Lecture 11 Flashcards
what are the two functional parts of the circulation?
Pulmonary circulation
systematic circulation
what is pulmonary circulation?
flow of blood through the lungs for oxygenation
-deoxygenated blood flows from the right ventricle to the lungs where it is oxygenated and then returned to the left atrium`to go to body
what is systematic circulation?
supplies blood fow to all the tissues of the body except the lungs
- then come back into right atrium
- also called greater circulation or peripheral circulation
stronger part of the heart that pushes blood out
ventricles
entire blood volume is about ____.
___% of whole volume is in systemic circulation
- ____% in veins
- ____% in arteries
- ____% systemic arterioles and capillaries
____% of whole volume is in Pulmonary circulation
- ____% in heart
- ____% in pulmonary vessels
5 Liters
84% in systemic
64% in veins
13% in arteries
7% arterioles and capillaries
16% in pulmonary
7% in heart
9% in pulmonary vessels
blood goes from _____ to lungs to get oxygenated.
Then back to _______.
_____ pumps blood out to go to body through the ______. goes through ______ where oxygen is dropped off.
makes its way to _____ then ____ returns blood to heart.
right ventricle
left atrium
left ventricle
aorta
arterioles and capillaries
veins
inferior vena cava
basic blood flow from the left ventricke?
elastic arteries
muscular arteries
arterioles
capillary beds
venules
veins
right atrium
main function of venous vessels are _______
blood reservoirs
-major storage compartment for blood
what is the relationship between cross-sectional areas to velocity of blood flow?
inversely proportional
- veleocity is slowest where cross sectional area is greatest
blood flow becomes ____ the farther away from the heart and is slowest in ______
when venules unite to form veins the total cross-sectional area becomes _____ and flow becomes _____
slower
capillaries
smaller
faster
the capillaries are located _______
at the far end of the blood flow loop
heart pumping is _____ and the arterial pressure alternates between ______ and ______
mean pressure is ____
pulsatile
systolic (120)
diastolic (80)
relatively high
which side of heart has more pressure
left
largest drop in arterial pressure occurs in the _____ from ____ to ___
arterioles
70 to 35
Rate of blood flow of each tissue of the body is almost always precisely controlled in relation to ______
tissue need
- increased flow = increased metabolic demand
cardiac output (CO) is controlled mainly by the ________
sum of all the local tissue flows
- all blood flowing thru tissue must return to heart
- increased flow thru tissue determines increased flow to the heart which increases CO
in general the arterial pressure is controlled ________ of _________
independently of local blood blow or CO control
baroreceptor reflex
- increases heart rate
- generalized vasoconstriction
endocrine hormonal secretion
when blood flows at a steady rate through a long smooth vessel in streamlines, with each layer of blood remaining the same distance from the vessel wall
laminar flow
in laminar flow velocity of the blood in the center of the vessel is ______ than the outer edges
greater
in laminar flow the conductnce of blood in a vessel increases to the _____ of the vessel ______
fourth power
diameter
when the fluid molecules touching the wall barely move because of adherence to the vessel wall.
parabolic profile
the farther the layer of blood is from the vessel wall, the ____ it is.
less impeded (less stuck)
blood flowing in all directions in a vessel and continually mixing within a vessel
turbulent flow
what can cause turbulent flow
when it passes an obstruction in a vessel or passes over a rough surface
what is it called when the blood in turbulent flow moves backward in a whorl
eddy currents
eddy currents cause much more ______
resistance
turbulent flow is seen in ________
it generates sound waves that can be heard with a stethoscope as _____ or _____
turbulent flow can lead to ______
diseased and stenotic arteries and heart valves
murmors or bruits
decrease in flow and blood clot formation and ischemia
the quantity of blood that passes a given point in the circulation in a given period of time
blood flow
ml/min
CO amout of blood pumped into the aorta by the heart/min
- 5000 ml/min
what main factors effect blood flow through a vessel
pressure difference (gradient)
resistance
pressure difference or gradient is?
pressure difference of the blood between the two ends of the vessel
what is resistance?
impediment to flow due to friction between blood and endothelium of the vessel wall
P1 vs P2
P1 is beginning
P2 is end
flow through the vessel can be cslculated using ____
Ohm’s Law
what is ohms law equation
F = (P1-P2) / R
R=resistance
Ohm’s law demonstrates that:
Blood Flow is _____proportional to the pressure difference and _______ proportional to the resistance.
