Chp 40- Circulatory System

heart and blood vessels

two main components of the cardiovascular system

arteries and veins

major types of blood vessels

arteries

blood vessels that take blood away from the heart (usually oxygenated)

veins

blood vessels that bring blood back to the heart (usually deoxygenated and high in CO2)

capillaries

exchanges gases, nutrients, and waste

arterioles

regulate blood flow to capillaries

venules

collect blood from capillaries

myocardium, pericardium, endocardium

layers of the heart wall

cardiomyocytes

specialized muscle cells of the heart

myocardium

thick, muscular, middle layer of the heart

made mostly of cardiomyocytes

pericardium

protective sac that surrounds heart

endocardium

thin inner lining of heart chambers

right and left atria, right and left ventricles

chambers of the heart

tricuspid valve, pulmonary valve, mitral valve

major valves of the heart

pulmonary circuit

receives blood from tissues (enters right atrium); circulates it to lungs for gas exchange

systemic circuit

receives oxygenated blood from lungs

circulates to body

blood enters the right atrium through the superior and inferior vena cava

blood moves to right ventricle

right ventricle pumps blood to the lungs for oxygenation via pulmonary arteries

oxygenated blood returns to the left atrium via the pulmonary veins

blood moves into the left ventricle

left ventricle pumps oxygenated blood to the body’s tissues through the aorta

how blood moves through the heart during circulation

sinoatrial (SA) node, atrioventricular (AV) node, Bundle of His, Purkinje fibers

parts of the cardiac conduction system

Sinoatrial (SA) node

“pacemaker”

starts signal

Atrioventricular (AV) node

located inbetween atria and ventricles

delays signals

Bundle of His

conducts from AV node to ventricles

Purkinje fibers

spread the signal throughout ventricles

systole

contraction of chambers pushes blood through valves

• from atria into ventricles

diastole

relaxation

blood flows into the heart while all chambers are relaxed

cardiac diastole → atrial systole, ventricular diastole → atrial diastole, ventricular systole

explain how coordinated contraction and relaxation move blood through the heart

blood pressure

force of blood pushing against walls of blood vessels

maintains blood flow to organs and tissues throughout the body

systolic pressure

pressure when heart contracts

diastolic pressure

pressure when heart relaxes between beats

cardiac diastole

all chambers are relaxed, and blood flows into the heart

atrial systole

atria contracts

ventricular diastole

pushes blood into the ventricles

atrial diastole

atria relaxes

ventricular systole

ventricles contract, pushing blood out of the heart