Anatomy and Function of the Autonomic Nervous System, Exams of Bioethics

Download Anatomy and Function of the Autonomic Nervous System and more Exams Bioethics in PDF only on Docsity! BIO 201 Exam 4 (271 Questions with Verified Solutions) Latest Update 2 024. Rostral - ANS toward the nose Caudal - ANS toward the tail Major portions of the brain - ANS Brain stem, Cerebrum, cerebellum Cerebrum is ___% of brain volume - ANS 83 Cerebellum contains ___% of the neurons - ANS 50 The brain weighs ___ pounds - ANS 3.5 Longitudinal Fissure - ANS separates 2 cerebral hemispheres (left/right) Central Sulcus - ANS Separates frontal & parietal lobe Gyri - ANS folds Sulci - ANS grooves cortex - ANS surface layer of gray matter nuclei - ANS deeper masses of gray matter tracts - ANS bundles of axons gray matter - ANS neuron cell bodies, dendrites & synapses -forms cortex over cerebrum & cerebellum -forms nuclei deep with in brain white matter - ANS bundles of axons -forms tracts that connect parts of the brain Meninges - ANS Dura Mater, arachnoid mater, pia mater Dura mater - ANS outermost, tough membrane -outer periosteal layer against bone -inner meningeal layer -subdural space (below dura mater) -where separated from inner meningeal layer forms dural venous sinusesdraining blood from brain supportive structures formed by dura mater - ANS falx cerebri, falx cerebelli & tentorium cerebelli Arachnoid mater - ANS spider web filamentous layer Pia mater - ANS a thin vascular layer adherent to contours of brain Meningitis - ANS Inflammation of the meninges -bacterial & virus invasion of the CNS by way of the nose & throat -signs: high fever, stiff neck, drowsiness & intense headache which could lead to coma -diagnose by examining the CSF fluid for bacteria Lumbar puncture - ANS (spinal tap) check spinal fluid -draws fluid from subarachnoid space between two lumbar vertebrae Lateral ventricles - ANS found inside the cerebral hemispheres Third ventricle - ANS single vertical space under corpus callosum Cerebral aqueduct - ANS runs through the midbrain (connects 3rd & 4th ventricle) Central canal - ANS runs down through spinal cord Ventricles - ANS Internal chambers within the CNS -lined with ependymal cells & containing choroid plexus of capillaries that produce CSF Cerebrospinal fluid - ANS clear liquid that fills ventricles & canals & bathes in its external surface (in subarachnoid space) The brain produces & absorbs ___ml/day of CSF - ANS 500 Functions of CSF - ANS Buoyancy: floats brain so its neutrally buoyant Protection: cushions from hitting inside of skull Chemical stability: rinses away wastes CSF escapes from ___ to surround the brain & is absorbed by ___ into venous sinus - ANS 4th ventricle/ arachnoid villi Circumventricular organs... - ANS ...in 3rd & 4th ventricles are breaks in the barrier where blood has direct access -monitoring of glucose, pH, osmolarity & other variations -allows route for HIV to invade the brain Blood-brain & Blood-CSF barriers - ANS Tightly joined endothelium -permeable to lipid-soluble materials (alcohol, nicotine, O2, CO2 & anesthetics) planning, mood, smell & social judgement Parietal Lobe - ANS Receives & integrates sensory info Occipital Lobe - ANS Visual center of the brain Temporal Lobe - ANS Areas for hearing, smell, learning, memory & emotional behavior Most of cerebrum is ___ matter - ANS white Projection tracts (Cerebral white matter) - ANS from brain to spinal cord Commissural [visual] tracts (Cerebral white matter) - ANS cross to opposite hemispheres (corpus callosum, anterior/posterior commisures) Association Tracts (Cerebral white matter) - ANS connect lobes & gyri w/ in a hemisphere Basal nuclei - ANS masses of gray matter deep to cerebral cortex receives input from substantia nigra & motor cortex plays a role in motor control & tremors Limbic system - ANS Loop of cortical structures surrounding deep brain (amygdala, hippocampus, fornix & cingulate gyrus) Hippocampus (limbic) - ANS important in memory important in organizing sensory & cognitive info into a memory Amygdala (limbic) - ANS important in emotion important in emotional memory Electroencephalogram - ANS records voltage changes from postsynaptic potentials in cerebral cortex Differences in ___ & ___ distinguish four different types of brain waves - ANS amplitude/ frequency Brain waves - ANS states of consciousness that can be correlated w/ EEG (4 types: alpha, beta, theta, delta) Alpha brain waves - ANS occur when awake & resting w/ eyes closed Beta brain waves - ANS occur w/ eyes open performing mental tasks Theta brain waves - ANS occur during sleep or emotional stress Delta brain waves - ANS occur during deep sleep Sleep - ANS temporary state of unconsciousness; controlled by hypothalamus, reticular formation thalamus & cerebral cortex Sleep paralysis - ANS inhibition of muscular activity Suprachiasmatic nucleus - ANS acts as a biological clock to set circadian rhythym Restorative effect (sleep) - ANS Brain glycogen levels increase memories strengthened (synoptic connections reinforced or eliminated) 4 stages of Non-REM sleep - ANS (occurring in the first 30-45 minutes of sleep) #1 is a drifting sensation (would claim was not sleeping) #2 still easily aroused #3 [reached in 20 mins] vital signs change: BP, pulse & breathing rates drop #4 is deep sleep, difficult to arouse REM sleep occurs about ___ times a night - ANS five REM sleep - ANS rapid eye movements under the eyelids, vital signs increase, EEG resembles awake person, dreams & penile erections occur -may help sort & strengthen info from memory Cognition - ANS Such as awareness, perception, thinking, knowledge & memory Association areas = ___% of brain tissue - ANS 75 -integration of sensory & motor info occurs Contralateral neglect syndrome - ANS brain lesion- parietal unaware of objects or limbs on one side of body Agnosia - ANS brain lesion- temporal inability to recognize objects Prosopagnosia - ANS brain lesion- temporal inability to recognize faces brain lesion-frontal - ANS problems with personality (phineas gage) inability to plan & execute appropriate behavior Phineas Gage - ANS spike through frontal lobe Ventromedial region of both frontal lobes personality change prefrontal cortex functions: planning, moral judgement, emotional control Pathological inability to forget (memory) - ANS Have trouble w/ reading comp Anterograde amnesia - ANS Can not store new data Retrograde amnesia - ANS can not remember old data Lesion- Hioppocampus - ANS causes inability to form new memories Emotion - ANS form in hypothalamus & amygdala -artificial stimulation produces fear, anger, pleasure, love, parental affection, etc. ___ ___ controls how emotions are expressed (seat of judgement) - ANS Prefrontal Cortex Somesthetic Sensation - ANS comes from receptors widely distributed throughout the body (touch, pain, pressure, stretch, movement, heat, cold) somatosensory area is postcentral gyrus Sensory Homunculus - ANS demonstrates that the area of the cortex dedicated to the sensations of various body parts is proportional to how sensitive that part of the body is Special senses - ANS organs of smell, taste, vision, hearing & equilibrium project to specialized regions of the brain Taste is located... - ANS lower end of postcentral gyrus smell is located... - ANS medial temporal lobe & inferior frontal lobe vision is located... - ANS occipital lobe Hearing is located... - ANS superior temporal lobe Equilibrium is located... - ANS mainly the cerebellum, but to unknown areas of cerebral cortex via the thalamus Association areas - ANS interpret sensory info Somesthetic association area - ANS parietal lobe position of limbs, location of touch or pain, and shape, weight & texture of an object Visual association area - ANS occipital lobe identify the things we see faces are recognized in temporal lobe Auditory association area - ANS temporal lobe