chapter 50 sense reception

sense receptors

mechanoreceptors, thermoreceptors, proprioceptors, nociceptors, chemopreceptors, photoreceptrs, electroreceptors, and magnetoreceptors

Hair cell and stereocilia

used by auditory and vestibular system, respond to physical stimulation to open ion channels. Stereocilia: projections on hair cells, that can be physically manipulated to change membrane potentials. bending opens ion channels, creating a graded potential, to transduce a signal.

statocyst, statolith

statocyst: balance sensory receptor, uses gravity to stimulate hair cells in dac like structure.statolih: mineral ctstals that touch and stimulate hair cells.

hearing:

ear transducing pressure waves in the air

sound, frequency, and pitch

sound: vibration that sends pressure wave through air. Frequency: cycles per second of the wave. Pitch: perception of frequency

Tympanic membrane:

ear drum: thin membrane that seperates outer and middle ear.

middle ear: bones that amplify sound

Eustachian tube, ossicles, oval window

Eustachian tube, ossicles, oval window

Eustachian tube: connects middle ear to nasopharynx. Ossicles: bones that amplify sound in middle ear: Malleus, incus, and stapes. Oval window : membrane covered opening connects middle to inner ear.

Inner ear

contains hair cells receptors responsible for sound detection and balance.

Vestibular system

Balance system: uses fluid to stimulate hair cells. Semicircular canals: fluid filled canals that detect motion.

Cochlea

spiral shaped cavity containing hair cells that detects sounds

Cochlear membrane:

three ducts: Basilar membrane: membrane in the middle that sits under the hair cilia. organ of corti: sits on basilar membrane and contains many hair cells that detect sound!!. Tectorial membrane: located, like an awning, above the organ of corti.

Round window

dampens waves. located in inner ear

Main parts of the eye

Sclera, cornea, iris, pupil, lens, Retina,

sclera

white of the eye: collagen and elastic fiber

Cornea

fluid filled transparent cover, over iris and pupil,

Iris

controls puil diameter and lens shape

pupil

hole lets light into lens

lens

changes shape to focus light from cornea

Retina

back of the eye containing photorecepots

photoreceptors in retina

Rods and cones

RODS

detect low levels of light and they are found around edges of the retina

rhodopsin

light sensitive receptor protein in rods

Retinal/opsin

Retinal: light absorbing molecule: Opsin: light sensitive protein: acts as g receptor protein that leads to the opening of NA+ ion channels.

cones

best for color vision

Retina composition

made of photoreceptors, bipolar cells, and ganglion cells. REceptor potential is generated by hyperpolarization of from opening of NA+ channels

Photo receptors and bipolarcells have graded potentials, ganglion cells have action poentials.

Ganglion cells, receive input from multiple rods and cones