A&P I Exam 4 Ch. 17 (EYE ONLY)

Which of the following are correctly matched? (know each bullet)

- Anterior chamber: between the cornea and the iris - Posterior chamber: between the iris and the lens - Retina:consists of a pigmented layer and a neural layer - Sclera: covers most of the ocular surface

All of the following are true of the fibrous layer of the eye

- Consists of the sclera and the cornea - Provides mechanical support and some protection for the eye - Contributes substantial focusing power - Is where extrinsic eye muscles insert

All of the following are true of the neural layer of the eye

- Contains ganglion cells - Contains the photoreceptor cells - Contains bipolar cells - is the innermost later of the eyeball

Which of the following are true about the resting state of rods?

- It is during darkness - Retinal is in 11-cis form - Gated sodium channels are open - Membrane potential is around -40mV

Which of the following is true regarding image formation?

- The greatest amount of refraction occurs at the cornea - The focal distance must equal the distance between the center of the lens and the retina to form a sharp image - A round lens has a short focal distance - Images arrive at the retinal upside down and reversed

Trace the circulation of aqueous humor from the site of production to the site of where it is reabsorbed: 1. posterior chamber; 2. anterior chamber; 3. ciliary body; 4. scleral venous sinus; 5. pupil A) 4, 3, 1, 5, 2 B) 2, 1, 5, 3, 4 C) 1, 3, 4, 5, 2 D) 3, 1, 5, 2, 4 E) 5, 2, 4, 1, 3

3. Ciliary body 1. Posterior chamber 5. Pupil 2. Anterior Chamber 4. Scleral venous sinus

The following steps occur in rods when they are excited by photons of light. What is the proper sequence for these steps? 1. Membrane sodium channels close. 2. Increased phosphodiesterase .breaks down cGMP. 3. Retinal changes from the 11-cis form to the 11-trans form. 4. The membrane hyperpolarizes and the rate of the neurotransmitter release declines. 5. Opsin activates transducin. 6. Opsin activation occurs.

3. Retinal changers from the 11-cis form to the 11-trans form 6. Opsin activation occurs 5. Opsin activates transducin 2. Increased phosphodiesterase breaks down cGMP 1. Membrane sodium channels close 4. The membrane hyperpolarizes and the rate of the neurotransmitter release declines

The visible spectrum for humans extends between a wavelength of

400 and 700 nm

Which of the following is a function of the pigmented layer of the retina?

Absorb light passing through the neural layer

________ cells connect photoreceptors in ganglion cells.

Bipolar

What structure changes the shape of the lens for far and near vision?

Ciliary body

Which of the following is INCORRECTLY matched?

Ciliary body: site of extrinsic eye attachment

A ray of light entering the eye will encounter these structures in which order?

Conjunctiva ---> Cornea ---> Aqueous humor ---> Lens ---> Vitreous body ---> Retina

_______, or pinkeye, results from damage to or irritation of the conjunctival surface

Conjunctivitis

Which structure of the eye is the most sensitive but contains no blood vessels?

Cornea

Under which condition would the release of neurotransmitter by photoreceptors be greatest?

In a pitch-black room after 30 minutes

Where are the visual pigments located in the rods and cones?

Inside membrane discs stacked in the outer segment

Tears pass through which of the following structures before emptying into the nasal cavity?

Nasolacrimal duct

Which of the following is not true regarding image formation?

The view a distance object the lens will become rounder

Which of the following is false concerning lacrimal glands?

They produce a strongly hypertonic fluid

Lacrimal glands produce lysozyme.

True

Lacrimal glands produce most of the volume of tears.

True

Lacrimal glands produce watery, slightly alkaline secretions.

True

The gelatinous material that gives the eyeball its basic shape is the

Vitreous humor

The abnormality that develops when a lens loses its transparency is known as

a cataract

Jonathon received a strong blow to the eye. The eyeball remained intact but he suddenly could not see. This has likely caused

a detached retina

The first step in the process of photoreception is

absorption of a photon by a visual pigment.

