Circulatory System

heart chambers

right/left atrium

right/left ventricle

right atrium

receives deoxygenated blood from superior and inferior vena cava

superior vena cava

collects deoxygenated blood from chest, arms, head, neck

inferior vena cava

collects deoxygenated blood from abs, pelvis, lower limbs

right atrioventricular (AV) valve

aka tricuspid valve

allows blood to flow from right atrium to right ventricle

right ventricle

pumps deoxygenated blood into pulmonary artery

pulmonary artery

carries deoxygenated blood to lungs

pulmonary semilunar valve

allows blood to pass from right ventricle into pulmonary artery

left atrium

receives oxygenated blood from pulmonary vein

pulmonary vein

carries oxygenated blood from lungs to heart

left atrioventricular (AV) valve

aka bicuspid or mitral valve

allows oxygenated blood to flow from left atrium to left ventricle

left ventricle

pumps oxygenated blood into aorta

aorta

directs oxygenated blood from heart into circulation

most muscular chamber of heart

contraction generates more pressure than right ventricle

pulmonary circulation

deoxygenated blood from heart to lungs via pulmonary artery and oxygenated blood from lungs back to heart via pulmonary veins

systemic circulation

transports oxygenated blood from heart to body via aorta and deoxygenated blood from body to heart via superior/inferior vena cava

cardiomyocytes

heart muscle cells

automaticity

ability of cardiac cells to generate electrical impulses without external stimulation

sinoatrial (SA) node

pacemaker of the heart

located in upper wall of right atrium

greatest automaticity

contracts right and left atria

transmits signal to AV node

atrioventricular (AV) node

briefly delays electrical current coming from SA node

lower wall of right atrium

passes electrical signal to Bundle of His

Bundle of His

passes signal form AV node to bundle left and bundle right branches

Purkinje fibers

receive electrical signal from bundle branches and stimulate ventricular contraction

intercalated discs

cell junctions between cardiomyocytes

provide physical/electrical connection (gap junctions)

systole

ventricular ejection phase

ventricles contract, increasing pressure w/in chamber until it is enough to push open semilunar valves

highest blood pressure

aorta was highest pressure

diastole

ventricular filling phase

ventricular myocardium relaxes, allowing maximal blood filling into atria

lowest blood pressure

cardiac output

volume of blood being pumped by heart per minute

heart rate

beats per minute

stroke volume

volume ejected per single beat

blood vessels

transport blood to and from the heart

arteries

transport blood AWAY from the heart

• highest pressure

arterioles

branches off of arteries with smaller diameters

• greatest drop in blood pressure is arteries → arterioles

capillaires

one-cell-thick branches off arterioles

connect arterial and venous circulations

• exchange gases/nutrients via diffusion

venules

intermittent vessel that transports blood from capillaries to veins

veins

transport blood TOWARD the heart

• hold more blood that arterial circulation

• contract surrounding skeletal muscle to push blood through

blood plasma

fluid blood component

about 55% of blood volume

what is plasma made of

water, proteins, nutrients, hormones, other water soluble stuff

leukocytes

white blood cells

cells of immune system that defend against infection

together with platelets only about 1% of blood

platelets

aka thrombocytes

anucleate, cytoplasmic cell fragments responsible for clotting

megakaryocytes

large, platelet precursor cells

found in bone marrow

cofactor needed for several clotting factors

Vitamin K

erthrocytes

red blood cells

transport gases (CO₂ and O₂) via hemoglobin proteins

45% of blood volume

lack a nucelus!

biconcave and flexible

structural component

initiates blood clotting cascade

collagen

platelet activation

exposed collagen initiates adhesion and activation

activated platelets release…

clotting factors that convert prothrombin into thrombin

what does thrombin do

convert fibrinogen into fibrin

fibrin

activated fibrin strands polymerize together, forming hemostatic plug

agglutination

clumping together of red blood cells and red blood cell antibodies

Rhesus factor

red blood cell surface marker (+ or -)

universal donor

type O- blood

universal acceptor

type AB+

placenta

source of fetal nutrients from mother, delivered via umbilical cord

barrier for gas and nutrient exchange

umbilical cord

houses umbilical vein and umbilical artery

umbilical vein

carries oxygenated blood from placenta to fetal heart

umbilical artery

carries deoxygenated blood from fetal heart back to placenta

ductus venosus

duct connecting umbilical vein to inferior vena cava

• bypasses nonfunctional liver

foramen ovale

hole connecting right and left atria

bypasses pulmonary circulation bc lungs and nonfunctional

ductus arteriosus

duct connecting pulmonary artery to the aorta

• bypasses pulmonary ciruclation

erythroblastosis fetalis

when a Rh (-) mother carries a Rh (+) fetus, which then becomes problematic upon a second pregnancy with another Rh (+) fetus

lymphatic system

subsystem of circulatory system that regulates fluid levels and produces immune cells

components of lymphatic system

lymph nodes, lymph vessels, adenoids, spleen, thymus

thymus

major immune center w/in lymphatic system

location of T cell maturation

spleen

site of blood filtration w/in lymphatic system

filters blood for pathogens and recycles old red blood cells

hydrostatic pressure

pushes fluid out of the blood vessels (arterial end) and into interstitial space

oncotic pressure

brings fluid back into the capillary (venous end)

lymph

consists of remaining fluid in interstitial spcae, bacteria, fats, proteins

lymphatic capillaries

collect the lymph out of the interstitial space

lymph nodes

centers for the immune system to eliminate infections