12.1 Observation and recording of the deference in quickness of response of the two types Of co-ordination (by asking a student to say few words in front of class and observe the changes in heart beat).
Response in nervous coordination
Distance meter rod cm)
at which the was caught (in
Shortest distance achieved: 10cm
Response in chemical (Hormonal) coordination
The rate of heart beat of the student after Heart Beat Rate speech increases due to release of hormone adrenaline.
Q. How the two types of coordination are different with respect to quickness of response?
Ans: The response in nervous coordination is quick and for a short time, while the response in hormonal coordination is slow but its effect remains for a longer time.
Post Lab. Activities.
Q.1 Name two most important pulse points in your body?
Ans: The two most important points to feel pulse are:
1. Redial – on the inner side of the wrist below the wrist joint.
2. Carotid – on both side of larynx in the neck BRAIN TEASERS:
Q.1 Give an example of stimulus response in plants.
Ans: Plant stems growing towards light when kept in a dark room with a small hole for light i.e. phototropism.
When we touch the leaves of touch-me-not plant (Memosa pud/ca or chhoi muei) the leaves at once close or wilt (nastic movement).
Q.2 What are the effectors In nervous coordination?
Ans: Effectors are, the parts of the body which receive messages from coordinators and produce particular responses. These are muscles which respond by contraction and glands which respond by secreting.
12.2 Experiment to observe the contraction in the shin muscle of frog in a petri dish filled with methylene blue and using 12V.DC current.
Observe changes regarding the contraction of shin muscle.
The muscle contract when currant is passed. The methylene blue gradually becomes decolorized. ,
Post Lab. Activities:
Q.1 Note down changes in color of methylene blue. Also write down reason for colour change.
Ans: Methylene blue decolorizes because of reduction and release of some chemicals from contracting muscles. Shin muscle gets required oxygen for cellular respiration from methylene blue which turns colourless.
Q.2 What is meant by antagonistic muscles? Give an example.
Ans: An antagonistic mechanism is a classification used to describe ..a pair of muscles that act in opposition to each other during a specific movement. When one contracts the other relaxes. They are located in opposite sides of a joint or bone. Biceps muscles in upper arm when contract bend the arm, the triceps at this time relax. The’triceps when contract straighten the arm, the biceps at this movement relax.
Q.1 What is the source of energy for muscle contraction and why do muscles contain many mitochondria?
Ans: The actual energy source for muscle contraction is ATP. When ATP gets broken into ADP+P, energy is released. Production of ATP occurs in mitochondria as a result of respiration, that is why muscle tissues contain more mitochondria.
Q.2 Which kind of muscle contract without any conscious message from the brain?
Ans: The contractions in smooth muscles and cardiac muscles are involuntary i.e., without conscious messages from brain.
12.3 Identify the different parts and draw a labeled diagram of longitudinal section of eye of a sheep or a bull.
Eye is located in a bony socket or orbit, in the skull. The eyeball is a spherical fluid-filled structure which contains three tissue layers. The outermost layer is tough white sclera, the middle layer is choroid and the inner layer is called retina. Internally the eye. ball is divided by the lens and ligaments into an anterior and a posterior chamber. The choroid extends anterior to lens as a ring called iris (dark colored). Iris in the centre has a hole called pupil. Behind the eye
TtM Structure «rf« typical mammalian «y«
Sclera i Choroid Layers Retina J of the eye
: Structure of
Structure of the eye of sheep ball is the optic stalk which encloses the optic nerve.
Post Lab. Activities: Q.1 Which part of the eye contains the sensory cells?
Ans: The inner layer of the eye ball i.e., retina is sensory and contains the photo sensitive cells called rods and cones.
214______________________ Caravan Biology Objective X
Q.2 List of pathway of light in the human eye.
Ans: When light strikes the eye, it passes through the transparent portion of the sclera called cornea. It then passes through aqueous humor. Next, there is iris that is the colored part of the eye and is visible through the cornea. It has a hole in the center, called the pupH, from aqueous humor, the light passes through pupil to the lens, which focuses it on to the retina. Before reaching retina, light passes through vitreous humor. The part of retina where the receptor cells (cones) are packed tightly is called fovea. Here, light is focused when you look straight at an object.
Q.1 When the animals are grazing, blades of grass may poke in the eye. Which part of the eye protects the inner eye?
Ans: Eye lids and eye lashes protect the eye ball from external stimuli such as dirt, grass.
Q.2 What type of lens is present in eye? Biconcave or biconvex? Ans: Biconvex lens is present in the eye.