Unit 1 Vision Flashcards
Where do the light rays from the image you view pass through?
Through the pupil. then lens, where they are focused on the retina.
What is the function of the iris?
It allows the right amount of light to enter the eye for proper focusing.
What is the orbital region?
It is the region that we see around the face. (external structure of our eye)
What is the Orbital region made up of?
Face around the eye and Lacrimal Apparatus.
What does the Lacrimal Apparatus do?
Tear production
What is the function of the Eyelids and which cranial nerve is used when we close our eyes reflexively?
Protects our eyes, and the corneal reflects where it closes the eyelids reflectively (CN7)
When we blink, it spreads the lacrimal fluid throughout the eye
What are three parts of the Lacrimal Apparatus?
Lacrimal gland
Lacrimal Canaliculi
Nasolacrimal Duct
What is the orbit?
Cone shaped cavity formed by the skull that houses and protects the eyeball.
What is the orbit (cavity formed by the skull) padded with?
Padded With fatty tissue that acts as a cushion to prevent injury
How many short muscles connect the eyeball to the orbit?
Six short muscles
What is the function of the six short muscles that connects the eyeball to the orbit?
It allows rotary movement so we can see in all directions.
Why do the eyelids close over the eye?
To protect it from light, foreign particles, or impact injury
What is the role of the Eyelashes in the eyelid?
It helps prevent large particles from entering the eye.
What is the role of the sebaceous glands (sties) of the eyelids?
They secrete oil to keep the eyelids soft and pliant (나긋나긋한) and make the eyelashes slightly sticky to trap particles.
What is the conjunctiva?
It is a membrane over the surface of the eyeball that acts as a protective covering for the exposed surface.
What is the role of the lacrimal apparatus?
Produce and Store tears
What does the lacrimal apparatus contain?
The lacrimal gland and its corresponding ducts.
What is the role of the tear that is produced by the lacrimal gland?
For cleaning and lubrication
Tears also act as an antiseptic
(prevents or slows the growth of microorganisms on the body’s external surfaces)
What is crying?
Crying is when there is too much fluid for the canal to handle
What is the globe-shaped eyeball organ of?
It is the organ of vision
What is the eyeball separated into?
It is separated into two chambers of fluid that help to protect the eye.
What are the fluids of the eye called?
Humors
What is the Aqueous humor and where does it bath?
It is watery and bathes the iris, pupil, and lens.
Which part of the chamber does the Aqueous humor fill?
Anterior and posterior chambers.
What is the Vitreous humor?
It is a clear jelly-like fluid.
Which part does the Vitreous humor occupy?
It occupies the entire cavity behind the lens
How many layers does the eye have?
Three layers
What are the three layers of our eye?
Fibrous Layer
Vascular layer
Inner Layer
What are part of the Fibrous Layer?
Sclera
Cornea
Which part of the eye is Sclera?
It is the tough, opaque part of the eye.
(the outer white part)
(opaque means not able to be seen through; not transparent.)
What is the role of the Sclera?
It provides attachment site for both the intrinsic and extrinsic muscles.
-Extrinsic muscles are muscles that originate outside of a body part and insert into that part.
-Intrinsic muscles are muscles that are located deep within the body or close to the axial and appendicular skeleton.
Which part of the eye is Cornea?
Transparent part of the eye
How many layers does Cornea contain?
6 layers
What are part of the Vascular Layer?
Choroid
Ciliary body
Iris
Pupil
What is the role of Choroid?
Blood supply to the eye
What is the role of the Ciliary Muscle?
It helps change the shape of our lens when our eyes focus on a near object.
Where is the Iris?
It is the area around our pupil
Iris has two muscles. What are they called?
Sphincter pupillae
Dilator pupillae
What do the Sphincter pupillae do?
Muscle contracts: Pupil constricts (size decreases)
What do the Dilator pupillae do?
muscle contracts: Pupil dilates (size increases)
Is Sphincter pupillae Parasympathetic or Sympathetic?
Parasympathetic
Is Dilator pupillae Parasympathetic or Sympathetic?
Sympathetic
What is the Choroid?
It is highly vascularized, pigmented middle layer that provides nourishment to the eye
Which portion is the Iris?
The colored portion that controls the opening of the pupil where light passes into the eye
What is the another role of the Iris?
