B10 Nervous System

Question 1

Examples of controlled human internal conditions

Answer 1

Blood pressure

Body temperature

Water balance

Question 2

Homeostasis

Answer 2

Process when body maintains stable internal environment

Question 3

Internal conditions need to be maintained

Answer 3

To allow enzymes to function efficiently

If internal environment isn’t maintained enzymes become denatured

Question 4

Pathway of control system

Answer 4

Receptor ——> coordination centre —–> effector

Question 5

Receptor

Answer 5

Detects change in the environment (temperature)

Question 6

Coordination centre

Answer 6

Processes information from receptor and sends instructions

Question 7

Effector

Answer 7

Responds to instructions and brings about a change to restore balance

e.g. sweat glands produce sweat to cool body

Question 8

Enzymes are essential

Answer 8

For metabolism

Question 9

Drugs which effect homeostasis

Answer 9

Stimulants, depressants, diuretics

Question 10

Stimulants

Answer 10

(Caffeine) can increase heart rate and blood pressure disrupting homeostasis

Question 11

Depressants

Answer 11

Alcohol - can slow down nervous system affect coordination and reaction times

Question 12

Diuretics

Answer 12

Cause increased urine production, disrupting water balance in the body

Question 13

Stimuli, receptors, coordination centres and effectors in examples of nervous and chemical responses

Answer 13

Example (hot object)

Stimulus - heat

Receptors - thermorereceptors in skin

Coordination centre - brain or spinal cord

Effector - muscles

Question 14

Differences between nervous and chemical responses

Answer 14

Nervous responses are fast and involve electrical impulses traveling through neurons

Chemical responses are slower and involve chemicals released in bloodstream

Question 15

Nose and tongue

Answer 15

Chemicals (smell, taste)

Question 16

Pathway of impulses from receptor to effector

Answer 16

Receptor - detects stimulus

Sensory neuron - transmits impulse to central nervous system (CNS)

CNS process information and sends impulse through motor neuron to effector

Question 17

How the nervous system coordinates a response

Answer 17

Nervous system detects a stimulus through receptors and sends electrical impulses by neurons

CNS process information and sends insturctions to effectors

Question 18

Neurone

Answer 18

Single nerve cell that transmits electrical impulses

Question 19

Nerve

Answer 19

A bundle of neurons that transmit signals between the central nervous system and rest of the body

Question 20

How information is passed along neurones

Answer 20

In the form of electrical impulses

These impulses travel along axon of neurone and passed to next neurone or effector across synapse

Question 21

Reflex reactions

Answer 21

Automatic responses to stimuli

(Blinking, pull hand away from something hot)

Question 22

How reflex actions are fast and automatic

Answer 22

They involve spinal cord (not brain) reducing time taken to process infromation

Question 23

How impulses travel across a synapse

Answer 23

At a synapse, the electrical impulse triggers release of chemicals (neurotransmitters) from the end of one neuron

These chemicals diffuse across synaptic gap and bind to receptors on next neurone, triggering new electrical impulse

Question 24

Why reflex actions are important

Answer 24

They protect body from danger by quick, automatic responses without conscious thought

Question 25

Apply knowledge of synapses to explain the effects of drugs

Answer 25

Certain drugs can increase or decrease the activity of neurotransmitters at synapses

stimulants may increase neurotransmitter release, speeding up synaptic transmission, while depressants slow down the transmission by reducing neurotransmitter release.

Question 26

order the events involved in a reflex action

Answer 26

Stimulus detected by receptor

Sensory neuron transmits impulse to spinal cord

Impulse travels through a relay neuron

Motor neuron transmits impulse to effector

Effector (e.g., muscle) carries out the response.

Question 27

describe the function of synapses

Answer 27

to allow electrical impulses to be passed between neurons

They also ensure that impulses travel in one direction only and enable integration