pnb exam 4
Ear
organ for hearing and and equilibrium
displacement towards tallest cilia? causes stretching channels open; K+ and Ca2+ flows indepolarization
Displacement away from the kinocilia causes.. hyperpolarization/inhibition
A circulatory route that has two sets of capillaries is known as a Permissive system *** Portal system Dual system Primary system
During childbirth, a woman suffers a serious hemorrhage and goes into shock. After she recovers, she displays symptoms of hypopituitarism. Which of the following can happen to this patient? Infertility Low basal metabolic rate Intolerance to stress *** All of the above
perilymph fills vestibular and tympanic ducts - containing low K+ and high Na+ concentrations
Helico-trema The small opening at the apical end of the cochlea where the vesitbular and and tympanic ducts connect
otolith organs fluid filled sacks containing hair cells that are stimulated by calcium rocks (otoliths) as the head moves. register head tilt and linear accelerationutricil and saccul
ampulla base of semicircular canals --> contains cristae with capula in them that move hair cells
central hearing loss damage to neural pathways or to cortex
central hearing loss damage to neural pathways or to cortex
kinocilium single long cilium of vestibular hair cells (work like cochlear hair cells)
Vestibular Apparatus An inner ear sense organ, which detects both linear and angular (rotational) acceleration of the head
sensorineural hearing loss damage to structure of inner ear... hair cells
equilibrium balance monitored by hair cells in vestibular apparatus
amplitude dB (peak to crest) --> intensity of a sound (loudness) 80dB < damage
hair cells specialized receptors that convert sound information into electrical signals in the inner ear
Lateral Superior Olive (LSO) sound localization via intensity (amplitude) diffs. -peak magnitude. -only useful for higher freq's -deviated from midline it tells you where
inferior colliculi auditory reflex center
cochlear duct endolymph High K+ low Na+
inner hair cells primary sensory receptors, single row
Cochlear Duct -filled with endolymph -space between vestibular and basilar membrane membranes of this duct are pushed by waves that move hair cells
vestibular, tympanic, and cochlear ducts a network of ducts that transmits pressure waves caused by sound to the organ of corti which is responsible for hearing.
middle ear - auditory ossicles - eustachian tube --> connects to pharnyx air filled
Malleus, Incus, stapes bones in middle ear --> conduct sound from external environment to inner ear (mechanical)
outer hair cells increase amplitude/clarity of sound, shorten when depolarized
Medial Superior Olive processes latency differences,----->encodes sound by relative activity of the left and right sides low frequencies
To focus on a nearby object, (click all that apply) *** ciliary muscles contract ciliary muscles relax *** tension on suspensory ligament decreases tension on suspensory ligament increases
The Gate Control Theory refers to: *** Non-noxious input suppresses pain at the spinal cord. Cortical control system suppresses pain. Electrical stimulation to the Raphe nuclei produces analgesia. Descending pain pathway suppresses pain.
When the stereocilia of the hair cell are displaced toward the kinocilium, hair cell hyperpolarized due to Na+ efflux. hair cell depolarized due to Na+ infflux. hair cell hyperpolarized due to K+ and Ca2+ efflux. No change in membrane potential. *** hair cell depolarized due to K+ and Ca2+ influx.
The localization of sound is processed by dorsal cochlear nucleus *** Superior Olive neurons Inferior colliculi Medial geniculate body Primary auditory cortex
Lateral inhibitions happen in? Fasciculus gracilis Pacinian corpuscles ventral root *** Thalamus All of the above
What loss would result from cutting through the left side of the fasciculus gracilis? Loss of pain sensation on the left side of the body *** Loss of fine touch sensation on the left side of the body Loss of pain sensation on the right side of the body Loss of fine touch sensation on the right side of the body Complete paralysis on the right side of the body
Which visual pathway is specialized for transmitting information about image color: Dorsal column pathway, which travels in cranial nerve II and synapses in the thalamus. *** P-blob pathway, which arises in the lateral geniculate nucleus (LGN). P-interblob pathway, which arises in the striate cortex of the occipital lobe. M-blob pathway, which starts from retinal ganglion cells wired to rods. M pathway, which arises in the lateral geniculate nucleus (LGN).
