Eye notes (smell and taste too)

hearing, smell taste, and sight

equilibrium

The special senses are: _____, _____, _____, ____.

A fifth is ______

eye, ear

taste buds, olfactory receptors

Special sense receptors are either 1) large and complex (____ &____) or 2) found in localized clusters (_____& _____)

90

Of all the sensory receptors in the body ___% are in the eyes

million

The optic tracts (eye to brain) contain over a ______ nerve fibers

learning, filled

Vision requires the most _____ and is the most easily ______

1, 17, fat, orbit

Anatomy-external; The adult eye is about ___ inches in diameter and we see only about ____% of the eye. The rest is protected by ____ and the bony _______

extrinsic

Anatomy-external; ______ eye muscles attach to the outer surface and allow gross eye movements

eyelids, medial, lateral

Anatomy-external; _______ protect the eye anteriorly and meet at the lateral corners.

(______ & ______ commissure or canthus)

eyelashes

Anatomy-external; ______ project from the eyelid

meibomian, ciliary

Anatomy-external; (Eyelashes)

a. modified sebaceous glands arer called the ______ glands (they lubricate the eye)

b. modified sweat glands are ______ glands

Conjunctiva, mucus

Anatomy-external; The ______ is a delicate membrane that lines the eyelid and covers part of the outer surface of the eye. It secretes a thin _______ to help lubricate the eye.

lacrimal

Anatomy-external; The _______ apparatus consists of the lacrimal gland and a number of ducts that drain lacrimal secretions into the nasal cavity.

gland, saline

Anatomy-external; (Lacrimal apparatus)

a. The lacrimal _______ is located above the lateral end of each eye. It continually releases a ____ solution (tears)

canals, sac, nasolacrimal

Anatomy-external; (Lacrimal apparatus)

b. The lacrimal ______ receives the salt solution from the eye and ducts it to the lacrimal ___ and then to the _________ duct

lysozyme

Anatomy-external; (Lacrimal apparatus)

c. __________ is an antibacterial enzyme released by the lacrimal glands

eyeball

Anatomy- internal; _______ is the eye itself. It is a hollow sphere

tunics

Anatomy- internal; ________ “coats” or layers of the eye.

sclera, cornea, blood supply

Anatomy- internal; (Tunics)

A. the FIBROUS layer (outmost tunic) is made up of:

1. ___________, a thick, white connective tissue (white of the eye)

2. the _______, which is he transparent window in the anterior portion of the sclera.

   • It allows light to enter

   • it is well supplied with nerve endings, and most of these are pain receptors

   • it is the only transplant organ that doesn’t require immunosuppressants, because it has no direct ______ _______ (so easiest to transplant)

   • Its ability to repair itself is extraordinary

Choroid

Anatomy- internal; (Tunics)

B. the VASCULAR layer (middle tunic) is made up of:

1. The _______, which is a blood rich nutritive layer that contains a dark pigment that prevents light from scattering inside her eye.

   .

Ciliary bodies, iris, pupil

Anatomy- internal; (Tunics)

B. The VASCULAR layer (part 2)

2. smooth muscles, modified regions of the choroid toward the anterior of the eye

   a. _______ _____ - to which the lens is attached by a suspensory ligament

   b. ________ this is a pigmented area muscle that regulates the amount of light that enters

   • the _____ is the hole in the middle of the iris through which light enters

Retina, pigmented, A

Anatomy- internal; (tunics)

C. the SENSORY layer (innermost tunic is made up of;

1. The _________, is a delicate 2 layered layer that extends only to the ciliary body.

   a. the _________ layer absorbs light, the cells act as phagocytes to remove dead or damaged receptor cells that they store Vitamin ____ needed for vision

Neural, photoreceptors, rods, cones

Anatomy- internal; (tunics)

C. the SENSORY layer (part 2) is made up of retina

b. the ________ layer contains millions of receptor ells called __________. which are located along the whole retina except for where the optic nerve leaves

