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test 2 Flashcards

1
Q

transduction of environmental info

A
  • It’s how info from external enviro turns into language the brain understands (action potentials)
    • Environmental stimuli (energy - heat, light, touch, sound) detected by sensory receptors
      ○ Receptors then convert info into action potentials
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2
Q

enviro stimuli

A
  • Enviro stimulus must be detected by sensory receptor
    • E.g.
      ○ Mechanical stimuli - touch, pressure, vibration, proprioception (muscle sense/ spindles), sound
      § Stretches sensory
      ○ Chemical stimuli - taste, pain, odors
      ○ Electromagnetic stimulus - light
      ○ Other stimuli include - gravity, motion, acceleration, heat
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3
Q

adequate stimulus

A
  • form of enviro stimulus to which sensory receptor is most sensitive
    ○ e.g. rod + cone cells of eyes is light, also respond to pressure on eyeball, but not as well as light
    ○ Hit hand w tip of pencil = activate cold receptor
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4
Q

receptor (generator) potentials

A

1 - sensory receptor stimulated by enviro stimulus,
2 - causes change in ion permeability = local depolarization (called generator/ receptor potential),
3 - RP spreads to area on neuron that doesn’t have voltage-gated ion channels (1st node of ranvier),
4 - then goes along axons, but if no axons, depolarization spreads to synapse

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5
Q

Recep potentials - shared characteristics w EPSPs and IPSPs

A
  • Generally depolarizing but can be hyperpolarizing as well
    • Caused by increase in permeability to Na ions (or K ions in case of hyperpolarizing stimulus)
    • Local + don’t propagate down the neuron like an AP, but spread like an EPSP, decreasing w time and distance from the stimulus
      Proportional to strength of stimulus - stronger stimulus = larger receptor potential = more likely to fire AP
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6
Q

Receptor potential + neural coding

A
  • Neural coding - heavier weight = more AP, that thing u learned earlier from last test
    • Somatosensory system - detects + processes touch, vibration, temp, pain - to do w the skin
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7
Q

all receptors in skin are called:

A
  • cutaneous receptors
    ○ Includes:
    § Hair follicle - fine touch, vibration
    § Free nerve endings - respond to pain + temp (hot/cold)
    § Meissner’s corpuscles - low frequency vibrations (30-40 cycles/ sec) + touch
    § Ruffini’s corpuscles - detect touch
    § Pacinian corpuscles - high frequency vibrations (250-300 cycles/sec) + touch
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8
Q

receptive fiedl

A
  • area on surface of skin where enough stimulus will activate a particular receptor to fire an AP
    ○ Stimulus applied outside receptor field = no action potential
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9
Q

2 somatosensory pathways to brain:

A

Spinothalamic (anterolateral) tract

Dorsal column, medial lemniscal system

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10
Q
  • Spinothalamic (anterolateral) tract
A
  • transmits info w basic sensations (pain, temp, crude touch)
    1- Info from sensory neuron (1st order neuron) enters spinal cord (at bottom, lower spinal cord), crosses now
    2- Synapses w second order neuron (upper spinal cord)
    3- 2nd order neuron crosses to opposite (contralateral) side of spinal cord and ascends to thalamus
    4- Thalamus is a relay station for all sensory info (except smell)
    5- 2nd synapse w 3rd order neuron happens here than goes to somatosensory cortex
    ○ Sensory info from right side of body goes to left side of brain vice versa
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11
Q
  • Dorsal column, medial lemniscal system
A
  • transmits info w advanced sensations of fine detailed touch, proprioception (muscle sense), vibration
    ○ From sensory neuron (1st order) goes to spinal cord + goes up
    ○ Unlike spinothalamic, instead of going to back (contralateral dies), sensory neuron goes to 2nd order, crosses to opposite side, goes to thalamus and synapses again onto 3rd order, then to somatosensory cortex
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12
Q

