Biology B5 - B7

Question 1

B5 - Homeostasis and Response

What is homeostasis?

Answer 1

Homeostasis is the regulation of the internal conditions of a cell or organism to maintain optimum conditions for function in response to internal and external changes.

Question 2

Homeostasis

What is meant by internal conditions?

Answer 2

in the human body, homeostasis is used to keep the blood glucose concentration the body temperature and water levels constant.
So, homeostasis consists of automatic control systems making sure that the internal conditions of the body stay as constant as possible

Question 3

Homeostasis

What are the general features of an automatic control system?

Answer 3

The automatic control systems in the human body can involve the nervous system or hormones.

• • receptor cells - detect changes in the environment -Stimulus - (concentration of glucose in the blood)
• co-ordination centre - the receptor cells pass information to a coordination centre eg. brain, spinal cord, pancreas. The coordination centre receives and processes the information from the receptor cells
• effector - The coordination centre sends instructions to the effector. An effector is a muscle or a gland and the job of the effector is to carry out the reponse (response - restore the optimum level)

Question 4

Homeostasis - The Nervous System

What are the names of the different parts of the Nervous System?

Answer 4

• Central Nervous System (CNS) -
• Sensory Neurones -
• Motor Neurones -
• Effectors -

Question 5

Homeostasis - The Nervous System

What do receptors do?

Answer 5

Receptors are the cells that detect stimuli.
There are many different types of receptors, such as taste receptors on the tongue and sound receptors in the ears.
Receptors can form part of **larger, complex organs**, eg. the retina of the eye is covered in light receptor cells

Question 6

Homeostasis - The Nervous System

What do effectors do?

Answer 6

Effectors respond to nervous impulses and bring about a charge.
Muscles and glands are known as effectors - they respond in different ways.
Muscles contract in response to a nervous impulse, whereas glands secrete hormones.