BMS Exam 2 Fall 2019
what is a good equation to under aortic pulse pressure
- pulse pressure (Pp)= Psystolic-Pdiastolic OR Pp= SV/ Ca SV= strove volume Ca= compliance
What is the Windkessel effect?
1. Pulse forces fluid into vessels, vessel distends 2. Valves close, decreased driving pressure 3. Vessel contracts, pushes blood forward describes pulse dampening ALSO this pathway (a) ventricular contraction 1) Ventricle contracts 2) Semilumar valve opens 3) aorta and arteries expands and stores pressure in elastic wall (b) ventricular relaxation 1) isovolumic ventricular relaxation occurs 2) semi-lunar valve shits, preventing flow back into ventricle 3) elastic recoil of arteries send blood forward into rest of circulatory system
What is Mean Aterial Pressure (MAP)? (number)
100 mm Hg
1 G equals
9.8 m/s2
The ability to adjust arterial pressure by local mechanisms to ensure constant flow through an organ is known as A) Autoregulation B) Flow-induced regulation C) Metabolic regulation D) Endogenous regulation
A) Autoregulation
What type of capillaries would do A) Diffusion B) Vesicular Fusion C) Bulk Flow (Convection)
A) Continuous B) Continuous C) Continuous, fenestration, discontinuous (sinusoid)
A patient with a complaint of leg pain is found to have a blood clot in a large artery in his leg. He is subsequently diagnosed with peripheral artery disease. Because peripheral artery disease is associated the endothelial dysfunction, which of the following could have contributed to the formation of the blood clot? A) Decreased endothelial production of nitric oxide B) Increased endothelial production of nitric oxide and prostacyclin C) Diminished endothelial production of ATP
A) Decreased endothelial production of nitric oxide
Central venous pressure is increased by A) Decreased venous compliance B) Decreased blood volume C) Increased cardiac output D) Increased arterial vascular resistance
A) Decreased venous compliance BECAUSE Decreased venous compliance results in an increase venous tone. Increased venous tone shifts the vascular function curve to the right and increases the peripheral driving force that pushes blood back to the heart. Increased venous return increases central venous pressure.
Activation of beta-2 receptors by epinephrine binding results in vascular smooth muscle A) Relaxation B) Basal tone C) Contraction
A) Relaxation
The most predominant adrenergic receptor found on vascular smooth muscle cell is the A) alpha 1 B) Alpha 2 C) Beta 1
A) alpha 1
long term regulation of arteial blood pressure is regulated by A) changes in blood volume B) arterial baroreceptor reflex C) metabloic autoregulation
A) changes in blood volume
if a vessel is able to easily distend with a small change in pressure A) it is compliant B) it is elastic
A) compliant
The rate at which blood leaves the veins is increased. If the rate at which blood enters the veins is maintained constant, the volume of blood in the veins will A) decrease B) increase C) stay the same
A) decrease because If outflow exceeds inflow, the net is a decrease in venous volume.
in order to maintain adequate perfusion to the brain, the heart must generate enough pressure to overcome A) hydro static pressure pulling blood down B) hydro static pressure pushing blood up C) diastolic pressure
A) hydro static pressure pulling blood down
degraded or lose of vison occurs during +Gz when A) intraocular pressure is greater than retinal arterial pressure B) intraocular pressure is less than retinal arterial pressure C) mean arterial pressure is increased resulting in an increase in retinal arterial pressure
A) intraocular pressure is greater than retinal arterial pressure
what are the two types of metabolic response?
Active hyperemia Reactive hyperemia
Aorta and veins have ___ elastin, ____ Smooth muscle/ collagen= higher compliance Other arteries have ___ elastin, ____ Smooth muscle/ collagen= higher compliance
Aorta and veins have HIGH elastin, LESS Smooth muscle/ collagen= higher compliance Other arteries have LESS elastin, HIGH (Smooth muscle/ collagen pick one)= higher compliance
what is the primary input for the medullary cardiovascular center?
Arterial barorecetors
Describe arterial compared to veins
Arterials LESS compliance HIGH elasticity than veins
As long as ___ and ___ remain constant, a change in arterial compliance affects only pulse pressure and not MAP
As long as CARDIAC OUTPUT and TOTAL PERIPHERAL RESISTANCE (TPR) remain constant, a change in arterial compliance affects only pulse pressure and not MAP
When an organ responds to an increase in the metabolic activity with a decrease in its arteriolar resistance, this is known as A) Metabolic vasoconstriction B) Active hyperemia C) Reactive hyperemia D) Flow-dependent vasodilation
B) Active hyperemia
Which of the following physical parameters would quickly and directly decrease the arterial blood pressure (before any nervous system adjustments occurred)? A) An increase in left ventricular end diastolic volume B) An increase in left ventricular end systolic volume C) An increase in ejection fraction D) An increase in venous return
B) An increase in left ventricular end systolic volume
If a coronary artery is occluded (blocked) for one minute and then the occlusion is released, A) Coronary flow increases because of vasoconstriction occurring during the ischemia B) Endothelial release of nitric oxide will contribute to the reactive hyperemia C) A period of active hyperemia follows D) Interstial adenosine concentrations will increase and constrict coronary arterioles
B) Endothelial release of nitric oxide will contribute to the reactive hyperemia
Turbulent blood flow can occur at all of the following locations except A) Next to damaged endothelial cells B) In large arteries C) At vessel branch points D) At a constriction in the vessel
B) In large arteries
The velocity of blood decreases from the aorta down to the capillaries. The primary reason for this drop is due to A) Decreased blood flow B) Increasing cross-sectional area of blood vessels C) Increasing resistance D) Increasing blood viscosity as water is absorbed out of the vessels
B) Increasing cross-sectional area of blood vessels
what type of flow pattern is present in cappilaries? A) tubulent flow B) Laminar flow
B) Laminar flow
Excess build-up of interstitial fluid is prevented by A) Increased reabsorption by the capillaries B) Removal of excess fluid by the lymphatic system C) Decreasing blood flow to the capillary bed D) Decreased oncotic pressure
B) Removal of excess fluid by the lymphatic system
Strech of aterial baroreceptors increase the afferent neruonal discharge rate to the medullar centers. This results in A) increased sympatheric efferent response B) decreased sympatheric efferent response C) decrease parasympathetic efferent response
B) decreased sympatheric efferent response
auto regulation implies that arterial pressure is adjusted by local mechanism to ensure constant flow through an organ A) true B) false
B) false, it is the arterial resistance is adjusted to maintain constant flow in spite of changes in arterial pressure
Arterial blood flows through an organ of the body at a constant rate. If the metabolic activity of that organ is decreased, the amount of oxygen in each millimeter of blood leaving the organ in the vein will A) decrease B) increase C) stay the same
B) increase because If metabolic activity decreases, less oxygen is required/utilized inside the cell. As a result, the concentration gradient between blood and cell is decreased. Since oxygen diffuses down its concentration gradient, the reduced gradient means less oxygen moves from the blood to the cell. Therefore, more oxygen remains in the venous blood.
the primary integration center for reflex regulation of the cardiovascular sstem is located in the A) Cerebellum B) medulla oblongata C) spinal cord
B) medulla oblongata
increase interstitial protein concentration will result in? A) movement of proteins into capillaries B) movement of water into interstitial space, resulting in edma C) no change in net movement of water or protein
B) movement of water into interstitial space, resulting in edma
Ang II influences vascular tone by causing which of the following? A) vasodilatation B) vasoconstriction
B) vasoconstriction
why should fluid regulation be the long term regulation?
