Physiology I 2

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Identify test sensations and give examples: Sweet - organic
Sour - acids
Salty - Na, NaCl
Bitter - coffee, nicotine, quinine, Ca, Mg salts
Umami - MSG
Describe taste buds: Supporting cells - insulate receptors
Sensory cells - high turnover, have apical and basal end. Apical end - hairs bathed in saliva, basal end - synapse with cranial nerves
Basal cells = stem cells -replacement to sensory cells
Gustatory pathway: Chemical dissolved in saliva --> taste pore --> hairs (chemical action on sensory cell) --> depolarization --> release NT -> NT binds sensory neuron to produce AP
Gustatory AP go to brain through CN's . Name them: CN VII - facial
CN IX - glossopharyngeal
CN X - vagus
Describe gustatory pathway starting with CN's: CN's - solitary nucleus (medulla) - thalamus - gustatory cortex in parietal lobe
Name some projections of gustatory nerves: Hypothalamus, limbic structures, reflexes in stomach + salivary glands
Identify 7 primary odors and give examples: Camphoric - moth ball
Musk - parfume
Floral - flowers
Peppermint
Ethereal - pear
Pungent - vinegar
Putrid - bad smell
What secreted mucus to nasal cavity: Bowmans glands
Describe olfactory pathway: Olfactory bulb (mitral/tufted cells) --> olfactory cortex in temporal lobe
Describe projections of olfactory cortex: Frontal lobe + thalamus --> interpret and identify smells
Hypothalamus and limbic --> emotional response
Stomach --> gastric juice
Describe auditory pathway: Sound --> auditory canal --> tympanic membrane vibrates --> ossicles amplify --> oval window vibrates --> fluid in cochlea moves --> basilar membrane moves up and down, round window moves up and down --> hair cells in organ of Corti bend --> organ of Corti sends signals to cochlear nuclei of medulla --> superior olivary nucleus in medulla --> inferior colliculus in midbrain --> medial geniculate nucleus in thalamus --> auditory cortex in temporal lobe
Vibration near oval window causes _ frequency sound, while vibration near cohlear apex causes _ frequency sound: high, low
If hair cell in organ of Corti bends toward tallest hair you get_, while if it bends away from talles hair you get_: Depolarization
Hyperpolarization
What is called blind spot in retina and why: Optic disc because there are no rods and cones there
Pigmented epithelium of retina has the function of ...: Preventing scattering of light and has phagocytes that destroy old receptors
Name cell layers of retina: Outer - rods + cones
Inner - interneurons, amacrine, horizontal, bipolar
Ganglion - axons from optic nerve
What is photopigment and where is it located: It is located in the outer segment of photoreceptor
Rods = rhodopsin
Cones = pigment sensitive to green, red, blue
What does inner segment of photoreceptor contain: Organelles that synthesize photopigment
What is a synaptic body in retina: Contacts bipolar neuron, releases NT with no light stmulation
Compare rods vs cones: Rods are:
-monochromatic
-have high efficiency in dark
-bleached in daylight
-located in periphery
-low acuity
- many rods - 1 bipolar cell

Cones are :
-trichromatic
-have no efficiency in dark
-active in daylight
-located in fovea
-have high acuity
-1 cone - 1 bipolar cell
Describe visual pathway: Light excites photoreceptors --> photoreceptors excite bipolar and horizontal cells --> bipolar cells excite amacrine and ganglion cells --> ganglion cell axons form optic nerve and leave through optic disc --> through optic chiasm they cross --> lateral geniculate nucleus --> striate cortex
Which cells in retina produce AP's: Ganglion and amacrine
All other cells - receptor potential
Projections of optic tract: Superior colliculus --> control eye muscles
Pretectal nuclei --> pupillary light reflex
Suprachiasmatic nucleus --> circadian rhythm, hypothalamus
Location of primary motor area: Pre central gyrus
What is the lowest level of cortical motor organization: Primary motor area
Where is Premotor area located: anterior to primary motor cortex and lateral to SMA
