Special Senses

Part of the nervous system

List the types of senses

List the types of senses

touch receptors, proprioceptors, visceral senses (sense of organs), special senses (smell, taste, vision, hearing, equilibrium)

How is smell sensed

by the olfactory nerve (first cranial nerve) and olfactory bulb; a chemical sensation

How is taste sensed

by taste buds on papilla (hill-like projections on the tongue); a chemical sensation, can regenerate, can also pick up texture and temperature

What structures protect the eye

the orbit, eyebrows, eyelashes, eyelids, and the conjunctiva

What glands are associated with the eye

the lacrimal gland, lacrimal caruncle, and the tarsal gland

What is the lacrimal gland, what does it do and where is it located

produces tears in the upper outer corner; tears drain down the nasal lacrimal duct; used to moisten and protect from infection (lysozyme: destroys bacteria)

What is the lacrimal caruncle, what does it do and where is it located

produces an oily substance in the medial corner of the eye; lubricates the eye and keeps tears in

What are tarsal glands, what does it do and where is it located

produces an oily substance inside of the eyelids; lubricates the eye and keeps tears in

What is the anatomy of the eye

Conjunctiva: specialized epithelium (lots of goblet cells), areolar ct (lots of bvs); fibrous tunic: sclera (white of eye) - desnse irregular ct, protect the eye, cornea (clear) - main focuser (light); vascular tunic: choroid - supply nutrients to the retina, ciliary body - smooth muscle, iris - smooth muscles, controls size of pupil, lens, suspensory ligaments - holds lens; neural tunic: retina - macula - the most focused part of the eye

What is conjunctivitis

inflammation of the conjunctiva (pink eye)

What is astigmatism

a blurry spot in the eye; treatment: lasik

What is gluacoma

too much aqueous humor, which increases pressure in the eye and destroys the bv layer; can lead to blindness due to lack of blood

What is the anterior cavity

filled with aqueous humor (fluid), nourish the cornea; ends at the lens

What is the posterior cavity

filled with vitreous humor (gel-like), maintain shape of the eye; starts at the lens

What does the ciliary body do when it’s focused on an object NEAR

it contracts and the lens become round

What does the ciliary body do when it’s focused on an object thats FAR

the ciliary body relaxes and the lens become elongated

What is presbyopia

unable to focus on close objects because the lens can’t snap back as they used to; cause: age (loss of elastin)

What is the anatomy of the retina

choroid, pigmented layer - absorb excess light; photoreceptor layer: rods (black and white) - work in dim light, less clear, cones (color) - work in bright light, more clear; nervous layer - neurons; blood vessel layer, optic nerve

What is cataract

lens get cloudy, due to age, treatment: replace lens

What is macular degeneration

fluid build up between the macula and the choroid

What is a detached retina

when the retina detaches, common in football or happens spontaneously, treatment: laser surgery for reattachment

What is myopia

near-sightedness, the eye is lightly elongated

What is hyperopia

far-sightedness, the eye is slightly shorter

What are the semi circular canals and what does it do

filled with hair cells and fluid, fluid moves and bends the hair cells which signals the brain the movement of the head

What is vertigo

when the hair signals the head is moving when its not

What is the vestibule and what does it do

detects the position of the head, contains otoliths (ear rocks) which fall and land on hair cells

What are the semi circular canals and the vestibule responsible for

equilibrium

What is the anatomy of the ear

external ear: auricle, external auditory meatus, tympanic membrane; middle ear: auditory ossicles - malleus, incus, stapes, eustachian tube (auditory tube); inner ear: bony labyrinth - filled with perilymph, membranous labyrinth - filled with endolymph

What is the cochlea responsible for

sound

Cross section of the cochlea

cochlea: hair cells, stereocilia, tectorial membrane, cochlear branch of vestibulocochlear (cn VIII), oval window, round window; semicircular canals, vestibule: vestibular branch of vestibulocochlear (ch VIII)

What is hydrocephalus

blockage in the cerebral aquaduct, can be born or form a tumor as an adult; treatment: chunt to release

What is meningitis

inflammation of the meninges which pushes the brain down, can lead to encephalitis; cause: infection; treatment: anti-inflammatory medication

How do you diagnose meningitis

lumbar puncture - a needle takes a sample of csf from the under end of the spinal cord and test it

What is subdural hemorrhage

blood in the subdural space, can lead to encephalitis; treatment: drilling a hole in the skull to drain the blood

What is epidural injection

an injection in the epidural space

What is inside a nerve

epineurium - dense irregular ct, fascicles - wrapped in perineurium, perineurium - moderatley dense ct, axons (myelin sheath) - wrapped in endoneurium, endoneurium - areolar ct

What is diabetic peripheral neuropathy, what is the feeling

when nerves start to die, loss of sensation and can only feel pins and needs PAINFUL

What is dermatomes

regions of skin innervated by a single spinal nerve

What is shingles

a nerve rash dormant in the post root ganglion, occurs in stripes through dermatomes, aka chicken pox

What is the autonomic nervous system and what are the two types

involuntary nervous system; sympathetic and parasympathetic

What is the sympathetic nervous system and what does it control

fight/flight, increase of heart rate, bp, breathing, sweat and vasoconstriction; decrease of digestive action, pupils dialate

What is the parasympathetic nervous system and what does it control

rest/digest, decrease of heart rate, bp, breathing; increase of digestive activity, pupils constrict

What is the anatomy of the autonomic nervous system (both sympathetic and parasympathetic)

sympathetic (thoracolmnar division of the and): short preganglionic neruon, ganglia next to spinal cord (sympathetic chain ganglia), long postganglionic neuron, solar plexus - goes to the digestive system; parasympathetic (craniosacral division, doesn’t go to the skin/limbs): long preganglionic neuron, ganglion located in organs, short post ganglionic neuron

List the cranial nerves

olfactory, optic, oculomotor, trochlear, trigeminal, abducens (opthalamic branch of trigeminal nerve, maxillary branch ““, mandibular branch ““), facial, vestibulochochlear, glossopharyngeal, vagus, accessory, hypoglossal

List the the cranial nerves if they are sensory, motor, or both

s, s, m, m, b, m, b, b, s, b, b, m

What is bells palsy

inflammation of nerve VII (facial nerve), usually virus