Lab Quiz #2 Flashcards
receptive fields
- the area surrounding cutaneous touch receptors where they can detect stimuli
- there’s an inverse relationship between the density of receptors & the size of primary receptive fields
- more receptors there are, the smaller their individual receptive fields are
rod cells
- photoreceptor cell in eye
- located more in peripheral areas
- high sensitivity
- work under low light conditions of night
- more light sensitive than cones
- light sensitive region points away from light/toward back of eye
cone cells
- photoreceptor cells in eye
- densely concentrated in the fovea
- respond to bright light
- responsible for color vision
- 3 types - blue, red, & green
- color blindness due to lack of one cone type
3 layers of cells - from front to back
- ganglion cells - axons merge to form OPTIC NERVE (which passes thru OPTIC DISC)
- bipolar cell layer - layer establishes pathways for nerve impulses; (bipolar cells, amacrine cells & horizontal cells)
- ganglion cells - only receptor cells w/action potentials
Fovea
- location of highest acuity
- only cones located here
Light sensitive pigment in rods
rhodopsin
What is rhodopsin comprised of?
opsin & retinal
ciliary body
- consists of ciliary muscle & capillary network that produces the aqueous humor
ciliary muscle
a circular ring of smooth muscle attached to the lens by SUSPENSORY LIGAMENTS
what does stimulation from the sympathetic system do to the pupil?
- ciliary muscle relaxes
- muscle ring is more open
- increases tension on suspensory ligament
- lens is flattened
- pupil dilates
iris
- controls the light entering the eye
- 2 rings of muscle ( circular & radial)
role of lens
- when object is far - little refraction needed. Parallel lines come in & bent to focal point
- when object is close - stronger/rounder lens needed to make the light converge on focal point. Light is still diverging when it enters eye
accommodation
ability to adjust the strength of lens by chaining its shape (making it rounder)
what does lens do under parasympathetic stimulation?
- ciliary muscles contract
- muscle ring gets smaller
- releases tension on suspensory ligament
- lens is rounder
- pupil gets smaller
myopia - eyeball too long or lens too strong
- nearsightedness
- far light is focused in front of the retina = blurry
- correct with a CONCAVE lens
hyperopia - eyeball too short or lens too weak
- farsightedness
- near objects are focused behind the retina = blurry
- correct with a CONVEX lens
blind spot (aka optic disc)
- point at which optic nerves leave & through which blood vessels pass
- contains no rods or cones
Two sensory systems of ear:
- cochlea - contains receptors for conversion of sound wars into nerve impulses
- vestibular apparatus - necessary for sense of equilibrium
external ear is composed of:
- pinna - large flap of ear
- ear canal
- tympanic membrane - thin membrane that separates the external & middle ear
eustachian (auditory) tube
connects the middle ear to the pharynx
middle ear transfers the vibrating movements of the tympanic membrane to the fluid of the inner ear via:
ossicles
1. malleus - attached to the tympanic membrane
2, incus - between two bones
3. stapes - attached to the oval window, entrance to the fluid-filled cochlea
perilymph
fluid within the scala vestibuli & scala tympani
endolymph
fluid within the cochlear duct
sympathetic nervous system
“Fight or Flight”
- Prepares body for strenuous physical activity
- part of the Autonomic System -> Efferent System -> PNS
