(Final) Exam 4 - Special Senses

part 1

Nervous System function?

detect

(Nervous System)

Optic?

vision

(Nervous System)

Olfactory?

smell

(Nervous System)

Gustatory?

taste

(Nervous System)

Auditory?

sound

What are the structures/organs for our vision?

• grow during fetal development as little knobs that come off of the cranial structure; part of the brain

• extra things for protection because they are vulnerable, not being protected by bone

eyes

What protects the eyes using “off-and-on” protection?

• act like windshield wipers

eyelids

What are primarily used as filters to protect the eyes?

• catch dust, dirt

• biologically there to catch flying objects

eyelashes

Getting sweat in our eyes can be problematic. What is thicker on the inside and funnels to the outside, and is designed to catch sweat from getting into the eyes?

eyebrows

What form of protection constantly washes the surface of our eyes (tears)?

• one of the biggest forms of external protection for our eyes

lacrimal system

What is the Lacrimal System composed of?

lacrimal glands, excretory ducts, lacrimal canaliculi, lacrimal sacs

Where are the lacrimal glands located?

superior external surface of eye, behind eyelids

Lacrimal glands are modified sudoriferous/sweat glands. T/F?

t

What produces tears, and travel through lacrimal tear ducts, on to the surface of the eye, to do so?

• come from the lateral corners of the eye

lacrimal glands

When you blink, water is pushed to the medial portion, or center, of the eye. Once it gets there, it goes through small tear canals called ______ ______.

lacrimal canaliculi

When you blink, water is pushed to the medial portion, or center, of the eye. Once it gets there, it goes through small tear canals called lacrimal canaliculi, and then into _____ _____, pouches on either side of the nose.

lacrimal sacs

Know this:

Excess fluid flows down into the nasal cavity when sinuses are being triggered and there is a need for more water to clean the eyes, or you’re simply crying. Your nose runs.

Answer with “ok”.

ok

Fluids in eye drain from lateral/medial corner to lateral/medial corner.

lateral, medial

Where does excess fluid from the eye drain to?

nasal cavity

When the surface of the eye gets irritated by pollen \, dust, etc, it triggers an excess production of what?

lacrima

The outer surface of the eye is the _____ ____ ____.

modified dura mater

You do have all 3 layers of meninges around the eye. T/F?

f

The optic nerve itself is covered with ____ ____.

dura mater

When the dura mater reaches the eye, it’s name is changed to _____.

sclera

The “whites of your eyes” are called the _____.

• they’re somewhat translucent, but for the most part opaque

sclera

Directly below the sclera is the blood vessel layer, or the _____.

choroid

Know this:

The blood vessels in the eye are very intricate, they’re tiny. There are a lot of capillary beds in the blood vessel layer, or choroid of the eye.

Answer with “ok”.

ok

When optometrists dilate your eyes to look at them, they’re look at the ____ _____ of the choroid layer.

• optometrists can often diagnose diabetes before a regular doctor will.

blood vessels

A problem with diabetes is when you have high levels of _____ in your system, the _____ adheres to blood vessel lining, and its so thick it can block blood vessels. Primarily capillary beds because they’re so tiny. Normally this just means blockage, so diabetics have issues with losing circulation in part of the body.

• In the eye, we don’t want nervous tissue dying, so when a capillary bed becomes clogged, because of ______, the blood vessels grow new capillary beds to replace them. Over time, you end up with so many capillary beds in the choroid layer, that it actually blocks your ability to have vision. This is Diabetic Blindness.

• Optometrists might ask “What’s your capillary content of your choroid layer?” and “Are there too many capillary beds in there?” This can help decide if you have high sugar levels.

glucose

In the very front of the eye, the sclera bends outward, and becomes transparent. You can see through this portion of the eye. Primarily light can pass through this section. This section is the _____.

cornea

Directly behind the cornea is cavity, the _____ _____.

anterior chamber

The anterior chamber is filled with a salty fluid called ____ ____.

• low concentration salt, mostly water

aqueous humor

The eye is filled with water, which means the image we see is refracted, modified, by the ______ ______.

occipital lobe

Why are our eyes filled with water?

