus (d) both a and b
29. These are special neuroglial cells located at regular intervals along axons
(a) flam cells
(b) Schwann cells
(c) epithelial cells
(d) somatic cells

‘ 58 Caravan’s Biology Objective
30. Myelin Sheath is a fatty layer secreted by
(a) Schwann cells (b) dendrites (c) epithelial cells (d) cell body
31. In certain parts of body, the cell bodies of neurons form a group enveloped by a membrane. This is called ‘ •
(a) Sehwann cells
(b) ganglion
(c) pons
(d) dendrites
\
32. A nerve is formed by the union of several axons-that are enveloped by a covering made of
(a) protein
(b) lipids
(c) polysaccharides
(d) both a and b
33. Optic nerve is an example of
(a) sensory nerve
(b) motor nerve
(c) mixed nerve
(d) associative nerve
34. Central nervous system consists of
(a) brain and receptors
(b) brain and endocrine system
(c) brain and spinal cord
(d) brain and heart
35 Which of the following is most highly developed in human? (a) fore brain (b) mid brain (c) hind brain (d) .all of these
36. Brain is covered by three layers called (a) peritoneums (b) memnges (c) scrotums (d) hippocampus
37. It lies just below cerebrum
(a) cerebellum
(b) hypothalamus
(c) thalamus
(d) medulla oblongata
38. Thalamus serves as a relay centre between various parts of brain and
(a) sensory organs
(b) locomotory organs
(c) spinal cord
(d) all of these
39. Thalamus is also involved in
(a) pain perception
(b) consciousness
(c) thirst centre
(d) both a and b
40. It also receives and modifies sensory impulses (except from nose) before ” ‘they travel to cerebrum
(a) cerebellum
(b) thalamus
(c) hypothalamus
(d) pons
4
41. ‘It links nervous system and endocrine system
(a) hypothalamus
(b) thalamus
(c) cerebrum
(d) cerebellum
42. Which of the following contains centers for breathing, blood pressure, and heart rate?
(a) medulla oblongata
(b) pons
(c) cerebellum
(d) hypothalamus
43. Brain is covered by
(a) two meninges
(b) three meninges
(c) four meninges
(d) five meninges
44. The major function of meninges is
(a) provide nutrients to brain
(b) protect brain
. (c) provide oxygen to brain tissue (d) all of these
Coordination and Control 59
45.
46.
47.
48.
49.
50.
51.
52.
The top most and largest part of the fore brain is
(a) cerebellum (b) cerebrum (c) pons (d) medulla
Hypothalamus controls the secretions of
(a) thyroid gland
(b) pituitary gland .
(c) parathyroid gland ‘
(d) all of these
Hypothalamus also controls feelings like
(a) rage
(b) pain
(c) pleasure and sorrow
(d) all of these
Cerebrum controls
(a) skeletal muscles
(b) thinking and intelligence
(c) emotions
(d) all of these
———— is divided into two
53. The upper hemispheres
» consists of (a) grey matter (c) red matter
hemispheres
(a) cerebrum
(b) cerebellum
(c) thalgmus
(d) medulla oblongata
Forebrain parts? (a) two (c) four
consists of how many
(b) three (d) five
The anterior parts of cerebral hemispheres are called
(a) hippocampus
(b) olfactory bulbs
(c) receptors
(d) axons
Olfactory nerves create the sensation
of
(a) smell (b) sight
(c) taste (d) touch
layer of cerebral i.e., cerebral cortex
(b) (d)
white matter both a and b
54. ‘Cerebral cortex is divided into (a) two lobes ” (b) three lobes (c) four lobes (d) six lobes
55. Which of these control motor functions, permit conscious, control of skeletal muscles and coordinates movements involved in speech (a) frontal lobe (b) parietal lobe (C) occipital lobe (d) temporal lobe
56. They contain sensory areas that receive impulses from skin (a) frontal lobe (b) parietal lobe (c) occipital lobe (d) temporal lobe
57. ———— receives and analyzes visual information ‘ (a) occipital lobe (b) olfactory lobe (c) frontal lobe (d) temporal lobe
58. ———— lobe is concerned with hearing and smell (a) frontal lobe (b) parietal lobe (c) occipital lobe (d) temporal lobe
59. Hippocampus is a structure that is deep in the
(a) cerebrum (b) cerebellum (c) mid brain (d) thalamus
60. It functions for the formation of new memories
(a) mid brain (b) hippocampus (c) grey matter (d) white matter
61. The medulla oblongata, pons and midbrain are collectively referred to as (a) brain root (b) brain stem (c) major brain (d) hind brain
60 Caravan’* Biology Objective
62. Many reflexes such as vomiting, coughing, sneezing etc. are controlled
by
(a) mid brain
(b) hippocampus
(c) medulla oblongata
(d) cerebellum
63. It coordinates muscle movements
(a) medulla oblongata
(b) cerebellum
(c) pons
(d) both a and b
64. Pons serves as a connection between cerebellum and
(a) cerebrum
(b) hind brain
(c) medulla oblongata
(d) spinal cord
65. The lowest most part of forebrain is
(a) hypothalamus
(b) pons
(c) medulla oblongata
(d) cerebrum
66. Spinal cord is the continuation of
(a) cerebellum
(b) medulla oblongata
(c) pons
(d) cerebellum
67. It is the tubular bundle of nerves . (a) pons (b) spinal cord (c) medulla (d) hippocampus
68. The length of spinal cord is roughly (a) 20cm (b) 25cm (c) 30cm (d) 40cm
69. How many pairs of spinal nerves arise from spinal cord? (a) 21 (b) 27 (c) 31 (d) 35