Primary somatosensory cortex

A
  • Is where sensory info goes to in brain
    • In parietal love on postcentral gyrus behind central sulcus
    • Sensory info is geographically preserved (all info for foot in one area, leg next to it, hip next to that, etc) -> this representation is called somatosensory homunculus
      ○ Some areas not proportionate bc some areas get for info and need more of brain to process that info
      ○ Face is on outside, then curving in its like a body w the hands up
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13
Q

visual system

A
  • Detects light, turns it into Aps, goes to visual areas for processing, lets up become aware of external enviro
    • Has eye (photoreceptors turning light), visual pathway (transmits AP), primary visual area in occipital lobe of brain (processes incoming signals)
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14
Q

the eye

A
  • Light goes through cornea, light regulated by iris (constrict w bright, dilate in low light), lens flips light (upside down + backwards) + focuses it onto retina at back of eye
    • Retina has rods + cones which point to back of head
    • Center of vision focused on part of retina called fovea - this area has highest conc of cone cells
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15
Q

Photoreceptors of eye

A
  • rods + cones
    • Rods sensitive to light, function best under low light cond
      ○ Have 1 type of photopigment, don’t detect colour
      ○ In region of retina outside + around fovea
    • Cones best under bright light, good for detecting detail
      ○ 3 types of cone cells, each have diff photopigment _ sensitive to one primary colour
      ○ Found in fovea - high conc
    • Neither have axons = no AP, but do have receptors potentials that release inhibitory neurotransmitter
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16
Q

transduction of light to AP

A
  • Retina has pigment layer at back of eyes that absorbs extra light
    ○ Cells are: bipolar cells, ganglion cells, horizontal cells, amacrine cells
    ○ These cells get the info from rods/ cones and make Aps
    • No light present = depolarized rod/ cone, release of inhibitory neurotransmitter, shut off bipolar cells
      ○ Na flows to photoreceptors = their depolarization
    • Light present = rod + cone hyperpolarized + shut down, no neurotransmitter release, bipolar cells depolarize themselves and can do AP in ganglion cells
      ○ Na channels close - w less Na in, K leaks out - cell hyperpolarizes
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17
Q

4 types of eye mvmts

A
  • Saccades - rapid, jerky; rapidly move eye to object of interest (looking around room w head still, reading words on computer)
  • Smooth pursuit - smooth movement to keep moving object of interest focused on fovea (following flight of bird while keeping head still)
    • Vestibular ocular reflect (VOR) - focus attention on object then move head back and forth/ shake up + down (staring at someone while nodding/ shaking head)
    • Vergences - object of interest approaching or moving away from you (moving away, eyes diverge; moving closer, eyes converge) (e.g. staring at pencil moving from/ to ur face, cross eye)
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18
Q

audotiry system

A
  • Sound waves to AP that go to auditory system of brain

- Our acute hearing is 1000-3000 Hz, but can do 20 (waves per sec - Hz) to 20 000Hz

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19
Q

auditory system - 3 parts

A

○ External/ outer ear - has ear/ auricle and external auditory canal
○ Middle ear - eardrum (tympanic membrane), ear ossicles (3 bones - malleus, incus, stapes) and Eustachian tube
○ Inner ear - vestibular apparatus (balance) and cochlea (processing of sound)

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20
Q

cochlea

A
  • shape of snail, has 3 compartments:
    ○ Upper scala vestibuli (vestibular duct), middle cochlear duct, lower scala tympani
    ○ Basilar membrane - contains organ of Corti and seperates cochlear duct + tympanic duct
    § Organ of Corti is where sounds waves turn into AP by special hair cells, which are embedded in tectorial membrane
    § Sound waves cause basilar membrane to vibrate, bends hair cells in tectorial membrane
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21
Q

what is sound

A
  • Sound is when wave of air pressure hits parts of ear/ microphone and turns it into AP, which is when it is interpreted as sound (so if tree falls and no one there = no sound)
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22
Q

frequency vs intesnity

A
  • Frequency - number of waves/ cycles per unit time

- Intensity (loudness) - height/ amplitude of sound wave

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23
Q

air waves path

A
  • Air waves go through external auditory canal and hit ear drum, which goes back/ forth & ear ossicles amplify it
    ○ Ear ossicles make oval window vibrate, which amplifies sound waves 15-20x
    ○ Fluid in cochlea (perilymph) transmits waves to hair cells, which detect vibration = AP
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24
Q
  • Diff frequencies of sound + the way we hear them due to vibration of basilar membrane
A