• _______ allows you to see gray tones. Used for vision in dim light. They are concentrated at the periphery of the retina and therefore, are responsible for peripheral vision

• ______ allows you to see color! They work best in bright light! They are densest at the center of the retina.

blue, red, green

Anatomy- internal; (tunics)

There are 3 cone types _______, _______, and ________

optic, blind spot

Anatomy- internal; The _____ nerve leaves the eyeball at a site called the optic disc,, or _____ ______

forea centralis

The ______ _______ is a tiny pit that contains only cones located lateral to the blind spot. It is the area of greatest visual acuity (sharpest vision).

lens

Anatomy- internal; The ______ is a flexible, bi-convex crystal-like structure that focuses the light that enters the eye on to the retina. The lens divides the eye into 2 chambers.

aqueous chamber

Anatomy- internal (2 chambers of the lens);

A) _______ _________: anterior to the lens. It contains a watery fluid called the aqueous numor which is secreted by the choroids layer and is similar to blood plasma. It helps to maintain ocular pressure and also provides nutrients to the lens and cornea. The humor is reabsorbed through the

vitreous chamber, humor

Anatomy- internal (2 chambers of the lens)

B) ________ _______: posterior to the lens. It contains a gel-like substance called the vitreous _________. This helps the eyeball from collapsing inward.

ophthalmoscope, fundus

Anatomy- internal;

An __________ is the instrument that allows you to see the interior of the eye, especially the posterior wall, or ______

refraction

Light Refraction and pathways:

____________ is when light is bent. (when it passes from one substance to another of different density it causes the speed to change and the light to bend)

cornea, aqueous humor, lens, vitreous humor, lens

Light Refraction and pathways:

Light must pass through the ______, ______ ______, ______ & _______ _______ to hit the retina. The refractive power of all but the ____ is constant, but the lens can change its shape to alter light’s path

more, less

Light Refraction and pathways:

The greater the lens convexity or bulge, the ________ it bends the light.

The flatter the lens, the ________ it bends the light

convergence

Light Refraction and pathways:

___________ is the ability of the eye to focus specifically for close objects

real image

Light Refraction and pathways:

_____ ________ is reversed left to right, upside down and smaller than the actual object veiwed

emmetropia

Light Refraction and pathways:

____________ is the term used for an eye that can focus images correctly on the retina. (harmonious vision)

(-) myopia

Light Refraction and pathways:

________ (short vision) is nearsightedness. image focuses in front of the retina. Lens is too strong, or long eyeball or cornea that is too curved,

(+) hyperopia

Light Refraction and pathways: _________(far vision) is farsightedness. Image focuses behind the retina. lens is lazy, or short eyeball. (Convex lens for correction)

astigmatism

Light Refraction and pathways:

__________: unequal curvatures of either the cornea or lens. (Light not points, but rather lines on retina and can cause blurs.)

acuity

Light Refraction and pathways:

Visual _______: sharpness of vision

nerves

Visual pathways:

optic ______: the bundle of axons that carry impulses from the retina to the brain

chiasma

Visual pathways

Optic _____: where fibers from the medial sides of the eyes cross over.

tracts

Visual pathways

Optic _____: the resulting fiber tracts leaving the optic chiasma

radiation, seeing

Visual pathways

Optic _____: axons (from thalamus) that synapse with the optic tracts and run into the occipital lobe of the brain, where they synapse with cortical cells for visual interpretation, or ____ occurs

binocular

Visual pathways:

Humans have _______ vision (2-eyed vision) which results from the overlapping of the “visual field” of each eye and ultimately gives us 3-D vision, or depth perception

convergence

Eye reflexes:

__________: reflective movement of the eyes medially when we close objects

photopupillary

Eye reflexes:

___________ reflex: pupils constrict when expected to bright light. (saves retina)

accommodation pupillary

Eye reflexes:

__________ _______ reflex: pupils constrict when we view close objects too, This allows for more acute vision.

astigmatism

Disorders:

unequal curvature of the cornea (or lens). blurred vision.

