Neurobiology Exam 2.txt

Make mucous that lines the epithelium, coat olfactory epithelium (helps to dilute odorants), reduce friction.

Axons leaving olfactory epithelium: collect into 20 or more bundles, penetrate cribriform plate of ethmoid, reach olfactory bulbs of cerebrum where first synapse occurs. Axons leaving olfactory bulb: travel along olfactory tract to reach olfactory cortex, hypothalamus, and portions of limbic system (w/o 1st synapsing in the thalamus)

Areolar tissue, blood vessels, nerves, olfactory glands.

Olfaction- yes audition- no equilibrium- no.

3 types of lingual papillae: Filiform papillae- provide friction and do not contain taste buds. Fungiform papillae: contain five taste buds each. Circumvallate: contain 100 taste buds each.

Taste receptors(or gustatory receptors) are distributed on tounge and portions of Pharynx and Larynx. Clustered into taste budsTaste

Sweet, Salty, Sour, Bitter, Umami (chicken/beef broths, glutamate), Water (receptors in pharynx). Salt and sour- chemically gated ion channels-stim produces depolarization of cell. sweet, bitter, and umami- g proteins = gustducins.

The External Ear: Auricle to tympanic membrane (eardrum), Middle ear/Inner ear boundary is oval window.

Auditory ossicles conduct vibrations to inner ear.

Equilibrium and hearing.

semicircular canals- contain semicircular ducts. Receptors stimulated by rotation of head. Cochlea- contains cochlear duct, receptors provide sense of hearing.Utricle & Saccule- provide equilibrium sensations

the saccule and the utricle are going to sense rotational and linear movement.(Movement of fluid within the horizontal semicircular canal corresponds to rotation of the head around a vertical axis (stereocilia bending produces receptor potentials in hair cells)

determined by which part of cochlear duct is stimulated.

sound waves arrive at tympanic membrane. movement of the tympanic membrane causes displacement of the auditory ossicles. movement of the stapes at the oval window establishes pressure waves in the perilymph of the vestibular duct. pressure waves distort the basilar membrane on their way to the round window of the tympanic suct, vibrations of the basilar membrane causes vibration of hair cells against the tectorial membrane. information about the region and the intensity of stimulation is relayed to the CNS over the cochlear branch of the cranial nerve VII

how is it formed???? the ganglion on the cochlear nerve, located within the modiolus, sending fibers peripherally to the organ of Corti and centrally to the cochlear nuclei of the brain stem.

Integrate sensory information about balance and equilibrium from both sides of head. Relay information from vestibular complex to cerebellum. Relay information from vestibular complex to cerebral cortex. (Provide conscious sense of head position and movement) Send commands to motor nuclei in brain stem and spinal cord.

En route to the retina, lightsuccessively travelsthrough: 1) the cornea 2) the aqueous humorof the anterior chamber 3) the pupil 4) the lens 5) the vitreous humor

light-sensitive tissue lining the inner surface of the eye. The optics of the eye create an image of the visual world on the retina. The retina is a complex, layered structure with several layers of neurons interconnected by synapses. The only neurons that are directly sensitive to light are the photoreceptor cells. These are mainly of two types: the rods and cones. Rods function mainly in dim light and provide black-and-white vision, while cones support daytime vision and the perception of colour. A third, much rarer type of photoreceptor, the photosensitive ganglion cell, is important for reflexive responses to bright daylight.Neural signals from the rods and cones undergo complex processing by other neurons of the retina. The output takes the form of action potentials in retinal ganglion cells whose axons form the optic nerve.

improper drainage or excessive production of aqueous humor may lead to glaucoma. increased intraocular pressure, blockage in the canal of schlemm

lubrication and oxigenation. nutrients.

Circular (constrictor) muscles act to Decrease the pupil size under parasympathetic control. Radial (dilator) muscles act to increase the pupil size under sympathetic control

From 20 feet away you can see what a person is supposed to see from 20 feet away. (400/20= from 20 feet you see what a person sees at 400 feet)

determined by number of hair cells stimulated

close object logn focal distance. (If the object moves closer, the focal point then moves behind the retina.)

flat lens = long focal distance. for round lens= the closer the light source the longer the focal point. the rounder the lens the shorter the focal distance.

refractive error (ametropia),in which light rays come to a point focus eitherbehind the retina (hyperopia) or in front of it (myopia). solution to hyperopia is a corrective (convex) lensthat augments the eye�s defective refractive power byconverging the light rays to a focus on the retina. solution to myopia is a corrective (concave) lens that reduces the eye�s excess refractive power by diverging the light rays to a focus on the retina.

Visual information is transmitted from photoreceptors to bipolar neurons and ganglion neurons before exiting the eye via the optic nerve (CN II).

production of tears.

mechanical supoprt, protection. (composed of the sclera and cornea)

The vascular tunic includes the iris, ciliarybody, and choroid. blood supply, help regulate light in the eye, secrete aqueous humor, shape.

The neural tunic is the actual retina containing the photoreceptors. retina and photoreceptor cells.

cornea- lacks blood vessels, connective tissue of corea secrete tenomodulin (prevents blood vessel growth), lack immune cells. iris- disk shaped with muscle that controls size. modulate amount of light entering eye. color determined by # of pigment producing melanocytes. pupil- opening in eye. lens- lens that light passes through (can accomodate). ciliary body- encircles lens, contains musculature that adjusts the refractive power of lens. canal of Schlemm- drainage for aqueous humor. fovea-the cone density is highest and its central region is rod-free (sharp vision). posterior chamber- contains vitreous humor. anterior chamber contains aqueous humor.

high acuity and color vision during day time when light levels are higher. red, green, blue cones. if all simulated equally color would be white.

Step 1: Absorption of a photon by a visual pigment leads to opsin activation and a change in the retinal configuration to initiate visual signaling. PhysiologyThe converted rhopdopsin molecule activates about 100 molecules of the G-protein transducin, each of which activates a molecule of phosphodiesterase. Each PDE breaks down 100s of molecules of cGMP, which causes several 100s of Na+ channels to close. The membrane hyperpolarizes and the rate of neurotransmitter release declines in the presence of light. Molecular cascade: 1) A photon converts a rhodopsin molecule (11cis-retinal + opsin to all-trans-retinal + opsin) 2) This activates 100 molecules of the G-protein transducin. 3) Each of which activates a cGMP phosphodiesterase molecule. 4) Each causes the breakdown of 100�s molecules of cGMP. 5) Which close several hundred Na+ channels. 6) The photoreceptor hyperpolarizes and fewer transmitters are released

Corpus Callosum, anterior commisure.

words- can recognize letters not words.

production of language

personality, insight, foresight.

Tactile (integrates sensory information from different modalities, particularly determining spatial sense and navigation.)

left is related with reading writing math. producing and responding to language. right- senses and recognition-faces and voices.

Computed tomography (CT)-brain-imaging method using computer controlled X-rays of the brain. Magnetic resonance imaging (MRI)-brain-imaging method using radio waves and magnetic fields of the body to produce detailed images of the brain. Functional MRI (fMRI) �computer makes a sort of �movie� of changes in the activity of the brain using images from different time periods. Positron emission tomography (PET)-brain-imaging method in which a radioactive sugar is injected into the subject and a computer compiles a color-coded image of the activity of the brain with lighter colors indicating more activity.