Lecture 2: Introduction to Neurophysiology

Question 1

In both the CNS and PNS, there are two nervous systems. What are these called?

Answer 1

somatic nervous system and autonomic nervous system

Question 2

What is the major function of the somatic nervous system?

Answer 2

this is for stuff we are aware of/have control over

Question 3

What is the major function of the autonomic nervous system?

Answer 3

this is for stuff we are not aware of/can’t control

Question 4

What are the two divisions of the somatic nervous system?

Answer 4

afferent (somatic sensory division)

efferent (somatic motor division)

Question 5

What are the two divisions of the autonomic nervous system?

Answer 5

afferent (visceral sensory division)

efferent

Question 6

What are the two divisions of the efferent autonomic nervous system?

Answer 6

sympathetic and parasympathetic nervous system

Question 7

What are the functions of the sympathetic nervous system (efferent autonomic nervous system)?

Answer 7

fight or flight, prepares the body for acute/stress response

Question 8

What are the functions of the parasympathetic nervous system (efferent autonomic nervous system)?

Answer 8

rest and digest, prepares the body for restful situations

Question 9

The dorsal root ganglia are part of which division of the spinal cord?

Answer 9

somatic (afferent)

Question 10

As well as the dorsal root ganglia, there are autonomic ganglia. What are these called?

Answer 10

sympathetic ganglia

parasympathetic ganglia

Question 11

Describe the somatic nervous system (voluntary control of skeletal muscle) organisation

• how many neurons between the brain and the effector?
• where is the UMN cell body located? Where is its axon located?
• where is the LMN cell body located? Where is its axon located?
• are they myelinated?
• what are the neurotransmitters that are released?

Answer 11

• 2 neurons between the brain and the effector
• the UMN cell body is in the brain and its axon is in the spinal cord
• the LMN cell body is in the spinal cord and the axon is in the PNS (sensory neuron)
• both neurons are myelinated
• the LMN releases ACh to the effector

Question 12

Describe the parasympathetic nervous system (autonomic) organisation

• how many neurons between the brain and the effector?
• where are the cell body located? Where is its axon located?
• where is the LMN cell body located? Where is its axon located?
• are they myelinated?
• what are the neurotransmitters that are released?
• where is the synapse?

Answer 12

• 3 neurons between the brain and the effector
• neuron 1 has the cell body in the brain, axon in the spinal cord
• neuron 2 has the cell body in the spinal cord, axon in the PNS
• neuron 3 has both the cell body and axon in the PNS
• neuron 2 is long and myelinated, neuron 3 is short and un-myelinated
• neuron 2 and 3 synapse in the parasympathetic ganglion which is distant from the CNS
• neuron 2 (presynaptic) releases ACh to neuron 3 (postsynaptic)
• neuron 3 releases ACh to the effector

Question 13

Describe the sympathetic nervous system (autonomic) organisation

• how many neurons between the brain and the effector?
• where are the cell body located? Where is its axon located?
• where is the LMN cell body located? Where is its axon located?
• are they myelinated?
• what are the neurotransmitters that are released?
• where is the synapse?

Answer 13

• 3 neurons between the brain and the effector
• neuron 1 has the cell body in the brain, axon in the spinal cord
• neuron 2 has the cell body in the spinal cord, axon in the PNS
• neuron 3 has both the cell body and axon in the PNS
• neuron 2 is short and myelinated, neuron 3 is long and un-myelinated
• neuron 2 and 3 synapse in the sympathetic ganglion which is close to the CNS
• neuron 2 (presynaptic) releases ACh to neuron 3 (postsynaptic)
• neuron 3 releases noradrenaline to the effector

Question 14

On which side of the brain is the stimulus recorded?

Answer 14

on the opposite side of the brain from the one where the stimulus occurred

Question 15

Where is the stimulus mapped in the brain?

Answer 15

in the primary somatosensory cortex

Question 16

Where does the primary somatosensory cortex send signals to?

Answer 16

to the secondary somatosensory cortex to process the information

Question 17

Describe how the body is mapped in the brain

Answer 17

the parts of the body with more receptors to perceive information (such as on the fingers) of the face are mapped larger in the somatosensory cortex compared to other parts of the body (such as the back) that does not perceive information and have as many receptors

Question 18

Are both neurons and glia excitable?

Answer 18

no, only the neurons are

Question 19

What three things do neurons have?

