A&P II ch.19 The heart

Cardiovascular system heart

Double pump that constantly pumps blood through blood vessels so blood can reach body cells and exchange materials

Heart left side

Pumps blood through the body's systemic blood vessels

Heart right side

Pumps blood through the lungs so blood can pick up oxygen and unload carbon dioxide

Mediastinum

Anatomical region between the lungs extending from the sternum to the vertebral column

Heart location

Located in the mediastinum of the thoracic cavity and situated obliquely

Heart apex

Pointed inferior end of the heart directed inferiorly to the left

Heart base

Superior portion of the heart positioned to the right

Pericardium

Protective membrane structure that surrounds the heart

Fibrous pericardium

Tough dense irregular connective tissue that prevents overstretching and anchors the heart in the mediastinum

Serous pericardium

Delicate double layer of serous membranes with serous fluid between the membranes

Parietal layer

Layer of the serous pericardium fused to the fibrous pericardium

Visceral layer

Layer of the serous pericardium that adheres tightly to heart muscle and is also called the epicardium

Pericardial fluid

Thin slippery lubricating serous fluid between the serous pericardial layers

Epicardium

Superficial visceral layer of the pericardium

Epicardium function

Contains blood and lymphatic vessels that supply the heart muscle

Myocardium

Middle layer of the heart wall made of cardiac muscle tissue

Myocardium fibers

Involuntary cardiac muscle fibers organized in bundles that swirl diagonally around the heart

Endocardium

Inner endothelium layer overlying connective tissue that lines heart chambers and valves

Endocardium connection

Continuous with the endothelia lining blood vessels

Atria

Two upper heart chambers that receive blood from veins

Auricle

Pouchlike structure on the anterior surface of an atrium that increases blood volume capacity

Ventricles

Two lower heart chambers that pump blood into arteries

Sulci

Surface grooves of the heart containing blood vessels and fat

Coronary sulcus

Surface groove containing blood vessels that separates the atria from the ventricles

Anterior interventricular sulcus

Surface groove on the anterior heart containing blood vessels

Posterior interventricular sulcus

Surface groove on the posterior heart containing blood vessels

Right atrium

Chamber that receives blood from the superior vena cava inferior vena cava and coronary sinus

Superior vena cava

Vein that delivers blood to the right atrium from the upper body

Inferior vena cava

Vein that delivers blood to the right atrium from the lower body

Coronary sinus

Structure that drains oxygen-poor blood from the heart muscle into the right atrium

Interatrial septum

Wall separating the right and left atria

Fossa ovalis

Remnant of the fetal foramen ovale located in the interatrial septum

Pectinate muscles

Ridges of cardiac muscle found in the anterior right atrium and extending into the auricle

Tricuspid valve

Right atrioventricular valve through which blood passes from the right atrium into the right ventricle

Right ventricle

Chamber that receives blood from the right atrium and pumps it toward the lungs

Interventricular septum

Wall separating the right and left ventricles

Trabeculae carneae

Raised bundles of cardiac muscle inside the ventricles

Chordae tendineae

Tendon-like cords connecting atrioventricular valve cusps to papillary muscles

Papillary muscles

Cone-shaped trabeculae carneae that attach to chordae tendineae

Pulmonary valve

Semilunar valve through which the right ventricle pumps blood into the pulmonary trunk

Pulmonary trunk

Vessel carrying blood from the right ventricle toward the lungs

Left atrium

Chamber that receives oxygen-rich blood from the four pulmonary veins

Pulmonary veins

Four veins that carry blood from the lungs to the left atrium

Bicuspid valve

Another name for the left atrioventricular or mitral valve

Mitral valve

Left atrioventricular valve through which blood passes from the left atrium into the left ventricle

Left ventricle

Chamber that receives blood from the left atrium and pumps it into the aorta for systemic circulation

Aortic valve

Semilunar valve through which the left ventricle pumps blood into the ascending aorta

Ascending aorta

Portion of the aorta that receives blood from the left ventricle and carries it to the heart wall and rest of body

Ligamentum arteriosum

Structure connecting the aorta to the pulmonary trunk and remnant of the fetal ductus arteriosus

Ductus arteriosus

Fetal blood vessel that shunted blood from the pulmonary trunk to the aorta bypassing the nonfunctioning fetal lungs

