Homeostasis And The Nervous System

Question 1

Why do we need to regulate blood glucose levels

Answer 1

Because not enough would leave you without sufficient energy as you need glucose to respire and too much would send you into a coma

Question 2

Why do we need to regulate our body’s temperature

Answer 2

Because we need to be warm. Too hot or too cold would mean your enzymes wouldn’t be able to control your cellular reactions.

Question 3

Why do we need to regulate water balance in our body

Answer 3

You need to have sufficient water as too little or too much water in your body would kill you.

Question 4

Three things homeostasis controls

Answer 4

Blood glucose levels
Body temperature
Water balance

Question 5

Definition of homeostasis

Answer 5

The regulation of the internal environment of a cell or organism to maintain optimal conditions for function in response to internal or external changes

Question 6

How can homeostasis changes be described

Answer 6

automatic and involuntary

Question 7

Which actions does the nervous system coordinate

Answer 7

Voluntary and involuntary actions

Question 8

How does nervous system coordinate our actions

Answer 8

By transmitting electrical impulses along your nerve cells

Question 9

Why do responses involving your nervous system happen very quickly

Answer 9

Because the nervous system coordinates our actions by transmitting electrical impulses along your nerve cells. These electrical impulses move very quickly along your neurones therefore the responses happen very quickly

Question 10

What macronutrient are hormones

Answer 10

Proteins because they are chemicals

Question 11

How do glands work

Answer 11

When it is needed and the gland is stimulated by signals, it releases a chemical called a hormone into the bloodstream. Hormones travel around the blood until they reach their target organ where they act.

Question 12

Why are homeostatic responses slower than those of nerve impulses

Answer 12

Because the hormones travel through the blood which is slower than via electrical impulses through nerve cells:

Question 13

Example of a response an effector can bring

Answer 13

Sweat glands might produce more sweat in response to a high temperature which is detected through the receptors and passed on to the coordination centres which signals the effector.

Question 14

Example of effector

Answer 14

A muscle or a gland

Question 15

Two difference between homeostatic responses and responses involving nerve impulses

Answer 15

Homeostatic responses are much slower but last for longer.

Question 16

Two similarities between homeostatic and nervous system responses

Answer 16

Both maintain internal balance and ensure appropriate body function
Both involve receptors and effectors

Question 17

Examples of coordination centres

Answer 17

Brain, spinal cord and pancreas

Question 18

Pathway of control system in homeostasis

Answer 18

Receptors -> coordination centres -> effectors

Question 19

Function of receptors

Answer 19

To detect stimuli/detect a change inside or outside your body

Question 20

Function of coordination centres

Answer 20

To receive and process information from receptors

Question 21

Function of effectors

Answer 21

To bring about responses that result in optimum levels being restored

Question 22

What organs make up the central nervous system (CNS)

Answer 22

The brain and spinal cord

Question 23

What do longer nerve cells have and why

Answer 23

Myelin sheath to insulate the electrical impulse and prevent signal loss

Question 24

What is the sense and stimuli for the eyes organ

Answer 24

Sight
Light

Question 25

What is the sense and stimuli for the ears organ

Answer 25

Hearing Sound

Question 26

What is the sense and stimuli for the tongue organ

Answer 26

Taste Chemicals in food

Question 27

What is the sense and stimuli for the nose organ

Answer 27

Smell Chemicals in air

Question 28

What is the sense and stimuli for the skin organ

Answer 28

Touch Touch, pressure, temperature, pain and itching

Question 29

What forms a nerve

Answer 29

A bundle of neurones

Question 30

Parts of the body with a lot of receptors

Answer 30

Fingertips and lips

Question 31

Two parts of body with less amount of receptors

Answer 31

Soles of feet and elbows

Question 32

What are the only cells completely within your CNS

Answer 32

Relay neurones

Question 33

Full pathway including synapses of nervous response

Answer 33

Stimulus -> receptor -> sensory neurone -> synapse -> relay neurone (in CNS) -> synapse-> motor neurone -> effector-> response

Question 34

Describe fully a nervous system response

Answer 34

Firstly, a stimulus must occur. Then receptors detect the stimulus and converts it into an electrical nerve impulse. This electrical impulse is then carried on through the sensory neurone. It then travels through a synapse where chemical neurotransmitters transmit the impulse into the relay neurones which is fully inside the CNS. The relay neurone processes the information and sends the signal through where it passes through another synapse where chemical neurotransmitters cross the synapse to the motor neurone which carries the impulse to the effector. The effector then carries out a response, and response occurs without conscious thought.

Question 35

Features of sensory neurone

Answer 35

Often none or very short dendrites Contains nucleus in cell body located midway (off to the side) Short axon Myelin sheath usually present

Question 36

Features of relay neurone

Answer 36

Many short dendrites Contains nucleus in cell body (located centrally) Short axon (entire neuron is short) Myelin sheath often absent or thi

Question 37

Features of motor neurone

Answer 37

Many branches dendrites Nucleus found in cell body located at one end of the neuron Long axon Myelin sheath usually present

Question 38

What is a synapse

Answer 38

A gap between the axon of one nerve and the dendrites of another where chemical neurotransmitters transmit the impulse

Question 39

How do electrical impulses travel through synapses

Answer 39

When an electrical impulse reaches the end of the axon it spreads out into the ends of the cell. At the tips of these ends are special areas that convert the electrical impulse into a chemical signal. These are called neurotransmitters and quickly diffuse across the synapse. On the other side the neurotransmitters meet the dendrites of the next nerve cell. Here they bind to receptors and trigger the start of the electrical impulse, which travels along that neurone until it reaches the next synapse

Question 40

What are neurotransmitters

Answer 40

Chemical messengers that transmit signals across a synapse

Question 41

What is a reflex response

Answer 41

An automatic response that you do not think about

Question 42

Example of reflex response

Answer 42

Moving your hand away from a hot radiator you have just touched by mistake.

Question 43

Is regulating your heart rate and controlling the amount of light that entered your eyes a reflex response

Answer 43

Yes because they are automatic

Question 44

What do reflex responses do

Answer 44

They often occur to stop you damaging your body by mistake

Question 45

What is a reflex arc

Answer 45

The pathway of neurones in a reflex action

Question 46

Do reflex responses go to your brain and why

Answer 46

Reflex responses must go through a CNS to coordinate a response however since they need to be rapid and automatic they go to the spinal cord or to the non-thinking part of your brain such as the brainstem this is so it can happen without conscious thought and therefore occur faster and automatically - the conscious part of the brain may receive the information after it has just happened as separate neurone carry an impulse to the brain

Question 47

Why are reflex actions rapid and automatic

Answer 47

Because they do not involve the conscious part of the brain

Question 48

One structure that is found at the end of neurones

Answer 48

Axon terminals

Question 49

Learn the required practical on reaction time

Question 50

Two examples of reflexes preventing injury

Answer 50

If someone shines a bright light in your eyes your pupils automatically get smaller so that less light gets into the eye. If you get a shock the body release the hormone adrenaline automatically