remember the name of a piece of music or id a person by his voice Vestibulocochlear Nerve - ANS Provides hearing & sense of balance; damage produces deafness, dizziness, nausea, loss of balance & nystagmus (dancing eyes/eyes vibrate) Glossopharyngeal Nerve - ANS swallowing, salivation, gagging, control of BP & respiration sensations from posterior 1/3 of tongue; damage results in loss of bitter & sour taste and impaired swallowing Vagus Nerve - ANS Swallowing, Speech, Regulation of viscera; damage causes hoarseness or loss of voice, impaired swallowing, fatal if both are cut Accessory Nerve - ANS Swallowing, head-neck-shoulder movement; damage causes impaired head, neck, shoulder movement- head turns toward injured side Hypoglossal Nerve - ANS tongue movements for speech, food manipulation & swallowing; if both are damaged cant protrude tongue, if one side is damaged tongue deviates towards injured side (ipsilateral atrophy) Trigeminal Neuraglia - ANS Recurring episodes of intense stabbing pain (like labor pain) Bell's Palsy - ANS A disorder of facial nerve causing paralysis of facial muscles on one side ANS - ANS aka Visceral Motor System Controls: glands, cardiac muscle, smooth muscle Regulates unconscious processes that maintain homeostasis (BP, body temp, resp air flow) Biofeedback (ANS) - ANS conscious control of the ANS Visceral Reflexes - ANS unconscious, automatic responses to stimulation of glands, cardiac or smooth muscle 1. Receptors (visceral reflexes) - ANS detect internal stimuli- stretch, blood chemicals, etc. 2. Afferent neurons (visceral reflexes) - ANS transmit sensory signals to interneurons in the CNS 3. Efferent neurons (visceral reflexes) - ANS carry motor signals to effectors, ANS in the efferent neurons of these reflex arcs 4. Effectors (visceral reflexes) - ANS glands, smooth or cardiac muscle -ANS modifies effector activity, rather than causing it. ANS visceral reflex arcs - ANS ANS is made up of the efferent neurons of reflex arcs The two neurons that span from CNS to effectors - ANS presynaptic neuron (cell body located in the CNS) postsynaptic neuron (cell body in peripheral ganglion Baroreceptors - ANS detect BP, then CN IX send signals to medulla, then CN X sends signals to heart to reduce BP (visceral reflex to high BP) Sympathetic Division (ANS) - ANS "fight or flight" response prepares body for physical activity (increase heart rate, BP, airflow, blood glucose levels, etc.) Parasympathetic Division (ANS) - ANS "rest & digest" calms many body functions & assists in bodily maintenance; digestion & waste elimination Autonomic Tone - ANS The normal rate of activity that represents the balance of two systems (shifts depending on the needs of the body) Sympathetic tone - ANS keeps most blood vessels partially constricted; maintains blood pressure; loss of sympathetic tone can cause a rapid drop in BP causing a person to go into shock Origin of presynaptic neurons (ANS) - ANS lateral horns of gray matter of thoracic to lumbar cord; fibers exit via spinal nerves T1-L2leading to sympathetic chain ganglia Sympathetic chain ganglia - ANS on average 3 cervical, 11 thoracic, 4 lumbar, 4 sacral & k1 coccxygeal ganglia; 2 branches called white & gray communicating rami suspend ganglia from spinal nerve Pathway of preganglionic fibers (SNS) - ANS Small myelinated preganglionic fibers travel from the spinal nerve to the white communicating ramus, then enter ganglia -Unmyelinated postganglionic fibers leave ganglia via gray communicating ramus Neuronal Convergence - ANS each postganglionic cell may receive signals from multiple preganglionic cells Neuronal divergence - ANS predominates -each preganglionic cell branches & synapses on multiple post ganglionic cells -there are ~17 postganglionic neurons for every preganglionic neuron in the SNS -produces widespead effects on multiple organs Sympathetic innervation (spinal route) - ANS effectors in body wall are innervated by