70.
71 .
72.
73.
74.
Spinal nerves are
(a) sensory nerves
(b) motor nerves
(c) mixed nerves
(d) all of these
The major function of spinal cord is
(a) it serves as a link between body parts and brain
(b) it acts as a coordinating centre
(c) it is responsible for some simple reflexes
(d) all of these
The peripheral nervous system is
composed of
(a) nerves (b) ganglia
(c) sensory organs
(d) both a and b
In peripheral nervous system, nerves arise or lead to brain and spinal cord, so they are named as
(a) cranial nerves
(b) spinal nerves
(c) mixed nerves
(d) all of these
The number of cranial nerves human is
(a) 8 pairs (b) 10 pairs (c) 12 pairs (d) 14 pairs
in
75. The number of spinal nerves in human is
(a) 12 pairs (b) 21 pairs (c) 24 pairs (d) 31 pairs
76. All spinal nerves are
(a) sensory (b) motor (c) mixed (d) all of these
77. Autonomic nervous system consists of motor neurons that send signals to
(a) cardiac muscles
(b) smooth muscles
(c) glands
(d) all of these
Coordination and Control 61
78. Autonomic nervous system comprises of
(a) sympathetic system
(b) parasympathetic system
(c) somatic system
(d) both a and b
79. Sympathetic nervous system prepares body to deal with
(a) change in temperature
(b) emergency situation
(c) reflex actions
(d) ail of these
80. Cranial nerves are
(a) sensory (b) motor (c) mixed (d) all of these
81. Which of the following nervous system prepares for fight or flight? (a) peripheral (b) sympathetic
(c) parasympathetic
(d) central nervous system
82. The organs or parts’ which are specifically built to detect particular type of stimuli are called (a) receptors. (b) effectors (c) detectors (d) none of these
83. A camera is based on the same principle as the human (a) ear (b) eye (c) brain (d) nose
84. The coloured and vascular second layer of the eyeball is known as (a) sclerotic (b) chorojd (c) retina (d) cornea .
85. The inner most layer of eye that is supplied by branches of optic nerve is (a) sclerotic “(b) choroid (c) retina (d) iris
./
86. One of the fallowings controls the amount of light entering the eye (a) iris (b) pupil (c) lens (d) cornea
87. The layer of eye that contains blood vessels is
(a) sclera
(b) vitreous humour
(c) choroid
(d) aqueous humour
88. Photosensitive cells are found in (a) retina *(b) choroid (c) sclera (d) pupil
89. How many types of photosensitive celts are found in retina? (a) 2 (b) 3 (c) 4 (d) 6
90. Which are the photosensitive cells of eyes? . (a) rods (b) cones (c) jons (d) rods and cones
91. It is a point on retina where the optic nerve enters retina (a) blind spot (b) red spot (c) blue spot (d) yellow spot
92. Sclera gives eye most of its (a) black colour (b) red colour (c) white colour (d) brown colour
93. Whicirof the following admits light to the interior of eye and bends light rays? (a) cornea (b) pupil
(c) iris . .
(d) aqueous humour
94. How many rod cells are present in human eye?
(a) 100000 (b) 12500000 (c) 13500000 (d) 14100000
95. How many cone cells are there in human eye?
(a) 7,00,000 (b) 900000, (c) 1100000 (d) 1400000
62 Caravan’s Biology Objective –
96. ———— part of eye of cat and dog shine in. the night (a) sclera • (b) choroid (c) tapetum (d) retina
97. Lens of eye is attached to ciliary muscles via a ring of
(a) redial muscles
(b) suspensory ligaments.
(c) fovea (d) tapetum
98. Name the two light sensitive points present on retina?
(a) fovea and optic disc
(b) fovea and retina
(c) optic disc and blind spot
(d) optic disc and retina
99. The iris divides the cavity of eye into how many champers?
(a) 2 (b) 3 (c) 4 <d) 6
100. The major function of vitreous humour chamber of eye is
(a) it helps maintain the shape of eye
(b) it suspends the delicate lens
(c) it is responsible for colour vision
(d) both a and b
*
101. Where the image of an object falls in eye
(a) sclera
(b) lens
(c) retina
(d) vitreous humour
102. Rods contain a pigment called (a) myopsin (b) pepsin (c) rhodopsin (d) heamoglobjn
103. Body synthesizes rhodopsin from (a) vitamin A (b) vitamin D (c) vitamin K (d) Vitamin C
104. Cone cells of eye contain (a) .rhodopsin (b) iodopsin (c) pepsin (d) myopsin
105. The elongation of eyeball results in
(a) myopia
(b) colourblindness
(c) night blindness
(d) hypermetropia «
106 In myopia the, image*of a distant
object is formed in front of ‘,(a) lens
(b) retina
(c) vitreous humour
(d) aqueous humour
107. The problems of myopia can be rectified by using
(a) vitamin C
(b) concave lens
(c) convex lens
(d) vitamin B complex
108. It happens when eyeball shortens
(a) myopia
(b) hypermetropia
(c) night blindness
(d) colourblindness
109. Convex lens is used to rectify the problem of
(a) hypermetropia
(b) myopia
(c) night blindness
(d) colour blindness
110. Ali ibn Isa wrote how many books on ophthalmology? (a) two (b) three (c) six (d) eight
111. Ali ibn Isa described how many eye diseases?
(a) 130 (b) 143 (c) 147 (d) 153
112.———— is regarded as the father of optics ^
(a) Ibn I Nafees (‘b) Jabin bin Hayan (c) Ali bin Isa (d) IbnalHaytham

