(04) 2 Flashcards
(22 cards)
(Arteries)
- conduit for what?
(high pressure reservoir)
- receive what?
- maintain what to drive flow?
(Blood moves down a pressure gradient)
- Arterial system converts the intermittent (pulsatile) blood flow generated by the heart into what?
- blood –> tissues
- pulsatile CO
- increased P
- virtually steady flow through capillaries
(Large arteries)
(Large Arteries: strong elastic walls)
- high pressure reservior for what?
- keeps P from going to high in what?
- recoil maintains high P during diastole –> ?
(examples of large arteries - main arteries of trunk, intial portion of extremities)
- are large arteries compliant? act almost like what?
- pulsatile CO
- systole
- flow continues to tissues
- yes; an auxillary pump
(Arteries)
(medium/small arteries - to extremities)
- progressively more what and less what?
2-3. as wall thickness/lumen increases… what two things occur?
(Arterioles: strong muscular walls)
- greatest increase in what?
- Act as what for flow to tissues?
- arterioles = ?
- more smooth muscle and less elastin
- vessel less compliant
- resistance to blood flow increases
- vascular resistance
- control valves
- resistance valves
lowest pressure is diastolic pressure
highest is systolic
- What causes the incisura?
- What is the pulse pressure?
- How is arterial mean pressure estimated?
- blood moving backward in aorta before it hits the closed valve (the time the aortic valve is closed)
- difference between systolic and diastolic
- more time is spent near diastolic, so mean is closer to diastolic
(Mean Arterial Pressure)
- Estimate as what?
- Mean P is a measure of what? Mean P decreases as energy lost from what?
- Mean P is used for calculating what?
- MAP is determined by what and what?
- diastolic + 1/3 Pulse P (although not totally accurate for Ao (aorta))
- the potential energy in the system; friction of flow
- Resistance
- CO and R
(then look at thing - sometimes RAP is ignored cause it is so low)
(Pulse Pressure)
- determines how strong what feels?
2-4. What are 3 factors affecting pulse P?
- Stroke volume (SV) = ?
- the pulse
- stroke volume of heart (direct relation)
- arterial compliance (inverse relation)
- character of ejection
- volume ejected/beat
when is his pulse palpably stronger?
because CO is the same - it means at 45 beats per minute he has a bigger stroke volume - also a longer period of time between heart beat - longer time for diastolic to go way down - more difference between diastolic and systolic
(What affects Stroke Volume (SV))?
1-3. three factors.. name them plus how they affect
- heart rate
increased HR shortens filling time –> decreased SV for each beat (if CO constant)
- resistance
decreased R facilitates flow to periphery; easier for heart to pump more blood out –> increase SV
- Blood volume back to heart
increased venous returned —> increased SV
(influenced by mean circulatory filling pressure)
(Blood flow to individual tissues)
- controlled by what and what? depends on what?
(Microcirculation)
- consists of what five things?
- degree of constriction or dilation of small arteries and arterioles; metabolic demands of tissues
- precapillary arteriole, capillary (=exchange vessels_, venule, interstitum, lymphatic
(for each pound of fat the body needs a mile of capillaries!!!)
(Capillary Structure and Functon)
- rate of diffusion = ?
- what is this called?
(Characteristic of capillaries in different organs help facilitate functions)
3-5. What are three types?
- constant*Area*([conc in cap] - [conc in interstitium])/change in x (distance over which substance has to travel)
- Fick’s law of diffusion
- continuous (most common)
- fenestrated
- sinusoidal (large, variable size and shape)
(How does and increase in metabolic rate increase delivery of O2 and other substances to cells?)
use equation
- more capillaries open will do what?
- increase in what else?
- increase in metabolic rate –> increased diffusion by affecting all except for what?
- increase area and decrease change in x (capillaries closer to cells that need them)
- driving force for diffusion (greater differece between Sc and Si)
- D - the constant
(Interstitium)
- area between what and what?
- fluid here = ?
- what is interstitial fluid P? how about average functional capillary P?
- So why doesn’t most fluid leak out of capillaries into the interstitium?
- vessels and cells (contains collagens and other filaments)
- interstitial fluid (an ultrafiltrate of plasma)
- P< or = to 0 mmHg; P = ~17 mmHg
4.
(Fluid Movement across capillary Wall)
- bulk flow can occur thorugh what? influenced by what?
- water also moves across capillary membranes by what? how is this allowsed?
- What is another way water can cross membrances? spped? based on what?
- capillary pores; hydrostatic pressure
- osmosis; semipermeable membrane, [] gradient on impermaeable solutes –> osmotic pressure difference –> driving force for osmotic H2O flow (flow proportional to pore r^4 - poisellse)
- diffusion; slower; [] difference; proportional to surface are aof pores
(Starling’s Forces)
1-2. Fluid movement across capillary membrane depends on sum of what forces?
understand the figure pretty well
- osmotic pressure
- hydrostatic pressure
(Starling’s Forces)
- Fluid is filtered out of capillary at what end? what percentage of filtered fluid is reabsorbd at venous side of capillary bed?
- small net fluid flow into what?
- arteriolar end; 90%
- the interstitium
(The Starling Equation)
…. just look at this slide
(What promotes interstitial edema?)
1-4. What four things?
- increased capillary hydrostatic pressure
- decreased capillary oncotic P
- increase capillary permeability
- decreased lymphatic flow
(Lymphatics)
- drain fluid from what?
- remove excess what?
- also pick up what else?
- interstitial space (~10% of fluid not absorbed by venous end of capillaries)
- interstitial protein - can get back to circulation (eg protein leaked due to tissue inflammation/capillary damage)
- particles and bacteria (removed in lymph nodes)
(What determines the rate of lymph flow)
- what is the big thing? what can increase this?
(lymphatic pump)
- one way valves –> ?
- intrinsic wall contractions (stretch)
- external compression… like what?
- interstitial fluid pressure; increased capillary hydrostatic pressure, reduced oncotic pressure, increased capillary permeability
- forward flow
- muscle contraction (the big one), movement, arterial pulsations
(What happens when interstitial fluid accumulation exceeds maximal lymph flow rate?)
1-2. two of them…
- edema (extra fluid in tissues) or effusion (fluid into cavities)
- rate of lymph flow can increase with chronic increase in pressure
(Veins)
- return blood to heart; how thick are walls? smooth muscle?
(blood storage areas)
- do they easily expand at low P?
(…)
- can constrict —> blood to where?
(venous pump)
- what kind of valves?
- action of what else?
- thin; yes
- yes; (spleen (dog, horse)
- central ciruclation
- one way
- surrounding tissues
(Veins)
- all systemic venous blood –> ?
- RAP influences what in all systemic veins?
3-4. RAP depends on what two things?
- venous return = ?
- RA = central venous pressure (CVP)
- P
- ability of heart to pump blood out
- amount of blood flowing from body
- CO