Which of the following visual cells responds preferentially to a dark spot in the center of its receptive field, surrounded by a ring of light? Complex cortical cell Simple cortical cell *** Retinal ganglion cell Rod All of the above
cochlear nerve branch of VIII
cochlear nuclei in medulla oblongata --> receive from primary auditory neurons from cochlea
secondary sensory neurons of hearing ipsilateral and contralateral -> project from medulla to cerebellum and thalamus (then to auditory cortex)
conductive hearing loss blockage of sound from outer or middle ear
hearing perception of sound waves
frequency Hz, peaks/second pitch of a sound
vision process through which light reflected from objects in our environment is translated into a mental image
orbit facial bones of the skull that protect the eye
vestibular complex primary sensor for equilibrium... in inner ear
pinna outer ear --> directs sound waves
organ of corti structure containing hair cell receptors, lies on basilar membrane/ tectorial membrane (both respond to fluid passing through vestibular duct)
stereocilia 50-100 stiffened cilia that are arranged in ascending hight, embedded in tectoral membrane
Detection of the frequency of a sound above 5 kHz is based upon: the direction of deflection of the hair cell cilia the frequency of action potentials in cranial nerve VIII *** the location along the cochlea of the most intensely stimulated hair cells the number of fibers discharging in cranial nerve VIII the phase difference between the sound waves at the two ears
Detection of the frequency of a sound around 1 kHz is based upon: the number of fibers discharging in cranial nerve VIII the direction of deflection of the hair cell cilia *** the location along the cochlea of the most intensely stimulated hair cells ***the frequency of action potentials in cranial nerve VIII *** both C and D For low frequency (<2000Hz), both firing pattern of cranial nerve VIII and the region of hair cell activation can give your brain ideas about the pitch. For high frequency (>2000Hz), the region of hair cell activation provides the primary clue about the pitch.
A decrease in the release of neurotransmitter from the photoreceptor would indicate a(n) change in focus of the lens onto a distant object *** increase in light intensity decrease in light intensity constant level of light intensity change in focus of the lens onto a closer object
On bipolar cells A. depolarize when photoreceptor release glutamate *** B. hyperpolarize when photoreceptor release glutamate C. synapse with horizontal cells D. establish the basis for motion detection E. B, C and D
round window membrane at the end of the tympanic duct, separates fluid from air of middle ear
inner ear innermost part of the ear, containing the cochlea, a semi circular canals, and vestibular sacs. transmits fluid movement to ion, electrical and chemical impulses sound goes to brain through vestibulocochlear nerve (VIII)
the parasympathetic system always antagonistically to sympathetic system has very long postganglionic nerve fibers. exhibits a greater degree of divergence and convergence than the sympathetic system. *** produces an increase in gastrointestinal function upon stimulation. Here the divergent means one preganglionic neuron synapses with multiple postganglionic neurons and convergent means one postganglionic neuron receives inputs from multiple preganglionic neurons. This arrangement is typically seen in sympathetic nervous system and contribute to "mass discharge", NOT in the parasympathetic nervous system.
Activation of Adrenergic beta 2 receptors will _______ the blood flow to the skeletal muscle? Decrease *** Increase No effect Epi activates both alpha and beta receptors. So for those vessels that express beta 2 receptors (to the skeletal muscles and heart), you will see vasodilation.
Atropine blocks Beta adrenergic receptors *** Muscarinic cholinergic receptors Nicotinic cholinergic receptors Alpha adrenergic receptors
Phenelzine, a common MAO inhibitor, will cause a(n) Over-activation of the gastrointestinal tract. *** Elevated blood pressure. bronchioles constriction. Increase in insulin release. Bradycardia.
Sara's nephew accidentally ingested a package of insecticide that contains anticholinesterase. What symptom(s) would you expect to observe Spastic paralysis (muscles contract uncontrollably) Sweating Nausea Tachycardia (heart rate exceeds the normal range) *** All of the above
Regarding the autonomic nervous system (ANS), which of the following statements is correct? Similar to Somatic Nervous system, ANS only activates the organ, rather than alter (increase or decrease) the activity of the target organ. The parasympathetic system is always inhibitory to the tissues that it innervates. Sympathetic preganglionic axons can be found in the ventral roots of the sacral cord. *** All the postganglionic-neuron cell bodies have acetylcholine (ACh) receptors on their surface.
Which of the following statements are true? (Choose all that apply.) Contraction of sphincter pupillae will cause pupil dilation. Increased light intensity will cause sphincter pupillae to contract. *** Parasympathetic activation will cause sphincter pupillae to contract. Sympathetic activation will cause sphincter pupillae to contract.
