Lecture 2 - Neurophysiology II

Question 1

what are the 2 divisions of the central nervous system?

Answer 1

somatic nervous system and autonomic system

Question 2

what composes the central nervous system?

Answer 2

brain and spinal cord

Question 3

what composes the peripheral nervous system?

Answer 3

cranial nerves and spinal nerves

Question 4

what does the somatic nervous system consist of?

Answer 4

somatic sensory division (afferent) and the somatic motor division (efferent) both of these compose the somatic integration centres

Question 5

what does the autonomic nervous system consist of?

Answer 5

visceral sensory division (afferent), sympathetic division (efferent) and the parasympathetic division (efferent), all compose the autonomic integration centres

Question 6

what are the 2 divisions of the peripheral nervous system?

Answer 6

sympathetic nervous system and parasympathetic nervous system

Question 7

what is the relationship between the peripheral nervous system + neuroendocrine system to the central nervous system?

Answer 7

the peripheral nervous system and neuroendocrine system have somatic and special receptors which detect a stimulus and relay it to the CNS

Question 8

what are the effectors of the somatic nervous system?

Answer 8

skeletal muscle and visceral receptors

Question 9

what are the effectors of the autonomic nervous system?

Answer 9

cardiac and smooth muscle; adipose and other tissues

Question 10

what is the spinal reflex arc?

Answer 10

a stimulus is perceived in the skin sent by afferent signals to the brain from the dorsal root ganglion and the spinal cord. The reflex is processed at the level of the spinal cord resulting in stimulation of the motor neuron to the skeletal muscle effector. A response is produced through the efferent nerve of the agonist skeletal muscle results in withdrawal from the stimulus (reflex). The antagonist muscle acts as the inhibitor.

Question 11

is the brain involved in the spinal reflex arc?

Answer 11

yes as it compares the actual response to the expected response and modulates to see if any further input is required

Question 12

what are the divisions of the brain?

Answer 12

pre-frontal cortex
basal ganglia (including thalamus)
hypothalamus
brainstem (including pons and medulla)
cerebellum
reticular formation
limbic system (including amygdala and hippocampus)
corpus callosum (part of the limbic system)

Question 13

what is the function of the pre-frontal cortex?

Answer 13

aggression and emotion

Question 14

what is the function of the basal ganglia (including thalamus)?

Answer 14

voluntary movement

Question 15

what is the function of the hypothalamus?

Answer 15

neuroendocrine and autonomic control

Question 16

what is the function of the brainstem (including pons and medulla)?

Answer 16

autonomic/somatic regulation

Question 17

what is the function of the cerebellum?

Answer 17

integration of sensory and motor information for smooth controlled movement

Question 18

what is the function of the reticular formation?

Answer 18

arousal

Question 19

what is the function of the limbic system (including amygdala and hippocampus)?

Answer 19

language, learning, emotion and short and long term memory

Question 20

what is the function of the corpus callosum (part of the limbic system)?

Answer 20

communication between the 2 brain hemispheres

Question 21

what is the somatotopic map?

Answer 21

the somatotopic map represents how some areas of the body are more innervated in the somatosensory cortex due to areas with a larger number of sensory receptors such as the face/hands compared to the back/feet and everything sensed at one side of the body activates the other side of the brain

Question 22

state the 6 major features of neurons?

Answer 22

1) excitable
2) store and pass on information
3) composed of axons and dendrites
4) form synapses between adjacent neurons
5) contain K+ ion channels and Na+ ion channels
6) resting membrane potential (RMP) is maintained by Na+/K+ATPase

Question 23

state the 6 major features of glia?

Answer 23

1) non-excitable
2) located in the ventricles of the brain where CSF is stored to maintain and regulate CSF signalling in the CNS
3) composed of myelin
4) aid in metabolism and maintain the local environment
5) contain K+ channels
6) resting membrane potential is maintained Na+/K+ATPase

Question 24

what are the 4 types of glia?

Answer 24

microglia
astrocytes
oligodendrocytes (and schwann cells)
ependymal cells

Question 25

what is the function of microglia?

Answer 25

mount the CNS immune response

Question 26

what is the function of astrocytes?

Answer 26

maintain the microenvironment and form part of the blood-brain barrier

Question 27

what is the function of oligodendrocytes (and schwann cells)?

Answer 27

wrap around the axon to form the myelin sheath

Question 28

what is the function of ependymal cells?

Answer 28

form the ventricular epithelium

Question 29

what are electrical synapses (gap junctions)?

Answer 29

channels in the membrane that connect from one neuron to the other and when open allow for the flow of ions between adjacent neurons

Question 30

what are gap junctions?

Answer 30

junctions between neurons where cell membranes are very close that form channels

Question 31

what do electrical synapses allow in terms of communication?

Answer 31

rapid communication

Question 32

what are the 5 key components of chemical synapses?

Answer 32

1) slower communication
2) relies upon chemical crossing the gap
3) complex series of events
4) neurotransmitter packed into vesicles
5) synapse strength can be modified

Question 33

what occurs when an AP arrives at a chemical synapse?

Answer 33

AP arrives at axon terminal –> depolarises axon terminal to allow Ca2+ influx into the presynaptic terminal –> increased intracellular Ca2+ promotes the diffusion of vesicles within the cell membrane (takes time) –> diffuses across the synaptic cleft –> activates receptor –> mediates post synaptic response