Because it takes hours to days to compensate but it will eventually over ride other regulatory mechanisms.
What controls blood flow into capillaries beds
Blood flow into capillary beds controlled by pre-capillary sphincters
How does Blood flow in the vascular system?
Blood flows passively from high pressure aorta to low pressure vena cava
Venous return is is influenced by
Blood volume, sympathetic activity and epi, respiratory activity, skeletal muscle activity
where would you find parasympathetic innervation of the vessel, how does it impact?
Brain and heart: little influence salivary glands, pancreas, gastric mucosa: influence secretion and motility External genitalia: increase vasodilation-> increase blood flow-> secretion and erection
How is normal oncotic pressure maintained?
By a pressure gradient. Because capillaries tend to have a net filtration (filtration), the lymphatics develop a pressure gradient to make fluid go in the lymphatics to over all prevent edema. In order to ensure this pressure gradient, the lymphatics will remove protein fromt he interstitial space to ensure that pressure gradient is in their favor.
A patient with traumatic injuries from an automobile accident suddenly shows a fall in arterial blood pressure accompanied by an increase in central venous pressure. These hemodynamic changes could be explained by A) increased systemic venous compliance B) Sympathetic nervous system activation C) A sudden fall in cardiac output D) Loss of blood volume
C) A sudden fall in cardiac output A fall in cardiac output causes arterial pressure to fall and blood to back up into the venous circulation, which leads to an increase in central venous pressure.
Concerning different types of blood vessels in a vascular network, A) Capillaries, as a group of vessels, constitute the greatest resistance to flow within an organ B) Large arteries are the most important vessel for blow flow and pressure regulation C) Capillaries are the primary site of fluid exchange D) Arterioles have the highest individual resistance
C) Capillaries are the primary site of fluid exchange
Arteriolar vasoconstriction tends to result in a/an A) increased transcapillary filtration B) Increased capillary hydrostatic pressure C) Decreased capillary hydrostatic pressure D) Increased blood flow through the capillary bed
C) Decreased capillary hydrostatic pressure
Net capillary fluid filtration is enhanced by A) Decreased venous pressure B) Increased tissue hydrostatic presure C) Decreased capillary plasma oncotic pressure D) Increased pre-capillary resistance
C) Decreased capillary plasma oncotic pressure BECAUSE Capillary plasma oncotic pressure opposes filtration; therefore, decreasing it will increase filtration.
the axis of most concern for accerleration effect is the A) Gx (chest to back) B) Gy (shoulder to shoulder) C) Gz (head to foot)
C) Gz (head to foot)
the most important mechanism regulating arterial pressure is/are A) positive feedback loops B) fluid balance C) arterial baroreceptor reflex
C) arterial baroreceptor reflex
The most common type of capillary is A) fenestrated B) sinusoid C) contintious
C) contintious
MAP is influenced by
CO and TPR
MAP=
CO x TPR
if TPR changes what must adjust?
CO, in order to adjust to CO, we change heart rate/ strove volume
Describe trans-capillary diffusion
Can occur through the entire capillary surface O2and CO2 (lipid soluble)
which vessel type does have the tuncia media? Why is this important?
Capillaries, this is important because it allows for exchange/ diffusion
What does Histamine generally do to the capillaries
Causes edema Increases blood flow which then causes an increase in capillary pressure Also causes an increase in vascular leakage of plasma proteins which decreases oncotic contribution overall leads to a net filtration rate
Describe efferent neurons in the cardiovascular system for the parasympathetic. What do they control?
Cell bodies in brainstem Control heart rate. post ganglion effects determined by activity of pre-ganglionic neurons.
Describe efferent neurons in the cardiovascular system for the sympathetic track. What do they control?
Cell bodies in spinal cord (have spontaneous activity modulated by brainstem center) Control HR and contractility, vascular tone
what happens when we have an increase in stroke volume BUT no decrease in heart rate?
Change in pulse pressure, not change in MAP
what changes will impact the distribution of blood flow? (big picture)
Changes depend on -environmental conditions -metabolic activity
Decrease Arteries and veins (generally- big picture)
Changes in diameter have less effect on flow through organ
What are some important hormonal influences?
Circulating catecholamines (EPI and NE) vasopressin (ADH) Angiotensin II Artial natriuretic peptide
Circulating plasma directly interacts with ________? Across which barrier?
Circulating plasma directly interacts with the interstitial fluid across walls of capillary vessels
describe the venous compliance and elasticity compared to arterioles
Compliance is HIGH Elasticity is LOW
Describe compliance (with equation/ words)
Compliance= change of volume for a given change in pressure Compliance (c)= change volume/ change pressure)
what do veins and lymphatics have in common?
Contain 1-way valves
what holds more volume (arteries/ veins OR arterioles and capillaries)
Contain larger volume of blood than arterioles and capillaries
Which of the following can increase the rate of oxygen diffusion from blood to the tissue? A) Decreased arteriolar partial pressure of oxygen (PO2) B) Increased tissue partial pressure of oxygen (PO2) C) Decreased number of flowing capillaries D) Arteriolar vasodilation
D) Arteriolar vasodilation BECAUSE Arteriolar vasodilation increases blood flow to the capillaries and increases PO2, which increases the gradient for diffusion out of the blood.
