special senses

Question 0

Types of sensory receptors

Answer 0

Mechanoreceptors- respond to movement, pressure, “feeling”
Chemoreceptors- respond to chemicals
Photoreceptors- respond to light
Thermoreceptors- respond to heat, temperature

Question 1

Sensory information is picked up by

Answer 1

Special Sensory receptors, confined to the head region
Distinct receptor cells
Neuron like epithelial cells or small peripheral neurons
-transfer sensory information via afferent pathways to the brain

Question 2

General senses

Answer 2

Scattered throughout body, simple in structure

Temperature, touch, pain (nociceptors), pressure, vibration, proprioception (body position)

Question 3

Referred pain

Answer 3

Pain is perceived to originate in a region of the body that is not the source of the pain

Question 4

Summarize how olfaction occurs

Answer 4

Occurs in response to airborne molecules called odorants that enter the nasal cavity

Question 5

What is a taste bud?

Answer 5

Taste receptor in the mucosa of the mouth and pharynx
found mostly in the peg like projection of the tongue mucosa called papillae
- 50-100 epithelial cells
-gustatory
-basal

Question 6

Sclera

Answer 6

-dense, white, opaque posterior four-fifths of the fibrous layer
white of the eye
Helps maintain the shape of the eye, protects the eye

Question 7

Iris

Answer 7

Colored part that can be seen between the cornea and lens

Consists of smooth muscle that varies the size of the pupil, regulating the amount of light entering the eye

Question 8

Cornea

Answer 8

anterior part
through which light enters the eye
Richly supplied with nerve endings, most are pain receptors

Question 9

Lens

Answer 9

capable of being flattened or thickened

Helps to focus light

Question 10

Retina

Answer 10

Two layers
Pigmented layer
Neural layer
-contains light sensitive photoreceptor cells
Also contains interneurons that process and modify visual information before it is sent to higher brain centers for further processing

Question 11

Conjunctiva

Answer 11

Mucous membrane covering the anterior surface of the eye and the inner lining of the eyelids

Question 12

Lacrimal glands

Answer 12

Produce tears, which pass over the anterior surface of the eye
Most of the fluid produced by the lacrimal glands evaporates from the surface of the eye, but excess tears are collected in the medial angle of the eye

Question 13

Cataract

Answer 13

Most common cause of blindness in the U.S

clouding of the lens occurs as a result of advancing age, infection, or trauma

Question 14

Glaucoma

Answer 14

excessive pressure buildup in the aqueous humor

may destroy the retina or optic nerve, resulting in blindness

Question 15

Myopia

Answer 15

Nearsightedness
eyeball too long
Or bending of the lense
Concave lenses correct this

Question 16

Cochlea

Answer 16

Portion of the inner ear involved in hearing

Shaped like a snail shell

Question 17

Tympanic membrane

Answer 17

Thin, translucent membrane 
covers the inner opening of the external auditory meats 
separates the middle and external ears
Vibrates in response to sound waves
The ear drum

Question 18

Semicircular canals

Answer 18

One of three canals in each temporal bone
Involved in the detection of motion
Equilibrium, rotational (angular) acceleration of the head

Question 19

Auditory Ossicles

Answer 19

3 of them

• Transmit the vibrations of the eardrum across the cavity to a fluid in the inner ear
• Malleus:attached to the medial surface of the tympanic membrane
• Incus: connects the malleus to the stapes
• Stapes:vibrates against the oval window

Question 20

Four traditional senses (and fifth special sense)

Answer 20

Smell, taste (gustation), sight, and hearing

Equilibrium (sense of balance) located in the ear

Question 21

The receptors for taste and smell

Answer 21

Chemoreceptors

Respond to food chemicals dissolved in saliva and to airborne chemicals that dissolve in fluids on the nasal membranes

Question 22

Gustatory epithelial cells

Answer 22

Taste buds

• has long microvilli(gustatory hairs) tht extend through a taste pore to the surface of the epithelium
  - where they are bathed in saliva containing the dissolved molecules that stimulate taste
• Gustatory cells then generate impulses to the sensory nerve fibers

Question 23

Five basic qualities of Taste sensations

Answer 23

Sweet, sour, salty, bitter, and umami

Question 24

Gustatory pathway

Answer 24

Taste info reaches the brain stem and cerebral cortex via this

Question 25

Sensory fibers carrying taste info occur in three cranial nerves

Answer 25

- Facial nerve: transmits impulses from taste receptors in the tongue - Glossopharyngeal: carries sensations from tongue and a little in the pharynx - Vagus: carries taste from taste buds on the epiglottis and lower pharynx

