Intro to Homeostatis and the nervous system COPY

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? and describe it

Answer 9

produce a quick reflex action. These are designed to protect the body from harm In order to make sure reflex reactions occur quickly, they do not require processing in the brain.

stimulus —> receptor —> sensory neurone —> spinal cord.—>relay neurone in the central nervous system —>motor neurone.—>effector.

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) From the CNS 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 neurons are junctions called synapses. electrical impulses trigger the release of chemical signals - neurotransmitters. The neurotransmitter diffuses across the synapse where it is then converted back into an electrical impulse after binding to the surface of a dendrite

neurones are not directly connected to each other

Question 15

What does the brain control and what is it made up of it?

Answer 15

The brain controls complex behaviour.

It is made of billions of interconnected neurones and has different regions that carry out different functions.

Question 16

What temperature should the body temperature be kept at and why?

Answer 16

37 because it is the optimum temperature of enzymes to wor

Question 17

What does the thermonregulatory centre in the brain do?

Answer 17

monitors and control body temperature

Question 18

How does the thermoregulatory centre monitor body temperature?

Answer 18

• has a receptor that monitors the temperature of the blood flowing through the brain
• receives information (impulses) from temperture receptors in the skin

Question 19

What happens when the body temp is too high?

Answer 19

1) temperature receptors detect

2) thermoregulatory centre acts as a coordination centre and triggers the effectors

3) blood vessels widen, directing more blood to the surface of the skin (vasodilation)

4) More sweat is produced from the sweat glands and evaporates

5) helps transfers energy from the skin to the environment

Question 20

What happens when the body temp is too low?

Answer 20

1) temperature receptors detect

2) thermoregulatory centre acts as a coordination centre and triggers the effectors

3) blood vessels narrow, directing more blood away from the surface of the skin (vasoconstriction)

4) sweating stops. Skeletal muscles uncontrollably contract and relax quickly ( shiver) which transfers more heat to the blood

Question 21

Draw motor, relay and sensory neuron

Answer 21