The primary necessity for vision is _____.

focus

The _____ is the colored portion of the eye.

• controls how much light comes in

• body has the ability to make the iris larger and pupil smaller, or vise versa to adjust how much light is coming into the eye.

• all lights on bright, pupil gets smaller, iris gets bigger.

• all lights off, pupil gets bigger, and iris gets smaller.

iris

Know this:

• body has the ability to make the iris larger and pupil smaller, or vise versa to adjust how much light is coming into the eye.

Answer with “ok”.

ok

All lights off, pupil/iris gets smaller, and pupil/iris gets bigger.

iris, pupil

All lights on bright, pupil/iris gets smaller, pupil/iris gets bigger

pupil, iris

No eye color gives us an advantage in terms of eye sight. T/F?

t

Darker/lighter eyes tend to be more advantageous in really bright light, because they can produce the amount of light that comes into the eye.

darker

Albinos, with no eye color, have no ability to block any light that comes into the eyes. T/F?

t

The ____ is a hole in the middle of the iris.

• where all of the light that we see comes through.

pupil

Directly behind the pupil is a protein gelatinous structure called the ____.

• looks like an onion with its folded layers

lens

What is the lens’ primary function?

finish up the focus

The lens is connected to the _____ _____ and ______, and this is stretched to adjust focus.

ciliary processes, ligaments

Behind the lens is the _____ ______.

posterior chamber

The posterior chamber is filled with _____ _____.

• thicker fluid, a little higher salt concentration

vitreous humor

Behind the posterior chamber (the yellow area on the diagram) is the nerve endings, the sensory portion of the eye called the _____.

• the light that hits this is what you actually detect, or see the best

retina

The point of the retina where I see the best, back of the eye, is called the _____ _____.

• yellow thickening

• similar to the cornea, curves slightly

• increase my ability to detect vision, because that’s where there are the most nerve endings, or sensory neurons

macula lutea

The very center of the macula is the _____ _____ or the central focus.

• the ONE thing you’re looking at

• ex. when reading a book, it’s the one word you’re reading in that exact moment in time, everything else (the other words) is somewhere on the retina.

fovea centralis

All of the retina is nerve endings, and they’re bipolar. There are dendrites on the surface detecting things, the cell body, and then the axon carries the image back to the _____ _____.

• crisscrosses in the middle, and goes directly the the occipital lobe to process my vision

optic nerve

Where the optic nerve actually hits the eye, also where the blood vessels come into the choroid layer, and at this point in time I have no retina. There are blood vessels there. This is the ____ _____, or my “blind spot.”

optic disc

Light passes through the ______. Anything that goes through the sclera doesn’t get seen.

cornea

When light goes through the cornea, _____ is initiated.

focus

Volume is controlled by ____.

iris

The bend is finished by the ____.

lens

Focal point is the _____.

fovea

For people who wear glasses, something is wrong with the _____, where It’s the wrong shape, or something is wrong with the whole eye and it’s the wrong shape.

cornea

When focus exceeds the fovea, it’s called _____ (far-sighted).

• eye is too short, or cornea is too flat

• glasses start the bend early.

hyperoptic

Know this:

Over time, the lens in the eye gets harder and doesn’t stretch as easily, and that’s why our vision gets worse as we get older.

Answer with “ok”.

ok

When focus is before fovea, it’s called _____ (near-sighted).

• eye is too long, or cornea has too much of a bend

• typically lenses on glasses are a lot thicker

myopic

How do we detect light?

What are the 2 types of sensory neurons in the retina?

rods, cones

Which type of sensory neuron in the retina fits this description:

• long and skinny

• detect light and dark stimuli

• nothing in color, only black and white images

• very sensitive to light

rods

Which type of sensory neuron in the retina fits this description:

• little knot on the end, cone shaped

• less sensitive to light

• not as good with vision, but can tell the difference between and dictate colors (red-violet)

cones

Everything you see by the time it gets to the occipital lobe is upside down. T/F?

t