Intro to Homeostatis and the nervous system

Question 1

What is homeostasis and what does it do?

Answer 1

the regulation of the internal conditions of a cell’s or organism in response to internal or external changes.

maintains optimal conditions for enzyme action and all cell functions.

Question 2

What conditions do homeostasis control?

Answer 2

• blood glucose concentration
• body temperature
• water and ion levels

Question 3

What type of communication do automatic control systems use?

Answer 3

nervous and hormonal

Question 4

What do all control systems include?

Answer 4

• cells called receptors, which detect stimuli (changes in the environment)
• coordination centres (such as the brain, spinal cord and pancreas) that receive and process information from receptors
• effectors (muscles or glands) which bring about responses which restore optimum levels.

Question 5

What does the nervous system allow us to do?

Answer 5

enables humans to react to their surroundings and to coordinate their behaviour

Question 6

Describe the pathway through the nervous system, starting at the receptor.

Answer 6

• information from the receptors passes to the central nervous system
• the CNS coordinates the response of effectors, ie muscles contracting or glands secreting hormones

Question 7

What’s the central nervous system?

Answer 7

brain and spinal cord

Question 8

describes how the body makes a response.

starting at the stimulus

Answer 8

stimulus –> Receptor –> Coordinator –> Effector –> Response

Question 9

What is a reflex action?

Answer 9

an automatic and rapid response to a stimulus so they can protect the body

they do not involve the conscious part of the brain

Question 10

How do we detect pain?

Answer 10

1) pain stimulus is detected by receptors
2) impulses from the receptor pass along a sensory neurone to the CNS
3) An impulse then passes through a relay neurone
4) A motor neurone carriers impulses to the effector
5) the effector (usually a muscle) responds

Question 11

What is the role of a sensory neurone?

Answer 11

A sensory neurone carries signals from the receptors to the spinal cord or brain.

Question 12

What is the role of a relay neurone?

Answer 12

A relay neurone carries messages from one part of the CNS to another

Question 13

What is the role of a motor neurone?

Answer 13

Motor neurones carry signals from the CNS to effectors.

Question 14

How are electrical impulses carried between neurones?

Answer 14

Between neurones are junctions called synapses. electrical impulses are converted into chemical signals as a neurotransmitter. The neurotransmitter diffuses across the synapse where it is then converted back into an electrical impulse.

neurones are not directly connected to each other