Autonomis NS + special senses

Question 1

what 5 things are in the involuntary branch of the ANS

Answer 1

• cardiac muscle
• smooth muscle
• most exocrine glands
• some endocrine glands
• adipose tissue

Question 2

structure + function of preganglionic fibres in the sympathetic NS

Answer 2

• release ACh onto nicotinic receptors (cholinergic fibres)
  -very short

Question 3

structure + function of postganglionic fibres in the sympathetic NS

Answer 3

• release NE onto andrenergic receptors (adrenergic fibres)
• very long

Question 4

what is different about sweat glands + blood vessels of skeletal muscles in SNS transmission

Answer 4

ACh is released by post ganglionic neurons onto nicotinic receptors

Question 5

structure + function of preganglionic fibres in the parasym. NS

Answer 5

• release ACh onto nicotinic receptors
• long

Question 6

structure + function of postganglionic fibres in the parasym. NS

Answer 6

• release ACh onto muscarinic receptors
• short

Question 7

describe the concept of dual innervation/antagonistic control

Answer 7

• innervation of tissue or organ w/ both pathways of autonomic NS
• each pathway has opposing effect on tissue/organ

-> enables precise control of function

Question 8

describe tonic control + how it occurs

Answer 8

• innervation of tissue/organ by only one branch of ANS (generally sympathetic pathway)
• increase or decrease in signal strength controls tissue/organ eg. vasoconstriction/vasodilation (intermediate signal always present)

Question 9

what is autonomic control

Answer 9

normal background rate of spontaneous activity - balance from both ANS pathways
- occurs for both antagonistic + tonic control mechanisms

Question 10

differentiate b/t somatic + autonomic nerve pathways

Answer 10

• somatic = 1 neuron from CNS to effector organs
• autonomic = 2-neuron chain from CNS to effector organs
• somatic neurons of CNS exert direct control over skeletal muscles
• autonomic motor neurons of CNS synapse onto visceral motor neurons in ganglia -> control effectors

Question 11

3 ways in which hypothalamus integrates activities of nervous + endocrine systems

Answer 11

• controls anterior pit. hormone secretion
• produces posterior pit. hormones
• controls activity of adrenal medulla

Question 12

how does memory consolidation occur on a neural level

Answer 12

via changes in neurons + synapses
- increased NT release
- facilitation at synapses
- formation of additional synaptic connections

Question 13

describe the effects of alzheimer’s on the brain

Answer 13

• impaired short term memory -> long term loss
• confusion, disorientation + personality changes
• extracellular plaques + neurofibrillary tangles

Question 14

function of the cornea

Answer 14

transparent portion of eye where light enters - focusses light

Question 15

function of the iris

Answer 15

contracts/ relaxes to increase/decrease size of pupil

Question 16

lens function

Answer 16

focuses light onto retina

filled w/ crystallins -> provide clarity + focusing power

Question 17

differentiate b/t the lens actions + ciliary muscles for close vs. distant vision

Answer 17

close = lens rounded + ciliary muscle contracted

far = lens flattened + ciliary muscle relaxed

Question 18

distinguish b/t myopia (near sightedness) +hyperopia (far sightedness)

Answer 18

myopia = eyeball too deep / curvature of lens too great
-> corrected w/ diverging concave lens

hyperopia = eyeball too shallow / lens too flat
-> corrected w/ converging, convex lens

Question 19

function of semi-circular canals

Answer 19

provide sense of rotation

Question 20

pathway of sound through ear

Answer 20

• air vibrations channeled through auditory canal of external ear
• vibrations reach tympanic membrane
• movement of bones in middle ear (malleus, incus + stapes)
• vibration of oval window

Question 21

function of cochlea + 3 things it contains

Answer 21

provides sense of sound

contains cochlear duct, vestibular canal + tympanic canal -> all filled w/ fluid

Question 22

structure of retina

Answer 22

3 layers:
- rods + cones
- bipolar cells
- ganglion cells

Question 23

distinguish b/t rods + cones

Answer 23

rods:
- black + white
- X discriminate light colours
- sensitive to light

cones:
- color vision
- densely clustered in fovea
- sharpest image @ centre of macula
- blue, green + red cones

Question 24

what pigments undergo a chemical change when they absorb light

Answer 24

rods = rhodopsin
cones = photopsin

Question 25

describe the 2 steps in the visual pathway

Answer 25

• photoreceptors are activated + the AP travels to the bipolar cell then the ganglion cell
• info travels along optic nerves, which cross before reaching the visual cortex of the occipital lobe

Question 26

structure + function of organ of corti

Answer 26

transduces sound in the cochlear

• basilar membrane: bottom of cochlear duct
• hair cells w/ assoc. sensory neurons
• tectorial membrane (overhanging, gelatinous membrane)

Question 27

complete process of sound transduction

Answer 27

1. sound waves arrive at tympanic memb.
2. movement of tympanic memb. causes displacement of auditory ossicles
3. movement of stapes @ oval window establishes pressure waves in perilymph of scala tympani
4. pressure waves distort basilar membrane on their way to round window of scala tympani
5. vibration of basilar membrane causes vibration of hair cells against tectorial memb.
6. info abt. region + intensity of stimulation is relayed to CNS over cochlear branch of cranial nerve 8

Question 28

what converts a sound wave into an AP

Answer 28

organ of corti

Question 29

function of saccule + utricle

Answer 29

supply info about whether body is moving or stationary

Question 30

how do the saccule + utricle supply eq. info

Answer 30

movement of the otolith on the gelatinous material stimulates hair cells - stimulate nerve fibres

-> involves superior colliculi