CCNM Phys II Outcomes

Question 0

Describe the receptors that mediate the sensation of pain and temp

Answer 0

Cold and warm receptors: thermal
Polymodal receptors: Chemical/thermal/mechanical nociceptors
Chemical nociceptor: itch

Question 1

Name the types of touch and pressure receptors found in the skin

Answer 1

Touch - Meissner corpuscles (tap/flutter)
Hair follicle receptor - motion
Pacinian corpuscles - deep pressure
Merkel cells - touch/pressure
Ruffini corpuscles - sustained pressure

Question 2

Define generator potential

Answer 2

AKA receptor potential. A non-propagated depolarizing potential resembling EPSP. As pressure pressure (in pacinian corpuscle) increases, generator potential increases. When large enough, an action potential is generated

Question 3

Explain the basic elements of sensory coding

Answer 3

Converting a receptor stimulus to recognizable sensation. All sensory systems code for modality, location, intensity, duration. Modality = mechanical, thermal, electromagnetic or chemical aka type of energy. Location - site on body or space where stimulus originiated, receptive field. Intensity - response amplitude or frequency of action potential generation
Duration - time from start to end of response (related to adaptation/desensitization)

Question 4

Explain the differences between pain and nociception first and second pain, acute and chronic pain, hyperalgesia and allodynia

Answer 4

Nociceptors respond to a variety of noxious stimuli (chemical, mechanical or thermal). Pain is a perceived stimulus. Nociceptor pain is mediated by free nerve endings whose ion channels are sensitive to a variety of stimuli. Modulated by local chemicals: K+, histamine and prostaglandins released from damaged cells, serotonin from platelets, substance P. These also modulate inflammatory and therefore pain.

Question 5

Describe visceral and referred pain

Answer 5

Pain in organs is poorly localized and may be far removed from point of stimulus.
Referred: felt far from stimulus
This is because multiple primary sensory neurons converge on a single ascending tract and the brain is unable to distinguish

Question 6

Compare the pathway that mediates sensory input from touch, proprioceptive and vibratory senses to the mediating information from nociceptors and thermoreceptors.

Answer 6

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Question 7

Describe the process involved in modulation of transmission in pain pathways

Answer 7

Crosses limbic system therefore may also have emotions.
Experience or suppressed in emergency (inhibited in thalamus)
Also suppressed in dorsal horn of spinal cord
C fibers can inhibit tonic inhibition
gate control theory - AB fibers help block pain transmission

Question 8

Botanicals and nutrients for pain relief

Answer 8

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Question 9

Describe the various parts of the eye and functions of each

Answer 9

Lacrimal apparatus - tears
lens suspended by zonules ligaments
anterior chamber filled with aqueous humour
posterior chamber filled with vitreous body
outer wall of eyeball called sclera composed of connective tissue, next is cornea
optic disc entry for nerves, vessels
optic nerve goes to optic chaism next and some fibers cross to other side and synapse to lateral geniculate body of the thalamus and terminate on occipital lobe of visual cortex

Question 10

Describe the organization of the retina

Answer 10

extends anteriorly almost to the ciliary body
organized in 10 layers and contains the rods and cones which are next to the choroid, synapse with bipolar cells which syanpse with ganglion cells which converge and leave he eye as optic nerve
Horizontal cells connect receptor cells to other receptor cells in outer plexiform layer
Amacrine cells connect ganglion cells to one another in inner plexiform layer
Neural elements of the retina are bound together by glial cells called Muller cells
Blind spot is the optic disc

Question 11

Explain how light rays in the environment are brought to a focus on retina and role of accomodation

Answer 11

parallel light rays striking a biconvex lens are refracted to a point (principal focus) behind the lens
Accommodation: process by which curvature of lens is increased. At rest lens is held under tension by ligaments therefore is flat. When gaze is on a near object the ligaments of the lens relax and lens is convex.

Question 12

Define hyperopia, myopia, astigmatism, presbyopia, and stabismus

Answer 12

Hyperopia = farsighted eyeball too short
Myopia = nearsightedness eyeball too long
astigmatism = curvature of the cornea is not uniform and light is refracted differently
Strabismus = misalighnment of the eyes, 4% children
Presbyopia = loss of accomodation, makes close work and reading difficult. Age related.

Question 13

Describe the electrical responses produced by the rods and cones and explain how these responses are produced

Answer 13

Responses of rods cones and horizontal cells are hyperpolarizing whereas amacrine cells produce depolarizing potentials and spikes that may act as generating potentials for propagated spikes produced in ganglion cells
Cone receptor sharp onset and offset while rod is sharp onset slow offset (proportionate to stimulus intesnity levels of illumination lower than cones).
Photosensitive compounds are opsin and retinene (aldehyde of vit A - retinOL) aka retinal.
Photosensitive pigment in rods is rhodopsin.