○ Basilar membrane wide + thin + loose at top and narrow + thick + tight at base near oval window
○ Low frequencies stimulate hair at apex (top) of cochlea, high freq stim near oval window (base)
○ When vibrates, hair cells are bent = ion channels open + cell depolarize = release of neurotransmitter = AP
§ Louder sound = stronger vibration = more bent hair = more neurotransmitter = more AP

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25
Q

vestibular system

A
  • Detects linear + rotational movement of head to body - balance, reflexes, equilibrium
    • Also responsible for vestibular ocular reflex

Hair cells at rest - release resting lvl neurotransmitter = AP, when bends towards kinocilium = more AP, bends away kinocilium = less AP

semicircular canals, otolith organs

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26
Q

2 main aprts - vestibular system

A

○ Semicircular canals - rotational/ angular accelerations of health
§ 3 canals - one for each plane
§ Filled w fluid called endolymph
§ End of canal is ampula - inside in crista ampullaris, contains sensory hair cells, cilia in gelatinous material called cupula
§ Move head to left = endolymph moves to right, hits cupula, bends hair
□ Hair bent is particular direction = depolarize + AP, bent in opp direction = hyperpolarize + no signals

Otolith organs - linear accelerations/ decelerations
§ 2 - one of vertical, horizontal
□ Utricle - horizontal (like in car)
□ Saccule - vertical (elevator)
§ Have hair cells at base, and cilia in gelatinous membrane
§ Gelatinous membrane also has otolith crystals to give weight
§ Otolith crystals also lag and seem to move in opp direction = bent hair in opp direction

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27
Q

4 main functions of CV system:

A
  • Transports O2 and nutrients to all cells of body
    • Transports CO2 and water products from cells
    • Helps regulate body temp and pH
    • Transports and distributed hormones and other substances within the body
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28
Q

heart strcuture

A
  • Left ventricle wall thicker bc delivers blood to whole body = contract more forcefully
    • Right atrioventricular (AV valve) - tricuspid, left av valve - bicuspid, mitral valve
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29
Q

circulation through heart

A
  • Vena cava to right atrium, right av valve, right ventricle, right vent contracts, blood out pulmonary valve, pulmonary artery, to lungs - removes co2 + picks up o2, blood back through pulmonary vein, left atrium, left av valve, left ventricle, left vent contracts blood out aortic valve, aorta, out to body
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30
Q

2 types pf myocardial cells

A

○ Contractile cells

○ Nodal/ conducting cells

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31
Q

○ Contractile cells

A

§ Walls of atria/ ventricle
§ Actin, myosin arranged in myofibril bundles surrounded by sarcoplasmic reticulum
§ 1 nucleus, lots of mitochondria (1/3)
§ Rlly efficient at extracting o2 (80% from passing blood, twice other cells)
§ Joined by intercalated discs
§ Have tight junctions binding cells together
§ Their gap junctions let ions move btwn cells & let heart do AP from cell to cell without nerves

32
Q

○ Nodal/ conducting cells

A

§ Contract weakly bc few myofibrils
§ Do AP spontaneously + conduct to artia/ ventricle quickly
§ Sinoatrial node (SA node) - upper posterior wall of right atrium
□ Depolarizes first, making AP
□ Called pacemaker of heart
□ AP goes from here through atria, atria contracts, to av node to Bundle of His to apex of heart, to Purkinje fibers, & distributes to ventricular muscles, which contracts
□ Na moves in easier here, + Ca comes in = depolarize
□ AP caused by mvmt of K, K always pumped in and less K leaks out so K buildup = more depolarization
□ Nodal cells don’t have resting potential, but still have threshold
□ Pacemaker potential - slow depolarization; responsible for setting pace of heartbeat
□ Hits threshold (-40), Ca channels open, Ca in = depolarization of SA node AP
® Ca channels close at same time as K opens, K repolarizes
Cells goes to -60 and pacemaker potential depolarizes and repeating itself