cataracts

Disorders:

lens becomes hard and opaque

color blindness

Disorders:

lack of proper function in any of the 3 cone types

conjuctivitis

Disorders:

inflammation of the conjunctiva

glaucoma

Disorders:

caused by high pressure in the eye (retina and optic nerve are compressed)

hemianopia

Disorders:

loss of the same side of the visual field in both eyes

myopia

Disorders:

nearsighted. (focus in front of the retina)

night blindness

Disorders:

Interference with rod function

pink eye

Disorders:

Infectious form of conjunctivitis, contagious!!!

stabismus

Disorders:

cross-eyed

watery eye

Disorders:

cold or inflammation of nose can lead to….

specific anosmia

Disorders:

odor “blindness” -partial or total impairment of the ability to detect certain odors

Hyperopia

Disorders:

farsighted. (focus behind the retina)

olfactory, molecules, adapt

Smell:

We have thousands of ______ receptors, receptors for the sense of smell.

• They are exquisitely sensitive- just a few ______ can activate them,

• they tend to ______ rather quickly when exposed to an unchanging stimulus (odor)

postage stamp

Smell:

They occupy an area the size of a _____ _______ in the roof of each nasal cavity

sniffing

Smell:

Air has to make a hairpin turn to enter the respiratory passage, so _____, which causes more air to flow superiorly across the olfactory receptors intensifies the sense of smell.

hairs

Smell:

The olfactory receptors cells are neurons equipped with olfactory _____, long cilia which protrude from nasal epithelium and are bathed in a constant layer of mucus

filaments, nerve, 1

Smell:

The olfactory receptors, located on the cilia, are stimulated by chemicals dissolved in the mucus and transmit impulses along the olfactory _______, which are bundled axons of olfactory neurons that collectively make up the ______ (cranial nerve____)

snapshots

Smell:

The olfactory nerve conducts the impulse to the olfactory cortex of the brain where the odor is interpreted and an odor “_______” is made. These olfactory impressions are long lasting and very much a part of our memories and emotions because the olfactory pathways are closely tied into the limbic system

neutral

Smell:

Our reaction to smell is rarely _____

anosmia

Smell:

________ describes a loss of chemical sense. Most result from head injuries, the after effects of nasal cavity inflammation (cold, allergy, smoking) or age.

auras

Smell:

olfactory ______: are olfactory hallucinations. (experiences sometimes by epileptics before a seizure)

taste

Taste:

_______ from the Latin word taxare: to touch, estimate, or judge

*often considered the most pleasurable of all of our senses

taste buds, 10,000, tongue

Taste:

The ______ ______, specific receptors for the sense of taste, are widely scattered in the oral cavity.

• We have about ________ or so, and most are on the ______, but some are scattered on the soft palate and inner surface of the cheeks

7-10

Taste:

Taste buds are subject to huge amounts of friction and routine burning, so they are replaced every _______ days by basal cells

papillae

Taste:

The dorsal tongue surface is covered with small, peglike projections, or ______.

circumvanate, fungiform

Taste:

Taste buds are found on the sides of the large, round ________ papillae and on the tops of the more numerous _______ papillae

gustatory, hairs, pore

Taste:

The ________ cells are the specific epithelial cells that respond to the chemicals dissolved in saliva. They have long microvilli, gustatory ______, that protrude through the taste ______

facial, glossopharyngeal, vagus

Taste:

Three cranial nerves carry the impulse to the gustatory cortex in the brain:

A). _______ nerve: serves the anterior part of the tongue

B.) _________ & _________ serve the rest

smell, temperature

Taste:

Taste is affected by many factors, especially our sense of _____ & _______

sweet

Taste Sensations:

Sugars, saccharine an some animo acids (also lead salts)

sour

Taste Sensations:

Hydrogen ions or the acidity in a solution

bitter

Taste Sensations:

alkaloids

salty

Taste Sensations:

metal ions in solutions

Umami

Taste Sensations:

Animo acid glutamine responsible for the “beef taste” of steak