The most important factor influencing local blood flow is A) Parasympathetic nervous system input B) Myogenic control C) Sympathetic nervous system input D) Metabolic control
D) Metabolic control
Vasopressin (anti-diuretic hormone) A) Is released in response to increased blood pressure B) Is converted from angiotensin II C) Is released in response to decreased osmolarity D) Stimulates vasoconstriction in long-term regulation of arterial blood pressure
D) Stimulates vasoconstriction in long-term regulation of arterial blood pressure
Circulating epinephrine is released from _________ and preferentially binds to ______ receptors. A) The adrenal medulla; alpha-1 B) Post-ganglionic neurons; alpha-1 C) Post-ganglionic neurons; beta-2 D) The adrenal medulla; beta-2
D) The adrenal medulla; beta-2
If a person rises rapidly from a lying position to an upright position, what change might be expected in the cardiovascular system to compensate for this positional change? A) Decrease in heart rate B) Venodilation C) Decrease in inotropy D) Vasoconstriction
D) Vasoconstriction
atherosclerosis (plaque formation on inside of arteries) result in A) decrease arterial compliance B) increase arterial compliance C) turbulent blood flow D) both A and C
D) both A and C
sustained elevation of mean arterial pressure leads to a/an A) increase in renin secretion B) increase in Angiotensisn II C) decreaes in urine volume D) decrease in aldosterone
D) decrease in aldosterone
Which of the following does NOT affect diffusion rate across a membrane? A: Surface Area B: Concentration (or pressure) gradient C: membrane permeability to substance (solute solubility) D: Time
D: Time
what leads to an increase in stroke volume?
Decrease After load decrease heart rate increase prelaod increase inotropy
Big picture idea: vasoconstrict impacts ___ blood pressure which in turns ends up doing what?
Diastolic blood pressure it then increase peripheral resistance which then causes an increase in diastolic pressure
What is hydrostatic pressure?
Driving force causing blood flow along vessels Drives fluidthrough the trans-capillary pores into interstitial fluid
What do cells do in response to shear stress (general idea)
Endothelial cells detect changes in blood flow due to changes in shear stress. Will cause a response to it (more questions on this later)
True or false: Epi has a higher affinity for alpha 1 than B2
FALSE! Epi has a higher affinity for B2 than alpha 1
True or false: There is not considerable variation in morphology of the capillaries even with various functions of the vascular beds.
FALSE: There is Considerable variation in morphology depending on function of vascular bed
True or false: there is a gradual increase in pressure due to elastic nature of aorta/ arteries
FALSE: there is a general decrease
what must be equal through each region? (AO, LA, SA, ART, CAP, VEN, SV, LV, VC
Flow
what does pulse dampening allow for?
Flow during diastole during this systolic systolic there is stretch. this leads to a diastolic recoil which allows for the flow
How does fluid move to the lymphatics?
Fluid pressure on the outside of the vessel pushes the endothelial cell's free edge inwards, permitting entrance of interstitial fluid (now lymph fluid). Fluid pressure on the inside of the vessel forces the overlapping edges together so that the lymph cannot escape. Overall, increase pressure on the outside causes the flaps to open. (another way to phrase this: during the expansion phase, hydro static pressure in the interstitial (Pif) excess that inside the initial lymphatic (Pf) causing micro valves to open and fluid to enter). decrease pressure on the outside means that no fluid can get into the lymphatics. (another way to say this: during the compression phase, hydro static pressure inside the initial lymphatic rises closing the micro valves and opening the secondary lymph valves causing fluid to flow downstream).
how does veno constriction impact venous return and central venous pressure?
For example if we veno constriction, we increase venous return because we pushing more blood yet we also increase ventral venous pressure because we are putting more blood in there.
What is shear stress?
Friction force, interaction between blood and endothelial cell lining vessels generates a shear stress (friction force) another way of saying it: Shear stress is the fluid frictional force acting at the apical surface of endothelial cells
EPI and NE are secreted from what?
From the adrenal medulla in response to sympathetic input
How can you tell if someone has turbulent flow?
Generates sounds (aka heart murmur)
where would you find a fenestration capillary?
Glomerulus (kidney filtration) Exocrine glands (sweat glands) Intestinal mucosa Choroid plexus (brain ventricles → CSF)
CO is influenced by
HR and SV
CO=
HR x SV
Describe fenestrated capillaries
Has some endothelial cells that contain pores (fenestrations) more permeable than continuous capillaries function in absorption or filtrate formation
how do changes in diameter impact arteries and veins compared to arterioles
Have lower resistance to flow through vascular bed than arterioles (and individual capillaries)
Describe the pathway of histamine in the cell and how it impacts the body (details)
Histamine is released from from mast cells (from allergies/ pathogens). This causes an activation of smooth muscle cells (by causing dilatation) -The Dilatation leads to an increase in blood flow which leads to an increase in capillary pressure which causes an increase in filtration in that area. Additionally histamine causes the activation of endothelial cells - this causes an up regulation of adhesion molecules and the breakdown of tight junctions (thus making the capillary more leaky) Now that the cells is leaky (due to the breakdown of tight junctions) we have plasma proteins leaking out and generally vascular leakage. This helps with a net filtration because water follows proteins
The hydrophobic solutes pass through what? Why is this important?
Hydrophilic solutes pass via intracellular clefts / channels The clefts constitute a small fraction of surface area (0.01%), but allow rapid equilibrium of small water-soluble substances
What is net filtration rate determined by?
Hydrostatic pressure (outward push) Oncotic (colloid osmotic) pressure (inward pull)
IN the arterial compartment we have ___ volume and ____ pressure. This means that it is more ____ IN the venous compartment we have ___ volume and ____ pressure. This means that it is more ____
IN the arterial compartment we have SMALL volume and LARGE pressure. This means that it is more ELASTIC IN the venous compartment we have LARGE volume and SMALL pressure. This means that it is more complent
A decrease in oncotic pressure results in a/an __________ in net filtration rate? why?
INCREASE Why?: By decreasing oncotic pressure we are decreasing the amount of salt found in the capillary. This means that less water will move into the capillary leading to an overall increase in net filtration.
If Net Filtration Rate is positive then we have _______ If Net Filtration Rate is negative then we have _______
If Net Filtration Rate is positive then we have filtration If Net Filtration Rate is negative then we have reabsorption
Turbulent flow mainly occurs where?
In reality, we don't want this so our body tries to not have it. However it can occur at branch points (like the arterioles) It also can occur when vasoconstriction occurs (because we narrow the cells which leads to an increase in velocity)
what are some characteristic pressure waveform
Incisura (dicrotic notch) Dicrotic Wave
How does radius impact shear stress?
Increase radius= decrease shear stress
How does velocity play a role in shear stress?
Increase velocity= increase shear stress
What things impact lymph flow? How?
Interstitial Pressure: Expansion of interstitial compartment pulls apart anchoring filaments Contraction of lymphatics: stretch induced contraction of lymphatic smooth muscle (due to increase lymph volume) External compression: Skeletal muscle pump- after the fluid enters the lymphatics-> there is smooth muscle that surrounds the lymph vessel that helps push fluid forward. 1-way valves: ensure that fluid only moves in 1 direction
What is turbulent flow?