The ciliary muscle contracts to

adjust the shape of the lens for near vision

The space between the cornea and the iris is the

anterior chamber

An irregularity in curvature in the cornea or lens, called ________, causes a reduction in visual acuity.

astigmatism

Which of the following is not true about the resting state of rods?

bleaching occurs

The human lens focuses light on the photoreceptor cells by

changing shape

The shape of the lens is controlled by the

ciliary muscles

Photoreceptors that convey our ability to see color are

cones

The ______ covers most of the exposed surface of the eye

conjunctiva

All of the following are true of the neural layer of the eye except that it

consists of dense fibrous connective tissue

Pupillary muscle groups are controlled by the ANS. Parasympathetic activation causes pupillary ________, and sympathetic activation causes ________.

constriction; dilation

During accommodation, the ciliary muscle _______ causing the ciliary body to move _________ and apply ___________ tension on the lens

contacts; toward the lens; less

A sudden increase of light into the eye would cause

contraction of the sphincter pupillary muscles

In the human eye, most refraction occurs when light passes through the

cornea

The transparent portion of the fibrous layer is the

cornea

Light of refraction takes place at the

cornea and lens

The primary cause of blindness is the United States is

diabetic retinopathy

The cornea is part of the

fibrous layer

An area of the retina that contains only cones and is the site of sharpest vision is the

fovea

The cell of the retina that produces an action potential that goes to the brain is a(n)

ganglion cell

The vitreous body

helps to stabilize the eye and holds the retina up against the eyewall.

Color blindness is a(n)

hereditary disease involving a lack of certain cones.

Amacrine and ________ cells facilitate or inhibit communication between photoreceptors and ganglion cells.

horizontal

A person suffering from _________ can see distant objects more clearly than those that are close

hyperopia

The purpose of the intrinsically photosensitive retinal ganglion cell (ipRGC) photoreceptors are

influence to circadian rhythm

The part of the eye that determines eye color is the

iris

What structure regulates the amount of light passing to the visual receptors of the eye?

iris

A structure that is located at the medial angle and contains glands that contribute to a gritty deposit is the

lacrimal caruncle

The eyelids are connected at the

medial and lateral angles

A person suffering from _____ can see objects that are close, but distant objects appear blurred

myopia

Dietary deficiency of vitamin A is likely to cause

night blindness

If your vision is 20/15, this means that you can see

objects at 20 feet that individuals with normal eyesight can see at 15 feet

In the light-adapted state,

photoreceptors are much less sensitive to stimulation

The space between the iris and the lens is the

posterior chamber

A type of farsightedness that results from a loss of lens elasticity with age is

presbyopia

All of the following are true of the fibrous layer of the eye EXCEPT

produces aqueous humor

The opening in the iris through which light passes is the

pupil

There are 3 different types of cones, each one sensitive to different light energies. These cones are designated

red, green, blue

When light encounters a medium of different density, it is

refracted

Rods exposed to a phosphodiesterase inhibitor would

remain in the resting state

Visual pigments are derivatives of the compound

rhodopsin

Photoreceptor cells that are most useful in dim light are

rods

A period of adjustment is required when moving from a dark room into bright light because

rods exposed to strong light need time to regenerate rhodopsin

An abnormal blind spot appearing in vision is called a(n)

scotoma

A(n) __________ is an infection in one of the glands on the eyelids.

sty

Modified sebaceous glands located along the margin of the eyelid that secrete a lipid-rich products are called ____ glands

tarsal

Which of the following produces lipid-rich secretion that prevents the upper and lower eyelids from sticking together at their edges?

tarsal gland

Old discs shed from rods and cones are phagocytosed by

the pigment epithelium

Lacrimal glands are located in

the recesses in the frontal bones

The optic disc is a blind spot because

there are no photoreceptors in that area

A young child has been diagnosed with a recessive hereditary disease that results in destruction of the lateral geniculate body. The result of this would be

total blindness

When all 3 cone populations are stimulated equally, we perceive

white