Which of the following statements correctly describe the functions of the external, middle, or inner ear? Contraction of the tensor tympani and stapedius muscles of the middle ear cause the amplification of the sound wave. The cochlea of the inner ear contains receptors for hearing and head tilt. Sound waves are transduced to electrical activity by the eardrum and auditory ossicles. *** sound waves are funneled through the external ear to the external auditory meatus and then they pass inward to the tympanic membrane.
Chromaffin cells The cells that the catecholamines (norepi, epi) are secreted from in the adrenal medulla adrenal cortex true endocrine gland, secretes hormones adrenergic epi or norepi, postganglionic /chromaffin cells, turned off by diffusion, degradation or active transport processes under hormonal control -fuel metabolism -reproduction -vascular function -cell growth -cell differentiation -behavior (immune and nervous system) phermones ectohormones act on other individuals of same species in physiological or behavior response growth factors hormones that stimulate growth and division of cells cellular mechanism of action responses from when hormones bind to receptors amine hormones modifications of single amino acids, tryptophan or tyrosine preprohormones one or more copies of a hormone, a signal sequence that directs the protein into the lumen of the rough endoplasmic reticulum, and other peptide sequences that may or may not have biological activity prohormone substance that precedes the hormone and from which the body can synthesize the hormone proteolytic enzyme chop prohormones into active hormones Cortisol a steroid hormone secreted by the adrenal glands that acts back on the hypothalamus and the pituitary to suppress the further release of CRH and ACTH parathyroid hormone increase in Ca2+, under a certain amount, inhibition ceases and PTH is secreted (negative feedback?) to increase Ca2+ in blood plasma Anterior pituitary portion of the pituitary gland, composed of glandular tissue posterior pituitary extension of neural tissue, secretes hormones from hypothalamus (strores and releases oxytocin and vasopressin (ADH)) trophic hormone hormone that causes another hormone to be secreted. Hypophseal Portal System: links hypothalamus to the anterior pituitary in the brain Portal system - 2 sets of capillaries connected by larger blood vessels- 2 other portals systems: kidney and digestive system Prolactin Anterior Pituitary Stimulates milk production and breast development
Growth Hormone (somatotropin) stimulates cell growth, division, CT growth, skeletal and muscular system growth, stimulates liver to produce insulin gonadotropin an anterior pituitary hormone that selectively stimulates the cells of the gonads to produce sex steroids and gametes FSH and Lh thyroid-stimulating hormone stimulates thyroid gland to produce and release hormones adrenocorticotrophic hormone hormone that stimulates adrenal cortex to secrete cortisol, aldosterone Long-Loop Negative Feedback -the third hormone can have a negative feedback effect on the hypothalamus or the anterior pituitary Synergism When the combined effects of hormones are amplified Permissiveness -one hormone must be present in adequate amounts for full exertion of another hormones effect-often by increasing second hormone's receptors antagonism one or more hormones opposes the action of another hormone ex. Insulin/glucagon, parathyroid hormone/calcitonin
Regarding the autonomic nervous system (ANS), which of the following statements is correct? Activity of the ANS tends to initiate the organ's activity, rather than alter (increase or decrease) the activity of the target organ. The parasympathetic system is always inhibitory to the tissues that it innervates. Sympathetic preganglionic axons can be found in the ventral roots of the sacral cord. *** All the postganglionic-neuron cell bodies have acetylcholine (ACh) receptors on their surface.
Regarding the sympathetic division of the ANS, which of the following statements is correct? *** The preganglionic fibers synapse with multiple postganglionic neurons. The preganglionic fibers is unmyelinated and relatively long. Postganglionic cell bodies can be found in the nuclei of the facial cranial nerve (VII). Some postganglionic fibers innervate the adrenal medulla causing the release of a hormone.
