The nervous system

Question 1

what is the central Nervous system

Answer 1

the brain and the spinal cord

Question 2

What is the peripheral Nervous system

Answer 2

everything else in the nervous system other than the brain and spinal chord

Question 3

What is a glial cell ?

Answer 3

one of a variety of cells that provide a framework of tissue that supports the neurons and their activities.

Question 4

Whats a neuron ?

Answer 4

Neurons are cells and
therefore have a soma, or cell body, but they also have extensions of the cell; each extension is generally referred to as a
process. There is one important process that every neuron has called an axon, which is the fiber that connects a neuron with
its target. Another type of process that branches off from the soma is the dendrite.

Question 5

what is a localised collection of neuron cell bodies in the CNS called ?

Answer 5

A localized collection of neuron cell bodies in the CNS is referred to as a nucleus

Question 6

What is a ganglion

Answer 6

In the PNS, a cluster of neuron cell bodies

is referred to as a ganglion.

Question 7

What is a tract ?

Answer 7

A bundle of axons, or fibers, found in the CNS

is called a tract

Question 8

What is a nerve ?

Answer 8

A bundle of axons, or fibers, found in the PNS

Question 9

what is gray matter

Answer 9

Group of Neuron Cell Bodies (neuron/ganglion)

Question 10

what is white matter

Answer 10

Bundle of Axons (tract/Nerve)

Question 11

what is a neuropeptide

Answer 11

a neurotransmitter molecule made up of chains of amino acids connected by peptide bonds. This is
what a protein is, but the term protein implies a certain length to the molecule.

Question 12

is glutamate exhibitory or excitatory

Answer 12

Glutamate is considered an excitatory amino acid, but only because Glu receptors in the adult cause depolarization of
the postsynaptic cell.

Question 13

is glycine exhibitory or excitatory

Answer 13

Glycine is considered inhibitory amino acids, again because their receptors cause
hyperpolarization.

Question 14

is GABA excitatory or inhibitory

Answer 14

GABA is considered inhibitory amino acids, again because their receptors cause
hyperpolarization.

Question 15

what are ionotrophic receptors ?

Answer 15

Ionotropic receptors are ligand-gated ion channels, such as the nicotinic receptor for
acetylcholine or the glycine receptor.

Question 16

what is an effector protein ?

Answer 16

An effector
protein is an enzyme that catalyzes the generation of a new molecule, which acts as the intracellular mediator of the signal
that binds to the receptor. This intracellular mediator is called the second messenger.

Question 17

what is a metabotrophic receptor ?

Answer 17

A metabotropic receptor is a complex that causes metabolic changes in the cell when the neurotransmitter
binds to it (1). After binding, the G protein hydrolyzes GTP and moves to the effector protein (2). When the G protein
contacts the effector protein, a second messenger is generated, such as cAMP (3). The second messenger can then
go on to cause changes in the neuron, such as opening or closing ion channels, metabolic changes, and changes in
gene transcription.

Question 18

what is the absolute refractory period ?

Answer 18

time during an action period when another action potential cannot be generated because
the voltage-gated Na+
channel is inactivated

Question 19

What is the function of an astrocyte

Answer 19

glial cell type of the CNS that provides support for neurons and maintains the blood-brain barrier

regulate ion concentration in the intercellular space

uptake/breakdown of neurotransmitters

formation of the blood brain barrier (the membrane separating the circulatory system from the brain)

Question 20

What is the autonomic nervous system

Answer 20

functional division of the nervous system that is responsible for homeostatic
reflexes that coordinate control of cardiac and smooth muscle, as well as glandular tissue

Question 21

what are proprioreceptors

Answer 21

are mechanoreceptors that detect the position or movement of a part of the body and help regulate movement

Question 22

What is a muscle spindle

Answer 22

is a kind of proprioceptor parallel to the muscle that responds to a stretch, and can cause contraction of the muscle

Question 23

what are the two afferent pathways to the brain

Answer 23

Dorsal column lemniscal for fine touch, vibration and position

Spinothalamic tract for crude touch temperature, and pain

Question 24

what is the function of the primary somatosensory cortex

Answer 24

Function (simple): receives sensory input from the body

Function: receives the bulk of the thalamocortical projections from the sensory input fields

Question 25

what is the function of the primary motor cortex

Answer 25

Function (simple): is one of the principal brain areas involved in motor function
Function: works in association with other motor areas to plan and execute movements

• Direct contraction of specific muscles
• Direct a combination of contractions to produce a specified outcome

Question 26

what does the prefrontal cortex do ?

Answer 26

response to lights, noises and other sensory signals

calculates predictable outcomes of actions and plans movement accordingly

Question 27

where is the prefrontal cortex ?

Answer 27

the front of the brain

Question 28

what does the premotor cortex do ?

Answer 28

• is active during preparation for movement and receives information about a target in space
• integrates information about position and posture of the body and organizes the direction of the movement in space

Question 29

what is the supplementary motor cortex useful for ?

Answer 29

Is important for organizing a rapid sequence of movements

Question 30

what is the supplemental parietal cortex useful for ?

Answer 30

contributes visual information (hand eye coordination!)

Question 31

What is one of the functions of the cerebellum ?

Answer 31

The cerebellum is a structure in the brain often associated with balance and coordination
Known as ‘the little brain’ it has more neurons than the rest of the brain (and has a cortex)!

Supplements and coordinates other motor areas to give a smooth output

Question 32

What would damage to the cerebellum cause ?

Answer 32

Damage to the cerebellum causes trouble with rapid movement requiring aiming and timing.
Examples: clapping hands, speaking, writing, etc.
Damage also leads to postural impairments, tremor, lack of coordinated movements (ataxia)

Question 33

How many parts does the basal ganglia have ?

Answer 33

3
Putamen
Caudate nucleus
Globus pallidus

Question 34

What actions does the basal ganglia help with

Answer 34

Basal ganglia is critical for learning motor skills, organizing sequences of movement, and learning “automatic” behaviors

Starting and finishing movements are influenced by the basal ganglia

Question 35

what does viscera mean ?

Answer 35

internal

Question 36

What does the viscera monitor ?

Answer 36

Monitor temperature, pain, irritation, chemical changes and stretch in the visceral organs
Brain interprets as hunger, fullness, pain, nausea, well-being

Question 37

what is the simplified pathway from the viscera ?

Answer 37

Simplified pathway: sensory neurons to spinothalamic tract (see lesson 4 notes) to thalamus to cerebral cortex

Question 38

what is the role of the amygdala

Answer 38

• Stimulates sympathetic activity, especially previously learned fear-related behavior
  
  • Can be voluntary when recalling frightful experience - cerebral cortex acts through amygdala
  • Some people can regulate some autonomic activities by gaining extraordinary control over their emotions

Question 39

what is an example of why is hard to localise referred pain from the heart

Answer 39

Nociceptive afferents from viscera synapse on the same polymodal neurons in the main sensory nucleus of the dorsal horn as do some of the Aβ fibres from skin mechanoceptors.