Lecture #12 Flashcards
What are two types of equallibrium?
Static and dynamic
What is static equilibrium?
Senses the position of the head when the body is not moving
What is dynamic equilibrium?
Senses rotation
How does static equilibrium work?
Basically it senses what direction gravity is pulling on the body
Where is dynamic equilibrium located?
In the three semicircular canals
What is a Krista ampullanis?
Sensory organ for dynamic equilibrium
How does Dramamine work?
It acts as an antihistamine for a type of neurotransmitter active in the vestibular neuron pathway
What are the four accessory structures for sight?
Eyelids, eyelashes, lacrimal apparatus, and extrinsic eye muscles
What does the lacrimal apparatus do?
Production of tears
What are the three layers of the eye?
The outer fibrous tunic, the middle vascular tunic, and the inner nervous tunic
What are the 2 structures of the outer fibrous tunic of the eye?
The cornea and the sclera
What does the cornea do?
It helps focus light And protects the eye
What does the sclera do?
It is the white of the eye so it protects the eye and attaches muscles
What is the anterior chamber of the eye?
It is located between the cornea and the lens and it contains fluid
What does the anterior chamber of the eye due/assistant in?
It focuses The eye and changes the shape of the eye
What are the three structures of the middle vascular tunic?
The choroid coat, ciliary body, and the iris
What does the choroid coat do?
Provides blood supply to the eye and contains melanocytes to absorb extra light
What does the ciliary body do?
It is the thickest portion of the eye and it changes the shape of the lens
What does the iris do?
It is in front of the lens and it is pigmented to control light entering the eye
What is aqueous humor?
It is a fluid in the anterior chamber of the eye
What does aqueous humor do?
It provides nutrients and maintains the shape of the eye
What is aqueous humor secreted by?
Epithelium
What does the ciliary body do?
Farms in internal ring around the front of the eye so it can change the eyes shape
What is accommodation in eyesight?
Changing of the lens shape to view close objects
What does the Eye do to focus on close objects?
The Lense thickens and becomes more convex
What does the Eye do to focus on distant objects?
The lens thins and becomes flatter
What is the function of the Eyes Iris?
It controls the amount of light that enters the eye
What does the iris consist of?
Connective tissue and smooth muscle
What is the pupil?
It is the opening at the center of the iris
What determines eyecolor?
Melanin
What does dim light stimulate in the eye?
It stimulates the radial muscles and the pupil dilates
What does bright light stimulate in the eye?
It stimulates the circular muscles constricting the pupil
What is in the inner nervous tunic of the eye?
The retina which contains photoreceptors
What are the three areas of the retina?
The macula lutea, the optic disc, and the fovea centralis
What is the macula lutea?
A yellowish spot in the retina that contains a very high concentration of cones
What is the optic disk?
A blind spot which is caused by the beginning of the optic nerve which means no visual receptors are in that spot
What is the Fovea centralis?
It is the center of the macula lutea and it produces the sharpest vision
What is the posterior compartment of the eye enclosed by?
The lens, ciliary body, and the retina
What does the posterior compartment of the eye hold/do?
It contains a gel that maintains the eyes shape
What are the three major groups/layers of retinal cells?
Photoreceptor cells, bipolar cells, and ganglion cells
