MIDTERM ANAPHY: THE SPECIAL SENSES

nose, tongue, eyes, ears

what are the special senses?

touch

is a generalized sense

nervous system, response

stimulus ____? brain _____?

general senses

Include somatic sensations (tactile, thermal, pain, and proprioceptive) and visceral sensations

general senses

Are scattered throughout the body

general senses

Are relatively simple structures

special senses

Include smell, taste, vision, hearing, and equilibrium

special senses

Are concentrated in specific locations in the head

special senses

Are anatomically distinct structures

special senses

Form complex neural pathways

smell

is the most primitive sense

smell

Evokes memories

smell

Most animals use this to distinguish good from bad

smell

this function has shifted to our emotions and helps us determine likes and dislikes

animals

which has a stronger sense of smell? humans or animals?

smell

humans dont need this as much

smell

it undergoes sensory adaptation

women

who have better sense of smell? men or women

20 and 40

smell is sharpest between what ages?

pheromones

play an important part in chemical communication in, for example, territorial behavior, mating and the bonding of mothers and their newborn

chemoreceptors

respond to changes in chemical concentrations

mucus

chemicals must be dissolved in?

sniffing

concentrates volatile molecules in the roof of the nose – increases the number of olfactory receptors stimulated and thus perception of the smell

inflammation of the nasal mucosa

prevents odorous substances from reaching the olfactory area of the nose, causing loss of the sense of smell

anosmia

it is the loss of the sense of smell

smell and taste

they are closely related

sense of smell

it may affect the appetite

sensory adaptation

is our ability to be less sensitive to an unchanging stimulus.

sensory adaptation

Chemical can stimulate receptors for limited time

sensory adaptation

Receptors fatigue and stop responding to chemical

sensory adaptation

No longer smell odor

gustation

what is the other term for taste?

taste

is much simpler than olfaction in that only five primary tastes can be distinguished

sour, sweet, bitter, salty, umami

what are the five primary tastes?

umami

is believed to arise from taste receptors that are stimulated by monosodium glutamate (MSG)

umami

a substance naturally present in many foods and added to others as a flavor

chemoreceptors

taste buds contain what?

chemoreceptors

found in the papillae of the tongue and widely distributed in the epithelia of the tongue

tongue and sense of taste

Consist of small sensory nerve endings of the glossopharyngeal, facial and vagus nerves (cranial nerves VII, IX, and X)

7, 9, 10

in the tongue and sense of taste what are the numbers of cranial nerves?

final destination

is the taste area in the parietal lobe of the cerebral cortex where taste is perceived

10,000 taste buds

humans have how many taste buds

tongue, soft palate, pharynx, larynx

We have nearly 10,000 taste buds located on the?

gustatory hair

A single, long microvillus, called a _______?, project from each receptor cell to the surface through the taste pore

10 days

Each gustatory receptor cell has a lifespan of about?

vallate papillae, fungiform papillae, foliate papillae

taste buds are found in 3 different types of papillae, what are these 3?

vallate papillae, 100-300

form a row at the back of the tongue (each

houses how many taste buds?)

fungiform papillae, 5

are mushroom-shaped and are scattered over the entire surface of the tongue (containing about how many taste buds each?)

foliate papillae

are located in small trenches on the lateral margins of the tongue, but most of their taste buds degenerate in early childhood

the entire surface of the tongues contains ______? that contain tactile receptors but no taste buds

filiform papilae

They increase friction between the tongue and food, making it easier to move food in the oral cavity

bitter

humans or most sensitive to _______? substances

three cranial nerves

contain axons of the first-orders gustatory neurons that innervate the taste buds

facial vii, glossopharyngeal ix, vagus x

what are the three cranial nerves?

facial vii

nerve serves taste buds in the anterior ⅔ of the tongue

glossopharyngeal ix

nerve serves taste buds in the posterior ⅓ of the tongue

vagus x

nerve serves taste buds in the throat and epiglottis

eye and sense of sight

Situated in the orbital cavity and supplied by the optic nerve (2nd cranial nerve)

eye and sense of sight

almost spherical in shape and about 2.5 cm in diameter

adipose tissue

The space between the eye and the orbital cavity is

occupied by?

sclera and cornea

the outer fibrous layer are?

choroid, ciliary body, iris

the middle vascular layer or uveal tract: consisting of the?

retina

the inner nervous tissue laye

sclera

(white of the eye) forms the outermost layer of the eyeball and is continuous anteriorly with the cornea

sclera and cornea

Consists of a firm fibrous membrane that maintains the shape of the eye and gives attachment to the extrinsic muscles of the eye

sclera

continues as a clear transparent epithelial membrane, the cornea

cornea, retina

Light rays pass through the ???? to reach the

????

sclera and cornea

Convex anteriorly and is involved in refracting (bending) light rays to focus them on the retina

choroid

Lines the posterior five-sixths of the inner surface of the sclera

choroid

Very rich in blood vessels and deep chocolate brown in color.

pupil, retina, choroid

Light enters the eye through the ????, stimulates the sensory receptors in the ???? and is then absorbed by the ????

ciliary body

The anterior continuation of the choroid consisting of ciliary muscle (smooth muscle fibers) and secretory epithelial cells

ciliary body

Acts like a sphincter

lens

is attached to the ciliary body by radiating suspensory ligaments, like the spokes of a wheel

ciliary body

Control the size and thickness of the lens (contraction)

ciliary body

Supplied by parasympathetic branches of the oculomotor nerve (3rd cranial nerve)

iris

Visible colored ring at the front of the eye lying behind the cornea and in front of the lens

iris

Circular body composed of pigment cells and two layers of smooth muscle fibers – one circular and the other radiating

iris

In the center is an aperture called the pupil

parasympathetic stimulation, sympathetic stimulation

???? constricts the pupil and ???? dilates it

color of the iris

is genetically determined and depends on the number of pigment cells present

albino

have no pigment cells and people with blue eyes have fewer than those with brown eyes

lens

Highly elastic circular biconvex body, lying immediately behind the pupil.

lens

Thickness is controlled by the ciliary muscle through the suspensory ligament

lens

bends (refracts) light rays reflected by objects in front of the eye – only structure in the eye that can vary its refractory power, which is achieved by

changing its thickness

retina

Innermost lining of the eye

retina

Extremely delicate structure and well adapted for stimulation by light rays

retina

Composed of several layers of nerve cell bodies and their axons – sensory receptor cells, rods and cones, contain photosensitive pigments that convert light rays into nerve impulses

retina

Near the center of the posterior part is the macula lutea, or yellow spot – little depression called the fovea centralis, consisting of only cones

optic disc or blind spot

Small area of retina where the optic nerve leaves the eye is the?

anterior chamber

front of lens

anterior chamber

Filled with aqueous humor – nourishes and bathes anterior eye

posterior chamber

Behind lens

posterior chamber

Contains vitreous humor – maintains shape of eyeball and holds retina in place

eyelids

Skin, muscle, and connective tissue

blinking

Prevents surface from drying out, Keeps foreign material out of eye

eye orbits

Eye sockets, Form a protective shell around the eyes

conjunctivas

Mucous membranes, Line inner surfaces of eyelids

lacrimal apparatus

Lateral edge of eyeballs, Produce tears

nasolacrimal ducts

Medial aspect of eyeballs, Drain tears into nose