Question 14

Trace the neural pathways that transmit visual information to visual cortex

Answer 14

rods and cones –> retina processing esp amacrine cells on centre field and off centre field.
Axons of retinal ganglion cells project a detailed spatial representation on lateral geniculate body which has six defined layers and two types large M and small P. First one carries movement depth and flicker and the second carries colour texture shape and detail. Lateral geniculate body projects a similar point representation on primary visual cortex (6 layers)

Question 15

Describe the responses of cells in visual cortex and the functional organization of dorsal and ventral pathways to parietal cortex.

Answer 15

simple cells = bars of light, lines, edges in particular orientation
complex cells = preferred orientation of linear stimulus but less dependent on location of a stimulus in the visual field
Orientation columns

Question 16

Define and explain dark adaptation and visual acuity

Answer 16

when in bright light for a long time then move to dark the retinas slowly become more accustomed to dark nearly maximal in 20 min
light adaptation 5 min more so the disappearance of dark adaptation
Visual acuity ???

Question 17

Describe the neural pathways involved in colour vision

Answer 17

hue, intensity, saturation
complementary colours mixed = white
black = seeing nothing
colour as various mixes of primary colours red green and blue with three kinds of cones
colour is mediated by ganglion cells that subtract or add input from one type of cone to input from another type. Processing in the ganglion cells and lateral geniculate nucleus produces impulses that pass along three types of neural pathways: red-green, blue-yellow and the difference between the two.

Question 18

Identify the muscles involved in eye movement

Answer 18

Six occular muscles innervated by oculomotor trochlear and abducens nerve
oblique msucels pull laterally and their action depends on the position of the eye
superior rectus, superior oblique, medial rectus lateral rectus inferior rectus inferior oblique

Question 19

Name the four types of eye movements and function of each

Answer 19

saccades = sudden jerky movements as gaze shifts from one object to another
smooth pursuit movements = tracking
vestibular movements = in response to stimuli in semicircular canals maintain visual fixation as head moves
convergence = bring the visual axes toward each other as attention is focused on objects near the observer

Question 20

Describe the components and functions of the external, middle and inner ear

Answer 20

external ear funnels sound waves to external auditory meatus and pass to tympanic membrane
auditory ossicles (malleus, incus, stapes)
manubrium of malleus is attached to tympanic membrane
foot plate of stapes attached to oval window
bony labyrinth - surround by perilymph is the membranous labyrinth suspended by perilymph and filled with endolymph
semicircular canals with otoliths saccule and utricle

Question 21

Describe the way that movements of molecules in the air are converted into impulses generated by hair cells in the cochlea

Answer 21

organ of corti contains hair cells = hearing
hair cells in four rows 3 rows of outer hair cells lateral to tunnel and one row inner medial to it
covered by elastic tectorial membrane the tips of the hair are embedded in
Inner hair cells much more innervated
when pushed in one direction depolarize membrane, in the other will hyperpolarize
tip links attach neighbouring cells these are next to cation channels.

Question 22

Explain the roles of tympanic membrane, auditory ossicles and scala vestibule in sound transmission

Answer 22

scalae = 3 chambers of cochlea
scala vestibui and lower scala tympani contain perilymph that communicate with each other through helicotrema. Scala media is continuous with membranous labrinth

Question 23

Explain how pitch, loudness and timber are coded in auditory pathways

Answer 23

loudness is amplitude
pitch is frequency
timbre (quality) primary frequency with harmonic vibrations and overtones

Question 24

Describe the various forms of deafness and the tests used to distinguish between them

Answer 24

Presbycusis = gradual hearing loss associated with aging monogenetic = syndromic (associated with other abnormalities) and nonsyndromic (only hearing loss) Conductive = impaired sound transmission in external or middle ear and impacts all frequencies sensorineural = most commonly loss of hair cells but also 8th cranial nerve or central auditory pathways differentiated with a tuning fork weber = base of fork placed on skull rinne = base of fork placed on mastoid process until no loner hears it then placed in air Schwabach = bone conduction of patient compared to that of normal subject

Question 25

Explain how the receptors in the semicircular canals detect rotational acceleration and how the receptors in the saccule and utricle detect linear acceleration

Answer 25

rotational acceleration in plane of given semicircular canal stimulates its crista endolymph because of inertia displaced in opposite direction pushing on cupula when rotation stops stimulates hair cells again linear acceleration utricle and saccule (horizontal and vertical) Otoliths more dense than endolymph and bending stimulates hair cells

Question 26

List the major sensory inputs that provide the information that is synthesized in the brain into a sense of position in space