Coordination and Control S3
113. Who described the principles of pin hole camera?
(a) Ibn al Haytham
(b) Aliibnlsa
(c) Abu-al-Qasim As-Zabrawi
(d) Jabir bin Hayan
114. In how many main parts human ear is divided?
(a) two (b) three (c) four (d) ‘five
115.-
helps to direct sound waves
into auditory canal
(a) eardrum
(b) cochlea
(c) eustachian tube
(d) pinna ‘
116. The wax and the hairs* in auditory canal protect ear from (a) germs (b) dust (c) small insects (d) all of these
117. This thin membrane separates external ear from middle ear
(a) pinna
(b) eardrum
(c) tympanic cavity
(d) chochlea
118. Which is the smallest bone of human body?
(a) stapes (b) incus (c) malleus (d) hyoid
119. Middle ear communicates with nasal cavity through
(a) Malpighian tube
(b) Eustachian tube
(c) trachealtube
(d) tympanum
120. The inner ear consists of how many parts?
(a) two (b) three (c) four (d) six
121. The cause of deafness is defect of
(a) eardrum
(b) cochlea
(c) middle ear ossicles
(d) all of these
122. To which part of ear the tympanum belongs?
(a) external ear (b) middle ear (c) inner ear (d) all of these
123. Which of these help maintain the balance of body?
(a) semicircular canals
(b) vestibule
(c) cochlea
(d) both a and b
123. Endocrine system regulates
(a) growth
(b) reproduction
(c) maintenance of glucose level in blood
(d) all of these
125.Which one of the following is not an endocrine gland?
(a) digestive glands
(b) pituitary gland
(c) thyroid gland
(d) adrenal gland
126. The chemicals secreted from endocrine glands are called
(a) enzymes
(b) hormones
(c) interferon
(d) all of these
127. Hormones are carried to the target organs or tissues through
(a) bloodstream
(b) ducts
(c) both a and b
(d) none of a and b
Coordination and Control 64
128. Hormones in animals
(a) regulate metamorphosis
(b) regulate cell division in invertebrates
(c) migration in birds
(d) all of a, b, and c
129. Which endocrine gland is found attached to the hypothalamus?
(a) thyroid gland
(b) adrenal glands
(c) pituitary gland
(d) pancreas
130. Growth hormone is called
(a) somatotrophin
(b) vasopressin (c) oxytocin (d) epinephrine
131. Thyroid stimulating hormone is secreted from
(a) thyroid glands
(b) parathyroid glands
(c) anterior lobe of pituitary
(d) posterior lobe of pituitary
132. Irregular release of somatotrophin hormone results in (a) dwarfism (b) gigantism (c) acromegaly (d) all of the above
133. Vasopressin increases the rate of reabsorption of ———— from nephron
(a) water (b) glucose (c) sodium (d) blood
134. Which hormone stimulates the contraction of uterus walls in mothers for child birth
(a) vasopressin (b) oxytocin (c) estrogen (d) adrenaline
135. Hypothyroidism is caused by
(a) over production of thyroxin
(b) under production of thyroxin
(c) low levels of calcium
(d) over production of calcitonin
136. Hyperthyroidism is caused by
(a) over production of thyroxin
(b) under production of thyroxin
(c) low levels of calcium
(d) over production of calcitonin
137. Calcitonin and
complement
each other and* regulate the level of calcium ions in the blood
(a) thyroxin
(b) oxytocin
(c) parathormone
(d) vasopressin
138. Epinephrine or adrenaline are secreted from
(a) adrenal cortex
(b) adrenal medulla •
(c) posterior lobe of pituitary
(d) anterior lobe of pituitary
139. Decreased blood calcium level results in
(a) goiter
(b) diabetes insipidus
(c) tetany • t
(d) diabetes mellitus
140. Islets of Langerhans secrete
(a) insulin
(b) glucagon
(c) both a and b
(d) none of a and b
141. Normally the blood glucose level after 8-10 hours fast is
(a) 70 to 99 mg/100ml
(b) 100-125 mg/100ml
(c) 100-140 mg/100ml
(d) 140-150 mg/100ml
142. Estrogen is secreted from
(a) testes . (b) ovaries
(c) both a and b
(d) thyroids
Coordination and Control 65