33
Q

Ion movement in/out cells

A
  • responsible for AP
    • Na, Cl, Ca more outside, moves in
    • K more inside, moves out
      More positive = depolarized
34
Q

Conducting system of heart

A
  • Sa node has slowest conduction speeds, AP speeds up in atrial muscle
    • Contraction goes top down to make sure blood forced down to ventricles
    • AV node slows conduction to let atria finish contracting before vent start contr
    • Goes through bundle of his rlly quickly, hits apex which contracts so blood forced up and out valves at top of ventricles
    • Purkinje fibers spread AP through ventricular so contracts apex up
35
Q

Electrocardiogram (ECG)

A
  • AP goes through heart, see electrical current on body (see through electrodes)
    • P wave - electrical activity w depolarization of atrial msucle leading to their contraction
    • QRS complex - depolarization go ventriclular muscle before contraction
    • T wave - repolarization of vent as it relaxes
    • No wave w repolarization for atrial -> it happens, but can’t see bc QRS is big
36
Q

systole vs diastole

A

Systole - period of contraction

Diastole - period of relaxing

37
Q

cardiac cycle

A

1) Atrial systole
○ Depolarization of atria (P wave)
○ Atria contracts, atria pressure higher than ventricular pressure
○ AV (mitral) valve opens, blood into ventricle
○ Ventricular volume inc slightly (20-30%)

2) Isovolumetric ventricular contraction (early ventricular systole)
○ Ventricles depolarizing (qrs complex) then contracting
○ Ventricular pressure inc quickly (above atrial, below aortic pressures)
○ Mitral valve closes, no change in ventri volume

3) Ventricular systole (ejection period)
○ For ejection, pressure in ventri must be higher than pressure in aorta
○ Aorta pressre (80mmhg, goes above than, aortic valve opens
○ Ventricles still contracting, but ventri pressure above aortic
○ Aortic valve open, blood flows into aorta, ventri volume dec

4) Early ventricular diastole (isovolumetric relaxation phase)
○ Ventri pressure falls below aortic pressure, aortic valve closes
○ Some blood stays in ventricles (end systolic volume)
○ Ventri pressure continues to fall, no change in ventri volume

5) Late ventricular diastole
○ Ventri pressure drops below atrial pressure
○ Mitral valve opens, blood flows into ventricle
○ Ventricular volume inc - most blood enters here (70-80%)
○ P wave begins, cycle repeats

38
Q

heart sounds

A
  • LUB - 1st, av valves close, low pitch, long duration
    • DUP - 2nd, closing semilunar valves, high pitch, slower duration
    • Sometimes 3rd sound in middle of diastole bc of blood flowing w rumbling into almost filled ventr - hard to hear
39
Q

cardiac output

A
  • amount of blood each ventri pumps in 1 min
    ○ 5 liters of blood/ min
    ○ Inc CO by inc in HR or SV or both
    ○ Exercise - 20L/ min for normal, 35-40 L/ min in athlete
    § This is to give muscles more O2 + nutrients
    ○ Cardiac output (CO)(L/min) = heart rate x stroke volume (mL)
    § Heart rate - # heart beats/ min
    § Stroke volume - blood pumped by 1 ventri during 1 contraction/ heartbeat
    § At rest - HR = 70bpm, stroke volume = 70ml/ beat
40
Q
  • Autonomic nervous system has control over HR
A

○ Parasympathetic nervous system (rest/ digest) - nerves to SA and AV nodes, and a lil to atrial and ventri muscles
§ Slows HR and dec force of contraction
§ Vagus nerve
○ Sympathetic nervous system (fight/ flight) - nerves to same areas but stronger innveration to ventri muscles
§ Inc HR and inc force of contraction
§ Sympathetic nerve
○ Both systems turned off = 100 bpm, but para always working keeping us at 70bpm - this called vagal tone

