Circulation, Pressure, Flow, and Resistance Flashcards
(22 cards)
Systemic circulation
- Serves?
- Blood volume
- AKA
Serves all tissues except lungs
Contains 84% blood volume
Peripheral circulation
Pulmonary circulation
-Serves?
-Blood volume
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Lungs
9% of blood volume and 7% heart
Arteries
Arteries- transport blood under high pressure to tissues and have strong vascular walls. Blood flows at high velocity in arteries
Arterioles
Small branches of arterial system. Releases blood into the capillaries. Has strong vascular walls.
Capillaries
Exchange fluid, nutrients, electrolytes, hormones, and other things between blood and interstitial fluid. Walls are very thin and filled with pores.
Venules
Collect blood from capillaries and progress into larger veins.
Veins
Transport blood from venules back to the heart and are a major reservoir of blood. Venous walls are thin due to low venous system pressure.
Relation between cross-section of pulmonary/peripheral circulation structures?
Capillaries have largest area of cross section so blood travels slower through capillaries. Aorta has smallest cross section and blood travels fastest. The lower the cross section, the faster the blood travels. The bigger the cross section, the slower blood travels. Think of water flowing fast through a stream (aorta) and then going slow once it flows into an open lake (capillaries).
Normal arterial systolic and diastolic pressure
Systolic-120mmHg
Diastolic-80mmHg
As blood flows through system circulation, arterial pressure?
0 mmHg
Systemic capillary pressure
Varies.
At arteriolar ends-35mmHg
At venous ends-10mmHg
Pulmonary artery systemic/diastolic pressure
25/8 mmHg
T/F Total blood flow through lungs each minute is same as through the systemic circulation
True-because systemic and pulmonary circulation are in SERIES. Right heart pumps same amount as left heart.
Arteries, arterioles, capillaries, venules, and veins are in series.
Organs in systemic circulation are in parallel or series?
Parallel. Rate of blood flow to each tissue can be regulated independently of each tissue.
Pathway blood flows
START SYSTOLIC CIRCULATION:Aorta (100mmHg)–>arteries(100)–>arterioles(slowly drops)–>capillaries(35)–>veins(7)–>vena cava–> END SYSTOLIC CIRCULATION–>BEGIN PULMONARY–>vena cava–>Pulmonary arteries(25)–>arterioles(drops)–capillaries(drops)–>venules–>pulmonary veins START SYSTOLIC
What are some things that would happen if arterial pressure dropped below 100mmHg?
- Increase the force of heart pumping
- Cause contractions of veins to push more blood to the heart
- Constriction of most arterioles throughout the body so blood can go to arteries to increase arterial pressure.
Ohms law
Blood flow= change in pressure of 2 ends of vessel (aterial-venous pressure)/ resistance
Laminar flow vs turbulent blood flow
Blood flows in layers going in one direction. Blood flow is silent. Turbulent blood flow happens when their is bloodflow in opposite directions (due to stenosis or some abnormality) and you can hear noises (murmur).
Blood pressure
The force exerted by the blood against area of vessel wall.
The rate of bloodflow through the circulatory system is equal to the rate of blood pumping by the heart
AKA
The rate of bloodflow through the circulatory system is equal to cardiac output.
Flow is proportional to what power of the radius? This means???
4th power. This means that small changes in radius of blood vessel can cause dramatic changes in blood flow through a tissue.
Besides pressure and resistance, what else can affect blood flow?
Viscosity (n) and length of vessel (l) demonstrated in Poiseuille’s Law.
blood flow=change in vessel pressureXradius^4/viscosityXlength
