How is sound transduced to a sense of hearing? Sound wave represents alternating areas of high and low pressure → tympanic membrane vibrates in response to sound wave → vibrations are amplified across ossicles → vibrations against oval window set up standing wave in fluid of vestibuli → pre...
BIO 446L Exam 2 Questions and Correct
Answers
How is sound transduced to a sense of hearing? ✅Sound wave represents alternating
areas of high and low pressure → tympanic membrane vibrates in response to sound
wave → vibrations are amplified across ossicles → vibrations against oval window set
up standing wave in fluid of vestibuli → pressure bends the membrane of the cochlear
duct at a point of maximum frequency for a given frequency, causing hair cells in the
spiral organ of the basilar membrane to vibrate
- spiral organ detects and transduces the sound
Structure of the cochlea and spiral organ ✅- cochlea = a spiral tube coiled with three
parts: the scala tympani, the scala vestibuli, and the scala media
- spiral organ = site of sound transduction; between the scala tympani and the cochlear
duct
Structure of the outer, middle, and inner ear ✅- outer: contains the auricle and external
acoustic meatus; ends at the eardrum
- middle: contains the auditory ossicles (stapes, incus, malleus), oval window, round
window, and tympanic cavity
- inner: cranial nerves, vestibule, cochlea, goes until the nasopharynx
Refraction of light in the eyeball and autonomic innervation ✅pupil construction =
parasympathetic
pupil dilation = sympathetic
Describe the nerve pathways for vision ✅- temporal vision fields detect movement
happening right in front of eyes/nose
- nasal vision fields detect movement happening on either side of the face (peripheral)
- L temporal and R nasal are processed on right side of occipital lobe
- R temporal and L nasal are processed on left side of occipital lobe
- refer to picture in study guide
Extra ocular muscles, actions and their innervation ✅move the eyeball and attach to
the sclera
- 6 muscles: superior oblique, superior rectus, medial rectus, lateral rectus, inferior
oblique, inferior rectus
- 3 axes of motion: A-P axis, transverse axis, vertical axis
- innervated by cranial nerves 3, 4, and 6
, What is the structure of the retina? ✅deepest nervous layer of the eyeball that lines the
inside
has lots of layers but most important are pigment layer and neural layer
- pigment layer: light bounces off and stimulates rods and cones
- neural layer: receptors, bipolar neurons that will send sensations to optic nerve
What are the fibrous and vascular layers of the eyeball ✅fibrous = the outer, protective
layer
- consists of the sclera and the cornea
vascular = the inner layer that supplies nutrients to the fibrous layer
- consists of the choroid, ciliary body, iris, and lens
Describe the arterial baroreflex - an autonomic reflex ✅1. High BP = increase in
parasympathetic, decrease in sympathetic activity (vasodilation)
- both decrease HR
2. Low BP = decrease in parasympathetic, increase in sympathetic activity
(vasoconstriction)
- both increase HR
Where are autonomic ganglia located? ✅Peripheral nervous system
- ventral and lateral to spinal cord
describe sympathetic nerves ✅1. PREganglionic fiber = short
2. POSTganglionic fiber = long
3. ganglia = paravertebral
4. duration = diffuse, long
5. PREganglionic neurotransmitter = acetylcholine
6. POSTganglionic neurotransmitter = norepinephrine or acetylcholine
7. reaction type = fight or flight
describe parasympathetic nerves ✅1. PREganglionic fiber = long
2. POSTganglionic fiber = short
3. ganglia = peripheral
4. duration = localized, short
5. PREganglionic neurotransmitter = acetylcholine
6. POSTganglionic neurotransmitter = acetylcholine
7. reaction type = fat and happy
Autonomic nervous system functions ✅involuntary control of functions that maintain
the internal environment of the body
- BP, HR, GI mobility, body temp, etc
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