Blood Vessels and Circulation - Exam 1 Flashcards
What happens to blood pressure as you move away from the heart?
Systemic blood pressure decreases
If the artery is farther away from the heart, what happens to it’s connective tissue and therefore pressure?
There is less connective tissue, therefore less pressure
What are arteries more composed of compared to capillaries and veins?
smooth muscle
What does the adventitia in arteries have and do?
cross sections of blood vessels to allow oxygen, nutrients, and blood from the outside in and vice versa
What are fenestrated capillaries?
capillaries that have holes, allowing for exchange of larger material such as proteins
What are sinusoid capillaries?
capillaries that have even bigger gaps for even larger exchange
Where are sinusoid capillaries found?
liver and bone marrow
What are the two types of pressures controlling fluid movement across capillary walls?
hydrostatic and colloid osmotic
What is hydrostatic pressure?
fluid pressure
fluid pressing on walls
higher fluid inside vs interstitial, fluid will push out
What is colloid osmotic pressure?
driven by solutes
colloid= something in suspension
high solutes and low water causes water to flow in
What happens if there is a high amount of sodium in the blood?
will go down concentration gradient to surrounding tissues
What is a good indicator of what is going on around it?
blood
What kind of exchange does interstitial fluid allow?
free exchange between plasma and fluid
What kind of exchange does intercellular fluid allow?
no free exchange
What organ requires highly regulated exchange with capillaries?
Brain
How do blood vessels in the brain behave?
endothelial cells that line vessels have tight junctions that cut off the free route between cells, which forces the fluid through the cell for higher regulation and less pressure buildup
If the walls of veins are thinner than arteries, why don’t they burst?
low pressure throughout the veins makes it less likely to burst
How much blood is in your veins and why?
65% because veins are a sink for blood
What are the 4 ways that blood returns to the heart under low pressure and which are most important?
muscular pump semilunar pump sympathetic NS respiratory pump most important are the first 3
What happens during muscular pump blood return?
most likely skeletal contractions to push blood through arteries and veins
What happens during semilunar valve blood return?
contractions cause blood to open semilunars
What happens during sympathetic NS blood return?
causes venoconstriction
What are varicose veins a result from?
deformed and nonfunctional venous valves
What actually happens during the formation of varicose veins?
pressure builds up if semilunars cant be pushed open
blood vessels are stretched due to blood buildup
Where are varicose veins most common?
superficial veins
What are varicose veins in the anus called?
hemorrhoids
What is an important nutrient needed to keep hemorrhoids less painful?
fiber
What is perfusion?
amount of blood flow to tissues
What is tissue perfusion influenced by?
vascular tone in supplying arterioles
relaxing the blood vessels will lower blood pressure and you will die because tissue perfusion will not occur
What are the three types of autoregulation?
metabolic controls
myogenic controls
long-term autoregulation
What is metabolic autoregulation?
byproducts of metabolism (CO2)
causes vasodilation and increased perfusion
What is myogenic autoregulation?
arterioles constrict to limit the amount of blood going to capillaries which decreases capillary BP
What is long-term autoregulation?
angiogenesis (formation of more blood vessels) for increased blood flow
What preludes capillaries to constrict and shunt blood?
Precapillary sphincters
What is blood pressure the result of?
flow is opposed by resistance
What causes resistance in arteries?
vasoconstriction
What are the three factors that maintain BP?
cardiac output
peripheral resistance
blood volume
What happens when you increase the influence of the parasympathetic nervous system?
increased heart rate
What are the short-term controls of blood pressure?
neural controls
hormonal controls
shear stress
What is the fastest short-term control system to regulate BP?
Neural controls
What are the two types of neural controls?
vasomotor center (brain stem) baroreceptors and chemoreceptors
What happens to baroreceptors when BP is too high?
blood pushes against them to tell brain that it is too high
What does stroke volume and the sympathetic nervous system do when BP is too high?
decreases stroke volume
sympathetic NS drops heart rate
cardiac output is decreased
What does vasodilation do to peripheral resistance?
decreases it
What happens to baroreceptors that would cause one to remain in a hypertensive state?
they reset with firing at a continuous rate
Where are chemoreceptors located?
aortic arch and large arteries of the neck
What do chemoreceptors detect?
pH, CO2, blood ox. levels
How do chemoreceptors respond to low O2, high CO2, or low pH?
signal generated to increase gas exchange by increasing cardiac output and vasoconstriction
What types of hormones increase blood volume?
epinephrine, aldosterone, ADH
What types of hormones decrease blood volume?
ANP, Angiotensin, Angiotensin II
What does shear stress do to blood pressure?
stimulates release of nitric oxide causing vasodilation
How do the kidneys contribute to long-term control of BP?
direct and indirect mechanisms
direct= change fluid filtration rate
indirect= renin-angiotensin-aldoesterone system
What are the 3 types of circulatory shock?
hypovolemic shock
vascular
cardiogenic
What is the BP values of hypertension?
140/90
What is essential/primary hypertension?
no known cause (95% of cases)
What is secondary hypertension?
known cause
What causes hypertension?
anything that increases SV, HR, BP
change in peripheral resistance, effect of ADH, aldosterone etc
What is the BP reading for prehypertension?
135/85
How does atherosclerosis start?
endothelial dysfunction (hyperlipidemia) turbulent blood flow which decreases sheer stress
What does atherosclerosis stimulate?
the release of LDL (bad cholesterol)
What engulfs LDL in atherosclerosis and what happens because of it?
macrophages digest it and become foam cells
macrophages eventually burst, causing the release of one fat cell
What are the consequences of a blocked artery in the heart?
coronary artery disease
can result in heart attack
What are the consequences of a blocked artery in the peripheral blood vessels?
peripheral artery disease
can result in gangrene and amputation
What are the consequences of a blocked artery in the brain?
stroke
What are the methods of treating blockages in coronary arteries?
coronary bypass surgery
angioplasty or stent implantation
What is a problem associated with angioplasty and stent formation?
restenosis (re-closure of vessels)
What are aneurysms?
localized dilatation of a part of the cardiovascular system
What causes aneurysms?
infection of arteriole wall
high BP
artherosclerosis
What are the treatment options for aneurysms?
repair blood vessels via clipping or coiling
