Anatomy L4 Exam 1 Senses, Eye Anatomy

the ____ and interprets nerve impulses from sensory receptors that detect environmental changes

central nervous system

CNS

what are the 5 different types of sensory receptors?

pain receptors = nociceptors

chemoreceptors

thermoreceptors

mechanoreceptors

photoreceptors – rods and cones in eye

what is refered pain?

pain that may seem to be coming from a different area of the body than the one actually being stimulated

example of refered pain?

heart attack

-may experience pain in the left arm or jaw but really whats stimulating that pain is the heart

acute pain fibers

characteristics

type of pain

where is it felt?

thin and myelinated nerve fibers that conduct nerve impulses rapidly

mostly produce sharp pain

sensed as coming from the skin

chronic pain fibers

characteristic

type of pain

where is it felt?

thin and unmyelinated nerve fibers that conduct impulses more slowly

mostly produce dull, aching pain

sensed as coming from deeper within the body

what organs/accessory structures are stored in the orbit cavity of the skull?

eyelids

lacrimal glands

extrinsic muscles

eye

what bones are on the medial wall of the orbit?

Maxilla bone

Lacrimal bone

Ethmoid bone

Palatine bone

Sphenoid bone

Frontal bone

all the bones EXCEPT for zygomatic

what bones are on the lateral wall of the orbit?

Zygomatic bone

Frontal bone

what bones are on the superior wall of the orbit?

Frontal bone

what bones are on the inferior wall of the orbit?

Maxilla bone

Zygomatic bone

Palatine bone

what is another word for eyelid?

palpebrae

what do meibomian gland secrete and where?

aka tarsal glands

lipid rich product keep the eyelid from sticking together

what is the nasolacrimal duct?

where does it drain to?

a duct going from the lacrimal bone region to the inferior nasal turbinate (located in the spetum)

drains to the inferior nasal turbinate

what is the lacrimal apparatus composed of?

lacrimal gland

lacrimal canaliculi

lacrimal sac

nasolacrimal duct

where is the lacrimal gland located in the orbit?

what is it also known as?

superior and lateral to the eye

superiolateral gland

what hormone do tears have?

lysozyme, which kills bacteria

what are the 2 different conjunctiva located in the eye?

palpebral conjunctiva

bulbar/ocular conjunctiva

what does the palpebral conjunctiva cover?

the inner surface of the eyelid

what does the bulbar/ocular conjunctiva cover?

cover the anterior surface of the eye, and extend to the edge of the cornea

• basically covers the sclera

what is the function of the conjunctiva in the eye?

keeps bacteria and foreign material from getting behind the eye

what are the muscles of the eye?

orbicularis oculi m.

levator palpebrae superioris m.

SR

SO

MR

IR

IO

what are the 3 layers of the eye?

fibrous tunic (outter layer)

vascular tunic (middle layer)

nervous tunic (innermost layer)

what is in the fibrous tunic?

sclera

cornea

what is in the vascular tunic?

uveal tract

• iris

• ciliar body

• choroid

what is in the nervous tunic?

retina

optic nerve (CN 2)

what are the two major divisions of the eye?

anterior cavity

posterior cavity

• visceral body

• visceral cavity

is there a subdivision of the anterior cavity?

yes

the anterior chamber and posterior chambers

what fluid is found in the anterior cavity?

aqueous humor

• IN BOTH anterior and posterior chambers

what secrets aqueous humor?

the ciliary body

what is the circulation pathway of the aqueous humor?

flows from posterior chamber → through pupil → anterior chamber

whats the function of aqueous humor?

maintains intraocular pressure (IOP)

what divides the anterior cavity into chambers?

the iris

what causes glaucoma if it gets blocked?

canal of schlemm

what is the canal of schlemm?

the route that aqueous fluid of anterior chamber escapes

what structure divides the eye into the two major cavities?

the ciliary body and lens

what is the visceral body also called?

visceral chamber

posterior cavity

what does the visceral body/cavity contain?

Lens

Ciliary body

Retina

Choroid

Sclera

Optic n. (CN II)

what fluid is found in the vitreous body?

vitreous humor

what does the sclera not cover?

cornea

the cornea is

transparent

avascular

strongest refracting element of the eye

is the cornea continuous with the bulbar conjuctiva?

yes

what does the cornea cover?

iris

pupil

anterior chamber

function of the cornea

aids the lens with focusing

where does the iris lie?

in between the cornea and lens

what 2 muscles are in the iris? what do they do?

Sphincter pupillae m.

• circular m., pupillary sphincter m.

Dilator pupillae m.

• radial m., pupil dilator m.

BOTH innervated by CN III

what is eye contraction called?

Miosis or myosis

what is eye dilation?

Mydriasis

what happens to the lens when the pupils dilate and contract?

dilation: rounds

constriction: flattens

what structure in the retina creates the sharpest vision?

fovea centralis aka central depression

what does the retina have?

visual receptors

2 different types of cells:

• rods

• cones

rods

sensitive to light and allow for low light and dark vision

• provide dark vision

cones

require more light

• provides color vision

describe the layers of the retina

Primary neurons (outter layer)

• rods and cones

Secondary neurons (middle layer)

• bipolar cells

Tertiary neurons (innermost layer)

• ganglion cells

what is the blind spot?

neurosensory patch, it lacks photoreceptors (optic disc/optic nerve)

describe the pathway light takes from entering the eye to being processed in the brain

1. Light must pass through the Cornea

2. Then thru the Anterior Cavity

3. Then thru Pupil (a hole in the Iris)

4. Then thru the Lens

5. Then thru the Vitreous Cavity

6. Absorbed by the Retina, the Retina converts light energy into electrical energy

7. The electrical energy travels down the Optic Nerve

8. Crosses at the Optic Chiasm

9. Optic tract to lateral geniculate in thalamus

10. Then travels to the Visual Cortex of the Brain (occipital lobe)

If you cut the optic chiasm then you will have?

bitemporal hemianopsia

• loss of vision in the outer temporal (sides) of both eyes

If we cut the optic nerve before it gets to the occipital cortex it is

homonymous hemianopsia

• same half of the visual field is lost in both eyes