41
Q

Change HR by changing pacemaker potential of SA node - Para

A
  • Pacemaker potential is Na and Ca leaking in and K permeability decreasing = gradual depolarization = AP
    • Change rate of depolarization = change HR
    • Para nerves activated = release acetylcholine onto SA and AV nodes = K channels open = K moves out more = membrane potential hyperpolarize + slope of pacemaker potential decreases = takes longer to reach threshold + HR slows
    • If HR dec, AP conduction through AV nodes must decrease to let atria finish contracting
42
Q

changing HR w sympathic NS

A
  • Increases HR, reaches threshold faster, inc slope of pacemaker potential
    • Releases norepinephrine and epinephrine (adrenaline) onto SA node = opens Na and Ca channels = more ions enter = faster depolarization = reach threshold faster + faster AP and HR increases
43
Q

stroke volume calc + resting for the things

A

Stroke volume = end diastolic volume (EDV) - end systolic volume (ESV)

  • At rest, EDV = 120ml, ESV = 50 ml, so SV = 70ml
    • EDV - how much blood is in ventri at end of diastole
    • ESV - how much blood in ventri at end of systole
44
Q

3 things can alter stroke volume:

A
  • Input from autonomic nervous system - either para or sympathetic
    ○ Para decreases force of contraction = dec stroke volume
    ○ Sympathetic increases forceful contraction = inc stroke volume
  • EDV and preload
    ○ Preload - load on heart just before it contracts; directly related to EDV
    ○ Higher EDV = more load on heart
    ○ Stretching opens Ca channels in heart muscle cells, more Ca = more forecful contraction = more blood ejected = lower end systolic volume and higher stroke volume
    § This is called Frank-Starling Law of the Heart - inc in EDV = inc in SV and vice versa
    ○ Squeezing veins = higher venous return = higher EDV
    § Squeeze veins by activating sympathetic bc it innervates veins, which will cause veins to constrict = inc EDV = inc SV = inc CO
    ○ Changing EDV by exercise
    § Repeated contraction/ relaxation of skeletal muscle can squeeze veins, and veins run btwn large muscles, exercise can squeeze veins
    § Muscle pump can inc EDV = inc SV = inc CO
  • ESV
45
Q

pulmoary vs systemic circ

A
  • Pulmonary circulation - loop right side vessels to capillaries to gas exchange in pulmonary capillaries (o2 in co2 out) to veins and blood returns to left side of heart

Systemic circulation - 2nd loop starting on left side of heart, oxygenated blood goes to body, capillaries exchange o2, nutrients, hormones to cells and pick up co2 and waste goes to veins ends up on right side of heart

46
Q

blood circ path - arteries to veins

A
  • Large arteries - smaller arteries - smaller arterioles - smaller vessels to capillaries (smallest of all blood vessels + function units of circ system where substances enter/ leave + gas exchange) - small venules - veins
47
Q

Blood volume distribution

A
  • Total blood volume (TBV) - 5L
    • largest portion in veins (70%), which is why called capacitance vessels or blood reservoir
    • Arteries have 10% TBV
    • Heart and lungs have 15%
    • Capillaries have 5%
48
Q

Blood velocity + cross-sectional area of vessels

A
  • Arteries - highest BP, low cross-sectional area, vessels quickly distribute blood throughout body
    • Arterioles - lower BP, cross-sectional area is higher, site of highest resistance in circulation and help regulate blood flow to an organ
    • Capillaries - lowest blood velocity, highest cross-sectional area
    • Venules, veins - BP and cross-sectional area decrease, blood velocity increases
49
Q

pressure gradient relation to blood flow

A

Pressure gradient moves blood through system, higher gradient = higher blood flow

50
Q

Pressure, flow, resistance

A
  • Flow = P1-P2 / resistance
    ○ P1-P2 is pressure gradient btwn 2 points
    • Blood flow through vessel called laminar (streamlined) flow
    • Flow slower at edges (bc dragging along walls), faster in center
51
Q

Factors affecting resistance

A
  • Thickness/ viscosity of fluid - thicker fluid = higher resistance
    ○ Generally, blood viscosity stays the same, but dehydration or doping = thicker blood
    • Length of vessel - longer vessel = higher resistance ; not major factor
      ○ Over time, vessels can get longer esp in obese ppl
    • Diameter (radius) of vessel - most important; smaller = higher resistance
52
Q