What is premotor area responsible for: More complex pattern of movements, "memory" of some complex motor skills . Also excites groups of primary motor cortex by direct or indirect pathway
Location of SMA: anterior to primary motor cortex, medial to premotor area
What does SMA do: Control of some bilateral motor skills - climbing
Position of head (eyes) for finer motor movements
Describe motor reflexes: Superior colliculus = visual
Inferior colliculus = auditory
Pontine/medullary nuclei = antigravity extensor muscles
Vestibular nuclei = change in position and acceleration (brainstem)
Describe corticospinal (pyramidal ) tract: Voluntary movements - motor (60%) + sensory (40%)
Lateral tract - 85 % - cross at pyramids
Ventral tracts - 15 % - do not cross
Collateral of corticospinal tracts: vestibular and reticular nuclei
cerebellum and basal ganglia
Describe Rubrospinal (corticorubral tracts): Voluntary movements
Aids fine movements of distal limbs (fingers)
Collateral of rubrospinal tracts: Cerebellum + brainstem
Describe reticulospinal tracts: LATERAL - pontine reticular nuclei - stimulate antigravity extensor muscles - can sustain erect position w/out brain input
VENTRAL - medullary reticular nuclei - inhibit extensors - less active than lateral system
In movement - corticospinal + rubrospinal tracts stimulate ventral system to override lateral not to interfere with movement
Collaterals of reticulospinal tracts: Cerebellum + basal ganglia
Describe vestibulospinal tracts: From vestibular nuclei in lateral medulla and pons
-Receives input from vestibular apparatus, detects changes in acceleration and position of body
Collaterals of vestibulospinal tracts: Cerebellum + basal ganglia
Describe tectospinal tract: From corpus quadragenium of tectum of midbrain (superior + inferior colliculus)
Mediate reflexes - head, neck , upper trunk movements in response to visual and auditory stimuli
Collateral of tectospinal tracts: Cerebellum
Describe descending tracts: Converge on alpha motor neurons via interneurons
Alpha motor neurons can be excited by stimulation or disinhibition
Damage between cortical motor areas and brainstem leads to: DECEREBRATE RIGIDITY - decreased activity (input) to medullary reticular nuclei
If also have loss of voluntary control will have SPASTIC PARALYSIS
Damage of spinal cord leads to: FLACCID PARALYSIS or weakness
After period of spinal shock you will see INCREASED reflexes because of decrease in net inhibitory input to spine by motor tracts
Damage to nerves leads to: FLACCID paralysis with DECREASED or absent reflexes
Describe function of cerebellum: Cerebellum receives information via spinocerebellar tract. It receives info about movement intention from collaterals and it calculates and corrects it accordingly.
It will correct it by either stimulating cortical motor areas via thalamus or stimulating reflex motor areas via midbrain and brainstem nuclei
Describe 3 parts of cerebellum and their functions: Cerebrocerebellum - planning, initiation, assesment/correction, motor memory
Spinocerebellum - medial body posture, modulates reticulospinal pathways
Vestibulocerebellum - eye movements, body equilibrium, modulates vestibulospinal pathways
Describe damage to cerebrocerebellum: DYSMETRIA - voluntary movements overshoot or undershoot target
ATAXIA - erratic gait
INTENTION TREMOR - tremor during voluntary movement
FAILURE OF PROGRESSION - complicated fast movements
DYSARTHRIA - complicated fast speech
Describe spinocerebellum damage: ATAXIA
If you have damage to deep nuclei - decreased extensor tone
Damage to vestibulocerebellum: NYSTAGMUS - slow movement of eyes in one direction followed by rapid movement back
Basal ganglia are located: below thalamus
Globus pallidus main function: Inhibition of thalamus
Describe two pathways of globus pallidus inhibitory output: DIRECT - striatum inhibits globus pallidus which decreases inhibitory thalamic tone
INDIRECT - stimulates globus pallidus which increases inhibition
