biology topic 5- homeostasis

Question 1

What is homeostasis?

Answer 1

The maintenance of a constant internal environment in order to maintain optimum conditions for enzyme and cellular function

Question 2

What types of responses are used in body control systems?

Answer 2

Nervous and chemical

Question 3

What three components do all control systems have?

Answer 3

-receptors
-coordination centres
-effectors

Question 4

What is a receptor?

Answer 4

Receptors detect changes in the environment (stimuli)

Question 5

What is the function of a coordination centre?

Answer 5

Coordination centres obtain and process information from receptors

Question 6

What is the function of an effector

Answer 6

Effectors(muscles or glands) bring about responses to stimuli

Question 7

What is the function of the nervous system?

Answer 7

Allows the body to react to its surroundings and coordinate an appropiate response

Question 8

How does a stimulus lead to a response being carried out by the body?

Answer 8

-stimulus is converted into an electrical impulse by receptors
-The electrical impulse passes along sensory neurones to the central nervous system(CNS)
-the CNS coordinates an appropriate response and an electrical impulse is sent along motor neurones to the effector, which carries out the response

Question 9

What sequence of events describes how the nervous system works?

Answer 9

Stimulus-receptors-coordinator-effector-response

Question 10

What is a reflex action?

Answer 10

An automatic and rapid response which does not involve any conscious input from the brain

Question 11

Why are reflex actions important?

Answer 11

Aid survival by preventing harm to the body

Question 12

Describe how a reflex action occurs via a reflex arc

Answer 12

-stimulus is detected by a receptor
-an electrical impulse passes along a sensory neurone to the spinal cord
-at a synapse between a sensory neurone and a relay neurone, a chemical diffuses across the gap and stimulates a new impulse which passes along the relay neurone
-the same process occurs at a synapse between a relay neurone and a motor neurone
At the effector, an appropriate response is carried out

Question 13

What is the function of the cerebral cortex?

Answer 13

Controls consciousness, intelligence, memory and language

Question 14

What is the function of the cerebellum?

Answer 14

Controls muscular coordination

Question 15

What is the function of the medulla?

Answer 15

Controls unconscious activities e.g. breathing

Question 16

Why is the investigation and treatment of the brain difficult?

Answer 16

-the brain is a complex and delicate organ
-the brain is easily damaged and destroyed
-certain membranes prevent drugs from reaching the brain
-the exact function of each part of the brain is not known

Question 17

What methods are used by scientists to determine brain function?

Answer 17

-studying patients with brain damage
-electrical stimulation of the brain
MRI scans

Question 18

What stimuli are the receptors of the eye sensitive to?

Answer 18

Light intensity and colour

Question 19

What are the two main functions of structures found within the eye?

Answer 19

-focusing on near or distant objects-accommodation
-adaption to dim light

Question 20

Describe the function and function of the retina

Answer 20

-The light sensitive layer found a the back of the eye
-light stimulates the retinal cells, resulting in impulses being sent to the brain