Flashcards in Neuro Deck (155)
What is the spinothalamic tract?
the majoroity of the second order ascending fibers termiante in thalamus, most prominent pain pathway
What is the Ventral posterior lateral nucleus?
Part of thalamus, 3rd order axons to SI cortex. Principally relays nucleus for discriminatory somatosensory info, localize pain
What is the central lateral nuclues?
Part of the thalamus (intralaminar nucleus), 3rd order axons project to many areas of cortex particulary limbic. Involved in emotional suffering
What is the spinoreticular tract?
Many 2nd order axons ascend from spinal cord and terminate in medulla and pons, in reticular formation.
MEDIATES change in attention to painful stimulus
What is teh spinomesencephalic tract?
Some 2nd order axons terminate in teh midbrain in teh superior colliculus and in a region of gray matter surrounding cerebral aqueduct; and is involved in pain modulation
Lesion of the insular cortex results in what?
integrates sensory, affective and congitive components of pain and when lesioned the patient don't display appropiate emotional response to pain
What descending pathways inhibit pain?
Neurons that have cells in periaqueductal gray midbrain send axons down to raphe nuclei in medulla and locus ceruleus
What trigeminal nuclei is involved in fine touch?
Main sensory nucleus in the pons
What trigeminal nuclues is involved in pain and temp?
Spinal trigeminal nucleus, a long column-like nucleus extending from pons to cervical spinal cord.
Where do nociceptors of teh face synapse at?
They descend spinal trigeminal tract and terminate in spinal trigeminal nucleus of V
What is Temperomandibular Joint Disorder
is a chronic pain localized at teh temperomandibular joint or in muscles of mastication and recurrent headaches
What are the layers of the cornea in order from outside to inside?
What s the bowmans membrane?
acelluluar layer of unorganized collagen fibers, barrier to infection
What is the Stroma?
Organized type 1 collagen bundles, binds water, maintains corneal clairty, contributes to corneal thickness
What is the Descemet's membrane?
THe corneal endothelial cells, increases in thickness with age
What is the endothelium of the cornea?
Simple squamous eppithelia that pumps water outof the stroma
What is the major refractive structure of the eye?
The cornea, ~50 D, protect the eye from the environment
What are the three structures of the Uvea?
Choroid, Cillary body, Iris
What are the three layers of the choroid out to in?
choriocapillary layer (capillaries arragned in one plane, fenestrated)
Bruch's membrane 3-4 micronsamorphous hyaline membrane that retinal pigment epithelia rests on
Describe the cillary body of the eye?
Contacts three regions, has projections called cillary processes. trabecular meshwork within cillar body near limbus (aqueous humor rains from anteriror chamber via the trabecular meshwork)
Describe the parts of the Iris?
Covers lens, anterior aspect made of vascular loose CT and determines eye color
posterior surface lined with double layer of pigmented epithelium to absorb light
two muscles masses rest upon pigmented epithelium
What are the two muscle masses that rest upon the pigmented eithelium and regulate iris opening?
Radially arranged myoepithelial cells form the dilator pupillae between teh vascular and pigment layer contract to dialate the eye
The concentric smooth muscle bundles at the pupil margin form the sphincter pupillae muscle, cotnract constricts
What is the anterior chamber of the eye?
Contains aqueous humor that is avascular. Involved in maintaining intraocular pressure [drection of aqueous flow: from cillary procsses to posterior chamber to trabecular meshwork to Schlemm's canal to veins of sclera)
What is the Lamina Cribosa?
Network of collagen fibers through which the fibers of the optic nerve exit the eye
What is the structure of the lens?
transarent, structure(avascular, little ECM, no organelles) capsule surrounds lens, epitherlium is on the anterior surface, lens fibers forms the body of the lens
What is the secondary structure of refactive power in the eye?
The lens which is supported by system of fibers attatched to the cillary body
What is accomodation of the lens?
Lens thinner when focused on distant objects and thicker when on neaer objects
What action of the cillary muscle causes the lens to get thinner?
When the cillary muscle is relaxed
What is the vitreous body?
nearly acellular, major macromolecules are type 2 collagen and hyaluronic acid.
It's transparent 99% water and avascular nutritive