2.2 - Biopsycholgy (set A - Nervous System)

Question 1

Explain the role of the central nervous system?

Answer 1

The CNS comprises of the brain and spinal cord

• 2 main functions - to control behaviour and regulate the body’s physiological processes

Question 2

Explain the role of the spinal cord?

Answer 2

• relays information between the brain and rest of the body - allows the brain to monitor and regulate bodily processes (eg digestion/breathing)

Spinal cord involved in performing simple reflexes

Question 3

Explain the basic structure of the brain?

Answer 3

Divided into 4 main areas cerebrum, cerebellum, diencephalon and brain stem

Cerebrum is largest part and is further divided into 4 different lobes
- cerebrum is split into 2 halves (cerebral hemispheres)

Cerebellum sits beneath the back of cerebrum

The diencephalon lies beneath the cerebrum and on top of the brain stem

Question 4

Explain the structure and role of the cerebrum?

Answer 4

• largest part of the brain
• divided into 4 different lobes - which each have a different primary function (eg frontal lobe involved in thought and production of speech)
• cerebrum split down middle into 2 halves (cerebral hemispheres) which communicate with each other via the corpus callosum

Each hemisphere is specialised for particular behaviours

Question 5

Explain the structure and role of the cerebellum?

Answer 5

• sits beneath the back of the cerebrum
• involved in controlling a persons motor skills and balance (controls muscles allowing movement)

Question 6

Explain the importance of the diencephalon?

Answer 6

Lies beneath the cerebrum and on top of the brain stem - contains 2 important structures thalamus and hypothalamus

Thalamus - acts as a relay station for nerve impulses, routing them to the appropriate part of the brain

Hypothalamus - regulatinon of body temperatures and links the endocrine system and nervous system

Question 7

Outline the division of the nervous system?

Answer 7

Nervous system divided into central nervous system and peripheral nervous system

central nervous system divided into spinal cord and brain

peripheral nervous system divided into somatic nervous system and autonomic nervous system

autonomic nervous system divided into sympathetic nervous system and parasympathetic nervous system

Question 8

Outline the components of the peripheral nervous system?

Answer 8

Divided into 2 main divisions somatic nervous system and autonomic nervous system (ANS)

• function of the peripheral nervous system is to really nerve impulses from the CNS to the rest of the body

autonomic nervous system further divided into sympathetic and parasympathetic nervous systems

Question 9

Explain the function of the somatic nervous system?

Answer 9

part of the peripheral nervous system and contains both sensory receptors and motor pathways

• sensory neurones carry sensory information to the CNS, where as motor pathways take information from the CNS to glands and muscles

Question 10

Explain the function of the autonomic nervous system?

Answer 10

regulates involuntary actions (eg heartbeat and breathing) which are important for maintaining homeostasis, regulating internal body conditions

• Contains motor pathways, does not contain sensory neurones

divided into sympathetic and parasympathetic nervous systems

Question 11

Explain the function of the sympathetic nervous system (SNS)?

Answer 11

Primarily involved in fight or flight response - increases heart rate and blood pressure to help deal with emergencies

Neuron’s from SNS travel to every organ and gland to prepare the body (eg triggering the release of stored energy, dilation of pupils, hair to stand on end ext)

Question 12

Explain the function of the parasympathetic nervous system (PNS)?

Answer 12

Returns the body to normal conditons after the emergency response - causes the heartbeat to slow down and reduces blood pressure
- digestion which is inhibited during fight or flight is resumed

**also called ‘rest and digest”

Question 13

Outline the key features of the somatic nervous system?

Answer 13

• connects external sensors organs though the brain to the muscles
• includes both sensory and motor neurones
• under voluntary control - involves us processing the information

Carries impulses from CNS to muscles

Question 14

Outline the key features of the autonomic nervous system?

Answer 14

• regulates involuntarily actions likes heartbeat and breathing
• involved in regulating internal processes (homeostasis)

motor neurones only

Question 15

What are the 3 types of neurons - outline brief structure?

Answer 15

• sensory neurons
• relay neurons
• motor neurons

neurons are specialised cells which carry neural information throughout the body

Structure typically consists of a cell body, dendrites and an axon

Question 16

Outline the structure of neurons?

Answer 16

Dendrites at one end of neurone receives signals from other neuron’s - they are connected to the cell body (the control centre of the neurone)

Impulse carried along axon - before terminating at axon terminal (myelin sheath, is an insulating layer around axon)

Question 17

Explain the role of the myelin sheath regarding the function of neuron’s?

Answer 17

Insulating layer which forms around axon

Function is to allow nerve impulses to transit more rapidly along the axon - damage to it can slow impulses down

Question 18

Outline the role of sensory neuron’s?

Answer 18

• carry nerve impulses from sensory receptors (receptors for vision,taste)
• found in eyes, ears, tongue and skin
• convert sensory information into neural impulses which are translated into sensations in the brain

not all sensory information travels to brain, some neuron’s terminate in the spinal cord - allowing for reflex actions

Question 19

Outline the role of relay neuron’s?

Answer 19

Allow sensory and motor neuron’s to communicate with each other

relay neurones are only found within the brain and spinal cord

Question 20

Outline the role of motor neuron’s?

Answer 20

• conduct signals from CNS to effector organs (eg muscles)
• have long axons which form part of PNS

Form synapses with muscles, when stimulated the neuron releases neurotransmitters that bind to receptors on the muscle and triggers a response, leading to movement

Question 21

What is a synapse?

Answer 21

Conjunction of the end of the axon of one neurone and the dendrite of another

gap between presynaptic neurone and post synaptic neurone is synaptic gap

Question 22

Outline synaptic transmission?

Answer 22

Synaptic vesicles, small sacs at the end of the axon of a nerve cell contain chemical messengers (neurotransmitters) that assist in the transfer of the impulses - they are released as the action potential reaches them

Neurotransmitters diffuse across the gap and bind to specialised receptors on the surface of their complementary cell where they are activated and produce either excitatory or inhibitory effect on the post synaptic neuron

Question 23

Explain the process of ‘re-uptake’?

Answer 23

Synaptic transmission ends when the neurotransmitter is taken up again by the presynaptic neurone, where its stored and made available for later

• how quickly the presynaptic neuron takes back the neurotransmitter determines how long its effects will be

antidepressant drugs prolong action of neurotransmitter by inhibiting re-uptake - increases levels of neurotransmitters

Question 24

Explain the role of excitatory neurotransmitters - give 2 examples?

Answer 24

Increase the likelihood that an excitatory signal is sent to the postsynaptic cell which is then more likely to fire

• acetylcholine
• noradrenaline

Question 25

Explain the role of inhibitory neurotransmitters - give 2 examples?

Answer 25

They decrease the likelihood of that neurone firing - generally responsible for calming the mind and body

• GABA
• serotonin

Question 26

Explain what determines whether a nerve cell will fire?

Answer 26

Nerve cell receives both excitatory and inhibitory neurotransmitters at the same time but the likelihood of firing is determined by by adding up the excitatory and inhibitory synaptic input (summation)