Write the names of all the major endocrine glands present in the human body. Which of these glands also function as exocrine glands ?
The endocrine gland present in the human body are:
(i) Pineal gland
(viii) Adrenal glands
(ix) Testes (in males)
(x) Ovaries (in females). Pancreas, testes and ovaries function as exocrine glands.
Match the hormones given in column I with their functions given in column II :
(a) Causes breast to develop in female
(b) Cause the male to start producing sperms
(c) Prepare the body for an emergancy
(d) Control the metabolic rates
(e) Regulate the amount of sugar in blood
A person walks across a room in barefeet and puts his foot on a drawing pin lying on the floor. He lets out a cry. Explain what happens in his nervous system in bringing about this response.
It is an example of reflex action. The stimulus here is drawing pin lying on the floor. The pain is sensed by the receptors in the skin which triggers and impulse in a sensory neuron and transmits the message to the spinal cord. The impulse is passed onto a relay neuron, which in turn, passes it to the motor neuron. The motor neuron passes the impulse to a muscle in the feet. The muscle then contracts and pulls our feet away from the drawing pin.
In what ways are puberty and adolescence result of the activity of some glands in the human body ?
Puberty and adolescence are the results of sex glands in human beings. In males, testes make male sex hormones called testosterone which is associated with male puberty, which the boys attain an age of 13-14 years. In females the oestrogen hormone is responsible for all the changes associated with female puberty which the girl attains at an age of 10-12 years.
List three ways in which neurons are similar to other cells.
Neurons and other cells have a cell membrane, cytoplasm and a nucleus.
Explain the difference between each of the following pairs of terms :
(a) receptor and effector (b) cerebrum and cerebellum
A receptor is a cell (or a group of cells) in a sense organ which is sensitive to a particular type of stimulus (or a particular type of change in the environment).
Example: Photoreceptors and Phonoreceptors.
An effector is the part of the body which can respond to the stimulus according to the instructions sent from the nervous system (spinal cord and brain).
Example: Muscles and glands.
(i) It is a part of forebrain.
(ii) It is the main thinking part of the brain. All our thoughts, sensation, actions and movements are controlled by cerebrum.
(i) It is a part of hindbrain.
(ii) It helps in maintaining posture and balance of the body. It enables us to make precise and accurate movements.
What is the difference between a voluntary and an involuntary action ? Which kind of action is digestion ? Explain your choice.
those action which need thinking and are performed by us knowingly are called voluntary actions. Example writing, Dancing
Those action which do not need thinking and are not performed by us knowingly are called involuntary actions. Examples : Respiration, Digestion
Digestion is an involuntary action as it does not involve the thinking process and is performed unknowingly by our digestive system.
What does CNS stand for ? Which part of CNS : (a) consists of two cerebral hemispheres, and (b) has spinal nerves attached to it ?
(i) CNS – Central nervous system.
(b) Spinal cord.
Which hormone :
(a) prepares the body for action ?
(b) controls the amount of glucose in blood ?
(c) gives boys a deep voice ?
(d) gives girls soft skin ?