Resistance calculations

A
  • Resistance = (length of blood vessel x viscosity of fluid) / internal radius of vessel ^4
    • Resistance = 1/ r^4
    • Blood flow = pressure gradient/ change x r^4
53
Q

Control of blood flow in body

A
  • Alter blood flow by changin pressure gradient or radius, but pressure usually stays same, so focus on radius
    • If blood flow decreases in 1 arteriole, blood flow increases in other 3 to maintain constant flow
54
Q

Changing blood flow to organ

A
  • Changing diameter changes BF to organ
    ○ By vasodilating or vasoconstricting arterioles
    • e.g. BF change from muscle to intenstine to help digest food, exercise so change from intestine to muscle
55
Q

BP and resistance

A
  • When mesuring BP, docs check to tapping sounds called Korotkoff’s sounds
    • Sounds come from when flow is squeezed by BP cuff
    • Pressure when sound first appears is systolic pressure (120), pressure when sound is gone and flow is fixed is diastolic (80)
    • Small arteries resistance begins and pressure goes up, but highest drop in pressure is arterioles (80 to 30)
    • Then 30 to 10 in cappillaries, and 10 to 5 in veins, then to 0 when reaches right atrium
56
Q

Structure of blood vessels

A
  • Outermost layer - tunica externa, made of fibrous connective tissue
    • Middle layer - tunica media, made of smooth muscle and elastic tissue
    • Innermost - tunica interna, made of endothelial cells
    • Veins have valves
    • Capillaries made of single layer of endothelial cells
    • Arteries have elastic tissue so can deal w pressure changes from heart contracting and vein walls thinner
    • Venules have no smooth muscle or elastic tissue bc BP is v low
57
Q

Exchange of substances across capillary

A
  • Thing endothelial cell - easier to move things across
    • Have clefts and fenestrations - holes that let mvmt of water + dissolved solutes (not large proteins)
    • Diffusion - o2, co2 w gradient
    • Filtration - fluid goes from capillary to interstitial space
    • Reabsorption - mvmt of fluid from interstitial space back to capillary
58
Q

starling forces

A
  • 4 forces on fluid to see if filtration or reabsorption will happen
    ○ 2 hydrostatic pressures, 2 osmotic forces (colloid osmotic presures)
    ○ Capillary (blood) hydrostatic pressure (Pc) - pressure on fluid forcing it out on walls; 30mmhg in arteries, 15 mmhg in venous end of capillary; causes filtration
    ○ Interstitial-fluid hydrostatic pressure (Pif) - pressure from fluid in interstitial compartment pushing back on capillary; varies by organ; no pressure in inter fluid
    ○ Osmotic force due to plasma protein conc (pi P) - casue by presence of large proteins in plasma (albmin) and inter fluid; cannot cross capillary and will cause osmosis; draws fluid back to capillary casuing reabsorption , 28 mmhg
    ○ Osmotic force due to inter-fluid protein conc (pi IF) - pulls fluid out of capillary causing filtration; inter fluid has few proteins so low force; 3mmhg
    ○ Net filtration pressure (NFP) = (Pc - Pif) - (pi P - pi IF); is about +10 mmjg
    ○ The positive value means fluid going out , neg value means reabsorbing
59
Q

lymphatic system

A
  • Excess fluid that enters inter space returned to circulation by lymphatic sustem, which is large network of capillaries and vessels
    • Lyphatic capillaries to larger collecting vessels thrhough lymph nodes
    • Lymph nodes filter + screen fluid before sening back to venous circ through collecting ducts
60
Q

edema

A
  • Accumulation of fluid in sinter space causing swelling
    • Usually doesn’t happen bc lympathic system removes excess fluid
    • Factors producing edemas:
      ○ Inc in capillary hydrostatic pressure caused by inc BP (e.g. weightlifting puinches off vein and BP inc in cap)
      ○ Dec in plasma osmotic force (malnutrition, causes bloating in abdomen of malnourished kids)
      ○ Blockage or disruption of lymphatic system (radial mastectomy that removes lymph nodes around arms)
61
Q