A sphincter (괄약근) that, in low light relaxes, allows the pupil to dilate so more light can enter.
What is located behind the pupil?
Lens
What is the Lens surrounded and attached by?
Ciliary muscles
What can the Ciliary muscles do?
They alter the shape of the lens, making it thinner or thicker to allow the incoming light rays to focus on the retina.
What is accommodation of the eye?
It is the eye’s ability to change the shape of its lens and size of the pupil to focus on objects at different distances.
This process allows the eye to see objects that are both near and far away.
What happens when you are looking at an object at a far distance? (Accommodation related)
Ciliary muscle is relaxed
Zonular fibers pull the Lens and flatten to focus on distant object.
What happens when you are looking at an object at a close distance? (Accommodation related)
Ciliary muscles contract
Zonular fibers relax and allow the lens to thicken to focus on close object
What is the shape of Lens controlled by?
Ciliary muscle
What happens to the Lens when we are looking at something that is close?
Lens gets thicker
What happens to the Lens when we are looking at something that is far?
Lens gets thinner
What is the normal Lens called?
Emmetropia
What is it called when Lens is not in the correct shape and the light is short?
Myopia
What is it called when Lens is not in the correct shape and the light overshoots?
Hyperopia
What is the role of the Retina?
It converts light into synapse (신경 접합부)
What are the two layers of Retina?
Pigmented layer and Neural Layer
What does the Pigmented Layer of the Retina do?
Prevent light scattering (흩어져 있는)
Phagocytic Activity (Phagocytosis is a critical biological activity through which the host can protect itself from infectious and non-infectious environmental particles and remove unwanted host cells in order to maintain tissue homeostasis.)
What is the Neural layer consist of?
Photoreceptors
What are the two types of Photoreceptors?
Cones and Rods
What is the retina?
It is a delicate (연약한) membrane that continues posteriorly and joins the optic nerve (CNII)
What are the two types of light sensing receptors that retina contains?
Rods cells
Cones cells
Rods cells
They are active in dim light and do not perceive (감지하다) color
Cones Cells
They are active in bright light and do perceive color.
What do the photoreceptors contain that cause a chemical change when light hits Rod and Cone cells?
Photopigments
What happens when the photoreceptors that contain photopigments cause a chemical change when light hits them (Rod and Cone cells)?
It causes impulses to be sent to the optic nerve (CNII)
What happens after the impulses are sent to the optic nerve?
The information is then sent to the brain where the impulse is interpreted in the visual cortex of the occipital lobe, and we “see” the object
Summary of what happens when light rays enter the eye
-Light rays enter the eye
-Pass through the cornea
-Aqueous humor
-pupil
-Lens
-vitreous humor
-And are focused on the retina.
-Then the photoreceptors in the retina cause an impulse to be sent to the optic nerve.
-Lastly it carries it to the occipital lobe of the brain for the interpretation we call vision.
Is Cones bright or dim light?
Bright light
Is Cones color vision or peripheral vision?
Color vision
How many Cones are per ganglia?
One Cone per ganglia
Is Rods Bright light or Dim light?
Dim light
Is Rods Color vision or Peripheral vision?
Peripheral vision
How many Rods are on one ganglion?
Many Rods converge on one ganglion
Which one is more accurate between Cones and Rods and Why?
Cones, because it has one per ganglia.
If we shine a light on the right eye, what should happen to the left eye?
Even the left pupil should have the same pupil or eyeball movements as the right eye.
What is the optic disc?
The point where your optic nerves converge to exit the eye and into the brain as a signal.
This area of the eye has no light-sensitive cells (Cone cells) to detect light rays. Lacking visual receptors and so creating a blind spot.
What are the two types of muscles used for eye movements?
Extraocular
Intraocular
Where is Extraocular muscle of the eye located?
Physically outside of the eyeballs
Where is Intraocular muscle of the eye located?
Inside the eyeballs
What is the Extraocular muscle of the eye consist of?
4 Recti Muscles
2 Obliques
How do you remember the Extraocular muscles?
LR6
SO4
What does LR6 of the extraocular muscle represent?
Lateral Rectus
CNVI
What does SO4 of the extraocular muscle represent?
Superior Oblique
CNIV
What are the rest of the extraocular muscles’ Cranial Nerve number?
CNIII
What does the oblique muscle do?
