Nervous System

Question 1

What does the central nervous system consist of

Answer 1

Brain and spinal cord

Question 2

What does the PNS consist of

Answer 2

Spinal nerves and cranial nerves

Question 3

What are the main parts of the forbrain aka prosencephalon

Answer 3

Telencephalon
Cerebral Cortex
Basal Ganglia Hippocampus
Amygdala
Diencephalon (Thalamus, Hypothalamus)

Question 4

What are the main parts of the midbrain aka mesencephalon

Answer 4

Tectum
Tegmentum

Question 5

What is the main arts of the hindbrain aka rhombencephalon (myelencephalon and metencephalon)

Answer 5

Medulla
Pons
Cerebellum

Question 6

Somatic;

Answer 6

Responsible for conscious perception and voluntary motor responses (contracting skeletal muscle)

Question 7

Autonomic;

Answer 7

Responsible for the involuntary control of the body to maintain homeostasis.

Question 8

Visceral;

Answer 8

referring to nerves innervating internal organs.

Question 9

Describe the differences in these elements of the nervous system
Afferent and Efferent;

Answer 9

Afferent is the sensory component. Efferent is the motor component.

Question 10

Sympathetic and parasympathetic;

Answer 10

the two systems are antagonistic and they differ in structure and function. The parasympathetic nervous system is said to be responsible for
“rest and digest” processes. The sympathetic nervous system is involved in “fight or flight” type processes.

Question 11

Info

Answer 11

Vision is received through the afferent nervous system.
Eye movement control signals are transmitted via cranial nerves,
Activation of the sympathetic system results in pupil dilation.
Activation of the parasympathetic nervous system result in pupil constriction.

Question 12

What is the function of the frontal lobe

Answer 12

Voluntary motor function, problem solving, behaviour and personality.

Question 13

Function of temporal lobe

Answer 13

Auditory perception and memory

Question 14

Function of parietal lobe

Answer 14

Interpreting sensory information (including vision)

Question 15

What is the function of occipital lobe

Answer 15

Primary visual cortex

Question 16

What is the function of myelin?

Answer 16

It protects and insulates nerve axons, increasing the speed of signal transmission of action potentials. It’s made up of concentric layers of Schwann cells wrapped around the axon.

Question 17

What is the function of the nodes of Ranvier?

Answer 17

This is a gap in the myelin allowing for the fast transmission of action potentials

Question 18

What would be the purpose of a nerve being highly myelinated

Answer 18

To facilitate salutatory conduction- very fast propagation of nerve impulses

Question 19

List the types of glial cells in the central and peripheral nervous system and briefly indicate their function

Answer 19

Gilal cells support neurons in functioning

CNS (central nervous system)
-Astrocyte - maintains chemical concentrations in the extra-cellular space, removes waste and helps repair neurons to support their function. It contributes to the blood brain barrier.
-Oligodendrocyte- Insulating axons
-Microglia - ingests cells and pathogens
-Ependymal cell - filter blood to make cerebrospinal fluid

PNS
-Satellite cell - supportive role. Found surrounding sensory and autonomic ganglia regulating the micro- environment around them
-Schwann cell - insulating axons

Question 20

Cranial nerve a are highly what

Answer 20

• Cranial nerves are highly myelinated, conditions such as infection and demyelinating diseases i.e, multiple sclerosis result in destruction of the myelin sheath thus reducing the speed and effectiveness of nerve conduction.

Question 21

Synapse Structure

Answer 21

The transmission of visual information from the retina to the brain relies on transmission of information between sensory nerve cells. In order to bring about eye movement motor nerves need to communicate with the eye muscles via the neuromuscular junction. When this process goes wrong then it can bring about specific clinical features of eye movements for example a condition called myasthenia gravis that you will learn about in year 2, hence it is important you understand this process well.

Question 22

steps that occur at the neuromuscular junction synapse;

Answer 22

At then end of each axon terminal is an enlarged area called a bouton terminal
-When an action potential arrives at the bouton terminal, it triggers the Synaptic vesicles in the bouton terminal release a transmitter called acetylcholine
-This flows across the gap (synaptic cleft) and increases the permeability of the next nerves cell membrane
-In the next nerve a substance called cholinesterase breaks down the transmitter into
acetyl and choline
-The 2 substances diffuse back across the gap to the original bouton terminal
* In bouton terminal enzyme called acetylase reunites acetyl and choline so that it’s ready to transmit the next impulse

Question 23

What is the name of the neurotransmitter that is present in the neuromuscular junction?

Answer 23

Acetylcholine

Question 24

What is the function of this neurotransmitter?

Answer 24

To allow commination/continuation of action potentials between neurons or between a neurone and a muscle fibre.

Question 25

What happens to the neurotransmitter once it has bound to the receptor and why?

Answer 25

A substance called cholinesterase breaks down the transmitter into acetyl and choline to allow it to diffuse back across the synaptic cleft and be used again. This is important for repeated or continuous signals to be transmitted.

Question 26

Crossing over

Answer 26

Crossing over of motor control from the cerebral cortex of the brain to control the opposite side of the body is common to vision and eye movement control as well as limb control hence why a right sided stroke will result in left sided visual loss and limb weakness