What are the major parts of the brain? Mention the functions of different parts.
Forebrain: It is composed of the cerebrum.
• Midbrain: It is composed of the hypothalamus.
• Hindbrain: It is composed of the cerebellum, pons and medulla oblongata.
Some main structures of the human brain are explained below.
(i) Cerebrum: The cerebrum is the largest part in the human brain. It is divided into two hemispheres; called cerebral hemispheres.
Functions of cerebrum:
(a) The cerebrum controls the voluntary motor actions.
(b) It is the site of sensory perceptions; like tactile and auditory perceptions.
(c) It is the seat of learning and memory.
(ii) Hypothalamus: The hypothalamus lies at the base of the cerebrum. It controls sleep and wake cycle (circadian rhythm) of the body. It also controls the urges for eating and drinking.
(iii) Cerebellum: Cerebellum lies below the cerebrum and at the back of the whole structure. It coordinates the motor functions. When you are riding your bicycle; the perfect coordination between pedaling and steering control is achieved by the cerebellum.
(iv) Medulla: Medulla forms the brain stem; along with the pons. It lies at the base of the brain and continues into the spinal cord. Medulla controls various involuntary functions; like heart beat, respiration, etc.
What does CNS stand for ? Which part of CNS : (a) consists of two cerebral hemispheres, and (b) has spinal nerves attached to it ?
(i) Name the hormones that are released in human males and females when they reach puberty.
(ii) Name a gland associated with brain. Which problem is caused due to the deficiency of the hormone released by this gland ?
(a) What does a plant root do in response to water ? What is this phenomenon known as ?
(b) What happens to the moonflower (i) during daytime, and (ii) at night ? What is this phenomenon known as ?
Which one term in each of the following includes the other three ?
(a) thyroid, ductless gland, thymus, pituitary, ovary
(b) adrenalin, insulin, hormone, thyroxine, estrogen
(a) Explain how auxins help in bending of plant stem towards light.
(b) State the objective of the experiment for which experimental set-up is shown in the given diagram.
What are 'hormones'? State one function of each of the following hormones:
(i) Thyroxine (ii) Insulin
(a) The human brain can be broadly divided into three regions. Name these three regions.
(b) What is cranium ? What is its function ?
A potted plant is made to lie horizontally on the ground. Which part of the plant will show
(i) positive geotropism?
(ii) negative geotropism?
What is the stimulus in : (a) phototropism ? (b) geotropism ? (c) chemotropism ? (d) hydrotropism ? (e) thigmotropism ?
Name the plant part :
(a) which bends in the direction of gravity but away from light
(b) which bends towards light but away from the force of gravity
(a) What is a reflex action ? Explain with the help of an example.
(b) Define reflex arc. Give the flow chart of a spinal reflex arc.
(c) How are involuntary actions and reflex actions different from each other ?
When you smell a favourite food your mouth begins to water (that is, you secrete saliva). Write down what the following are examples of :
(a) the smell of the food
(b) the cells in your nasal passages which perceive the smell
(c) the gland which is stimulated to secrete saliva.
What are meanings? What are their functions? Name the fluid, which is filled in between meanings.
(a) Write the names of the regions in hindbrain. Give one function of each region.
(b) Name the functions of cerebrum.
Write one example each of the following tropic movements :
(i) Positive phototropism (ii) Negative phototropism
(iii) Positive geotropism (iv) Negative geotropism
(v) Hydrotropism (vi) Chemotropism
Name one example of the movement of a plant part which is very quick and can be observed easily.
(a) Explain any three directional movements in plants.
(b) How brain and spinal cord are protected in human ?
(c) Name the master gland present in the brain.
What is chemotropism? Give one example. Name any two plant hormones and mention their functions.
Name the plant hormones which help/promote (i) cell division (ii) growth of
the stem and roots?
Plant parts show two types of movements, one dependent on growth and the other independent of growth. Give one example of the movement in plant parts :
which depends on growth
which does not depend on growth
(a) What does a Mimosa pudica plant do in response to touch ? What is this phenomenon known as ?
(b) What happens to the dandelion flower (z) during daytime, and (ii) at night ? What is this phenomenon known as ?
What is a tendril ? Name the two types of tendrils. What does a tendril do in response to the touch of a support ? What is this phenomenon known as ?
What is the name of in-built ‘arrangement’ in our body which controls the timing and amount of hormones released by various endocrine glands in the body ?
State the functions of the following hormones :
(a) Thyroxine (b) Adrenaline (c) Growth hormone