Module 7: The Cardiovascular System

general characteristics of circulatory systems

one or more pumps that provide unidirectional driving force for circulatory fluid, system of tubes, and an aqueous circulatory fluid where vital substances are dissolved

how many circulatory fluids to closed circulatory systems have

2; the blood and interstitial fluid

how many circulatory fluids do open circulatory systems have

one

which animals have an open circulatory system

invertebrates

which animals have an open circulatory system and a tracheal system

insects

important excepion to vital substances that dissolve in aqueous solutions

oxygen

which animals have a closed circulatory system

vertebrates and some invertebrates

for closed circulatory systems respiratory pigment in located

in cells

for open circulatory systems respiratory pigments is located

in solution

tracheal system of insects

used for gas exchange and gas transport

hemolymph of open circulatory system circulates in

hemocel

open circulatory system bathes

all cells in the body

open + tracheal system properties

tracheal system used for gas exchange

in closed circulatory system blood/lymph circulate where ?

in the vessels

in an open circulatory system pressure and rate of O2 exchange is

low

in closed + tracheal system pressure and O2 exchange are ?

low, high

in closed circulatory systems pressure and the rate of O2 exchange is

high

where is pressure reserved in maintain blood flow during ventricular relaxation

arteries

capilaries

where exchange between the blood and cells takes place

blood components

RBCs, WBCs, platelets, plasma, and proteins and other solutes

blood flows through the

vessels

systemic circuit componenets

aorta, arteries, arterioles, capillaries, vanules, veins, vena cava

systemic circuit allows blood to travel

to/from the body

the pulmonary circuit allows blood to travel

to/ from lungs

parts of the pulmonary circuit

pulmonary artery, pulmonary capillaries, and pulmonary veins

where is blood oxygenated

in the pulmonary arteries

where is blood deoxygenated

capillaries

cardiovascular pathway (start at L side)

left side of heart → systemic circuit →right side of heart → pulmonary circuit

systemic circuit pathway

aorta → arteries → arterioles → capillaries → venules → veins → vena cava

pulmonary circuit pathway

pulmonary artery → pulmonary capillaries → pulmonary veins

where is blood pressure high

in arteries and arterioles

where is blood pressure low

the veins/ venules

blood pressure decreases as

it gets farther from the heart

blood vesels

tubes of endothelial cells with layers of smooth muscle ans supporting structures

what causes higher flow rates

higher pressure differences

endothelium

most inner layer composed by endothelial cells that is seen in all blood vessels, only one layer

endothelium function

secretes paracrine factors, regulates BP, blood vessel growth and absorbtion

when the right ventricle contracts during systole where does it pump blood to

pulmonary valve → pulmonary artery → lungs

is the blood pumping out of the right ventricle oxygenated or deoxygenated

deoxygenated

what occurs in the lungs

gas exchange

after blood goes through the lungs where does it return to

the left atrium

after the left ventricle contracts during systole where does the blood go

aorta → throughout the body

in which blood vessels is smooth muscle absent

venules and capillaries

which vessel has the most smooth muscle

arteries

which blood vessels have smooth muscle

arteries, arterioles, and veins

arteries

pressure resovoirs with lots of smooth muscle and connective and fibrous tissue

arterioles

regulated site of resistance

alpha receptors cause arterioles to

constrict

beta2 receptors cause arterioles to

dialate

capillaries

very small vessels with thin walls that lack smooth muscle

metarterioles

branch from arterioles and can act as bypass shunts

precapillary sphincters

surround capillary entry points and can close them off in response to local signals

when do precapillary sphincters allow blood to flow

when theyre relaxed

venules

recieve blood from heart and convergent pattern of flow

functions and location of veins

volume resovoirs that take blood back to the heart, one way valves that are closer to body surface than arteries

what type of tissue are veins made of

vascular smooth tissue

what helps propel blood in veins

compression by muscle

where are the pressure waves in blood vessels the highest in ampltude

the left ventricle

where is your systolic pressure taken from

the arteries

what are pressure waves made from

ventricular contraction

systole

ventricular contraction that pushes blood into the elastic arteries, causing them to stretch

diastole

ventricular relaxation where elastic recoil in the arteries maintains driving pressure

systole chain of events

systole → semilunar valve opens and blood ejected into arteries → aorta and arteries expand and store pressure in elastic wall

diastole chain of events

diastole → semilunar valve shuts preventing backflow → elastic recoil of blood forward into rest of circulatory system

Mean Arterial Pressure (MAP)

function of cardiac output and resistance in arterioles, the driving force for blood flow

BP is highest in _ and lowest in _

arteries, veins

MAP=

diastolic pressure + (1/3) pulse pressure

vascular resistance

resistance that must be overcome to move the blood through the blood vessels

what happens if blood volume decreases

MAP and BP decrease and vasoconstriction

what branch of the nervous system controls most of the vascular smooth muscle

autonomic nervous system

sympathetic innervation of systemic arterioles pathway

Norepinephrine binds α receptors → vascular smooth muscle
contraction → vasoconstriction → increased resistance → decreased blood flow

what neural structure releases epinephrine into blood

adrenal medulla

what happens to action potential firing rate when more norepinephrine is released into alpha receptors

the rate increases and the smooth muscle contracts causing vasoconstriction

what happens to action potential firing rate when less norepinephrine is released into alpha receptors

the rate decreases and the smooth muscle relaxes causing vasodilation

if the flow of one vessel is constricted what happens to the rest of the vessels and the total output

the other vessels overcompensate so the total output remains the same

cardiac output at rest

5L/min

trancytosis

vesicular transport used for larger molecules

paracellular pathway

gaps between endothelial cells the allows movement by bulk flow

fenestrations

pores that allow movement by bulk flow

4 ways plasma and interstitial fluid exchange substances

paracellular pathway, vesicular transport, fenestrations, and movement by diffusion

Exchange between plasma and interstitial fluid by diffusion

gases and small hydrophobic molecules diffuse freely down pressure gradient,

extensive exchange capillary beds characteristics

large gaps between endothelial cells, fenestrations, transcytosis, found in lover and bone marrow

substantial exchange cappilary beds characteristics

Small gaps between endothelial cells, transcytosis, Fenestrations may be present, found in kidneys and intestine

limited exchange capillary beds

tight junctions between endothelial cells, no fenestrations, transcytosis, found in cerebral capillaries

as blood velocity get lower exchange efficiency gets

higher

why is flow rate in the arteries so high and so low in that capillaries

capillaries have high cross sectional area and arteries have a low cross section

how much fluid is filtered out the capillaries

3L/day

filtration excess pathway

picked up by the lymph vessels and returned to veinous circulation near right side of the heart

bulk flow

mass movement of a substance as a result of hydrostatic or osmotic pressure gradients

filtration in capillaries

moves fluid out, due to hydrostatic pressure (P_H) which gradually decreases due to friction

absorption in capillaries is caused by

colloid osmotic pressure/ oncotic pressure

colloid osmotic pressure/ oncotic pressure (π) is due to

presense of capillary plasma proteins

what is interstitial fluid osmostic pressure

0

Net pressure formula

P_net= P_H-π

net filtration at arterial end (Pnet)

P_H > π

net absorbtion at venous end (Pnet)

P_H > π

how does π and P_H change from arterial end to venous end

π remain constant as 15 mmHg, while P_H goes from 32 mmHg at the arterial end to 15 mmHg at the venous end

2 characteristics of the lymphatic system

allows for return of interstitial fluid back to circulatory system
no centralized pump

how does insterstitial fluid move through the lymph system

contraction of smooth muscle in wall propels fluid, body movements and compression of lymph vessels, and one way valves