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88 terms

Physiology

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tonic receptor
detects presence of stimulus
phasic receptor
detects change in stimulus
Merkel receptors
sense steady pressure (tonic)
Meissner's corpuscle
responds to flutter and stroking movements (phasic)
Sensory nerves
carry signals to spinal cord
Ruffini corpuscle
responds to skin stretch (tonic)
Pacinian corpuscle
senses vibration (phasic)
Olfactory pathway
olfactory nerves, bulb, tract, cortex
5 flavors
salty, sweet, acid, bitter, umami
Magnocellular ganglion cells
movement, location, depth
Parvacellular ganglion cells
color, form, texture
superior colliculus
eye movement, balance, head/body movement control
inferior colliculus
hearing and sight
Where are Autonomic reflexes centered?
Hypothalamus
How many neurons in the autonomic pathway
2 neurons that synapse at an autonomic ganglion
Describe sympathetic neuropathway with neurotransmitters and receptors
short preganglion nerve, ACh with nicotinic receptors, long postganglion nerve, Norepinephrine with adrenergic receptors
Describe parasympathetic neuropathway with neurotransmitters and receptors
long preganglion nerve, ACh with nicotinic receptors, short postganglion nerve, ACh with muscarinic receptors
Name the exception to sympathetic pathway with receptor and neurotransmitter
Sweat glands used cholinergic receptors with ACh
Name the 4 classes of adrenergic receptors, what neurotransmitter it responds to, and location
Alpha 1 - NE>E, sympathetic
Alpha 2 - NE>E, Pancreas
Beta 1 - NE=E, heart, kidney
Beta 2 - E>NE, smooth musc.
Where does the vagus nerve originate and what pathway does it involve
Medulla, parasympathetic
Axon varicosities open what channel and use what neurotransmitter in response to an action potential
Calcium channel, NE
What is the function of AChE?
Breaks down ACh
NAChR is permeable to what ions?
Na and K
What is the role of Troponin and Tropomyosin?
Troponin is bound by Ca and moves Tropomyosin which exposes the myosin-binding site on the actin
What is the role of Titin and Nebulin
Titin provides stability and elasticity to myosin
Nebulin helps align actin
what is the composition of myosinn?
2 coiled heavy chain tails with 2 heads
What part of the sarcomere gets shorter during contraction?
the I band
Describe the power stroke steps to muscle contraction.
Tight binding in the rigor state, ATP binds to myosin which causes myosin to release actin, ATP hydrolized (ADP + Pi) myosin head binds in cocked position, Release of Pi initiates the power stroke, ADP falls off and myosin resumes the rigor state.
Function of DHP receptors
responds to the action potential in the T-tubules, opens ryanodine receptors which let Ca out of the Sarcoplasmic reticulum
Red fibers
Slow twitch oxidative, long periods of contraction, small cell diameter
Intermediate muscle fibers
fast twitch oxidative, less fatigueable, both oxidative and glycolytic processes
White fibers
fast twitch glycolytic, quick fatigue, anaerobic, large cell diameter (recruited last due to fatigue)
Motor unit
Group of muscle fibers controlled by a single somatic motor neuron. (small motor units for fine movements and large units for gross movements) (all fibers are of the same type)
What component is found in skeletal but not smooth muscles?
Troponin
Single unit smooth muscles
numerous gap junctions, unified contraction (found in blood vessels, intestinal tract)
Multi unit smooth muscle
No gap junctions, fine, graded contractions (found in iris, male reproductive tract)
Molecular events of smooth muscle contraction.
Ca channels open causing Ca release from SR, Ca binds to CaM, Ca-CaM activates MLCK, MLCK phosphorylates myosin heads (ATP), phosphorylated myosin heads increase muscle tension (no ATP needed to hold contraction)
Autonomic reflexes are monosynaptic or polysynaptic. Where are the synapses
Polysynaptic. at least one in CNS and another in an autonomic ganglion.
Muscle spindle function
sends information about muscle stretch to the CNS
Golgi tendon organ function
detects strain in the tendon (sensory nerve endings interwoven among collagen fibers)
What 2 regions control voluntary movements
Cerebral Cortex, Basal Nuclei
What 2 regions control postural reflexes and hand and eye movements
Brain stem, Cerebellum
what relays information from spinal cord, basal nucleus, and cerebellum to the Cortex
Thalamus
What integrates porprioception?
