What is meant by stimulus and reaction?
Stimulus is the change in the environment or environmental factors to to which the organism can respond or react. Theresponse shown by organisms towards or awaya stimulus is called reaction.
Write the major function of each.
a. Cerebrum:
- It governs the mental abilities (thinking, learning).
- It enables sense organs to observe things.
b. Corpus callosum:
- It transmit info from one to other hemisphere of cerebrum.
c. Cerebellum:
- It maintain equilibrium and maintains posture.
- It regulates and coordinates the contraction of voluntary muscles.
d. Pons varolii:
- It transmit signal to and from cerebrum from and to cerebellum.
- It regulates respiration.
e. Medulla oblongate:
- It controls breathing, blood pressure, heart beat.
- It controls contraction and relaxation of blood vessels.
f. Spinal cord:
- It connects large part of peripheral nervous system to the brain.
- It controls reflex actions.
g. Pituitary gland:
- It controls the secretion of other glands.
h. Thyroid gland:
- It stimulates the rate of metabolism.
- It regulates the activities of the nervous system.
i. Adrenal gland:
- It helps body to face emergy conditions.
- It enables kidneys to retain sodium.
j. Pancreas:
- It secrets insulin which regulates blood sugar level by regulating the conversion of glucose to hydrogen.
- It also stimulates the deposition of extra glucose in the form of hydrogen in liver and muscle.
k. Ovaries:
- It produces oestrogen that determine the secondary sexual characterstics.
- It produces progesterone that plays an important role in ovulation.
l. Testes.
- It produce testosterone that determine the secondary sexual characteristics.
- It produces sperm that has role in ovulation.