Answer 19

axons, dendrites, synapses

Question 20

What features do neurons have that allow them to have ionic excitability?

Answer 20

K+ ion channels
Na+ ion channels
Na+/K+ ATPase

Question 21

What other features do neurons have?

Answer 21

transporters and synapse specialisation

Question 22

Are glia excitable?

Answer 22

no

Question 23

If glia are not excitable, what are they used for?

Answer 23

they maintain the local environment and support the neurons

Question 24

What are some features of glia?

Answer 24

they have myelin

Question 25

What are some of the roles of glia?

Answer 25

they maintain the metabolism of the neurons and maintain the cerebrospinal fluid

Question 26

Do glia have a resting membrane potential?

Answer 26

yes, despite not being excitable

Question 27

Despite not being excitable, glia have a resting membrane potential, what allows them to have this?

Answer 27

K+ channels, Na+ channels Na+/K+ ATPase

Question 28

What other features do glia have?

Answer 28

they express transporters

Question 29

What are the four types of glia?

Answer 29

oligodendrocytes/Schwann cells ependymal cells astrocytes microglia

Question 30

What is the function of oligodendrocytes/Schwann cells?

Answer 30

they wrap around the axon to form the myelin sheath

Question 31

What is the function of astrocytes?

Answer 31

they maintain the micro environment and form part of the blood-brain barrier

Question 32

What is the function of the microglia?

Answer 32

mount the CNS immune response

Question 33

What is the function of the ependymal cells?

Answer 33

it forms the ventricular epithelium

Question 34

What is the purpose of saltatory conduction?

Answer 34

it increases the speed of the action potential propagation

Question 35

What are the two types of synapses?

Answer 35

electrical (gap junction) | chemical

Question 36

Describe an electrical synapse (gap junction)

Answer 36

this is the gaps between the neurons where the membranes are very close and channels are in the membrane that connect one to another to allow the flow of ions between adjacent neurons. This is very fast

Question 37

Describe a chemical synapse

Answer 37

an action potential arrives at the axon terminal and depolarises it to allow Ca2+ to flow into the terminal of the presynaptic neuron. This influx of Ca2+ promotes vesicles to move to the cell membrane. The neurotransmitter is released across the cleft and is received on the post-synaptic neuron which activates the neuron to conduct an action potential (of there is sufficient synaptic activation)

Question 38

What is the function of the pre-frontal cortex (right at the front of the brain)?

Answer 38

aggression and emotion

Question 39

What is the function of the basal ganglia?

Answer 39

voluntary movement

Question 40

What are the basal ganglia?

Answer 40

group of structures found deep within the cerebral hemispheres

Question 41

What is the function of the hypothalamus?

Answer 41

neuroendocrine and autonomic control

Question 42

What is the function of the brainstem?

Answer 42

autonomic/somatic regulation

Question 43

What is the function of the cerebellum?

Answer 43

integration of sensory and motor information for smooth controlled movement

Question 44

What is the function of the reticular formation?

Answer 44

arousal

Question 45

What is the function of the limbic system? This includes the amygdala and hippocampus

Answer 45

language, learning, emotion, short and long term memory

Question 46

What is the function of the corpus callosum?

Answer 46

communication between two hemispheres

Question 47

What is the function of Broca's area?

Answer 47

speech production

Question 48

What is the function of the auditory association area?

Answer 48

it monitors sensory activity in the auditory cortex and recognises sounds such as spoken words

Question 49

What is the function of the primary auditory area?

Answer 49

monitoring sound formation

Question 50

What is the function of Wernicke's area?

Answer 50

language comprehension

Question 51

What is the purpose of the visual cortex?

Answer 51

receives info from the lateral geniculate bodies

Question 52

What is the purpose of the visual association area?

Answer 52

it monitors the patterns of activity in the visual cortex and interprets the results

Question 53

Afferent information that enters the spinal cord within the somatic nervous system, crosses over at which level?

Answer 53

at the spinal cord

Question 54

Where is the primary motor cortex?

Answer 54

in the precentral gyrus

Question 55

What is the function of the primary motor cortex?

Answer 55

direct voluntary movement by controlling somatic motor neurons in the brainstem and spinal cord

Question 56

Where is the primary somatosensory cortex?

Answer 56

in the post central gyrus

Question 57

What is the function of the primary somatosensory cortex?

Answer 57

neurons here somatic sensory information from receptors for touch, pressure, pain, vibration or temperature