Ch 10

Question 1

Sensory Receptors

Answer 1

-transduce (convert energy into a different form) different forms of energy in the “real world” into nerve impulses

• different modalities of sensations (sound, light, pressure) arise from differences in neural pathways in CNS and synaptic connections
• ->ex. optic nerve delivers an impulse: brain interprets it as light even though the impulse is the same as for hearing

Question 2

What are the functional sensory receptors?

Answer 2

chemoreceptors
photoreceptors
thermoreceptors
mechanoreceptors

Question 3

chemoreceptors

Answer 3

*functional sensory receptor

sense chemicals in environment (taste/smell) or blood

Question 4

photoreceptors

Answer 4

*functional sensory receptor

sense light

Question 5

thermoreceptors

Answer 5

*functional sensory receptor

respond to cold or heat

Question 6

mechanoreceptors

Answer 6

*functional sensory receptor

stimulated by mechanical deformation of the receptor (touch, hearing)

Question 7

What are the information sensory receptors?

Answer 7

proprioceptors
cutaneous
special senses

Question 8

proprioceptors

Answer 8

• information sensory receptor
• found in muscles, tendons, and joints
• provide a sense of body position and allows find muscle control

Question 9

cutaneous skin receptors

Answer 9

• information sensory receptor

- touch, pressure, heat, cold, and pain

Question 10

special sense receptors

Answer 10

• information sensory receptor

- vision, hearing, taste, smell, equilibrium

Question 11

What are the origin-named sensory receptors?

Answer 11

exteroceptors

interoceptors

Question 12

exteroceptors

Answer 12

• origin-named sensory receptor
• respond to stimuli from OUTSIDE the body
• inclues cutaneous receptors and special senses

Question 13

interoceptors

Answer 13

• origin-named sensory receptor
• respond to INTERNAL stimuli
• found in organs
• monitor BP, pH, and oxygen concentrations

Question 14

Phasic

Answer 14

*fast adapting
respond w/burst of activity when stimulus is first applied, but quickly adapt to stimulus by decreasing response
-sensory adaptation - cease to pay attention to constant stimuli (becomes new normal)
-ex. smell, touch, taste

Question 15

Tonic

Answer 15

*slow adapting
maintain a high firing rate as long as stimulus is applied
-ex. pain

Question 16

What sensory pathway does not go to the thalamus first?

Answer 16

olfactory

Question 17

Taste & Smell

Answer 17

Chemoreceptors

• taste (gustation) responds to chemicals dissolved in food/drink
• smell (olfaction) responds to chemical molecules from the air, olfaction increases gustation

Question 18

Gustation

Answer 18

• receptors: taste buds
• consists of 50-100 specialized epithelial cells w/long microvilli
• each taste bud has taste cells sensitive to each taste (salty, sour, sweet, unami, bitter)
• microvilli come in contact w/chemicals
• cells behave like neurons by depolarizing and producing action potentials
• cells release neurotransmitters onto sensory neurons

Question 19

Olfactory Receptors

Answer 19

• bipolar neurons w/ciliated dendrites projecting into nasal cavity
• proteins in cilia bind to odors
• 380 genes code for 380 different olfactory receptors (complex)
• one odorant molecule simulates one protein

Question 20

Vestibular Apparatus

Answer 20

• provides sense of equilibrium
• located in inner ear
• consists of:
  1. Otolith Organs
• utricle and saccule (linear acceleration)
  2. Semicircular Canals (rotational acceleration)

Question 21

Inner Ear

Answer 21

• consists of bony labyrinth surrounding a membranous labyrinth
• between two is fluid called perilymph
• endolymph: fluid in membranous labyrinth, cilia are, high K concentration = depolarization

Question 22

perilymph

Answer 22

fluid between bony and membranous labyrinth

-needed b/c if it was up against bone we wouldn’t have flexibility to detect subtle movements

Question 23

Sensory Hair Cells

Answer 23

• in endolymph
• modified epithelial cells w/stereocilia and one kinocilium
• fluid/sound wave movement bends hairs
• when stereo cilia bend toward kinocilium, K channels open and K rushes in = depolarization
• cells release neurotransmitter that depolarizes sensory dendrites in vestibulocochlear nerve

Question 24

Middle Ear

Answer 24

air-filled cavity between tympanic membrane and the cochlea

• containes three bones called ossicles: malleus, incus, stapes
• vibrations are transmitter/amplified along the bones
• stapes is attached to oval window which transfers vibrations into cochlea

Question 25

Cochlea

Answer 25

- hearing part of inner ear - fluid filled - Three chambers: 1. Upper Chamber: portion of bony labyrinth called scala vesibuli (perilymph) 2. Lower Bony Chamber: called scala tympani (perilymph) 3. Cochlear Duct: contains a membranous labyrinth, called scala media (endolymph)

Question 26

Hearing

Answer 26

- when sound waves enter scala media, the tectorial membrane vibrates, bending stereo cilia in hair cells of Organ of Corti 1. opens K channels that are facing endolymph 2. K rushes in (high on outside, backwards) 3. releases glutamate onto sensory neurons 4. K returns to perilymph at base of stereocilia

Question 27

Vision

Answer 27

- comes from light energy transducer into nerve impulses | - only limited part of electromagnetic spectrum can excite photoreceptros

Question 28

Path of Light

Answer 28

1. Light passes through the cornea 2. enters into anterior chamber of eye 3. passes through pupil: can change shape to allow more/less light in 4. passes through lens, can change shape to focus image 5. passes through posterior chamber and vitreous body 6. lastly, hits retina: photoreceptors are found and absorbed by the pigmented choroid layer

Question 29

Pupil and Iris

Answer 29

- iris can increase/decrease the diameter of pupil | - iris also has pigmented epithelium for eye color

Question 30

Pupil/Iris Constriction

Answer 30

contraction of circular muscles via parasympathetic stimulation

Question 31

Pupil/Iris Dilation

Answer 31

contraction of radial muscles via sympathetic stimulation

Question 32

Lens

Answer 32

- composed of layers of living cells that are normally completely clear - avascular - cell metabolism in anaerobic - attached to muscles called ciliary bodies - suspended from suspensory ligaments

Question 33

Visual Fields

Answer 33

- part of the external world projected onto retina | - right side projected onto left side of retina, vice versa

Question 34

Lens Accommodation

Answer 34

- ability of the lens to keep an object focused on the retina as the distance between the eye and object moves - -> contraction= ciliary muscles causes lens to thicken/roundup (close vision) - -> relaxation= ciliary muscle causes lens to thin/flatten (distant vision) -glasses: help focus light onto retina where photoreceptor cells are

Question 35

Retina

Answer 35

- extension of the brain, neural layers ace outward toward incoming light - neuron axons in retina are gathered at a point called optic disc (blind spot) and exit as the optic nerve (blood vessels enter/leave here) - photoreceptors (rods and cones) are the inner layer (toward vitreous body) - ->these synapse on middle layer of bipolar cells, which synapse on the outer layer of ganglion cells - ->also horizontal cells and amacrine cells within the layers

Question 36

Rods

Answer 36

black and white vision in low light | -contain rhodopsin

Question 37

Cones

Answer 37

color vision an acute | -contain photopsin which vary depending upon cone

Question 38

Rods/Cones

Answer 38

outer segment: full flattened discs w/photopigment molecules inner segment: contains the cell organelles

Question 39

Vision

Answer 39

- dissociation of opsin closes Na channels - photorecptors are hyper polarized and inhibition on bipolar cells is lifted - bipolar cells activate ganglion cells that transmit action potentials to brain