Substantia nigra _ direct pathway, _ indirect pathway: stimulates, inhibits
Describe Parkinsons disease: Damage to substantia nigra causes loss of dopaminergic input, direct pathway is gone, have indirect only --> inhibition of thalamus
Symptoms :
-tremor at rest
-bradykinesia - decreased voluntary movement
-cogwheel rigidity
-cognitive losses
-swallowing/breathing problems - later stages
Describe hemiballismus: Ballistic voluntary movements
Ipsilateral lesion of superthalamic nuclei
Huntingtons chorea: basal ganglia lesion
Wilsons disease: degeneration of globus pallidus + striatum
Tardive dyskinesia: Chronic neuroleptic use
Athetosis - snake like movements, tremor at rest
Name types of spinal nerves: Sensory + motor
Sensory can be somatosensory and viscerosensory
Motor can be autonomic + voluntary
2 types of efferent fibers: Type A - large + myelinated
Type C - small + unmyelinated
Type A fibers: Large myelinated
1. alpha - control muscle fibers
2. gamma - control muscle spindle by setting its length
3. preganglionic autonomic - myelinated
Type C fibers: small, unmyelinated
Postganglionic autonomic
Reflex arc is: entire pathway of reflex
Describe general reflex pathway: From receptors through AFFERENT fibers to CNS nuclei/PNS ganglia --> through EFFERENT fibers send motor signals to effector
Two types of efferent fibers: Dynamic and static gamma fibers
Two types of intrafusal fibers: Nuclear bag - Ia - primary afferent
Nuclear chain - II - secondary afferent
Describe static response: Slow stretch
-Output directly proportional to DEGREE of stretch
-Nuclear chain fibers
Describe dynamic response: -Rapid stretch
- Ia nuclear bag fibers
- Outpur directly proportional to RATE of stretch
Muscle spindle functions: - Maintain muscle length and force
-Maintain erect position in anti-gravity muscles
-Inform CNS of muscle conditions via spino-cerebellar tract
If you have decreased reflexes you have_, if increased reflexes you have_: lower motor neuron damage, upper motor neuron damage
Describe clonus, in what condition do you see it: You see clonus in decerebrate rigidity caused by damage between cortex and brainstem.
It is pendulum like oscillations in limb movement when muscle spindle reflex is facilitated by upper motor neuron
Describe withdrawal (flexor ) and cross extensor reflex: When you have pain to limb, it will cause withdrawal - flexion - of that limb and extension of the other side limb
POLYSYNAPTIC reflex
What can cause muscle spasms (cramps): 1. Local irritation - muscle contraction causes even more irritation
2. Electrolytes (decreased Ca)
3. Ischemia
Describe abdominal spasm: Spinal reflex - peritonitis, appendicitis, surgery
Describe mass reflex: Caused by strong pain stimulus or overdistnetion of hollow organs
-Strong flexor response
-evacuation of bladder/bowel
-increased BP
-increased sweating
What are autonomic reflexes: Reflexes w/out CNS input, can be defecation or urination (but also can be with CNS input)
Vestibular placing reflex: Limb is extended when it encounters solid object
Righting reflex: Restoring upright position
Name some brainstem reflexes: Visual, auditory, breathing, autonomic
What stimulates release of hormone: NT
Another hormone
Pulsatile - circadian rhythm
Which hormones are dissolved in plasma: Amino acid and protein derived hormones - synthesized in advance, stored in vesicles, can be cleaved from pre pro hormones
Which hormones are bound to plasma proteins: steroid hormones - from cholesterol, hydrophobic - produced on demand
Distinguish between extracellular and intracellular hormone receptors: Extracellular - peptide hormones, activate 2nd messensger system
Intracellular - cytoplasm, hormone-receptor complex binds to DNA
Up regulation is _ Down regulation is_: Increase # of receptors
Decrease # of receptors
ED50: In dose response curve, 1/2 way between threshold and max response
Shift right in dose response curve causes_ Shft left causes _ Why?: decreased affinity - takes more concentration to get same response
Shift left - increased affinity
