Heart and Fetal circulation

In the mediastinum

Between the 2nd rib and 5th intercostal space

2/3 of the heart lies to the left of the midsternal line

rest on the diaphragm

Location of the heart

Base of the heart

Towards the right shoulder

Great vessels (pulmonary trunk and aorta) exit here

Apex of the heart

Points towards the left hip

Composed primarily of the left ventricle

Two atria; right and left (receiving chambers)

Two ventricles; right and left (discharging chambers)

Name the four chambers

Pectinate muscles

Ridged wall of atria (contracts)

Trabeculae carneae

Ridged wall of the ventricles (contracts)

Papillary muscles

Have chordae tendineae that are attached to the valve flaps so they don't prolapse

Superior Vena Cava

Inferior Vena Cava

Coronary sinus

The right atrium receives deoxygenated blood from:

Foramen ovale, remnant structure is fossa ovalis

During embryonic development, shunts blood from the right atrium to the left atrium to bypass the nonfunctional lungs

The four pulmonary veins (right superior, right inferior, left superior, left inferior)

The left atrium receives oxygenated blood from:

From: Left atrium through the bicuspid valve

To: Aorta through semilunar valve to systemic system

The left ventricle receives blood from:

and sends it:

From: Right atrium through tricuspid valve

To: Pulmonary trunk (artery) through semilunar valve to lungs then pulmonary veins

The right ventricle receives blood from:

and sends it:

Ductus arteriosus

During embryonic development, shunts blood from the pulmonary trunk to the aorta to bypass the nonfunctional lungs

Atrioventricular valves (tricuspid and bicuspid)

Prevents back flow into atria

Semilunar valves (aortic and pulmonary)

Prevents back flow into ventricles

Both have three flaps

Don't have papillary muscles

False, the changes in pressure open and close the AV valves

True or False: The contraction and relaxation of the papillary muscles open and close the AV valves

True

True or False: The ventricles and papillary muscles contract concurrently

Lub

The first heart sound

Closing of the AV valves (tricuspid and bicuspid)

Signifies the beginning of ventricular systole (contraction)

Dub

The second heart sound

Closing of the semilunar valves

Signifies the beginning of ventricular diastole (relaxation)

Coronary arteries (right (A) and left(D))

First branch off the base of the aorta

Blocked when aortic semilunar valve opens

Supplies blood to the heart muscles

Marginal artery (C) and Posterior Interventricular artery (B)

Branches of right coronary artery

Anterior Interventricular artery (F) and Circumflex artery (E)

Branches of the left coronary artery

Intrinsic conduction system

The cardiac muscle is able to depolarize and contract without impulses from the nervous system because of the

Sinoatrial (SA) node -> Atrioventricular (AV) node -> Atrioventricular Bundle or Bundle of His -> Right and Left Bundle Branches -> Purkinje Fibers

Intrinsic conduction system pathway