Irregular streamlines (i.e. currents) vortice formation. not forward moving blood.
What are continuous capillaries?
Is the most common type contain inter cellular clefts, clefts, which are gaps in the tight junctions between the cells. It allows small particles to enter and exit the capillary.
how is MAP sensed?
It has multiple sensors throughout the body
When CO increases, where does the blood come from? What does it help with (in times of exercise) and what nervous system is activated.
It is diverted from the venous reservoirs so it can help Muscular activity (skeletal muscle pump) Sympathetic nervous system activation
where would you find the arterial baroreceptro? what is the most important role for this?
It is found int in the aorta. this is important because it will response to suddent redcutions in arterial pressure
how does stroke volume impact aortic pulse pressure?
It is proportional to the stroke volume (increase SV=increase Pulse pressure)
What does vasopressin do?
It will increase osmolarity by causing vasoconstriction and fluid retention. vasopressin is released, it bind to V1 receptors on the vascular smooth muscle cell this causes a chain reaction that leads to Ca2+ being released from the SR which then causes constriction which leads to vasoconstriction. Because the cell is vasoconstriction, it causes hydrostatic pressure to decrease which means that net filtration goes down meaning that more fluid is retrained.
Capillaries tend to have large _______ and thin ________ (think of flick's law)
Large Surface areas; thin walls (thickness)
What is the venous reservoir?
Like a storage unit for blood
what are the three types of acceleration?
Linear Radial Angular
arteriolar radius is influenced by
Local metabolic control and extrinsic vasoconstriction control
What is the MAP equation?
MAP = CO x TPR MAP= ((Psystolic-Pdiastlic)/2) + Pdiasltoic
What is the main job of the cardiovascular system?
Maintain homeostasis
Why is the net movement of fluid between blood and interstitial compartment important?
Maintaining circulating blood volume Intestinal fluid absorption Edema formation Saliva, sweat, and urine production
What holds the majority of blood at rest in the vascular system?
Majority (~60 - 70%) of blood at rest is in venules and veins
Explain exchange in the vascular system
Movement of substances between blood and tissues
what is Oncotic (colloid osmotic) Pressure (π)
Movement of water due to presence of proteins Balancing force to hydrostatic pressure
what is teh anti G straining maneuver? what does it do when done properly?
Muscle tension (butt and legs) Breathing technique that allows for rapid air exchange, blood air at glottis increase chest pressure, which increase lung pressure, which increases heart pressure which increase pressure blood pressure so blood can get to brain
what are examples of immediate mechanism to regular local blood flow?
Nerual influences, local influences (auto regulation)
what does the arterial baroreceptor reflex control system
Nerual portion: mechanoreceptor, afferent input, intergrators, efferent output. Effector portion: heart, peripheal blood vessel
Starling hypothesis
Net filtration = forces favoring filtration - forces opposing filtration it is the relationship between factors influencing trans-capillary fluid movement
re absorption means
Net movement intocapillaries = reabsorption
_______ is important between blood and interstitial compartment.
Net movement of fluid
Filtration means
Net movement out of capillaries = filtration
what happens if we have no arterial pressure?
No flow through organs
what metabolites are does metabolic control look at?
O2, adenosine, H+, lactic acid, CO2
Why is there usual filtration occurring in the capillaries?
On the arterial end of the capillary there is a net pressure leading out (therefore filtration). Towards the venous end of the capillary, there is a net pressure in leading to re absorption. The re absorption is primarily due the fact that proteins do not leave the capillary and so water follows the proteins. However, the pressure is so much higher on the arterial end that it leads to a an overall filtration in the system
Why is osmotic pressure important?
Osmotic pressure only mechanism for movement of water between interstitial fluid compartment and intracellular fluid compartment
what two types of pressure determine movement of water? Between what two compartment is this found?
Osmoticand hydrostatic pressures determine movement of water between intravascular (plasma) fluid compartmentand interstitial fluid compartment
generally what happens to pressure as it goes around the body?
Pressure decreases
Explain how Pressure, Solubility, molecular weight, surface area for diffusion, and thickness of membrane impact the flow of molecules through certain tissue barrier (FLICK's Law)
Pressure: Increase pressure= increase flow Solubility: Increase solubility= increase flow molecular weight: Increased MW= decrease flow surface area for diffusion: Increase SA= increased flow thickness of membrane: Increase thickness= decrease flow
B2 receptors are primarily found where? What stimulates them, and what does that lead to?
Primarily found in vascular smooth muscle -vascular B2 adrenergic receptors not in innervated by sympathetic input. It is only stimulated by circulating epinephrine (which comes the adrenal medula). When epi binds to B2, it leads relaxation/ vasodilation
what would an intermediate response response to changes in MAP?
Renin-angiotensin II and stress relaxation go vessles
what do cappilaries do
Site of Exchange, Allow large amounts of materials to enter and leave blood
What is the Bayliss effect?
Smooth muscle in the wall of arterioles response to stretch due to changes in blood pressure and blood flow
What is laminar flow?
Smooth, streamline flow. Very little mixing, very efficient, it is the majority of flow thru cardiovascular system.
What is pulse dampening?
So as we pump blood around in the heart, it stops, however the bloodflow around the heart and body don't stop. So the larger arterioles will stretch with a lot of blood. As the heart pumps, the smooth muscle around the arterioles will contact keeping blood flow flowing. Recoil occurs, so increase the pressure and thus blood can still travel.
Describe how lymphatics are able to get the extra water?
So the lymphatics will have cross section areas just like the blood capillaries. They branch around the blood capillaries allowing fluid to move through to it.
where would you find sinusoid (discontinuous) capillary? Why?
Spleen (immune system), Bone marrow (to get red blood cells out), liver (for toxin removable)
how does the volume of blood change while standing vs supine position. Which position will leads to equilibrium
Supine: less blood in legs= less volume. we will reach equilibrium in this postions Standing: More blood in legs= more volume
true or false: under normal conditions, short term hormonal influences on blood vessel is minor
TRUE because local metabolic influences play largest role then neural influences.
True or false: Cardiac output does equals venous return
TRUE. it does
Overall what is the result of myogenic control?
The overall result is constant perfusion by preventing large fluctuation in local blood flow.
Explain the reservoir we have in the circulatory system
The reservoir found in the veins can stretch to hold a lot of blood (volume of blood) so that in time of need we can increase the amount of volume sent to the heart to increase CO.
