Nervous System - Short Answers

Question 1

blood brain barrier importance

Answer 1

• protects the brain and supplies the brain with nutrients and oxygen
• blood capillaries that lead to the brain are made of tightly fused epithelial cells
• forms barrier that blocks many toxins and infectious agents
• barrier allows nothing to seep in and destroy it

Question 2

3 homeostatic functions

Answer 2

• as food leaves the body peristalsis decreases, as food enters peristalsis increases
• when oxygen levels are low rate and depth of breathing increases, when oxygen levels are high rate and depth decreases
• when temperature gets hotter body temp decreases when temp gets colder body temp increases

Question 3

events that occur at the synapse

Answer 3

• impulse travels along the presynaptic axon; when impulse reaches the synaptic knob or axon terminal, calcium ions enter the synaptic knob
• as calcium ions enter, vesicles containing the neurotransmitter acetylcholine ACH, migrate toward the presynaptic membrane
• vesicles attach to the presynaptic membrane and the ACH is released into the tiny synaptic cleft by exocytosis
• ACH travels across the cleft and attaches to the protein receptors on the postsynaptic membrane; this temporary attachment causes the postsynaptic membrane to become permeable to sodium ions and an impulse is initiated in the next neuron
• after an impulse is conveyed in the next neuron, an enzyme called acetylcholinesterase (ACHase) breaks down the ACH in the synaptic cleft; breakdown fragments are taken up by the presynaptic membrane by endocytosis
• ACH fragments are we synthesized into ACH within the vesicle

Question 4

sensory and motor gyrus

Answer 4

sensory

• found in the cerebrum
• receive input from receptors and interprets impulses

motor
-send impulses for all voluntary movement and position of moveable body parts

Question 5

pis and dura mater

Answer 5

2 of the 3 meninges
dura
-thick, outer layer of dense connective tissue; most protective layer

pia
-inner most layer of delicate connective tissue that is closely attracted to the surface of the brain and spinal cord; contains blood vessels that nourish the neutrons and neuroglial cells

Question 6

rods and cones

Answer 6

cones

• seeing colour is dependent upon the surfaces ability to reflect various wavelengths of white light
• each cone sends and independent message to the occipital lobes

rods

• responsibility for vision in dim light; contain protein rhodopsin
• groups of up to 159 rods send only one message to occipital lobes

Question 7

brocas and wernickes

Answer 7

broca

• coordinates the muscles for speaking and translates thought into speech
• left side of the cerebral cortex
• if damaged -> doesn’t affect understanding of language but unable to to speak

wernickes

• stores the info involved with language comprehension
• if damaged -> ability to utter words isn’t affected but words don’t make sense

Question 8

white and grey matter

Answer 8

white
-corpus callosum contains mylinated fibres which allows both hemispheres to communicate with each other; looks like upside nike swoosh

grey
-cerebral cortex is the outside later of the cerebrum that contains many cells bodies of association neutrons and motor neurone; interconnected by unmyelinated neurons

Question 9

csf

Answer 9

• crystal clear colourless solution
• shock absorber for the brain and spinal cord
• circulates through the brain ventricles then I it the subarachnoid space

Question 10

axon function

Answer 10

• fibre which carries impulses away from the cell body

- myelinated and nonmyelinated (schwann cells)

Question 11

neuron structure

Answer 11

• dendrite
• cell body
• axon
• neurilemma
• node of ranvier
• terminal branches

Question 12

myelin sheath characteristics

Answer 12

-schwann cells produce a white fatty substance called myelin which encircles the axon which conducts impulses at a faster rate

Question 13

meninges

Answer 13

• dura the thick outer layer of dense connective tissue
• arachnoid a thin middle later if delicate connective tissue
• pia inner most later of delicate connective tissue

Question 14

glossopharyngeal nerves

Answer 14

• mixed nerve
• stimulation of secretion in paranoid gland (salivary)
• sense of taste, touch, temp in palate tonsils and pharynx

Question 15

sodium potassium pump

Answer 15

• actively transports 3 sodium ions outside the cell for every 2 potassium ions moved inside the cell
• resting membrane potential and repolarized membrane

Question 16

nerve impulse

Answer 16

• polarized membrane
• depolarized membrane
• repolarized membrane (2)