sympathetic fibers that travel through spinal nerves -sweat glands, piloerector muscles, blood vessels of skin & skeletal muscles Sympathetic innervation (sympathetic route) - ANS effectors in head & thoracic cavity are innervated by fibers in specific sympathetic nerves -sweat, salivary, nasal glands, blood vessels, heart, iris Sympathetic innervation (splanchnic route) - ANS effectors in abdominal cavity are innervated by sympathetic fibers in splanchnic nerves that lead to 3 major collateral ganglia Adrenal glands - ANS paired glands; sit on superior pole of each kidney Cortex - ANS secretes steroid hormones (andogens, cortisol, etc) Medulla - ANS modified sympathetic ganglion that secretes neurotransmitters (in the form of hormones) into blood rather than onto other neurons -complementary involvement in mass activation that occurs during fight or flight reaction Catecholamines - ANS secreted by Muedulla 85% epinepherine, 15% norepinepherine Origin of preganglionic fibers - ANS -pons & medulla oblongata (cranial nerve nuclei) -spinal cord segments (S2-S4) Pathways of preganglionic fibers (PSNS) - ANS -CN III, VII, IX & X (cardiac, pulmonary, esophageal, abdominal aortic plexus) -arising from sacral spinal cord (pelvic splanchnic nerves & inferior hypogastric plexus- enervate the pelvic & genitle organs regulating the emptying of the urinary bladder & the rectum as well as sexual functions like erection & orgasm) Parasympathetic Cranial nerves - ANS Oculomotor (III)- narrows pupil, focuses lens Facial nerve (VII)- tear, nasal & salivary glands Glossopharyngeal (IX)- parotid salivary gland Vagus nerve (X)- all major viscera as far as proximal half of colon; cardiac, pulmonary & esophageal plexus Enteric Nervous System - ANS Nervous system of the digestive system; composed of 100 million neurons found in the walls of digestive tract (no components in CNS); has its own reflex arcs; regulates motility & secretion of digestive enzymes & acid in concert w/ the ANS Cholinergic fibers - ANS secrete ACh Adrenergic fibers - ANS secrete NE (noe-epinepherine) -only postganglionic sympathetic fibers are adrenergic Referred/Misinterpreted Pain - ANS brain "assumes" visceral pain is coming from skin (ie. heart pain felt in shoulder or arm because both send pain input to spinal cord segments T1 to T5) CNS Modulation of Pain - ANS -Receptor sites for opium, morphine & heroin were investigated & endogenous opioids discovered (enkephalins, endorphins & dynorphins; block the transmission of pain signals; found in central gray of midbrain and the dorsal horn of the spinal cord) -Spinal gating stops pain signals at dorsal horn [descending analgesic fibers (midbrain central gray area)- secrete inhibitory enkephalins onto dorsal horn pain fibers; dorsal horn fibers inhibited by input from touch fibers] Gustation - ANS the sensation of taste resulting from the action of chemicals on the taste buds Lingual papillae - ANS -circumvallate: at rear of tongue, contains 1/2 of taste buds, largest -fungiform: scattered throughout tongue surface Physiology of Taste - ANS -To be tasted, molecules must dissolve in saliva 5 primary sensations (taste) - ANS salty, sweet, sour, bitter & umami (taste of amino acids such as MSG (meaty flavors)) Taste is also influenced by... - ANS food texture, aroma, temperature, and appearance. -hot pepper stimulates free nerve endings (pain) ___ tastes concentrated on tip of tongue, ___ & ___ on lateral margins of tongue & ___ at rear - ANS Sweet/ salty & sour/ bitter Sugars & umami flavors... - ANS bind to receptors & activate 2nd messenger systems; sodium & acids penetrate cells & depolarize them Olfaction - ANS Sense of smell Receptor cells for olfaction form olfactory mucosa. -smell is highly sensitive, more so in women than men; we can distinguish as many as 10,000 odors Covers 5cm2 (sq cm) of superior concha & nasal septum Olfactory cells - ANS -neurons with 20 cilia called olfactory hairs (binding sites for odor molecules in thin layer of mucus) -axons pass through cribiform plate -survive 60 days Physiology of Smell - ANS Odor molecules must be volatile -bind to a receptor on an olfactory hair triggering the production of a second messenger -opens the ion channels & creates a receptor potential Receptors adapt quickly due to synaptic inhibition in the olfactory bulbs ___ cells form the axons of the olfactory tracts - ANS Bulb -lead to temporal lobe, amygdala, hypothalamus emotional responses to odors; cough, salivate, sneeze or vomit in response to odors -cerebral cortex sends feedback to bulb cells -- changing quality & significance of odors when hungry Sound - ANS is any audible vibration of molecules -Vibrating object pushes air molecules into zones of compression separated by zones of rarefaction -Molecules collide with eardrum & make it vibrate. The ___ at which parts of the ear vibrate give us sense of pitch (high or low pitched sounds) - ANS frequency -hearing range is 20 - 20,000 Hz (cycles/sec) ___ is perception of intensity of sound energy - ANS Loudness -how much the air molecules are compressed in decibels Outer Ear - ANS Fleshy auricle (pinna) directing air vibrations down auditory canal (external auditory meatus) -cartilagenous & bony, S-shaped tunnel ending at eardrum Middle Ear - ANS Air-filled cavity in temporal bone separated from air outside the head by tympanic membrane 1 cm in diameter, slightly concave, vibrates freely Tympanic cavity - ANS continuous with mastoid air cells -filled with air by auditory tube (eustachian tube) connected to nasopharynx ---opens during swallowing or yawning to equalize air pressure on both sides of eardrum (tympanic membrane) Ear ossicles - ANS span tympanic cavity Malleus attached to eardrum, Incus, stapes attached to membranous oval window of inner ear Inner Ear - ANS Passageways in temporal bone = bony labyrinth (perilymph fluid) -Endolymph-filled tubes floating in perilymph inside the bony labyrinth = membranous labyrinth Cochlea - ANS 3 fluid-filled chambers -2.5 coils -Organ of Corti -Stereocilia of hair cells attached to tectorial membrane. -Hearing comes from inner hair cells -- outer ones adjust cochlear responses to different frequencies Physiology of Hearing (Middle Ear) - ANS Eardrum vibrates quite easily -18 times the area of the oval window ---creates enough force/unit area at oval window to vibrate the perilymph in the scala vestibuli Protection of cochlea by muscle contraction in response to loud noises - ANS -tensor tympani pulls eardrum inward, tightening it -stapedius reduces mobility of stapes -designed for slowly building noises like thunder not gunshots (irreversible damage by breaking stereocilia) -muscles also contract while speaking -- can hear others Stimulation of Cochlear Hair Cells - ANS -Sound is produced by vibration of ossicles and then vibration of basilar membrane under hair cells -Can happen as often as 20,000 time per second Sensory Coding - ANS -Loudness produces more vigorous vibrations & excites more hair cells over a larger area ---triggers higher frequency of action potentials ---brain interprets this as louder -Determination of pitch depends on which part of basilar membrane is vibrated at peak amplitude of standing wave --membrane is narrow & stiffer at basal end (collagen) --- brain interprets signals from IHC basal end as high-pitched --at distal end is 5 times wider & more flexible --- brain interprets signals from IHC distal end as low-pitched Equilibrium - ANS Control of coordination and balance -Receptors in vestibular apparatus --Semicircular ducts contain crista --Saccule & utricle contain macula Static equilibrium - ANS perception of head orientation -- perceived by macula Dynamic equilibrium - ANS perception of motion or acceleration -- linear acceleration perceived by macula -- angular acceleration perceived by crista The Saccule and Utricle - ANS chambers containing macula