Describe sinusoid capillaries
There are large inter cellular gaps. Adjacent cells do not meet to form clefts. there is an incomplete basement membrane.
describe flow dependent dilatation? (AKA- what happens when you have a high shear stress)
There is an increase shear stress produced by blood flow on the endothelial cell this causes eNOS (an enzyme) to be made with the help of eNOS, L-arginine is converted into NO. NO leaves the endothelial cells and enters the smooth muscle cell. This relaxation of the smooth muscle cell which dilators the area making shear stress go down. -NO is a vasodilator (more on this later in quizlet)
describe the blood flow in turbulent flow situation? How does it impact the cells around it?
There is more internal mixing, less forward flow. It is less efficient flow this ultimately leads to more friction= increase resistance= shear stress
how do fenestrated capillaries stop proteins from going through
They are negatively charged on the endothelial cells, meaning that proteins (that are also neg. charged) can't go through. The holes contain collagen and proteoglycans that are neg. charged.
are vascular B2 receptors innervated? Why or why not?
They are not, because they only response to epi. Epi is only secreted by the adrenal medulla and only travels in the blood.
Describe lymphatics
They are similar in structure and function to veins They tend to hold fluid
Explain why plasma protein generally cannot cross the capillary wall and why this is important.
They are too large generally to fit through the capillaries wall. This allows us to retain water.
what do arterioles do (generally- big picture)
They get rid of the pulsatile nature of pressure and flow nearly eliminate Vascular resistance Arteriolar constriction Arteriolar dilation
why do blood vessel generally lack parasympathetic innervation?
They lack this because veins are already naturally relax/ dilated (have low basal tone) arteriole dilation by removal of sympathetic input or local control
TRUE OR FALSE: non arterial baroreceptors influences causes arterial pressure and sympathetic activity to change in the same direction
True
How does the arterioles influence vascular resistance?
Variable due to change in arterolar diameter it regulars blood flow through an organ and blood pressure through vessels
in what 4 way does the endothelium dependent regulation of cascular tone
Vaso-dilators -through NO, PGI2, endothelim dervided hyperpolsing facor vaso-constrictor: - via endothelin
Vaso is where Veno is where
Vaso= aterioal side Veno= vein side
What happens to velocity as it goes through the body
Velocity decreases (from art to cap) starting at venous it begins to increase
SV is influenced by
Venous return
How does the sympathetic nervous system affect the venous side?
Very little basal tone, normally in a dilated state. When SNS is activated, it leads to venoconstriction because it NE will activate alpha 1 and alpha 2 Smooth muscle.
Explain distribution in the vascular system
Vessels responsible for distributing the blood to the tissues and returning it to the heart
If we have low arterial pressure and we do not try to reset it, what can happen?
We end up have insufficint flow to brain. which means we take a little nap (per Dr. Maresh words)
Why must blood flow be consistency through out the body?
While it is true that blood flow can vary the closer you are to the heart, the further away go from the heart the most consistent blood flow is. This is to ensure that blood flow is steady around the capillaries to maintain gas/ nutrient exchange
gravity is a __ force
acceleration force
release of NE as a neurotransmitter acts via what? what does it cause?
act alpha 1 adrenergic receptors, which causes vasoconstriction in the vascular side. If it acts via Beta 1 receptors, it causes increase heart rate by causing the heart to contract more (becuase Ca2+ is released). if it acts on alpha 2, it can causes vasoconstriction (depending where it is) or if it activates the alpha 2 on the nerve then it stops NE being released
Because arterial are have lower compliance they can act as what?
act as a pressure reservoir (keeps blood moving forward)
We are exercising, what happens in our body? what happens when we stop exercising?
active hyperemia: Our body will have a decrease O2, increased adenosine, increase H+, increased Lactic acid and increase CO2. The increase in metabolites, causes vaso dilation. Vaso dilation causes an increase in flow in order to remove the metabolites and get more oxygen to the tissues. Once all of the metabolites are gone, (or to say that metabloism has gone down) we can decrease flow.
big picture: How does peripheral vascular adjustment made?
adjustments are due to arterial baroreceptors reflex primary in organs with strong sympathetic vascular control
smooth muscle and collagen do what for veslls
allow for high resistance to stretch
How does having high elasticity impact the arterial
allows arteries to act as a pressure/ blood reservoir on a beat to bear basis
What does the compliance and elasticity combo do for arterials
allows for pulse dampening AKA reduces pulse pressure
which baroreceptor is the most important for short term mechanism?
arterial baroreceptor reflex
between diastolic (pd) and systolic (ps) pressure what fluctuates?
arterial flow and pressure fluctuates with each cardiac cycle between diastolic (pd) and systolic (ps) pressure
TPR is influenced by
arteriolar radius and blood viscosity
Which are the resistance vessels?
arterioles
sympathetic nervous system innervates what
arterioles which regulates blood flow to organs
what mechanism counteract temporary changes in arterial pressure? why? Why can't this mechanism be long term?
atrial barorecptors reflex its adaptability to sustained elevated mean arterial pressure is potentially advantageous-> ensure blood flow to organs it can't be long term because it changes set point too often
What is autoregulation?
automatic adjustment of blood flow to each tissue in proportion to its requirement at any given instant
what factors impact heart rate?
autonmoic nervous system (PANS, SANS and the adrenal gland) SANS would increase, causing more NE to be related, meaning that more CA is released and contractility is increased (inotropy). taking away sympathic would decrease heart rate. PANS input would increase, which causes a decrease in HR because it causes hyperpolization.
what would an immediate response to changes in MAP
autonomic nervous system input. (it will go to heart and increase heart rate and contracility) and it will causes the vessels to dilate or constriction
resting vascular one =
basal (intrinsic) tone
why must flow be equal through each region?
because CO=VR
Aldosterone binds to what? what does this do?
binds to receptors in the distal convoluted tubule of the nephron leads to up regulation of sodium channels and insertion on lumen side which thus increase sodium absorption of water OVERALL: increases blood volume which increase arterial pressure
How is blood flow regulated to skeletal muscle?
blood flow to skeletal muscle under local control rather than autonomic nervous system?
we are vasodilation, what is happening up and down stream
blood pressure goes down in arteries blood pressure goes up in capillaries Think about a hose
we are vasoconstriction, what is happening up and down stream
blood pressure goes up in arteries blood pressure goes down in capillaries Think about a hose
what is absolute incapacitation
brain suffering from stagnate hypoxia due to changes in G that impact how the cardiovascular system works
How are veins and lymphatics differ?
by a lot but the biggest thing here to know that lymphatics holds fluid (left over from the veins because they have a net filtration out). While veins hold blood and such.