aqueous humor fills anterior and posterior chambers of the anterior cavity of the eye, secreted by ciliary epithelium vitreous humor chamber behind lens, filled with vitreous boyd, supports eye shape optic disk area in the retina where blood vessels and optic nerve exit the eye- blind spot optic chiasm optic nerves meet, some cross sides Depth of Field distance between the nearest and farthest objects in a scene that appear acceptable sharp in an image (pupil constricts to achieve) Accommodation the focusing of light by changing the shape of the eye's lens ciliary muscle round muscle about the lens attached by ligaments that tighten to flatten lens - pulled in, release tension, more rounded lens phototransduction process by which animals convert light energy into electrical signals (retina) layers of retinal neurons photoreceptor layer (contains rods and cones), bipolar cell layer, and ganglion cell layer, amacrine cells, horizontal cells Pigment Epithelium Absorbs stray light that does not get absorbed by the retina fovea the center of the retina, where cones are densely packed, no blood vessels to scatter light ganglion/ bipolar cells passes from bipolar to ganglion, integrate signals from rods and cones, axons form the optic nerve cones retinal cells that respond to higher levels of illumination and result in color perception Rods adapted for vision in dim light, no color Rhodospin visual pigment of rod cell 2 major parts: protein opsin and vitmain A derivitve retinal rod cell contains 1 rhodopsin with absorption peak at wavelength of 500 nm Visual pigment A light sensitive chemical that reacts to light color-blindess caused by defective cones in the retina in the eye (usually one kind) Phototransduction Conversion of light energy into neural impulses Opsin combines with retinal to make photopigments or color (rods)
Retinal Vitamin A derivative that absorbs light energy. Attached to some type of opsin (will bind to in absence of light) , which makes up the pigment of a rod or cone. bleaching when activated retinal no longer binds to opsin and is released from the pigment Cyclic nucleotide gated channel cAMP or cGMP bind to the intracellular side of the channel, opening the channel for visual transduction... Na+ and ca2+ go into rod and K+ out horizontal cells interconnects adjacent photoreceptors and the outer processes of bipolar cells Amacrine Cells horizantal cells; side to side connections b/n rods and cones, bipolars cells, and ganglion cells light on bipolar cells activated when glutamate secretion by photoreceptors decreases (mGLUR6, hyperpolarizes cell when glutamate is bound in the dark) off bipolar cells excited by glutamate release in the dark visual field associated with ganglion cells, receptors that are activated by light, (more photoreceptors converge to a single ganglion, less acuity) (on and off center types) Binocular Zone area in the visual field where both eyes can see an object. (depth perception, interpreted slightly differently and integrated) Monocular zone Extreme temporal part of visual field Light from monocular zone strikes the retina of only the ipsilateral eye 2d vision Lateral giniculate nucleus A group of cell bodies within the lateral giniculate body of the thalamus. It's function is to receive functions from the retina. topographical organization maintained in the visual cortex, with the six layers of neurons grouped into vertical columns Somatic motor nerve pathway only requires a single neuron running from the CNS to the target skeletal muscle (excitatory) Neuromuscular Junction Synapse between a motor neuron and a skeletal muscle fiber; myoneural junction. motor end plate specialized part of a muscle fiber membrane at a neuromuscular junction (folds) nAChR nicotinic ACh receptor ion channel (fast, excitatory) conductance for Na+ (at neuromuscular junction) acetylcholinesterase Enzyme in the snaptic cleft that cuts actylcholine in two to form acetic acid and choline That are reabsorbed by the neuron end (axonal ending) nicotnic cholinergic receptors chemically gated ion channels with two binding sites for ACh (when bound, open for ions) (triggers AP) (always excitatory)
Regarding the sympathetic division of the ANS, which of the following statements is correct? *** The system can act as a unit ("mass discharge"). The preganglionic fibers is unmyelinated and relatively long. Postganglionic cell bodies can be found in the nuclei of the facial cranial nerve (VII). Some postganglionic fibers innervate the adrenal medulla causing the release of a hormone. B is wrong because the preganglionic axon is short in SNS. C is wrong because SNS preganglionic cells are not found in the spinal cord T1-L2, not in the brainstem and sacral region. D is wrong because preganglionic fibers innervate Adrenal Medulla.
The adrenal medulla is important to the sympathetic branch of the autonomic nervous system because it is considered a modified sympathetic ganglion. it is a source of catecholamines. it reinforces the sympathetic activation. *** All of the above.
6 extrinsic muscles of the eye: 4 rectus: move eyeball up and down, side to side. 2 obliques: rotate eyeballs. cranial nerves 3,4,6
lacrimal apparatus accessory structures of the eyes that produce, store, and remove tears -- nerve 7
Pupil the adjustable (pupillary muscle) opening in the center of the eye through which light enters.