Regulation of CV system

- 3 ways:

A

○ Local control mechanisms in organs themselves
○ Humoral mechaisms that rely on chemicals in blood
○ Autonomic nervous system, which alters cardiac output and blood flow to organs

62
Q

autoregulation + 2 theories

A
  • indiv capillary beds keep constant blood flow when therea re moderate changes in BP

○ Myogenic theory - changes in blood flow by contraction and relaxation of smooth muscle in walls of blood vessels (vasoconstriction/ vasodilation)

	○ Metabolic theory - changing metabolic activity to an organ changes blood flow to organ (e.g. exercsiing does shit to working muscle, casuing vasodilation and inc blood flow to tissue)
63
Q

humoral regulation

A
  • regulating blood flow by chemical substances circulating in blood; divided into vasoconstrictors and vasodilators
    • Sympathetic causes overall vasoconstriction (stressed, BP goes up), para causes overall vasodilation
64
Q
  • Vasoconstrictors:
A

○ Epineprhine - fight/ flight, weak effect on blood vessels of intestine
○ Angiotensin II - most powerful
○ Vasopressin - antidiuretic hormone

65
Q
  • Vasodilators
A

○ Epinephrine - vasodilation
○ Kinins - hormones formed in plasma and tissue
○ Histamine - rleeased from cells after they’ve been damaged
○ Atrial natriuretic factor - madee by atrial muscle cells

66
Q

Mean arterial pressure

A

Mean arterial pressure = cardiac output x total peripheral resistance

- Mean arterial press - avg pressure in arterial side of circ
- Total peripheral resistance - sum of all resistance in blood vessels in body through circ system
67
Q

Baroreceptor reflex

A
  • neg feedback
    • Set point - Normal bp 120/80, control center - cv center in brains stem, effector - heart and blood vessels, controlled variable - BP, sensors - baroreceptors
    • Inc BP = vessels streth = activate receptors in aortic arch and carotid sinus
    • Baroreceptors will inc frequency of AP and activate para
68
Q

Functions of respiratory system

A
  • Transport o2 from air to blood
    • Remove co2 from blood to air
    • Control blood acidity (pH)
    • Temp regulation
    • Forming line of defense to airborne particles
69
Q

Anatomy lungs

A
  • Pharynx to larynx (voice box) to trachea to dividing into 2 main c=bronchi to bronchioles to alveoli (site of gas exchange)
    • Dense network of capillaries around each alveolus - thin endothelial walls, large total cross sectional area, low blood velocity
70
Q

Structure of alveolus

A
  • Walls are 1 cell thick - made of alveolar epithelial cells (type I cells)
    • Type II cells release surfactant that lines alveoli
    • Respiratory membrane - where gas exchange happens
    • Macrophages and lymphocytes protect body from airborne particles that end up in alveoli
71
Q

Lungs - pleural

A
  • 2 thin pleural membranes - one sticks to ribs, other sticks to lungs
    • Btwn is intrapleural space that has pleural fluid to reduce friction when breathing
72
Q

Pressures of lungs

A
  • Alveolar pressure (intrapulmonary press) - press in intrapleural space
    • Atmospheric pressue - outside body, 760 mmhg, btwn breaths alveolar pressure is also 760
    • Intrapleural space pressue is 765 bc chest wall and lungs moving in diff directions
    • Transpulmonary pressure = alveolar pressure - intrapleural pressure
      ○ This pressure holds lungs open
      ○ Healthy lungs = pressure is + (outwards) and keeps alveoli open
73
Q

Pneumothorax

A
  • transpulmonary pressure is 0, lungs collapse
    • Intrapleural space is punctured so alveolar and intra pleural pressure both become 760
    • Only one lung collapses bc seperated
74
Q

Boyle’s law

A
  • Volume of container dec, pressure inside inc and vice versa
    • Pressure inversely proportional to volume
    • e.g syringe
75
Q

Inspiration vs expiration

A
  • Inspiration - high press outside lungs, low inside = air moves in
    • Expiration - high press inside lungs, low outside = air moves out

phys (5 decks)

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