IF we vaso dilate what happens?
by vasoconstriction, we decrease arteriole tone decrease arteriolar resistance increase forward movement of blood increase peripheral driving pressure increase venous return
IF we vasoconstriction what happens?
by vasoconstriction, we increase arteriole tone increase arteriolar resistance decreases forward movement of blood decrease peripheral driving pressure decrease venous return
what happens if we change in arteriolar tone?
causes a rotation of venous function curve rather than a shift. This happens because we are changing the volume of blood that is being shift (which thus changes the venous return), however, it does not change central venous pressure.
radial acceleration
change direction with no speed change (like in a circle)
angular acceleration
change in speed and direction (roller coasters)
what can cause a change in stretch in the vessel? What happens when we have changes in stretch?
changes in stretch causes stretch receptors to be activated, which then causes Ca2+ be released. There is an increase of blood volume which means there is an increase in pressure. The arterioles want to recoil in order to maintain a constant flow, so the stretch receptors will activate. This increased stretch causes vasoconstriction via stretch regulated Ca2+ channels (L-type) If there is no stretch, then the vessel are vasodilated. another way to put this pathway: increase diameter =in crease flow/ volume = increased pressure =increase stretch =increase Ca2+ influx = vasoconstriction (myogenic autoregulation) to maintain constant flow
local changes to flow lead to what?
changes in total peripheral resistance (TPR) due to parallel nature)
What is incisure (dicrotic notch)
closing of aortic valves. Basically that little bump in pressure is due to blood filling the space after the value closes
_____ is very different between arteries and veins because
compliance and elasticity is very different between arteries and veins because the ratio of elastin fibers to smooth muscle and collagen in vessel walls
compare compliance and elasticity
compliance= ease of stretch elasticity= recoil when stretched
what is pulse dampening
converting pulsatile flow form heart to steady flow
when we have an decrease in MAP what happens normally?
decrease ABR afferent firing rate increase SANS to vessel decrease dilatation increase pressure
Explain vasodilation
decrease arterial pressure= increased downstream volume= increase capillary and venous pressure= increase hydro static pressure= increase filtration
what happens as we age/ obtain cardiovascular disease?
decrease compliance= increase pulse pressure
generally speaking, dilation means increase or decrease resistance?
decreased
artial natrieretic peptide does what?
decreases renin release= decrease aldosterone secretion which means less sodium is reasbsorped which means increase sodium in urine which means we pee more. NET EFFECT: decrease blood volume= decrease arterial pressure
arteriole vascular tone affects ___ blood pressure because
diastolic because if we vasoconstrict (for example) then we increase peripheral resistance which in turns increases diastolic pressure
What is the dicrotic wave?
diastolic run-off (ie no flow from left ventricle)
venous basal tone=
dilated
cardiovascular response to stress consist of
direct influences of primary distrubance and compensatory resopnse that are trigged by the primary disturbance
SV=
ejection fraction X end diastolic volume
fluid intake should what?
equal urinary output rate
what is diuresis?
excessive production of urine because of natriursis (water follows Na)
What is natriuresis?
excretion of sodium in the urine
What does angiotensin II do?
extremely potent vasoconstriction. Once made it makes us thirsty AND act on the adrenal cortex. Once it acts on the adrenal cortex, it releases aldosterone which causes renal sodium to be retained. AND it causes sysemtic vasoconstriction Because water follows Na+, water is then retained. Both of these increase blood volume this increase cardiac output which then causes increase arterial pressure
we regulate arteriole resistance to adjust for what
flow to meet local metabolic demands
what would an long term response to changes in MAP
fluid retention. regulation by kidney
B1 receptors are found where? What do they do?
heart, increase heart rate and contractility
If we have high arterial pressure and we do not try to reset it, what can happen?
high arterial pressure= increase afterload (systemic pressure/ resistance) which leads to potential damage to vessels endothelial damage means endothelial dysfunction this means decrease NO production which means we decrease vascular reactivity then we have vascular remodeling which can then cause potential end organ damage
what are examples of long term mechanism to regular local blood flow?
hormonal influences
What is compliance? what does it mean when we have a decrease in compliance?
how easy is it for it to stretch The vessel is more stiff, so it can't stretch, therefore there is more pressure on the the vessel.
what determines GFR
hydro static pressure and oncotic pressure
changes in body position alter what?
hydrostatic pressure when flat: blood volume is even when standing, veins allow blood to be pulled towards feet by gravity
vasopressin does what?
increase aquaproin channels in collecting duct which causes water absorption NET EFFECT: increase blood volume= increase arterial pressure
Explain vasoconstriction
increase atrial pressure= decrease downstream volume= decreased capillary and venous pressure= decrease hydro-static pressure= increase re absorption
Increase stroke volume leads to ____ aortic pulse pressure.
increase in aortic pulse pressure
Increase sympathetic activity to veins leads to what
increase sympathetic activity to veins= = increase contraction of vascular smooth muscle = increase peripheral venous pressure = increase venous return = increase ventral venous pressure
generally speaking, constriction means increase or decrease resistance?
increased
when we have an increase in MAP what happens normally?
increases ABR afferent firing rate decrease SANS to vessel increase dilatation decrease pressure
how does medulla center react to an increase arterial pressure?
initial distance: Increase arterial pressure response: decrease SANS which will decrease pressure. It will send this signal out to the medulla, this then causes a receptor to be activated and thus inhibit the sympathetic output. which in turns decreases vessel tone/ SV/HR which decrease blood pressure. The decrease sympathetic output accompanied by a simultaneous increase in parasympathetic output will work together to decrease blood pressure.
what causes ejection fraction to increase or decrease?
input of the SANS and adrenal gland Venoconstriction
how does aortic compliance impact aortic pulse pressure?
inversely proportional to aortic compliance (decrease compliance leads to increase Pp).
if we INCREASE SNS input what happens to the upstream and down stream blood pressure
it causes vaso constriction, Upsteam: increases blood pressure Downsteam: decreases blood pressure
What effects does artial natriuretic peptide have? How?
it causes vasodilation in two ways by inhibiting NE and EPI which decreases vascular resistance It also causes the inhibition of renin which means less angiotensin II is made, which means less aldosterone and therefore NA leaves the blood and water follows. This overall causes a decrease in blood volume because we are peeing off the volume of blood. thus it causes natriresis which then causes diuresis
if we decrease SNS input what happens to the upstream and down stream blood pressure
it causes vasodilation, Upsteam: decrease blood pressure Downsteam: increase blood pressure
Artial natriuretic peptide is a long term regulation of arterial blood pressure because
it deals with NA and water balance by influencing the water volume.
when is the baroreceptor activated? what does it do when it is activated?
it is actived when there is a blood volume increase. it released atrial natriuretic peptide.
