Homeostasis and response - The nervous system

Question 1

what are the names of the 2 parts of the nervous system

Answer 1

1. Central nervous system (brain and spinal cord)
2. the peripheral nervous system – nerve cells that carry information to or from the CNS

Question 2

what is the role of the nervous system

Answer 2

enables humans to react to their surroundings and co - ordinate their behaviour

Question 3

what is the CNS connected to the body by?

Answer 3

sensory and motor neurones

Question 4

what are sensory neurones

Answer 4

the neurones that carry information as electrical impulses from the receptors to the CNS

Question 5

what are motor neurones

Answer 5

the neurones that carry electrical impulses from the CNS to EFFECTORS

Question 6

Nerve cell specializations

Answer 6

long axon insulated with a fatty sheath which are long so that they can carry messages up and down the body
- dendrons which branch further as dendrites which receive incoming impulses from other neurones

Question 7

receptor to effector line

Answer 7

Stimulus → receptor → coordinator → effector → response

Question 8

what is the CNS

Answer 8

A co- ordination centre, which recieves information from receptors then co-ordinates a response, carried out by effectors

Question 9

what order does the reflex arc go in

Answer 9

Stimulus → receptor →sensory neurone→ relay neurone→ motor neurone→ coordinator → effector → response

Question 10

what are relay neurones and what do they do

Answer 10

located in the spinal cord, these neurones connect sensory neurones to motor neurones.

Question 11

what are synapses

Answer 11

the gap where two neurones meet

Question 12

what is the cerebrum/ cerebral cortex responsible for

Answer 12

controls intelligence, personality, conscious thought and high-level functions, such as language and verbal memory.

Question 13

what is the cerebellum/ responsible for

Answer 13

controls balance, co-ordination of movement and muscular activity.

Question 14

what is the medulla responsible for

Answer 14

controls our heart and breathing rate

Question 15

3 reasons why the brain is so hard to study

Answer 15

• it is protected by the skull, so it is difficult to access
• structures of the brain are complex, so it’s difficult to work out which parts of the brain carry out which function
• brain is delicate and easy to damage

Question 16

how does electrical stimulation work

Answer 16

• by stimulating the brain with a current and monitoring the effects on the persons behaviour

Question 17

what are nerve cells (neurones) adapted to do

Answer 17

to carry electrical impulses from one place to another

Question 18

examples of effectors carrying out a response

Answer 18

• a muscle contracting
• a gland releasing a hormone

Question 19

what is a reflex action

Answer 19

an automatic and rapid response to a stimuli

Question 20

how does the reflex arc work

Answer 20

1. the stimulus is detected by a receptor
2. electrical impulses now pass from the receptor along a sensory neurone to the CNS
3. at the end of the sensory neurone, there is a junction called a synapse
   - at the synapse a chemical is released and these chemicals diffuse across to a relay neurone in the central nervous system where it triggers an electrical impulse
4. the electrical impulse now passes along the relay neurone and reaches another synapse
5. chemical is released again and diffuses and the chemical triggers an electrical impulse in a motor neurone
6. the electrical impulse now passes down the motor neurone to an effector
7. effector carries out response

Question 21

what happens at a synapse

Answer 21

1. an electrical impulse travels through the first axon
2. this triggers the nerve ending of a neurone to release chemicals called neurotransmitters
3. these chemicals diffuse across the synapse and bind with receptor molecules on the membrane of the second neurone
4. The receptor molecules on the second neurone bind only to the specific neurotransmitters released from the first neurone. This stimulates the second neurone to transmit the electrical impulse.

Question 22

what is the hypothalamus responsible for

Answer 22

regulates temperature and water balance within the body

Question 23

advantages of electrical stimulation

Answer 23

• they can observe the electrical activity in the brain
• allows us to narrow down specific regions to their functions

Question 24

disadvantages of electrical stimulation

Answer 24

people can experience hunger, anger, fear or thirst whilst a relevant part of the brain is being stimulated, as they do the procedure whilst the patient is still conscious

Question 25

what do MRI scans do

Answer 25

• use strong magnetic fields and radio waves to show details of brain structure and function
• they are able to show exactly which part of the brain is affected
• allow us to look at which parts of the brain are most active during different activities

Question 26

Problems with brain surgery

Answer 26

-drugs do not always reach the brain through the membranes which surround it
- surgery is difficult because it is not fully understood what each part of the brain actually does, so may cause unintended damage
- surgery can cause unwanted side effects which may ruin a persons quality of life

Question 27

what does the brain do

Answer 27

controls complex behaviour

Question 28

what is the brain made out of

Answer 28

billions of interconnected neurones

Question 29

features of the nervous system

Answer 29

• fast, rapid and precise
• effects are short lived

Question 30

what does the brain do

Answer 30

controls complex behaviour such as language

Question 31

3 ways scientists study the brain

Answer 31

• observing patients who have suffered brain damage
• electrically stimulate the brain
• use MRI scans

Question 32

why do scientists observe patients with brain damage

Answer 32

• by looking to see where the damage has taken place, they can try to link that part of the brain to its function