Lab 9- The Eye Flashcards
What is the diameter of the human eye?
About an inch
What are the main components of the lacrimal apparatus?
- Lacrimal Glands
- Lacrimal Canals
- Lacrimal Sac
- Nasolacrimal Duct
What is the purpose of the lacrimal apparatus?
To produce and secrete tears that flow laterally to medially on the eyeball
What enzyme is contained in tears?
Lysozyme
What are the medial and lateral canthus?
Junctions of the upper and lower eyelids
What is the function of the conjunctiva?
Mucous membrane lining the eyelid. To secrete mucus to help lubricate the eye
Where are ciliary glands located and what is their function?
Between hair follicles; they secrete fluid to lubricate the eye
What do Meibomian glands secrete?
(Tarsal) Close to eyelashes and secrete An oily substance
Name the extrinsic eye muscles.
- Lateral Rectus
- Inferior Rectus
- Medial Rectus
- Inferior Oblique
- Superior Rectus
- Superior Oblique
What are the three tunics of the eye?
- Outer Fibrous tunic
- Middle Vascular tunic (Uvea)
- Innermost Tunic (Neural Tunic)
What does the outer fibrous tunic consist of?
Also called the Uvea
* Sclera - white of eye (helps maintain shape, aids
* Cornea
What makes up the middle vascular tunic?
- Choroid Coat (posterior)
- Ciliary Body (anterior)
- Iris (muscular ring around pupil)
What is the function of the ciliary muscles and processes
Muscles by way of suspensory ligaments To control lens shape
And processes secrete aqueous humor
What does the iris do?
Regulates the diameter of the pupil
What are the two layers of the neural tunic?
- Outer pigmented layer
- Inner neural layer - contains rods and cones
What are rods and cones?
Photoreceptors in the retina
Fill in the blank: The lacrimal apparatus flushes tears into the _______.
Lacrimal Sac
True or False: The conjunctiva is a muscular structure.
False
What is the function of cones in vision?
Cones are for more acute vision and see in color
Cones require high light and are not used in the dark.
What is the function of rods in vision?
Rods are adapted for low light and see in gray tones
Rods are not as acute as cones.
What is the blind spot?
The blind spot (optic disk) is where there are no rods or cones
This area is crucial in understanding visual perception.
What is the macula lutea?
The macula lutea is the area of greatest visual acuity with high cone concentration
It is essential for sharp central vision.
What is the fovea centralis?
The fovea centralis is the center of the macula lutea and contains only cones
It is responsible for the highest visual acuity.
What role does the lens play in vision?
The lens focuses light on the retina
It is held in place by suspensory ligaments.
How does the shape of the lens change?
Contraction of the ciliary body muscle changes the shape of the lens
This process is crucial for focusing on objects at varying distances.
What are cataracts?
Cataracts are a result of the hardening of the lens
This condition can impair vision significantly.
What is the difference between aqueous humor and vitreous humor?
Aqueous humor is constantly made and reabsorbed; vitreous humor is not
Aqueous humor is located in front of the lens, while vitreous humor is behind it.
What are the three cell layers of the retina?
- Photoreceptor cells
- Bipolar cells
- Ganglion cells
These layers are arranged with photoreceptor cells deepest inward.
Where do rods and cones synapse?
Rods and cones synapse onto bipolar cells, which then synapse onto ganglion cells
This synaptic arrangement is essential for visual signal processing.
What is the function of the optic nerve?
The axons of the ganglion cells join to leave the eyeball as the optic nerve
This is critical for transmitting visual information to the brain.
What holds the lens in place?
Suspensory ligaments
Where do and cones converge?
Rods converge on bipolar cells while cones have a one to one ratio
What is presbiopia
“Old vision”, the elasticity of the lens decreased with age, resulting in difficulty in focusing for close vision
What is a blockage or infection in the tarsal gland
A chalazion
What is an inflammation of the ciliary glands
A sty
Antior of vascular tunic
Becomes the intrinsic muscles of the eye which change the diameter of the pupil and the shape of the lens
Sclera
The white of the eye
Helps maintain shape, aids in movements, and protects internal structures
Cornea
Transparent avascular structure that allows light to enter the eye and aids in focusing
Innermost tunic
The neural tunic, aka the retina
Choroid coat
Dark layer with a large amount of dark melanin containing cells. In other animals had a tapetum lucidum
How do suspensory ligaments work
Flatten lens for long distance and round up for near vision
