2.6 - systemic and pulmonary circulation

Systole

Generated a pressure gradient that drives blood forward

Diastole

During ________, the pressure gradient must be sustained to keep the blood moving

flow

the quantity of blood that passes a given point (volume per time)

True

T/F - blood flow of most tissues is controlled according to tissue needs

pressure difference and resistance

2 main factors that affect blood flow

pressure change / resistance

F = _____ / _______

Arteries

The pressure reservoirs

Stretch

During systole and blood is ejected from the heart, how do large arteries "react"

recoil

During diastole, how do large arteries "react"

allows blood to continue to push forward even when the heart is relaxed

What is the purpose of the recoil of large arteries

Veins

The volume reservoirs that can hold up to 60-70% of the total blood volume

Skeletal and respiratory pumps

2 ways that veins facilitate venous return without the same elasticity/recoil of an artery

muscle contractions squeeze the veins and push blood towards the heart

How does the skeletal muscle pump help facilitate venous return

prevent backflow

How do valves facilitate venous return

Pressure in the thoracic cavity pushes blood forward

How does the respiratory pump help facilitate venous return

resistance

The force opposing the movement of blood through vessels

Vessel radius, blood viscosity, and vessel legnth

3 factors that determine the vessel resistance

Poiseulles law

Describes how blood flow through a vessel is influenced by various factors

smaller radius = exponentially higher resistance

According to Poiseulles law, how does radius affect resistance

Total Peripheral Resistance

combined resistance of all blood vessels within the systemic circuit, mainly arterioles

MAP

The TPR determines how hard the heart must pump to maintain the ______

Increased TPR and MAP

During vasoconstriction, how is the TPR and MAP affected

Decreased TPR and MAP

During vasodilation, how is the TPR and MAP affected

vasodilation in active muscles, but a balance of vasoconstriction in non-active tissues

Why does the TPR only slightly decrease during exercise

Maintain BP

Why is there vasoconstriction in non-active tissues

pulmonary circulation

focuses on oxygenating blood and removing carbon dioxide, operating at a low pressure

Compliant vessels with low resistance

What allows for pulmonary circulation to have such low pressure

Systemic circulation

responsible for delivering oxygen and nutrients to the body at a high pressure

Blood pressure

the force exerted by blood against the vessel walls

120mmHG

average pressure of the aorta during systole

80mmHg

average pressure of the aorta during diastole

MAP

average pressure driving blood into tissues

CO x TPR

MAP = ___ x ___

systolic pressure

highest arterial pressure during heart contraction

increases a lot

How does the systolic pressure change during exercise

Stays the same or slightly decreased

How does the diastolic pressure change during exercise

Pulse pressure

difference between systolic and diastolic pressure