Help cause rotation
Which side should the right sensory information finish in the brain?
Left side of the brain
Where does the sensory information end? Like what is the ending point called after the information comes into our eye? Which part of the brain is his part of?
Lateral Geniculate Body
(a part of the thalamus that processes visual information)
After Lateral Geniculate Body, where does the information go and what does it do?
To the occipital lobe for conscious perception.
Which optic nerve side of the left eyeball will capture the images of the left temporal visual field?
(Medial or Lateral of the Left eye?)
Medial side optic nerve of the left eyeball
Which optic nerve side of the Right eyeball will capture the images of the Right temporal visual field?
(Medial or Lateral of the Left eye?)
Medial side optic nerve of the right eyeball
Which optic nerve side of the Left eyeball will capture the images of the Left Nasal visual field?
(Medial or Lateral of the Left eye?)
Lateral side optic nerve of the left eyeball
Which optic nerve side of the Right eyeball will capture the images of the Right Nasal visual field?
(Medial or Lateral of the Left eye?)
Lateral side optic nerve of the right eyeball
What is the part of the brain where the optic nerves cross and is therefore of primary importance to the visual pathway
Optic Chiasm
Which side of the brain do the images/information that were captured on the left temporal visual field go?
And which fiber of the left eye did it cross or used?
Right visual cortex of the brain
Nasal fibers of the left eye
Which side of the brain do the images/information that were captured on the right nasal visual field go?
And which fiber of the right eye did it cross or used?
Right visual cortex of the brain
Temporal fibers of the right eye
Which side of the brain do the images/information that were captured on the right temporal visual field go?
And which fiber of the right eye did it cross or used?
Left visual cortex of the brain
Nasal fibers of the right eye
Which side of the brain do the images/information that were captured on the left nasal visual field go?
And which fiber of the left eye did it cross or used?
Left visual cortex of the brain
Temporal fibers of the left eye
Which Retinal fibers crosses at the optic chiasm?
(Temporal or Nasal)
Nasal Retinal fibers
Which Retinal fibers does not cross at the optic chiasm?
(Temporal or Nasal)
Temporal Retinal fibers
What happens to the vision where there was a stroke at the optic chiasm?
We don’t lose vision completely.
We lose half of the vision.
We won’t be interpreting the information from left nasal fibers (Left vision of the left eye) and Right nasal fibers (Right vision of the right eye)
What happens to the vision where we lose the right eye completely?
We will be losing just the eyeball
(just not clear enough)
What happens to the vision where there was a stroke at the occipital lobe or parietal lobe?
We will lose a quarter of the vision from each eyeball
what are the two nucleus located in the midbrain?
Pretectal nucleus
Edinger Westphal nucleus (part of the 3rd cranial nerve nucleus)
Where does the oculomotor nerve (CNIII) originate?
Edinger Westphal nucleus
What does the oculomotor nerve (CNIII) contain and travel along with?
Parasympathetic nerve fibers
Where does the oculomotor nerve travel to from the Edinger Westphal nucleus?
ciliary ganglion
What happens after ciliary ganglion?
It will synapse with another neuron and this other neuron is then going to send this signal to pupil.
Why is ciliary muscle important?
Because it essentially (근본[기본/본질]적으로) changes the shape of our lens and thus how much light is coming into our eye.
Why is iris important?
It is the color that makes up our eye and it contains muscles and is responsible for how big or how small our pupils are.
What are the two things that iris contain that is responsible for how big or how mall our pupils are? Nahhhhh
Circular muscles
Radial muscles
What is the role of Circular muscles Radial muscles of the iris? Nahh
Depending on which muscles are stimulated, this will determine if the pupils are constricting or dilating.
If circular muscles of the iris is stimulated, will the pupil constrict or dilate? Nahhhh
Constrict
If the Radial muscles of the iris are stimulated, will the pupil constrict or dilate? Nahhh
dilate
What stimulates the sphincter muscles of the iris and eventually causes constriction of the pupil?
Parasympathetic nerve fibers stimulate the spincter muscles of the iris.
What is the parasympathetic nerve fibers traveling with?
Oculomotor nerve, CNIII
What nerve is responsible for the dilation of the pupils?
