Lab 11 Flashcards
Scattered throughout the body that include the somatic senses - touch, pressure, pain, temperature and proprioception and the visceral senses, which provide information about internal organs
General sesnses
Vision, hearing, equilibrium, taste and smell have distinct receptor cells that are restricted to the head and are localized in complex sensory structures (eye and ear) or in distinct epithelial structures (taste buds and olfactory epithelium)
Special senses
Functions as padding and insulation within the orbit to protect the eye
Adipose tissue
“White of the eye”
Protects and shapes the eyeball and provides a sturdy anchoring site
Sclera
Transparent, anterior portion of the sclera
Allows light to enter the eye and it helps bend (refract) light rays so they are focused on the photoreceptors in the retina
Cornea
Solid white cord of sensory nerve fibers
Optic Nerve III
Skeletal muscles provide rotary movements of the eye, focus the eye for optimum vision and anchor the eye in the bony orbit
Appear as flat bands on the surface of the eye
Extrinsic eye muscles
Found in front of lens between lens and cornea (anterior cavity)
Aqueous humor
Forms a fluid cushion, retain eye shape, provides a root for nutrient an waste transport
Aqueous humor
Outermost layer of the eye
Sclera and Cornea
Middle layer of the eye includes:
Iris, ciliary body, choroid
The coloured, circular portion of the eye that lies anterior to the lens
Consists of two layers of muscles - inner circular and outer radial smooth muscles
Iris
Inner circular and outer radial smooth muscles arranged around a central opening called the:
Pupil
In close vision and bright light, the circular smooth muscles of the iris _______ and the pupil becomes _______, as a result, less light enters the eye
Contract: constricted
In distant vision and dim light, the radial smooth muscles _______ and the pupil _______, allowing more light to enter the eye
Contract; dilates
Is normally flexible and changes shape to focus light rays for close and far vision
Crystalline lens
The lens is held in place by _______ _______ which are attached to the ciliary body
Suspensory ligaments
Is attached to the iris posteriorly and is made up of ciliary processes and ciliary muscles
Ciliary body
Control the shape of the lens
Ciliary muscles
Contain capillaries that produce the aqueous humor
Ciliary processes
Continuous with the ciliary body and extends around the posterior of the eye
Highly vascular and darkly pigmented tissue
Functions to absorb excess light rays to prevent reflection and scattering of light within the eyeball
Choroid
Choroid has an iridescent portion (“rainbow”, in sheep) that enhances night vision by reflecting light back onto the:
Retina
Forms the innermost layer of the eye, is very thin and easily separated from the choroid
Very thin yellow layer which most likely has fallen inwards onto the vitreous body/humor
Held in position up against the choroid by the vitreous body in the intact eye
Retina
The retina consists of two layers:
Outer pigmented layer (next to the choroid)
Inner neural layer