Answer 26

In part from vestibular receptors but visual cues also important proprioceptors in joint capsules impulses from cutaneous exteroreceptors (touch, pressure)

Question 27

Describe the basic features of the neural elements in the olfactory epithelium and olfactory bulb

Answer 27

Olfactory epithelium is in the nasal mucosa and contains olfactory sensory neurons 10-20 million bipolar olfactory receptors and supporting cells and basal stem cells. Each neuron has one thick dendrite that projects into nasal cavity and terminates in a knob with 10 to 20 cilia that contain odorants axons pass through cribiform plate of ethmoid bone and enter olfactory bulbs In olfactory bulb primary dendrites contact mitral and tuffed cells to form olfactory glomeruli and inhibitory connections between them

Question 28

Describe signal transduction in odorant receptors

Answer 28

1000 different odorant receptors. Action potential by second messenger G protein. Each neuron projects to one or two glomeruli which have lateral inhibition by periglomerular cells and granule cells to sharpen and focus also field potential of glomerulus oscillates

Question 29

Outline the pathway by which impulses generated in olfactory epithelium reach the olfactory cortex

Answer 29

Axons of mitral and tufted cells pass posteriorly through lateral olfactory stria to terminate on apical dendrites of pyramidal cells in five regions of olfactory cortex: anterior olfactory nucleus olfactory tubercle, piriform cortex, amygdala, and entorhinal cortex Then travels directly to frontal cortex or via thalamus to orbitofrontal cortex (conscious)

Question 30

Describe the location and cellular composition of taste buds

Answer 30

Four types: basal cells, dark cells Type I, light cells Type II, intermediate cells Type III, respond to tastants apical ends of taste cells have microvilli that project into a pore each innervated by 50 nerve fibres which in turn draw from 5 buds located on the tongue, epiglottis, pharynx, walls of papillae on tongue

Question 31

Name the five major taste receptors and signal transduction mechanisms

Answer 31

Salt - Na+ selective channel ENaC sour - H+ protons Umami - truncated metabotropic glutamate receptor mGluR4 Sweet - G protein gustducin bitter - variety of unrelated compounds, many of these are poisons

Question 32

Outline thepathways by which impulses generated in taste receptors reach the insular cortex

Answer 32

Sensory nerve fivers from taste buds on anterior 2/3 tongue travel in the chorda tympani branch of facial nerve and posterior 1/3 reach brain stem via glossopharangeal nerve. Areas other than tongue reach via vagus nerve Thalamus - anterior insula - frontal operculum in ipsilateral cerebral cortex

Question 33

Describe the elements of the stretch reflex

Answer 33

When skeletal muscle with an intact nerve supply is stretched it contracts. Sense organ is a small encapsulated spindle like or fusiform shaped structure called the muscle spindle in the fleshy part of the muscle. Uses glutamate gamma motor neuron discharge - cause contraction of intrafusal fibers to shorten and therefore stretches the nuclear bag portion of the spindles. Increases spindle sensitivity.

Question 34

Describe the role of the golgi tendon organ in control of skeletal muscle

Answer 34

Inverse stretch reflex or autogenic inhibition. Net like collection of knobby nerve endings among the fascicles of a tendon. Stimulation leads to IPSP on motor neuron of that muscle and excitatory to neurons supplying antagonists. In series with muscle fibers stimulated by both passive stretch and active contraction of the muscle threshold is low

Question 35

Descrive elements of the withdrawal reflex

Answer 35

typical polysynaptic reflex that occurs in response to a painful stimulus of the skin or subcutaneous tissues, muscles. Response is flexor muscle contraction and inhibition of extensor muscles. STrong stimulus also includes extension of opposite limb.

Question 36

Define spinal shock and describe the initial and long term changes in spinal reflexes that follow the transection of the spinal cord

Answer 36

Spinal shock = loss of sensation accompanied by motor paralysis with initial loss but gradual recovery of reflexes following spinal cord injury.

Question 37

Describe how skilled movements are planned and carried out

Answer 37

supplementary motor area prjects into primary motor cortex. It organizes and plans while primary executes. Premotor receives input from sensory and involved in control of proximal limb muscles needed to orient body for movement posterior parietal cortex somatic sensory and coordination corticospinal and corticobulbar initiation of skilled movement

Question 38

Compare the organization of the central pathways involved in the control of axial and distal muscles

Answer 38

pontine and medullary reticulospinal vestibulospinal and techospinal tracts = axial and proximal distal = lateral corticospinal tract rubrospinal tract excites flexor motor neurons and inhibits extensor motor neurons

Question 39

Define decerebrate and decorticate rigidity and comment on the cause and physiologic significance of each

Answer 39

Decerebration: a complete transection of the bain stem between the superior and inferior colliculi permits the brain stem pathways to function independent of input from higher brain structures. Midcollicular decerebration = reflexes present Decerebrate rigidity - the dominance of drive from ascending sensory pathways to excitatory reticulospinal pathway leads to hyperactivity in extensor muscles. Hyperextends all four limbs.