Myocardial thickness

Thickness of heart muscle that varies among chambers according to their function

Atrial walls

Thinner heart walls that deliver blood to the ventricles with assistance from gravity

Left ventricular wall

Thicker than the right ventricular wall because it pumps blood throughout the entire body

Right ventricular wall

Thinner than the left ventricular wall because it only pumps blood to the lungs

Heart valves

Structures that open and close in response to pressure differences and ensure one-way blood flow

Blood pressure and valves

Blood flows from areas of high pressure to areas of low pressure

Atrioventricular valves

Valves located between the atria and ventricles

Semilunar valves

Valves located between the ventricles and arteries

Tricuspid valve location

Right atrioventricular valve between the right atrium and right ventricle

Bicuspid valve location

Left atrioventricular valve between the left atrium and left ventricle

AV valves open

Open when pressure in the atria is higher than pressure in the ventricles

AV valves close

Close when the ventricles contract and ventricular pressure rises

Papillary muscles function

Contract to tighten chordae tendineae and prevent AV valve cusps from pushing into the atria

Chordae tendineae function

Prevent AV valve cusps from inverting into the atria during ventricular contraction

Semilunar valves

Pulmonary and aortic valves that each have three moon-shaped cusps

Pulmonary valve

Right semilunar valve between the right ventricle and pulmonary trunk

Aortic valve

Left semilunar valve between the left ventricle and aorta

Semilunar valves open

Open when ventricular pressure exceeds pressure in the arteries

Semilunar valves close

Close when ventricles relax and blood begins flowing backward into the cusps

Semilunar valve function

Prevent backflow of blood from arteries into ventricles

Circulation

Flow of blood with each heartbeat

Two circulatory circuits

Pulmonary and systemic circuits that operate as two separate closed circuits in series

Pulmonary circulation

Circulation of oxygen-poor blood from the right side of the heart through the lungs and back to the left side

Systemic circulation

Circulation of oxygen-rich blood from the left side of the heart through the body and back to the right side

Coronary circulation

Circulation that supplies the heart muscle with oxygen and nutrients and removes wastes

Pulmonary circulation pump

Right side of the heart

Pulmonary circulation function

Unloads carbon dioxide and picks up oxygen in the lungs

Pulmonary blood flow

Right ventricle to pulmonary trunk to pulmonary arteries to lung capillaries to pulmonary veins to left atrium

Pulmonary trunk

Receives blood from the right ventricle and carries it toward the lungs

Pulmonary arteries

Carry oxygen-poor blood from the pulmonary trunk to the lungs

Pulmonary capillaries

Sites where gas exchange occurs in the lungs

Pulmonary veins

Carry oxygen-rich blood from the lungs to the left atrium

Systemic circulation pump

Left side of the heart

Systemic circulation function

Delivers oxygen to body cells and picks up carbon dioxide

Systemic blood flow

Left ventricle to aorta to systemic arteries to capillaries to systemic veins to right atrium

Aorta

Main artery receiving blood from the left ventricle and distributing it throughout the body

Systemic arteries

Carry oxygen-rich blood from the aorta toward body tissues

Systemic capillaries

Sites where gas and material exchange occurs with body tissues

Systemic veins

Carry oxygen-poor blood back to the right atrium

Coronary arteries

Right and left arteries that branch from the ascending aorta to supply oxygen-rich blood to the myocardium

Coronary artery branches

Extend through the sulci to supply both atria and ventricles

Anastomoses

Connections where two or more arteries supply the same region and provide alternate routes if an artery is obstructed

Coronary capillaries

Capillaries where gases nutrients and wastes are exchanged in the heart

Coronary veins

Veins that collect oxygen-poor blood from the myocardium

Coronary sinus drainage

Coronary veins collect oxygen-poor blood into the coronary sinus which empties into the right atrium

Cardiac muscle tissue

Muscle tissue with fibers connected end-to-end through intercalated discs

Intercalated discs

Structures connecting cardiac muscle fibers end-to-end

Desmosomes

Structures in intercalated discs that provide strength

Gap junctions

Structures in intercalated discs that allow action potentials to conduct from one cardiac muscle fiber to its neighbor

Autorhythmic fibers

Cardiac fibers that spontaneously depolarize and generate action potentials