Sympathetic nerve fibers
What nerve is responsible for stimulating the radial muscles and what does this cause? Nahhh
Sympathetic nerve fibers
It will cause dilation of the pupil
if we shine light on the left eye, what do we call the thing that happens to the right eye ball?
Consensual response
When we shine a light on the left eye or any eye, what will pick up this light?
The optic nerve, CNII
After the optic nerve picks up the light, what will happen after? (Visual pathway, perception)
It will synapse with other nerves in the lateral geniculate body and these nerves will carry along the optic tract and down to the occipital lobe.
What happens to the light that needs to cross over?
It will cross over in the optic chiasm and will bring information to the other side.
What is another place that the information from the left eye will go to excluding the occipital lobe?
They will also bring some information to the pretectal nucleus in the midbrain.
What receives the signal in the pretectal nucleus in the midbrain?
Neurons in the pretectal nucleus
Where will the information from the left eye go after the pretectal nucleus?
The neurons in the pretectal nucleus will bring this information to the nucleus of Edinger Westphal.
What is so special about this movement of information from the pretectal nucleus to Edinger Westphal nucleus?
The neuron in the pretectal nucleus will not only bring the information to same side of the Edinger Westphal nucleus, but it will cross over as well and bring the information to the opposite Edinger Westphal nucleus.
Which side of Edinger Westphal’s nucleus is being stimulated from just the left eyeball?
Both sides of the nucleus
What do the neurons in the Edinger Westphal’s nucleus stimulate?
Oculomotor nerve, CNIII
Where does the Oculomotor nerve originate from?
Edinger Westphal’s nucleus
What happens after the Neurons in the Edinger Westphal’s nucleus are stimulated?
Oculomotor nerves, both in the left and right, will synapse in the ciliary ganglion with another neuron, the short ciliary nerve.
What happens after the oculomotor nerve synapses in the ciliary ganglion with the short ciliary nerve on both sides?
The short ciliary nerve will bring this information to the pupil, to the iris, causing the iris to constrict.
Tell me the order of the pupillary reflex.
Retina
Optic nerve, (CNII)
Prerectal Nucleus (Bilateral innervation happens here)
To the Edinger Westphal nucleus
Oculomotor nerve will be stimulated.
Ciliary Ganglion
Short ciliary nerve to stimulate the circular muscle(iris)
Causing pupillary constriction
What happens when we have a lesion on the left optic nerve and we shine a light on the left eye?
We will get no pupillary response or constriction on either side.
What happens when we have a lesion on the optic chiasm and we shine a light on the left eye?
The signal is still being sent to the pretectal nucleus and cross-overs to the nucleus of Edinger Westphal.
Because the optic nerve that transfers information to the left side of the brain is not affected.
Thus, the light reflex will still be present and you will still see pupil constriction.
What happens when we have a lesion on the left occulomotor nerve and we shine a light on the left eye?
The information is still being received by the midbrain, the nucleus of Edinger Westphal.
But you won’t see any pupil constriction on the left side.
What happens when we have a lesion on the right oculomotor nerve and we shine a light on the left eye?
The information is still being received by the midbrain, the nucleus of Edinger Westphal.
But you won’t see any pupil constriction on the right side.
What is the effect of the sympathetic nervous system on the pupil?
The sympathetic nervous system dilates the pupil (mydriasis) by stimulating the dilator pupillae muscle.
Why does the sympathetic nervous system dilate the pupil?
To allow more light to enter the eye and enhance vision in low-light or stressful conditions.
What is the effect of the parasympathetic nervous system on the pupil?
The parasympathetic nervous system constricts the pupil (miosis) by activating the sphincter pupillae muscle.
Why does the parasympathetic nervous system constrict the pupil?
To reduce the amount of light entering the eye in bright conditions.
How does the sympathetic nervous system affect the ciliary muscle?
It inhibits (억제하다) the ciliary muscle, relaxing the lens for distant vision.
How does the parasympathetic nervous system affect the ciliary muscle?
It contracts the ciliary muscle, enabling the lens to thicken for near vision (accommodation).
What is the role of the sympathetic nervous system in the “fight or flight” response regarding the eye?
It dilates the pupil and relaxes the lens for distant vision to enhance vision in stressful conditions.
What is the role of the parasympathetic nervous system in the “rest and digest” response regarding the eye?
It constricts the pupil and enables accommodation for near vision, optimizing eye function for relaxation and close-up tasks.