Put simply, as blood flow increases:
The pressure gradient _____
The resistance __________
directly
inversely
increases
decreases or stays the same
what influences vascular resistance
size of lumen
blood viscosity
total blood vessel length
how does the size of the lumen influence vascular resistance?
the smaller the lumen of blood vessels, the greater the resistance
vasoconstriction ____ the diameter and vasodilation ____ the diameter
narrows
widens
normally moment to moment fluctuations in blood flow through a given tissue are dependent upon whether the _____ in that tissue are under _______ control
arterioles
sympathetic
what is blood viscosity?
resistance to flow
depends on the ratio of RBC to plasma (hematocrit)
and to a smaller extent the concentration of plasma proteins
how does blood viscosity influence vascular resistance?
the higher blood viscosity, the higher the resistance
hematocrit for males and females
RBC to plasma
males = 42
women = 38
high blood viscosity found in conditions of ________ and ________
dehydration and polycythemia
- high #RBC
- increases blood pressure
what influences does total blood vessel length have on vascular resistance?
resistance of blood flow through a vessel is directly proportional to total blood vessel length
longer = more resistance
why do obese have higher rates of hypertension
additional blood vessels increase blood vessel length, so more resistance
the ______ has a cardiovascular center that regulates heart rate, contractility (force of contraction), and blood vessels diameter
medulla oblongata
CVC controls neural, hormonal, and local _____ systems that regulate blood flow to specific tissues
negative feedback systems
some neurons in the CVC in medulla oblongata stimulate heart (_______ center) or inhibit the heart (______ center).
cardiostimulatory center
cardioinhibitory center
some neurons in CVC control blood vessel diameter by causing _________ in ______ center
vaso constriction or dilation
vasomotor center
neurons regulating blood vessel diameter
vasomotor neurons
sympathetic neurons that reach the heart and increase heart rate
cardiac accelerator nerves
parasympathetic neurons that reach the heart and decrease heart rate
vagus nerve
input to CVC by what three main sensory receptors?
Proprioceptors
Baroreceptors
Chemoreceptors
what are proprioceptors
monitor joint movement and provide input to CVC during physical activity
increased movement = increased blood flow requirement
- also increase activity when postural muscles are firing at a high rate (indicating standing position)
what are baroreceptors responsible for ?
pressure sensitive sensory receptors
- carotid sinus
- wall of ascending aorta
- walls of these vessels stretch stimulating baroreceptors
drop in BP : increase sympathetic stimulation, increase HR and contractility. This increases CO, vascular resistance, and BP (negative feedback)
increase in BP : increase in parasympathetic, decrease in HR and contractility. This decreases CO, vascular resistance, and BP (negative feedback) (baroreceptor reflex)
carotid sinus is _____ nerve
glossopharyngeal nerve
CN IX
ascending aorta and arch of aorta is _____ nerve
vagus nerve
CN X
what are chemoreceptors responsible for?
monitor chemical composition of blood
- detect changes in blood O2, CO2, and H+
_________stimulates the chemoreceptors to send signals to the CVC. The CVC then ____ ____ stimulation to arterioles and veins producing _________ and an _______ in BP as well as stimulating the respiratory center to _______ breathing.
hypoxia, acidosis, or hypercapnia
increases sympathetic
vasoconstriction
increase
increase
where is chemoreceptors found
close to baroreceptors od the carotid sinus and arch of aorta
found in small structures called carotid bodies and aortic bodies
Blood pressure measured in _____ by ______.
A pressure of 120 mmHg in a blood vessel will push a column of mercury to 120 mm height in a vertical column.
mmHg
mercury manometer
regulation of blood pressure and blood flow
intrinsic regulation
- autogenic regulation
explain autogenic regulation in blood pressure and blood flow
increase in arterial pressure = immediate rise in blood flow.
in less than a minute, the blood flow in these tissues return back to normal even though arterial pressure is still elevated.
what two theories try to explain autogenic regulation
metabolic theory
myogenic theory
metabolic theory
when arterial pressure becomes too great, the excessive flow provides too much oxygen and nutrients to the tissues.
-The nutrients, especially excess oxygen, cause the blood vessels to constrict and the flow to return to normal despite the increased pressure.
myogenic theory
sudden stretch of blood vessels walls causes the smooth muscle of the wall to contract for a few seconds.
- high arterial pressure stretches the vessel, causes vascular constriction that reduces blood flow nearly back to normal
- elicited by stretch induced depolarization, which rapidly increases calcium ion entry from the ECF into cells causing them to contract.
- Conversely at low pressures the degree of stretch is less, so that the smooth muscle relaxes and the flow increases.
several types of cells release a wide variety of ______ that alter _______
chemicals
blood vessel diameter
vasodilation chemicals
potassium
hydrogen
lactic acid
ATP
prostacyclin
nitric oxide
kinins
histamine
vasoconstricting chemicals
Thromboxane A2
superoxide radicals
serotonin
endothelins
EPINEPHRINE.