Question 26

Olfactory epithelium

Answer 26

- receptors for smell are part of this - covers the superior nasal concha and superior part of the nasal septum - Pseudostratified columnar epithelium, contains bipolar neurons called olfactory sensory neurons

Question 27

How olfaction works

Answer 27

Each olfactory sensory neuron has an axon These axons gather into nerve bundles that synapse with mitral cells Mitral cells relay olfactory info to other parts of the brain 1. The Limbic system, where smells elicit emotions and 2. The primary olfactory cortex, which processes the info into odor

Question 28

External ear

Answer 28

Consists of the auricle and external acoustic meatus

Question 29

External acoustic meatus

Answer 29

Short tube that runs from the auricle to the eardrum Contains earwax (traps dust and repels insects Sound waves enter though here

Question 30

Auricle

Answer 30

The actual ear itself Surrounds the opening of the external acoustic meatus Function: gather and amplify sound waves

Question 31

The middle ear

Answer 31

Small air filled space inside the petrous part of the temporal bone Lateral boundary: tympanic membrane Medial boundary: wall of bone that separate it from the inner ear Spanned by the three smallest bones in the body the auditory ossicles

Question 32

Internal ear

Answer 32

Contains two main divisions | Bony labyrinth and membranous labyrinth

Question 33

Bony labyrinth

Answer 33

Cavity consisting if a system of twisting channels | Contains the cochlea, the vestibule, and the semicircular canals

Question 34

Membranous labyrinth

Answer 34

Continuous series of membrane walled sacs and ducts Main parts 1. Semicircular ducts: one inside each semicircular canal, contain sensory receptors for turning movements of the head 2. Utricle and saccule: located in the vestibule, contain sensory receptors that monitor position and linear acceleration of the head 3. Cochlear duct: contains sensory receptors for hearing

Question 35

Vestibule

Answer 35

Equilibrium: static equilibrium and linear acceleration of the head

Question 36

The role of the cochlea in hearing

Answer 36

1. Sound waves vibrate the tympanic membrane 2. Auditory ossicles vibrate, pressure is amplified 3. Pressure waves created by the stapes pushing in the oval window move through fluid in the scala vestibuli 4a. Sounds with frequencies below hearing do not excite hair cells 4b. Sounds in the hearing range go through the cochlear duct, vibrating the basilar membrane and deflecting hairs on the inner hair cells

Question 37

Auditory pathway

Answer 37

Transmits audio information primarily from the cochlear receptors of the inner hair cells to the cerebral cortex

Question 38

Equilibrium pathway

Answer 38

Transmits information in the position and movements of the head via the vestibular nerve to the brainstem Info mostly goes to the lower brain (reflex) centers not cerebral cortex

Question 39

Why our eyes get tired reading

Answer 39

If the ciliary muscles are relaxed, it pulls on the ligaments (zonules), stretches lens (when seeing far away) If ciliary muscles contract, zonules slack, lens becomes thicker (see things close up)

Question 40

Ciliary muscles

Answer 40

Focuses the lens

Question 41

Three layers of the external wall of the eye

Answer 41

Fibrous layer Vascular layer Sensory layer (retina)

Question 42

Fibrous layer

Answer 42

Most external layer Dense connective Sclera and cornea

Question 43

Vascular layer

Answer 43

middle coat of the eyeball Choroid Ciliary body Iris

Question 44

Choroid

Answer 44

Highly vascular, darkly pigmented membrane | Many blood vessels nourish the other layers of the eye

Question 45

Ciliary body

Answer 45

Thickened ring of tissue that encircles the lens | Consists of smooth muscle called ciliary muscle

Question 46

The inner layer

Answer 46

Retina and optic nerve

Question 47

Optic nerve

Answer 47

Runs from the eye to the brain | Axons from the ganglion cells run along the internal surface of the retina and converge to from the optic nerve

Question 48

Hyperopia

Answer 48

Far sighted ness Eye is too short, focal point occurs behind the retina Convex lenses correct this

Question 49

Presbyopia

Answer 49

Lense becomes thicker and less elastic Unable to see things close up Convex (reading glasses) lenses correct

Question 50

Astigmatism

Answer 50

Cornea or lens has unequal curvature in diff regions Blurred vision Corrective lenses or laser eye surgery

Question 51

Emmetropia

Answer 51

Normal vision I think

Question 52

Visual pathways

Answer 52

Visual information leaves the eye and travels to the brain for complex processing Most goes to the cerebral cortex