Saladin Chapter 19: Heart

pulmonary circuit

right side of heart, carries blood to lungs for gas exchange and back to the heart

systemic circuit

left side of heart, supplies oxygenated blood to all its tissues of the body and returns it to the heart

Aorta

blood sent to all organs of body via __________

inferior and superior vena cava

supplies right atrium with lesser deoxygenated blood

pulmonary trunk

carries blood to the lungs

apex

bottom of the heart, tilts to left

visceral pericardium

serous membrane covering the heart

Mycoardium

thick muscular middle layer, fibrous skeleton made of collagenous and elastic fibers for attachment of cardiac muscle and structural support

endocardium

smooth inner lining of heart

pericardial cavity

contains 5-30ml of pericardial fluid

right and left atria

recieves blood returning to heart

right and left ventricle

pumps blood into arteries

atrioventricular sulcus

separates atria and ventricles

anterior and posterior sulci

grooves that separate ventricles

atrioventricular valves

control blood flow between atria and ventricles

Right AV valve

valve between right atrium and ventricle

Left AV valve

valve between left atrium and ventricle

Chordea Tendineae

cords that connect AV valves to papillary muscles on floor of ventricles

semilunar valves

control blood flow into great arteries; open and close because of blood flow and pressure

pulmonary semilunar valve

in opening between right ventricle and pulmonary trunk

aortic semilunar valve

in opening between left ventricle and aorta

left coronary artery

supplies blood to the left ventricle, left atrium, and interventricular septum

right coronary artery

supplies blood to right atrium and SA node

circumflex branch

-passes around left side of heart in coronary sulcus

-gives off left marginal branch and then ends on the posterior side of the heart

-supplies left atrium and posterior wall of left ventricle

posterior interventricular branch

supplies posterior walls of ventricles

right marginal branch

supplies lateral aspect of right atrium and ventricle

myocardial infarction

interruption of blood supply to heart due to blood clot or fatty deposit and causes death of cardiac cells within minutes

cardiocytes

striated, short, thick, branched cells, one central nucleus surrounded by light-staining mass of glycogen

intercalated discs

joins cardiocytes end to end

metabolism of cardiac muscle

rich in myoglobin and glycogen; aerobic respiration; oragnic fuels of fatty acids, glucose and ketones

cardiac conduction system

coordinates the heartbeat; composed of an internal pacemaker and nerve-like conduction pathways through myocardium

sinoatrial node

pacemaker of the heart; initiates each heartbeat and determines heart rate

systole

contraction

diastole

relaxtion

sinus rhythm

normal heartbeat triggered by SA node

ectopic focus

another part of heart fires before SA node, 60-100 bpm

nodal rhythm

if SA node is damaged, heart rate is set by AV node, 40-50 bpm

intrinsic ventricular rhythm

if both SA and AV node not working, rate is set at 29-40 bpm

arrhythmia

any abnormal cardiac rhythm

atrial flutter

atrial fibrillation, atria beats at 200-400 times per min

ventricular fibrillation

serious arrhythmia caused by electrical signals reaching different regions at widely different times

defibrillation

the use of electrical shock to restore the heart's normal rhythm

P wave

atrial depolarization

QRS complex

ventricular depolarization

ST segment

ventricular systole

T wave

ventricular repolarization (diastole)

cardiac cycle

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

S1

the first heart sound, heard when the atrioventricular valves close; lubb sound

S2

the second heart sound, heard when the semilunar valves close; dupp sound

congestive heart failure

results from the failure of either ventricle to eject blood effectively

left ventricular failure

blood backs up into lungs causing pulmonary edema

right ventricular failure

blood backs up in the vena cava causing systemic or generalized edema

cardiac output

the amount of blood ejected by ventricle in 1 minute; heart rate x stroke volume

pulse

pressure produced by each heartbeat that can be felt by palpating superficial artery with fingertips

average blood pressure

120/80

positive chronotropic agents

factors that raise the heart rate

negative chronotropic agents

factors that lower the heart rate

Proprioceptors

Sensory receptors, located in the muscles and joints, that provide information about body position and movement.

Baroreceptors

monitor blood pressure

Chemoreceptors

chemical sensors in the brain and blood vessels that identify changing levels of oxygen, carbon dioxide and pH