Describe loop between hypothalamus and pituitary: Hypothalamus releases CRH - cortico releasing hormone which acts on pituitary and it releases ACTH which acts on adrenal cortex to release cortisol. Cortisol then goes and inhibits hypothalamus and pituitary
If you have adrenal insufficiency and not producing any cortisol, what happens to CRH and ACTH: They will increase, because cortisol is not inhibiting hypothalamus and pituitary any more
Which part of pituitary is a direct continuation of hypothalamus: Posterior pituitary
If you have large pituitary tumor, which structure will it press on?: Optic chiasm, causing visual disturbances
Prolactin secreting tumor will cause_ in males, and _ in females: Visual disturbances
Breast discharge
Which hormones are made and stored in hypothalamus but released from posterior pituitary: Oxytocin + ADH
Releasing hormones always come from - What kind of hormones are they: Hypothalamus
Excitatory
Name hormones derived from hypothalamus: Releasing hormones
DA
Somatostatin
DA inhibits _: Prolactin from anterior pituitary
Somatostatin inhibits _: Prolactin and growth hormone from pituitary
Posterior pituitary releases: ADH and oxytocin
ADH is stimulated by: Increased blood osmolality or decreased blood volume
Main function of ADH: RETAINING WATER - by increasing number of channels in kidney
Oxytocin is stimulated by _: Breastfeeding + child birth
Functions of oxytocin: Labor induction
Increased milk ejection
Uterus contractions
You can see decreased ADH in which disease: Diabetes insipidus - polyuria, polydipsia
If your ADH is increased , what systemic effect will it have: Edema
Hormones produced by anterior pituitary: FLAGTOP
FSH
LH
ACTH
Growth hormone
TSH
Prolactin
If you remove hypothalamus from posterior pituitary you will see increase in which hormone: Prolactin, since its no longer inhibited by DA
Name 3 zones of adrenal cortex: Zona reticularis
Zona fasciculata
Zona glomerulosa
ACTH acts on two zones in adrenal cortex. What are they: Zona fasciculata and zona reticularis
Which zone produces cortisol in adrenal cortex: Zona fasciculata
Which zone produces androgens in adrenal cortex: Zona reticularis (very low)
Which zone produces aldosterone: Zona glomerulosa
Cortisol is made from: cholesterol
Describe actions of cortisol: Liver - increase gluconeogenesis and glycogenolysis
Adipose - lipolysis
Main function of aldosterone: Salt retention
Renin angiotensin aldosterone system function: Decrease Na excretion
Retain water and salt
Adrenal medulla makes _: Catecholamines - NE + EPI
Describe regulation of thyroid hormone: Hypothalamus releases TRH --> acts on pituitary which releases TSH --> acts on thyroid follicles to produce thyroid hormone. Thyroid hormine inhibits both anterior pituitary and hypothalamus and induces production of somatostatin which also inhibits anterior pituitary
Name two thyroid hormones: T3 - 25 %
T4 - 75 %
Thyroid gland has two types of cells. Describe and what produce: Follicular - filled with colloid, produce T3 and T4
Parafollicular - produce calcitonin - decrease Ca in blood
3 main stages of thyroid hormone synthesis: Thyroglobulin synthesis
Iodide uptake
Iodothyronine formation
Describe thyroglobulin formation: Produced in ribosomes , rough ER.
Undergoes dimerization and glycosylation in smooth ER
Packaged in Golgi, released to colloid
Describe iodide uptake: Requires ATP, concentration above blood level, released to colloid
Formation of iodothyronine is catalyzed by_: Thyroid peroxidase
Iodothyronine is composed of _: MIT + DIT linked to thyroglobulin
T4: 2 DIT
T3: 1 MIT + 1 DIT
Thyroid hormones travel by_: binding to plasma proteins
Which thyroid hormone is active form: T3
Which symptoms would you have if you had hyperthyroidism: Excitability
Sweating
Weight loss but increased appetite
Diarrhea
Fatigue
Muscle weakness
Tremor
Protruding eyes
Which symptoms would you have if you had hypothyroidism: Obesity with reduced appetite
Excessive sleeping
Mental slowing down
Constipation
Decreased body temp.