lens suspendent by zonules (ligaments ) devides compartments of eye, focuses light
maximum frequency waves maximum displacement of basilar membrane, not transmitted far along cochlea
low frequency waves maximum displacement of basilar membrane near distal end
Cochlea coiled tubular structure of the inner ear that contains the organ of Corti sensory receptors for hearing initial for pitch and loudness
oval window opening in wall of tympanic cavity stapes vibrates against it to move fluid in inner ear
cochlear nuclei respond from one ear
photoreceptors rods and cones found in retina, bottom of retina facing backward
ear canal external ear --> amplifies sound waves
tympanic membrane end of the ear canal; sound waves cause it to vibrate and these vibrations are transmitted to the ear bones
Myasthenia gravis a chronic autoimmune disease that affects the neuromuscular junction and produces a serious weakness of voluntary muscles -loss of Ach receptors motor pathways formed from cerebral nuclei, cerebellum, descending projection tracts, and motor neurons descending projection tracts motor pathways that originate from the cerebral cortex and brain stem Upper Motor Neuron cell body lies in a CNS processing centerSynapses on the lower motor neuronexcite or inhibit lower neuron lower motor neuron cell body housed w/i anterior horn of spinal chord or w/i brainstem cranial nerve nucleus, axons project to skeletal muscles - always excitatory pyramidal pathway direct pathway - originates in pyramidal cells of primary motor cortex -axons project to brian stem or spinal chord to synapse with lower motor neurons rubrospinal tracts movement of the limbs form the red nucleus corticobulbar tracts synapse on lower motor neurons in motor nuclei of cranial nerves -provide conscious control over skeletal muscles that move the eye, jaw, and face and some muscles of neck and pharynx Corticospinal Tracts descend from the cerebral cortex through the brainstem and from the pyramids of the medulla oblongata Indirect Pathways Integrate sensory information (muscle length, body position) to moderate ongoing movements -upper motor neurons originate in brainstem nuclei Lateral indirect pathway regulate/control precise, discrete movements & tone in flexor muscles of limbs -rubrospinal tract (originate in red nucleus) Medial indirect pathway regulate muscle tone & gross movements of head, neck, proximal limb & trunk muscles -reticulospinal, tectospinal, & vestibulospinal Reticulospinal tracts - fibers originate in the reticular formation of the brainstem- control rhythmic gait patterns-communicate with autonomic nervous system- posture/balance tectospinal tracts reflex movement of head, eye and head in response to visual and auditory stimuli-tectum of mesencephelon to spinal cord Vestibulospinal Tract balance during sitting/standing/walking -originate w/i vestibular nuclei of brainstem cerebral nuclei receive impusles from entire cerbral cortex -output goes to primary motor cortex cerebellum receives convergent input from motor pathways, follows path of movement, and corrects Autonomic nervous system parts Sympathetic - emergenciesParasympathetic - relaxation osmoreceptors in hypothalamus - monitor concentration of solutes (release ADH) Thermoreceptors Respond to heat or cold and help regulate body temperature by signaling both surface and body core temperature Spinal Reflexes simple, automatic behaviors that are processed in the spinal cord -urination, defecation, erection preganglionic neuron -cell body in CNS -myelinated axons (type B fiber) exit CNS as part of a cranial or spinal nerve and extend to an autonomic ganglion autonomic ganglion synapse where two neurons meet in autonomic pathways
postganglionic neuron conducts APs from the ganglion to the organ ('effector') (multiple may be affected by one pregnaglionic neuron) (DIVERGENCE) vagus nerve plays a significant role in parasympathetic innervation to thoracic and abdominal organs adrenic receptors postganglionic sympathetic neurons secrete norepinepherin to this receptor muscarinic cholinergic receptors for ACh of sympathetic neurons (also sweat glands) Neuroeffector Junction The synapse between a postganglionic autonomic neuron and its target cell varicosity pack with neurotransmitter vesicles, branching network (postganglionic axons) monoamine oxidase main enzyme responsible for degradation of catecholine alpha receptor strong response to norepi, weak to epi Beta one receptors heart rate and contractive force of the heart equal response to norepi and epi Beta two receptors Most important action is bronchodilation -higher response to epinephrine beta 3 receptors adipose tissue, innervated, respond to norepi catecholine binding to beta receptors increases cyclic AMP and trigger phophorylation of intracellular proteins Alpha 2- Receptors At presynaptic adrenergic neuron terminals Activation inhibits release of norepinephrine -smooth muscle relaxation cholinergic post and pre ganglion, ACh, turned off by enzymatic degradation or diffusion role of alpha one receptors: postsynaptic. they are located on the effector organs(blood vessels, skeletal muscle). the main role of alpha one receptors is to stimulate the contraction of smooth muscle. adrenal medulla neuroendocrine tissue associated with the sympathetic nervous system, secretes epinephrine (core of adrenal glands on top of kidneys)
