Nervous System

Question 1

What is the nervous system

Describe the divisions of the NS

Answer 1

Essentially a communication system

CNS
PNS - sensory/motor division
Motor - autonomic/somatic
Autonomic - PSNS/SNS

Question 2

Explain the effects on the body system when SNS is activated

Answer 2

Flight or fright

Reduced GI activity 
Bronchodilation
Reduced UO
HR increased
RR increased
Dilated pupils 
Increases metabolic rate 
Piloerection

Question 3

Explain what happens to the body system when PSNS is in effect

Answer 3

Rest and digest

Bronchiole construction
Relaxes urinary sphincters
Pupil constriction
Stimulates production of saliva, tears, gastric juice

Question 4

What are the meningeal layers

Answer 4

PAD

Pia - inner
Arachnoid - middle
Dura - outer (has 2 layers - thick outer one connected to the skull, inner thin layer. Space between is where the venous blood from the cerebral circulation collects)

Question 5

Describe the cerebellum

Function

Answer 5

Large cauliflower like structures that projects dorsally under the occipital lobe.

Responsible for proper balance and posture. Provides instructions to the cerebral motor cortex resulting in smooth coordinated muscle movements

Question 6

Describe the brain stem

Answer 6

Size of a thumb, approx 3 inches long

Midbrain - visual and auditory reflex centre

Pons - relays info from the cerebrum to the cerebellum

Medulla oblongata - relays sensory pathway impulses from skin/proprioceptors

Reticular formation - maintains cerebral alertness. Extends the entire length of the brain stem

Question 7

Describe the diencephalon

Answer 7

Sits atop the brain stem

Thalamus - relays sensory impulses to the cerebral cortex, involved in memory

Hypothalamus - regulates ANS and body processes

Epithalamus - forms the roof of the third ventricle

Limbic system - mediates emotional responses

Question 8

What is meningitis

Answer 8

Inflammation of the meninges

Question 9

What is hydrocephalus ?

Answer 9

Water on the brain

In a newborn this can cause the baby’s head to enlarge as the brain size increases

Question 10

What is the blood brain barrier?

Answer 10

Least permeable capillaries in the whole body; seamlessly bound together by tight junctions all around

Water soluble substances i.e water, glucose, essential amino acids pass easily through

Question 11

What does CSF do?

Answer 11

Forms a watery cushion that protects the fragile nervous tissue from blows and other trauma

Question 12

What is a concussion?

Answer 12

A form of minor TBI - when they are showing signs of mild brain injury but no visible injury is seen on a CT

Question 13

What kind of brain contusions result in coma?

Answer 13

Brain stem

Question 14

What is a CVA?

If there is left sided paralysis what is likely to be involved ?

What about if there is aphasia?

Answer 14

Cerebrovascular accident - STROKE.
Either by ischemia or haemorrhage

Right motor cortex of the frontal lobe

Left cerebral hemisphere where the language areas are located

Question 15

What is a TIA?

Answer 15

Transient ischemic attack - people call these mini strokes.

Temporary brain ischemia or restriction to Bf, symptoms disappear within 24hrs

Question 16

Neural tissue has two kinds of cells, what are they?

Answer 16

Neurons - excitable cells that transmit electrical signals

Glial cells - surrounds, supports and protects neurons. Non excitable

Question 17

What are the two major functional properties of neurons?

Answer 17

Irritability - ability to respond to a stimulus and convert it into a nerve impulse

Conductivity - ability to transmit the impulse to other neurons, muscles and glands

Question 18

What are interneurons?

Answer 18

They transmit directly between affector/effector pathways to create motor reflexes such as the knee jerk response

Question 19

Neurons.

Efferent ?

Affferent?

Answer 19

Motor neuron - away from the CNS

Sensory neuron - towards the CNS

Question 20

What is a nociceptor?

Answer 20

Specialised nerve endings associated with pain that we associate with tissue damage.

Question 21

What is nociceptive pain?

Answer 21

Pain we consciously interpret as a warning or evidence of tissue damage such as a burns

Question 22

What are reflexes?

Answer 22

Rapid predictable involuntary responses to a stimuli

Question 23

What are the two reflex pathways reflexes occur over?

What are these called?

Answer 23

Somatic - all that stimulate the skeletal muscle
Autonomic - regulates the activity of smooth muscles, heart, glands, changes in pupil size

Reflex arcs

Question 24

Name some glial cell types

Briefly explain each one

Answer 24

Astrocytes - roles include regulation of water volume and electrolyte connection of neural tissue

Microglia - sense the presence of infection, inflammation or physical damage to the tissue surrounding the neurons

Schwann cells -provide the myelin sheath material for the neurons of the PNS

Ependymal cells - line the fluid filled ventricles of the brain, helps from the CNSF and regulates its flow

Oligodendrocytes - proxies the physical support to the axons as well as produce myelin for the axonal sheath of the neurons

Question 25

Describe the electrochemical events of neuronal repolarisation What is an electrochemical event?

Answer 25

*transmission of an impulse Axon potential reaches an axon terminal - the electrical change opens calcium channels. Calcium causes tiny vesicles containing the neurotransmitter chemical to fuse with the axonal membrane, pore like openings form - releasing the transmitter The neurotransmitter molecules diffuse across the synapse and bind to the membrane of the next neuron. If enough neurotransmitter is released, the whole series of events will occurs (as above)

Question 26

What are the two divisions of the PNS?

Answer 26

Somatic. Contains the nerves that transmit afferent signals that we are consciously aware of Autonomic. Also has two divisions - sympathetic and para sympathetic. Transmit efferent signals to muscles and organs that automatically regulated

Question 27

What’s quadriplegic vs paraplegic?

Answer 27

All four limbs | Legs only

Question 28

What is the collection of spinal nerves at the end of the spinal cord called?

Answer 28

Cauda equina

Question 29

What is pulsus paradoxus?

Answer 29

Abnormal decrease in stroke volume, blood pressure and pulse wave amplitude during inspiration.

Question 30

Explain the nerve impulse cycle (6 steps )

Answer 30

If can’t - watch a video, try to explain it again

Question 31

Pain. | C fibers vs A fibers

Answer 31

C = associated with slow and less localised pain A = sharp fast and localised sensations

Question 32

Explain pain physiology

Answer 32

If can’t - watch video, try to explain again

Question 33

Factors that influence pain interpretation

Answer 33

Age Previous experience Gender Ethnic and cultural mores

Question 34

What is vestibular sense ?

Answer 34

Comes from our inner ear, when it’s activated and there is a change in gravity or head moves. Helps us to maintain positioning/balance and stops objects blurring when head moves

Question 35

What is proprioception?

Answer 35

Sixth sense Sense of self movement and body position. Mediated by proprioceptors, mechanosensory neurons located in the muscles tendons and joints

Question 36

How many cranial nerves are there?

Answer 36

12

Question 37

What is the cranial nerve that extends to the thoracic and abdominal cavities

Answer 37

Vague nerve

Question 38

Name the cranial nerves Explain briefly

Answer 38

``` Olfactory Optic Oculomotor Trochlear Trigeminal Abducens Facial Vestibulocochlear Glossopharyngeal Vagus Accessory Hypoglossal ``` Watch video if can’t answer the second question

Question 39

What is the Babinskis test?

Answer 39

To test for a sign of an underlying nervous system or brain condition causing your reflexes to react abnormally Run a pointed object against the lateral aspect of the lower foot, towards the big toe