How does angiotensin II made?
it is converted fromt he blood-borne angiotensiogen (which was made in the liver) under the regulation of renin which is produced in kidney. Angiotensinogen (in blood) goes to kidney Renin in kidney makes angiotensin 1 angiotensin 1 goes to lungs, in lungs ACE acts on it to make angiotensin II
what is the medullary cardiovascular center
it is like the control center. It simultaneously integrates input from multiple sensors and processes them
where is artial natriuretic peptide formed?
it is realsed from artria when blood volume increases (baro receptor response)
Why is vasopressin released? what does it do?
it is released to response to decreased vessel tone, blood pressure (hypo tension), and blood volume (hypovolemia) It will increase osmolarity
What is active hyperemia?
it is the active response Organs with highly variable metabolic rate, blood flow closely follows metabolic rate. flow changes rapidly with changes in metabolites. If we have decrease metabolism, we therefor have decrease flow
what is the aortic pulse pressure?
it is the differences between systolic and diastolic pressure
what is inertial force?
it is the opposite force as acceleration
what happens if we have too much angiotensin II?
it leads to increase blood volume which leads to hypertension
what does inertial force do for physiology effects?
it produces the physiological effect by redistribution of blood and displacement of organs in direction of inertial force
What does the parasympathetic nervous system do to the vascular system?
it releases Ach as a neurotransmitter. this causes vasodilation via the NO pathway. Not very active/ as important as SNS.
describe pharmomechanical How does it activate vascular smooth muscle
ligand gated channels ROC= receptor operated (ligand gated channels) A vaso-constrictor agonist will bind to a ROC, this leads to a chain reaction that ultimately leads to Ca2+ being released from the sarcoplasmic reticulum which leads to contraction
Arteriolar and pre-capillary sphincter tone is influenced by what?
local conditions which arteriolar smooth muscle response to changes in interstitial fluid which represents cellular environment
vasopressin has a long or short term effect on arterial blood pressure?
long term because it is regulating blood volume. By keeping water in, it is changing perload and cardiac output (via starling mechansim). Thus this will cause an increase in venous return and ventral venous pressure
sympathetic tone means what?
low-level SANS input
arterial pressure is tightly regulated to
maintain appropriate perfusion to organs at all times (MAP must stay around 100mmHg)
Where does histamine come from?
mast cells (allergies)
If flow increases with an increase in metabolic activity then what type of regulation is happening?
metablic autoregulation is more prominent-> vasodilation myogenic vasoconstriction will still occur but to a lesser extent
the chemical composition of ateriolar and pre-capillary sphincter tone is the balance between
metabolic activity and blood supplies
What is the most important factor influencing local blood flow?
metabolic control
higher vascular tone=
more constriction
Elastin fibers allow for what in vessles
more elastin means little resistance to stretch
If flow increases without an increase in metabolic activity then what type of regulation is happening?
myogenic autoregulation is more prominent-> vasoconstriction as a result of an increase stretch from increase flow
changes in stroke volume normally leads to what
normally leads to changes to MAP and Pp due to changes in CO.
What does it mean for a capillary to be nutritional or non-nutritional (give examples to explain your answer).
nutritional: Passing nutrition like water, ions, etc. Kidneys non-nutritional: Regulation of temperature in the skin.
Passive movement of water is driven by_____?
osmolarity (solute concentration) of compartment (osmotic pressure)
HR is influenced by
parasympathetic activity and sympathetic activity and epi
arteriole basal tone =
partial constriction
blood volume is influenced by
passive bulk flow fluid shifts between vascular and interstitial fluid compartments salt and water balances (which is contacted by vasopressin and angiotensin)
what is relative incapacitation
period following the return of consciousness once blood flow returns with o2. still lack of normal motor control and vision. still out of it.
Where does vasopressin come from?
posterior pituitary
why is the carotid body super important?
quantitatively the most important for regulating arterial pressure. Small changes in MAP mean increase receptor firing which means increase response.
Define glomerular filtration rate
rate of movement from capillaries to renal tubules
big picture: disturbances in the heart or vessel cause what?
reciprocal changes in arterial pressure and sympathetic activity
long term regulation of arterial pressure is better served by what?
regulation of fluid balance by regulating blood volume
what is one of the most important mechanism for regulating kidney absorption?
renin- angiotensin-aldosterone system
how is aortic pulse pressure represent?
represents the force generated by heart dueing systole - pulse pressure (Pp)= Psystolic-Pdiastolic
what happens when our leg falls asleep?
restricted blood flow leads to build up of metabolites in interstitial fluid. This causes decrease O2, increased adenosine, increase H+, increased Lactic acid and increase CO2. When blood flow returns, the metabolites causes the vessel to vaso dilate Vaso dilation causes an increase in flow in order to remove the metabolites and get more oxygen to the tissues. Once all of the metabolites are gone, (or to say that metabloism has gone down) we can decrease flow.
What is reactive hyperemia?
restricted blood flow leads to build up of metabolites in interstitial fluid. Removal of restriction results in large initial flow reach in response due to vaso dilation effect of most metabolites. Flow restored to normal when metabolites are flushed out and restored to normal concentrations. So leg falls asleep, metabolites build up. When flow is restored, it must decrease in order to remove all of the build up metabolites.
Too much shear stress can result in what? (in the cell)
results in unidirectional cell deformation
Mechano (baro) receptors do what? what happens if there is a increase in stimulus?
sense arterial pressure in response to stretch. it sense the amount of stretch which will change the firing rate. More stretch means increase rate of action potential generation in afferent neurons. which will try to vasoconstrict so we move blood out.
what happens to the GFR if we have an increase in arterial pressure
significantly increase renal output of water (diuresis) significantly increase the output of salt: known as pressure natriuresis (which increases water loss because water follows salt).
describe mechanical influences How does it activate vascular smooth muscle
stretch-activated channels When there is too much pressure in the vascular bedding, it leads to a stretch response which leads to Ca2+ being released
Big picture idea: Venoconstriction impacts ___ blood pressure which in turns ends up doing what?
systolic blood pressure it then increase venous return, which increases diastolic blood volume which increase stroke volume which increase CO
lower elasticity in venous compartment means
that we require skeletal muscle contraction or SANS stimulation to increase venous smooth muscle contraction to increase venous return
what determines urine volume
the balance of water filter from vessel and water absorbed by kidney
vascular tone is
the degree of vascular constriction
arterial pressure is generated as______
the heart pumps blood into the systemic circulation
how does auto regulation allow for?
the intrinsic ability of an organ to maintain a constant blood flow despite changes in perfusion pressure
blood viscosity is influenced by
the number of red blood cells
Since both epi and NE are circulating in the blood, what happens to the overall response of the smooth muscle?