Cerebellum
What maintains posture subconciously
Brainstem
Lateral corticospinal tracts cross in the ____ while Anterior CST cross in the ______
medulla, segment
Extrapyramidal system controls _____
Postural reflexes (tonic state of contraction)
Poiseuille's law. Flow
Resistance = Length of tube * viscosity / radius^4
Flow = 1/resistance
Name right and left heart valves
Right AV (tricuspid), Left AV or Mitral (bicuspid), Pulmonary semilunar valve, aortic semilunar valve.
What allows waves of depolarization to pass through the cardiac muscles?
Desomosome and Gap junctions in the Intercalated disks transfer the electrical signal from cell to cell
Starling's Law of the Heart
As you stretch the heart, increasing length, you increase tension
Cardiac action potential steps
Na channels open and then close (-90 - 20mV), K close and Ca open (plateau 10mV), K open Ca close (repolarize -90)
Skeletal vs. Cardiac contraction length and refractory period
cardiac contraction is much longer (10X), cardiac refractory period lasts as long as the contraction (opposite of skeletal)
How do sympathetic and parasympathetic stimulation of the heart affect the action potential
sympathetic hypopolarizes the cell (due to high Ca levels) while parasympathetic hyperpolarizes the cell (due to extra K let out of the cell, muscarinic receptor activated K channels)
Electrical activation of the heart: the pathway
SA node depolarization, Atria, AV node, Ventricle
PR interval
atrial contraction
QRS complex
Electrical stimulation that leads to ventricular contraction
QT interval
ventricular contraction
T wave
ventricular repolarization
cardiac output equation
CO = heart rate * stroke volume
Baroreceptor function and location
stretch-sensitive mechanoreceptors used to monitor blood pressure.
Located in the walls of the carotid arteries and aorta.
Baroreceptor reflex
sensory neurons to the CVCC, decrease sympathetic (dilation of arteries/veins), increase parasympathetic (decrease heart rate)
1st and 2nd most abundant WBCs
Neutrophils, Lymphocytes
what defines RBC shape?
cytoskeleton
What uses Fe to make Hb?
bone marrow
What organ converts Hb to bilirubin? where does bilirubin go?
Spleen, bilirubin is metabolized in the liver and excreted through bile
steps of platelet aggregation
collagen binds and activates platelets, release of platelet factors, attracts more platelets, forms platelet plug
What inhibits platelet adhesion in the blood?
Prostacyclin and NO (also causes vasodilation)
Which pathway is longer, intrinsic or extrinsic?
intrinsic
common pathway steps
prothrombin converted to thrombin which converts fibrinogen to fibrin. (those fibers become part of the clot)
role of thrombin in clot resorption
thrombin creates plasmin from plasminogen. plasmin breaks down the fibrin.
muscles of inhalation
external intercostals, diaphragm, scalenes, sternocleido-mastoids
muscles of exhalation
internal intercostals, abdominnals
name 4 lung volumes
residual volume, expiratory reserve volume, tidal volume, inspiratory reserve volume
Name the 4 lung capacities
Total lung capacity, inspiratory capacity (IRV + Vt), vital capacity (Vt + IRV + ERV), Functional residual capacity (ERV + RV)
Law of Leplace (equation)
Pressure = 2 * Tension / radius
Function of alveolar type I and type II cells
type I is thin for gas transport, type II produces surfactant
What causes arteriolar vasoconstriction around an alveolus?
low O2 levels
Factors that decrease Hb O2 binding affinity
increased Temp, Pco2, 2,3 DPG, and decreased pH
How is a majority of the CO2 transported in the blood?
as bicarbonate ions (HCO3-)
What is the function of Carbonic anhydrase (CA)?
converts co2 and h2o into carbonic acid (h2co3)
How is excess bicarbonate removed from the RBC?
by the Cl/HCO3- antiport
What nerve activates the diaphragm?
the phrenic nerve
dorsal respiratory group (DRG) function
muscles of inspiration
Role of central H+ chemoreceptor
senses increased CO2 levels and stimulates increased ventilation
Peripheral chemoreceptors are responsive to what molecules?
CO2, O2
protective ventilation reflexes
bronchostriction in response to noxious particles
coughing - stimulation of carina
sneezing - nasal cavity irritation
function of albumins
maintain oncotic pressure