Chapter 14- Cardiovascular Physiology

heart, blood vessels, blood

components of the circulatory system

veins

carry blood to heart

arteries

carry blood away from heart

bulk flow

Heart moves blood through blood vessels via generation pressure gradient

transportation

main function of cardiovascular system

oxygen, nutrients, water

substances coming into the body

waste, immune cells, hormones, stored nutrients

substances exchanged between cells

waste, heat, CO2

substances leaving the body

heart

Acts as a mechanical pump in cardiovascular system

pressure generated by heart

moves blood throughout closed vascular system

capillaries

where does exchange between blood and tissues occur?

plasma, blood cells, platelets

elements that make up blood

between the lungs in the thoracic cavity

where is the heart located?

pericardium

connective tissue membranes surrounding the heart that protect and anchor it

apex

free surface of the heart located down and to the left

base

area of heart that has connections and is found under sternum

4 chambers, septum, and valves

basic anatomy of the heart

septum

wall that divides the left region of the heart from the right

right atrium

-receives blood from body via vena cavae

-deoxygenated

left atrium

- receives blood from pulmonary veins
- oxygenated

pulmonary vein

vein that carries oxygenated blood

right ventricle

pumps blood to lungs via pulmonary trunk (arteries)

left ventricle

-contracts to send blood to body via aorta

ensure one way flow

function of heart valves

Tricuspid

right side AV valve

Bicuspid

left side AV valve

atrioventricular

valves found in between the atrium and ventricles

Aortic valve

valve found between LV and Aorta

Pulmonary valve

valve found between RV and pulmonary trunk

pulmonary artery

artery that carries deoxygenated blood

pulmonary circulation

flow of blood from heart to lungs

systemic circulation

circulation of blood throughout the body

venous return

what is it called when blood returns to right side of heart?

right atrium, tricuspid valve, right ventricle, pulmonary semilunar valve, pulmonary trunk, lungs, pulmonary veins

how does blood flow through the right side of the heart?

pressure

what drives blood forward in circulation

pulmonary veins, left atrium, bicuspid valve, left ventricle, aortic semilunar valve, aorta, systemic circulation

how does blood flow through the left side of the heart

coronary circulation

Arteries supply blood to heart muscle, veins drain blood

coronary sinus

end of coronary circulation

portal system

circulation where blood flows through 2 capillary beds on the way to the heart

hepatic portal system

Blood directly from intestines to liver via hepatic portal vein

contractile, autorhythmic

cardiac muscle is made of mostly ___________ muscle fibers with a few specialized __________ cells

contraction

main function of the heart

single nucleus, single branched cells, mitochondria, striation

characteristics of cardiac muscle cells

intercalated disks

special connections b/w cardiac cells

desmosomes

cells anchored together and connections cause forceful contraction

gap junctions

electrically coupled junctions for cytoplasmic connection coordinate movemnet

paler, no sarcomeres, specialized ion channels

appearance of autorhythmic cells

Calcium

signaling molecule that controls contraction

Ca2+, Na+

during cardiac relaxation, _______ is pumped out of the cell while ______ is pumped in

-90

what is RMP in mV?

depolarization

gap junctions

-inc. membrane potential

-opens v-g Na+ and Na+ influx (+ 20 mV)

initial repolarization

Fast v-g K+ channels open,
-K+ efflux

plateau

v-g Ca2+ Channels open,
-Ca2+ influx

rapid repolarization

Slow v-g K+ opens

Sinoatrial (SA) Node

location of autorhythmic cells where contraction begins

Atrioventricular (AV) Node

Electrical depolarization travels here which causes contraction of atria

AV bundle

Electrical depolarization travels from AV node to __________ towards the apex

Purkinje Fibers

pale, branching fibers that spread electrical depolarization to ventricles

Electrocardiogram

shows record of electrical activity of the heart over time

heart rate and rhythm

what variables are measured by an ECG?

P wave

point on ECG where atria depolarize (contract)

QRS Wave

point on ECG where ventricles depolarize (contract) and atria repolarize

T wave

point on ECG where ventricles repolarize

PR segment

represents conduction through AV node and bundle

ST segment

duration of ventricular contraction

TP segment

electrically quiet until next cycle

systole

cardiac contraction

diastole

cardiac relaxation

isovolumic

what type of contraction occurs during the QRS phase?

ventricles contract while AV and semilunar valves are closed so no blood moves

what happens in the process of isovolumic contraction

pressure increases in ventricles and when it becomes greater than pressure in pulmonary artery semilunar valves open and blood flows out

What happens in the ejection phase of contraction?

50-60mL

what is the end systolic volume after contraction?

semilunar valves close after ventricular pressure closes, AV valve is closed so no volume is changed while the heart is relaxed

what happens in isovolumic relaxation?

passive filling

• once atrial Pressure > ventricular pressure the AV valves will open,
• blood flows from atria into ventricles

depolarization of SA node leads to atrial contraction which actively pumps blood into ventricles

What happens during active filling?

120-130mL

what is the approximate end diastolic volume after filling

AV valves, Semilunar valves

S1: Sound of _________ closing
S2: Sound of __________ closing

valves closing

what sound do doctors listen to in your heart?

heart murmur

Caused by turbulent blood flow

Regurgitation

Caused by backward flow of blood from valvular insufficiency

stenosis

Ex. Systolic ejection murmur
• Valve opening narrows
• Increased pressure and turbulent flow

Wiggers Diagram

Relates electrical, mechanical, volume and pressure events in the heart

cardiac output

volume of blood pumped out of the heart per unit time

stroke volume and heart rate

two factors that account for cardiac output

stroke volume

volume of blood ejected from left ventricle per beat

mL

units of stroke volume

epinephrine

produced by adrenal medulla in response to stress

norepinephrine

production stimulated by sympathetic nerves in cardiac modulation

increase rate of cardiac action potentials and increase force of contraction

what do adrenergic receptors do when norepinephrine and epinephrine bind?

Adrenergic receptors

where do norepinephrine and epinephrine bind?

decrease

the parasympathetic nervous system can __________ the rate of cardiac Action Potentials

by changing end diastolic volume

how is stroke volume changed?

skeletal pump

compresses veins

Respiratory pump

pressure changes in abdominal and thoracic cavities during respiratory cycles

frank-starling law

Indicates optimal sarcomeric overlap to generate maximal force