the overall response will depend on -type of receptors number of receptors binding affinity ligand type ligand concentration For example: If the adrenal medulla released a little bit of epi, then it will bind to the few b2 receptors leading the relaxation. HOWEVER if the adrenal medulla released a ton of epi, it will bind to b2 receptor first due to its high biding affinity. However, it will also bind to alpha 1 receptors. Since there is more alpha 1 receptors it will leads to contraction.
linear acceleration
the rate of change in linear velocity with no direction change.
what happens if MAP remains elevated for long periods? what does this mean for long term regulation?
the set point will move/ change. Because of this adaptability, arterial baroreceptors reflex not sufficient to serve as the sole mechanism for long-term regulation.
how are changes in blood flow controlled intrinsically?
they are controlled intrinsically by modifying the diameter of local arterioles feeding the capillaries via two mechanisms -myogenic auto regulation -metabloic auto regulation
where would find alpha 2 receptors? what stimulates alpha 2 receptors? what does this lead to?
they are less prominent receptor on the vascular smooth muscle. However on the vascular smooth, NE binds to Alpha 2 receptors, this leads to vasoconstriction, this leads to increase Ca2+ which causes contraction They are primarily found on the endothelial cells, NE binds to endothelial alpha 2 adrenoceptors which causes the relaxation of vascular smooth muscle through a release of endothelium derived nitric oxide (NO) it is also located on the sympathetic nerve terminal which will inhibits the release of NE.
B1 receptors are primarily found where? What stimulates them, and what does that lead to?
they are primarily found in the cardiac myocytes (the heart). NE will bind to B1 which leads to increase contractility (positive inotropic effect) and increased heart rate (positive chronotrpoic effect) NE is released from the sympathetic nerve, it binds to B1, which causes a chain reaction that leads to the release of Ca2+ in the SR, which ultimate leads to contraction
what do alpha 2 adrenoceptor agonists do?
they are used very occasionally as centrally acting sympathetically vaso-dilators for the treatment of hypertension they increase the binding of alpha 2 with a different molecule which leads to the shut off of Alpha 2 on the sympathetic nerve. this means that NE will not be realsed and alpha 1 or alpha 2 on the vascular smooth muscle will not be stimulated and no contraction will occur meaning that the vessel relaxes and thus the pressure goes down for someone that is hypertensive.
how doses of epi can cause _____ via ____. like in skeletal muscle
they cause vaso dilation via B2 receptors
What do EPi and NE do via alpha 1 receptors
they vaso constrict
why is regulation of the vascular system important?
to maintain homeostasis
Blood flow (supply) is adjusted to do what?
to meet metabolic need/ demand to maintain homeostasis
true or false: Alpha 1 receptors have higher affinity for NE than EPI
true
What is pulsatile flow?
variable velocity, dynamic with time, generated from the heart, such as arteries So blood flow is like la duh for awhile, creates a waveform. the pulsatile flow causes pressure waveform to form
Distribution of blood is regulated by
vascular resistance of individuals organs which is influenced by extrinsic mechanism (like neural and humeral) and intrinsic mechanisms (local)
alpha 1 receptors are the predominant receptor on ___ what stimulates alpha 1 receptors? what does this lead to?
vascular smooth muscle NE binds to Alpha 1 receptors, this leads to vasoconstriction, this leads to increase Ca2+ which causes contraction
High SANS input means what?
vaso construction
Angiotensis II does what?
vasoconstriction effect on the vessels ANG 11 stimulates sodium reabsorption in nephron (water follows sodium) secretion of vasopressin and the secreation of aldosterone NET EFFECT: increase blood volume= increase arterial pressure
decreased SANS input means what?
vasodilation
who has less smooth muscle? arterioles or veins
veins
what are more compliant than arterioles and cappillaries?
veins more compliant than arteries arterioles and capillaries
what causes end diastolic volume to change?
venous return which is impacted by blood volume, veno-constriction, and the skeletal muscle pump
Venous tone affect ___ blood pressure because
venous tone affects systolic blood pressure. For example if we veno constriction, we increase venous return then we increase end diastolic blood vlume which increase stroke voulme which increases cardiac output
what influences pressure required for blood to come to brain?
vertical heart to eye/brain disance influecn pressure required to adequtely perfuse the brain and maintain function/ consciousness
describe electro-mechanical. How does it activate vascular smooth muscle
voltage-gated channels Due to changes in voltage, the membrane will depolarize, causes the sarcolemma to release Ca2+ which then leads to contraction
High compliance in venous compartment allows for ____ therefore ____
volume reservior therefore small changes in venous pressure mean a large change in venous volume
What is the sinusoid (discontinuous) capillary permeable to?
water, protein, other solutes. Red blood cells can migrate between blood and tissue
when we VENOconstrict what happens
we cause an increase blood volume or venous ton (meaning venous return increases and pressure increases)
if we decrease volume of the blood what happens? what mechanism would we do this with?
we decrease volume, then we decrease entral venous pressure which causes decrease CO, which decreases MAP.
when we VENOdilate what happens
we have decrease blood volume or venous tone (meaning we have decreased venous return and decrease ventral venous pressure)
we lose what as we age. what does this lead to
we lose the compliance of our aortic as we age. it leads to a larger change in pressure
what happens if vasovagal syncope, deep pain or increase central venous pressure happens?
we lower set point for the medullary center. This leads to decrease SANS output decrease vessel tone/ SV/ HR decrease pressure
what happens in response to excerise, sense of danger, cushing reflex, increase in co2/ decrease of o2, decrease of central venous pressure?
we raise set point for the medullary center. This leads to increase SANS output increase vessel tone/ SV/ HR increase arterial pressure pressure
Net change in vessel diameter depends on what? (for auto regulation) Give examples
which condition is more prominent.
What is the primary pressure that drives blood flow to organs
while both Ps and Pd are important clinically, neither are the primary pressure that drives blood flow to organs. Mean arterial pressure (MAP) is the main driving force
why are circulating cateholamines not important in normal vascular regulation?
while do they play a minor role, autoregulation is more important. NE is also found in the nervous system (SNS) which is a quicker response than circulation NE/ epi
Big picture: what functions do endothelial cells perform in the vascular system?
while they do act a barrier they also have other important functions produce vasoactive substance that regulate smooth muscle vascular tone (they do have other function but this is the only one we care about)
What are Fenestrae?
window-like openings in the endothelial cells of the certain capillaries
What drives water out of the trans capillary? Where does this occur?
ΔP drives water OUT→ filtration (arterial end of capillary)
What drives water to move in (absorption) in? Where does this occur?
Δπpulls water IN→ absorption (venous end in capillary)