Action of IGF1: Liver - tissue growth
Long bones growth in kids
Which anterior pituitary hormone has anti insulin action: Growth hormone (similar to cortisol)
Main action of growth hormone: Makes muscle and adipose resistant to glucose, increases gluconeogenesis
Describe pituitary dwarfism: If you lack of GH only you can still go through puberty, just shorter
If you lack GH and other anterior pituitary hormones you will not go through puberty
What happens if you have excess GH: Gigantism
Acromegaly - bones, organs hypertrophy
Also insulin resistance and hyperglycemia
Three types of cells in pancreas: Alpha cells - glucagon
Beta cells - insulin
Delta cells - somatostatin
Insulin functions: Growth + differentiation
Glucose transport + glycogen synthesis
Which two tissues require insulin: Muscle and adipose
Effect of insulin on liver: Facilitates metabolism but doesnt insert transporters as in muscle and adipose
In liver insulin increases_: Glycogenesis
Glycolysis
Protein synthesis
Lipogenesis
In muscle insulin increases: Glycogenesis
Protein synthesis
Glucose oxidation
In adipose insulin increases: Lipogenesis
In liver glucagon increases _: Glycogenolysis
Gluconeogenesis
Ketogenesis
Lipolysis
In pancreas glucagon increases_: Production of insulin
Describe general features of diabetes: Frequent urination
Increased thirst and appetite
Weight loss
Describe type I DM: Insulin dependent
Inadequate insulin production
Insulin gene mutation
AUTOIMMUNE (usually not inherited)
REQUIRES insulin injections
Describe Type II DM: Non insulin dependent
Insulin RESISTANCE - receptor defect
Normal or increased levels of insulin in blood, but it doesnt work
Strong genetic component
Treat for type II DM: Diet + exercise
Sulfonylurea drugs
In some cases insulin treatment
What is similar and different between type I and II DM: Both have high glucose
Type I - low insulin
Type II - high insulin
Describe action of PTH: Acts on kidney and bone, released when there is LOW Ca in blood
-Activates osteoclasts to break down BONE - release Ca in blood and P
-Increase Ca reabsorption from food
-Promotes activation of vitamin D in KIDNEY --> increase Ca reabsorption
-Decrease P reabsorption
Describe action of vitamin D: acts on intestine + bone
-Increase intestinal abdorption of Ca
- Increase bone formation and resorption
-Small increase in kidney Ca reabsorption
Calcitonin acts on _: Bone - deactivates osteoclasts to stop breaking bone down
If you have excess PTH, you also have _: 1) Hypercalcemia
2) Hypercalcinuria - renal stones
3)Hypophosphatemia
4) Decreased bone mass
If you have lack of PTH , you have _: 1) Hypocalcemia
2)Hyperphosphatemia
3) Increased bone mass
If you have excess vitamin D, you would have same effects as with increased_: PTH
Lack of vitamin D causes: Rickets
Temporal vs Spatial summation: Temporal - one neuron fires at different times
Spatial - two neurons fire at same time
Sympathetic nervous system is also called_ Parasympathetic is also called _: Thoracolumbar
Craniosacral
Length of pre vs post in parasympathetic neurons: Long pre, short post
Ratio of pre vs post in parasympathetic neurons: 1:1
Preganglionic parasympathetic receptor: Nicotinic
Postganglionic parasympathetic receptor: Muscarinic
Muscarinic receptors 1, 3, 5 are _ 2, 4 are _: excitatory
inhibitory
Nicotinic receptor vs Muscarinic receptor: Nicotinic - chemically mediated
Muscarinic - mediated by G protein
But both activated by Ach
Ratio of pre to post in sympathetic: 1 : many
Preganglionic sympathetic receptor: Nicotinic, activated by Ach
Postganglionic sympathetic receptor: Adrenergic, activated by NE
In adrenal gland preganglionic neurons synapse directly on_: Adrenal medulla
What acts as postganglionic neurons in adrenal medulla: CHROMAFFIN CELLS - release EPI - 80%, and NE - 20%
In sweat glands postganglionic sympathetic cells are different from rest because they _: release Ach (not NE) and bind muscarinic receptor (not adrenergic)
Beta 1 adrenergic receptor binds_, while alpha 1 binds_: cAMP
IP3
Eyes - parasympathetic: Pupil CONSTRICTION
Circular + ciliary muscle contraction - M3
Eyes - sympathetic: Pupil DILATION
Radial muscle contraction - alpha 1 receptor
Heart - parasympathetic: Slow down SA node, decrease contractility - M2
Heart - sympathetic: Increase SA node, increase contractility - beta 1 receptor
Blood vessels - parasympathetic: Very little dilation
Blood vessels - sympathetic: DILATION - beta2
CONSTRICTION - in skin and internal organs - alpha1