Question 40

Identify components of the basal ganglia and the pathways that interconnect them, along with neurotransmitters in each pathway

Answer 40

5 interactive structures on each side of the brain caudate nucleus, putamen, globus pallidus (external and internal), subthalamic nucleus, substantia nigra (pars compacta and pars reticulata). Main inputs to basal ganglia terminate on the striatum discharge before movements begin (lateral) Diagram in notes

Question 41

Explain the pathophysiology and symptoms of Parkinson's disease and Huntingtons disease

Answer 41

Huntington's: initial detectable damage is to meidum spiny neurons in the striatum. Loss of this GABAergic pathway is to the globus pallidus external segment releases inhibition permitting the hyperkinetic features of the disease to develop. Jerky trajectory of the hand when reaching to touch a spot esp toward the end. Later hyperkinetic choreiform movements appear and gradually incapacitate patient. Usually death in 10-15 years after onset. Located on short arm of chromosome 4. Parkinsons: both hypokinetic and hyperkinetic features. From degeneration of dopamineric neurons in substantia nigra pars compacta fibers to the putamen are most severely affected. One of the most common neurodegenerative disease sporadic idiopathic. Domaminergic neurons and dopamine receptors are gradually lost with age. Hypokinetic = cogwheel rigidity and tremor at rest.

Question 42

Discuss the functions of the cerebellum and the neurologic abnormalities produced by diseases of this part of the brain

Answer 42

Vestibulocerebellum: equilibrium and eye Spinocerebellum: Proprioceptive input and copy of motor plan from motor cortex Cerebrocerebellum: interact with motor cortex in planning and programming movements Damage leads to several characteristics including hypotonia, ataxia and intention tremor rebound phenomena - cannot break movement of limb inability to perform rapidly alternating opposite movements Difficulty with simultaneous motion at more than one joint = decomposition of movement

Question 43

Explain the pathophysiology and symptoms of myasthenia gravis

Answer 43

Antibodies that block the muscle cells from receiving messages from nerve cell. Autoimmune. weakness of voluntary muscles including breathing eye drooping double vision blocked acetylcholine receptors post synaptic

Question 44

Describe the location of the cell bodies and axonal trajectories of preganglionic and postganglionic sympathetic and parasympathetic

Answer 44

Cell bodies of preganglionic are in the intermediolateral of the spinal cord and motor nuclei of some cranial nerves. Myelinated slow conducting B fibers diverges to average of 8 or 9 post ganglionic Post ganglionic unmyelinated C fibers terminate on visceral effectors.

Question 45

Name the neruotransmitters that are released by preganglionic autonomic neurons, postganglionic sympathetic neurons and adrenal medullary cells

Answer 45

Preganglionic autonomic - Ach | postganglionic sympathetic - NE

Question 46

Name the types of receptors on autonomic ganglia and on various target organs and list the ways that drugs can act to alter the function of the process involved in transmission within the autonomic nervous system

Answer 46

transmission in autonomic ganglia is mediated by N2 nicotinic cholinergic receptors that are blocked by hexamethonium N1 cholinergic receptors at neuromuscular junction are blocked by atropine release of NE from sympathetic phostganglionic fibers acts on alpha 1 beta 2 and beta 1 adrenoreceptors depending on target organ small granulated vesicles in postganglionic noradrenergic neurons contain ATP and norepinephrine and large granulated vesicles contain neuropeptide Y

Question 47

Describe fucntions of the sympathetic and parasympathetic nervous systems

Answer 47

both final common pathway from CNS to viscera sympathetic terminate mainly on smooth muscles parasympathetic visceral structures in head, sacral outflow to walls of organ complementary functions antagonistic sympathetic = flight or flight parasympathetic = relax rest and digest

Question 48

Describe the location of some forebrain and brainstem neurons that are components of central autonomic pathways

Answer 48

direct projections to autonomic preganglionic neurons include hypothalamic paraventricular tract, ventrolateral medulla and medullary raphe indirect projections cerebral cortex, amygdala, and periaqueductal gray matter

Question 49

Describe the composition and functions of the enteric nervous system

Answer 49

3rd division of ANS located in wall of digestive tract esophagus to anus. two well-organized neural plexuses. myenteric plexus - btw longitudinal and circular layers of muscles - control of digestive motility submucosal plexus - between circular muscle and luminal mucosa - senses environment of lumen and regulates gastrointestinal flow and epithelial cell function as many neurons as entire spinal cord can function autonomously, usually healthy digestion requires communication with CNS