ANSWERS

1. c
2.
d
3. c
4. c
5.
d
6. a
7.
d
8.
b

9. c
10.
d
11. b
12. d
13.
a
14. a
15.
b
16.
a

17. a
18.
b
19. c
20. b
21.
b’
22. a
23.
d
24.
c

25. a
26.
b
27. d
28. a
29.
b
30. a
31.
b
32.
b

33. a
34.
c
35. a
36. b
37.
c
38. c
. 39.
d
40.
b

41. a
42.
a
43. b
44. d
45.
b
46. b
47.
d
48.
d

49. a
50.
b
51. b
52. a
53.
a
54. c
55.
a
56.
b

57. a
58.
d
59. a
60. b
61.
b
62. c
63.
b
64.
d

65. a
66.
b
67. b
68. d
69.
c
70. c
71.
d
72.
d

73. d
74.
c
75. d
76. c
77.
d
78. d
79.
b
80.
d

81. b
82.
a
83. b
84. b
85.
c
86. a
87.
c
88.
a

89. a
90.
d
91. a
92. c
93.
a
94. b
95.
a
96.
c

97. b
98.
a
99, a
100. d
101.
c
102. c
103.
a
104.
b

105. a
106.
b
107. b
108i b
109.
a
110. b
111.
a
112.
d

113. a
114.
b
115. d
116. d
117.
b
118. a
119.
b
120.
b

121. d
122.
a
123. d
124. d
125.
a
126. b
127.
a
128.
d

129. c
130.
a
131. c
132. d
133.
a
134. b
135.
b
136.
a

137. c
138.
b
139. c
140. c
141.
a ‘
142. b

REVIEW QUESTIONS
1. Processes that carry nerve impulses 5. away from the cell body are called; (a) axons – (b) dendrites (c) synapses (d) myelirv sheath
2. The portion of the nervous system that is involuntary in action –
(a) somatic nervous system
(b) motor nervous system 6.
(c) autonomic nervous system
(d) sensory nervous system
3. Which neurons are present inside the central nervous system?
(a) sensory neurons only
(b) motor neurons only
(c) sensory and motor neurons both 7-
(d) intemeurons only
4. The part of the brain responsible for muscle movement, interpretation of the senses and the memory is the;
(a) pons
(b) medulla oblongata
(c) cerebrum
(d) cerebellum
Apart from hearing, what other major body function is performed by the ear? .
(a) hormone secretion
(b) body balance
(c) reduction in nerve pressure
(d) All of these
The myelin sheath is formed by—-, which wraps around the axons of some neurons.
(a) hormone secretion
(b) axons
(c) dendrites
(d) Schwann cells
This is not a part of the hindbrain
(a) pons
(b) medulla oblongata
(c) cerebrum
(d) cerebellum
Coordination and Control 66
8. If you look at an intact human brain, what you see the most is a large, highly convoluted outer surface. This is the
(a) cerebrum
(b) cerebellum
(c) pons . *
(d) medulla oblongata
10.
Insulin and glucagon are produced in the;
(a) hypothalamus
(b) anterior pituitary
(c) liver *
(d) pancreas
All of these are hormones except; (a) insulin (b) thyroxin (c) glucagon (d) pepsinogen
ANSWERS
1. a 9. d
2. d 10. d
3. d
4. c
5. b
6.-d
7. c
8. a
Interneuron
Sensory neuron

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