Bronchi - para: Bronchiolar smooth muscle CONTRACTION - M3
Bronchi - symp: Bronchiolar smooth muscle relaxation - beta 2
Intestines - para: Increase motility and tone, sphincter relaxation, enzyme secretion
Intestines - symp: Decrease motility and tone
Sphincter CONTRACTION
Kidney - para: No effect
Kidney - symp: Renin release + increase ADH - beta 1
Bladder - para: Bladder CONTRACTION + neck RELAXATION
Bladder - symp: RELAXATION of detrusor + contraction of neck
Penis - symp: Ejaculation
Penis - para: Erection (Point and Shoot)
Uterus contractions are mediated by _ nervous system, relaxation by _: Both,
Sympathetic
Skin has _ nervous activity only: Sympathetic - increase sweat gland activity + hair smooth muscle contraction
Effect of symp. system on adipose: Increased lipolysis
Liver has mostly _ effect of nervous system: Sympathetic - increased glycogenolysis and gluconeogenesis
_ nervous system increases insulin, while _ decreases it: Parasympathetic
Sympathetic
Baroreceptors location: Carotid sinus + aortic arch
Path of carotid sinus baroreceptors: Carotid sinus nerve (Herings) to glossopharyngeal nerve (brainstem)
Path of aortic arch baroreceptors: Vagus nerve to nucleus solitaris (medulla)
Which baroreceptors are more sensitive: Carotid sinus because they have thinner walls
Name CNS medullary centers: Vasoconstrictor (pressor ) - sympathetic
Vagal - parasympathetic
Baroreceptors do not respond above _ or below _ mm Hg: 180
60
If you clamp carotids, what will happen to BP: It will spike and remain high until carotids are released, then returns to normal
Receptor firing rate depends on: Rate and absolute BP
In systole receptor firing rate is _, in diastole its _: higher
lower
Can baroreceptors be used for long term control of BP, if not why not: No, they adapt to maintained mean BP, for long term use RENAL SYSTEM by controling amount of body fluid
Normal mean pressure: 94 mm Hg
Beta 1 receptors _ heart rate and contractility: INCREASE
Alpha receptors are responsible for: Vasoconstriction
_ receptor decreases heart rate and conduction velocity: M2
What happens when pressure increased: Increased baroreceptor stretch --> increase afferent input to CNS --> pressor (vasoconstrictor) center is inhibited -> causes vasodilation --> decreases heart performance --> decreases BP
Cardioinhibitory (vagal)center is stimulated, decreases heart rate --> BP falls
What happens when pressure is decreased: Decreased baroreceptor firing --> removes inhibition from pressor vasoconstrictor center (symp)- cardioinhibitory center inhibited --> increases heart rate --> increases BP
If you stand on your head what happens to BP and heart rate: Heart rate DECREASES --> gravity on carotid sinus stretches it --> will think increased pressure and will decrease it
Febrile illness means you have_: Fever
Heat production occurs as _: By product of metabolism
Heat loss occurs via _: Skin and respiration
Describe transfer of heat within body: Insulation = body fat
Forced convection = movement of blood
Vasodilation - remove heat
Vasoconstriction - conserve heat
Heat transfer from body :: 1. Radiation - 60%
2. Conduction- 3 %
3. Convection - 15 % air + water
4. Evaporation - 22 % - sweat
Heat retention is achieved via _: 1. Vasoconstriction
2.Clothing
3. Shivering - break ATP by muscle contraction
4.Increase thyroid hormone --> increase metabolism
Hypothermia can cause: Ventricular fibrillation
Two types of thermoreceptors and where located: Cold - periphery, extremities
Warm - core + CNS
Heat loss center is in: Anterior hypothalamus
Heat conservation center is in: Posterior hypothalamus
Set point is a _: Reference temperature
Fever is _: increase in set point, caused by pyrogens which induce action of IL1
If patient presents with onset of chills (shivering, pale) it means _, while if patient presents with "crisis/flush" (sweating, red skin) it means _: Dangerous, set point is high, immune system did not cleal pyrogens
Patient is getting better, set point has been reset to normal
Polyomyelitis is an example of _ Name symptoms too: Lower motor neuron damage
-Muscle atrophy
-Flaccid paralysis
-Decreased reflexes
Stroke is an example of _ Name symptoms too: Upper motor neuron damage
Increased reflexes
Increased knee jerk reflex, ankle clonus
Positive Babinski reflex
Positive Babinski sign means you have _: Plantar dorsiflexion
Flaring of toes
Normal in infants, but disappears in adults, if present means you have brain damage

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