Cardiovascular System A&P

apex

pointed end of the heart

visceral pericardium

serous membrane that adheres directly to the surface the heart

parietal pericardium

serous membrane that adheres to the the diaphragm and the sternum

serous fluid

lubricates the organs and allows them glide without friction

epicardium

the outermost layer of the heart

myocardium

thick middle muscle layer of the heart

endocardium

membrane lining the cavities of the heart

atrium

upper chamber of the heart that receives blood

ventricle

each of the two lower chambers of the heart that pumps blood out of the heart

atrioventricular valve

either of two heart valves through which blood flows from the atria to the ventricles

bicuspid valve

also known as the mitral valve; located between the left atrium and left ventricle

tricuspid valve

valve between the right atrium and the right ventricle

pulmonary semilunar valve

lies between the right ventricle to the pulmonary artery

aortic semilunar valve

lies between the left ventricle and the aorta

chordae tendinae

fibrous tissue cords that anchor the flaps of the A-V valves to the ventricles

papillary muscles

attache to the chordae tendinae to limit movement of valve cusps and prevent backflow of blood

regurgitation

backflow of blood through a defective heart valve

aorta

largest artery in the body; conducts freshly oxygenated blood from the heart to the tissues

pulmonary arteries

arteries that carry deoxygenated blood from the right ventricle to the lungs

inferior vena cava

carries deoxygenated blood from lower limbs and abdominal organs to right atrium

superior vena cava

carries deoxygenated blood from the head and arms and chest and empties into the right atrium

pulmonary circuit

carries blood to the lungs for gas exchange and returns it to the heart

systemic circuit

carries oxygen-rich blood to all body organs and then returns oxygen-poor blood to the right atrium via the veins

coronary arteries

blood vessels that branch from the aorta and carry oxygen-rich blood to the heart muscle

cardiac veins

collects deoxygenated blood from heart muscle tissue empty into right atrium

coronary sinus

enlarged vein from junctions of all cardiac veins which empty into the right atrium

sinoatrial node

the heart's pacemaker, located in the wall of the right atrium

atrioventricular node

located in the lower wall of the right atrium; delays impulses from the SA node to allow the atria to completely empty before the ventricles contract

septum

divides the right and left sides of the heart

atrioventricular bundle

a.k.a. Bundle of His; transmits impulse from the AV node to the ventricles through the septum

Purkinje fibers

extend from branches of AV bundle, stimulate muscle fibers in the ventricular walls

electrocardiogram

the graphic record/representation of the heart's electrical activity

sphygmomanometer

instrument for measuring arterial blood pressure

P wave

atrial depolarization

QRS complex

ventricular depolarization

T wave

ventricular repolarization

systole

ventricular contraction

diastole

relaxation of the ventricles

medulla oblongata

part of the brainstem that controls heart rate, breathing, blood pressure

Rh factor

antigen found in red blood cells; used in blood typing

ABO Blood group

blood type determined by the hereditary presence or absence of antigens A and B on red blood cells

coagulation

blood clotting

hemostasis

the stoppage of bleeding

hematopoiesis

formation of blood cells in bone marrow

agranulocytes

lymphocytes, monocytes

granulocytes

neutrophils, eosinophils, basophils

platelet

cell fragment released by bone marrow that helps in blood clotting

leukocyte

cells that fight infection, also called white blood cells

erythrocyte

red blood cell that transports oxygen and carbon dioxide within the bloodstream

formed elements

cellular portion of blood

plasma

colorless watery fluid of blood in which cells are suspended

shock

condition characterized by profound hypotension and reduced tissue perfusion

arteriosclerosis

thickening, loss of elasticity, and hardening of arterial walls

hypertension

elevated blood pressure

hypotension

abnormally low blood pressure

viscosity

a liquid's resistance to flow

peripheral resistance

opposition to blood flow caused by friction of the blood vessel walls

tissue perfusion

blood flow through the body tissues

vasodilation

widening of the blood vessels that allows for increased blood flow

vasoconstriction

rapid constriction of the blood vessels to decrease blood flow to the area

lumen

opening of a blood vessel

tunica externa

outer layer of a blood vessel which connects it to surrounding tissues

tunica media

middle layer of a blood vessel; made up of smooth muscle fibers and thick layer of elastic connective tissue

tunica intima

innermost layer of a blood vessel

vein

vessel that returns blood to the heart

venule

tiny vein that drains blood from capillaries

capillary

tiny blood vessel where substances are exchanged between the blood and the body cells

arteriole

tiny artery that takes blood into capillaries

artery

blood vessel that carries blood away from the heart

Starling's Law of the Heart

cardiac muscle fibers will contract more forcefully when fibers are stretched (the more you fill it with blood the stronger force of contraction)

stroke volume

measurement of amount of blood ejected from a ventricle in one contraction

cardiac output

volume of blood pumped by one ventricle per minute; stroke volume x heart rate

acetylcholine

neurotransmitter that slows heart rate

vagus nerve

parasympathetic nerve of the heart; activation slows heart rate

parasympathetic nervous system

division of the autonomic nervous system that calms the body, conserving its energy

norepinephrine

hormone stimulates the sympathetic nervous system; speeds up heart rate

sympathetic nervous system

division of the autonomic nervous system that arouses the body, mobilizing its energy in stressful situations

cardiac cycle

one complete contraction and relaxation of all four chambers of the heart

blood pressure

the pressure that is exerted by the blood against the walls of blood vessels

baroreceptor reflex

reflex that maintains appropriate blood pressure; responds to changes in pressure in the aorta and carotid arteries

Type O blood

no A or B antigens, makes A & B antibodies; universal donor

Type AB blood

both A & B antigens, does not make A or B antibodies; universal recipient

hemoglobin

specialized protein containing iron that carries oxygen on red blood cells

depolarization

the electrical impulse that initiates a chain reaction resulting in a contraction

repolarization

recharging of the cell back to a resting state

atrial natriuretic peptide

hormone released by cells of the heart, lowers blood pressure

angiotensin II

a hormone that causes vasoconstriction and stimulates of aldosterone release, raising blood pressure