Heart Anatomy [2]

Each fiber consists of many smaller units called

MYOFIBRILS

these units contain sarcomeres

myofibrils

these are repeated structures approximately 2 µm in size

sarcomeres

this filament is composed mainly of myosin

thick filament

this filament is composed mostly of actin

thin filaments

what law: tensions developed during myocardial contraction are directly proportional to the number of cross-bridges between the actin and myosin filaments

frank-starling law

this circulation begins with the aorta on the left ventricle and ends in the right atrium.

systemic circulation

this circulation begins with the pulmonary artery out of the right ventricle and ends in the left atrium.

pulmonary circulation

Venous, or deoxygenated, blood from the head and upper extremities enters the right atrium via what veins

superior vena cava

venous blood from the abdomen and lower body enters right atrium via what veins

inferior vena cava

amount of blood flow per minute

cardiac output

these are also referred to as resistance vessels

arterioles

this circulation maintains a constant exchange of nutrients and waste products for the cells and tissues of the body.

capillary system

capillary system is also called

microcirculation

these vessels act as a reservoir for the circulatory system.

veins

components of the venous system, especially the small, expandable venules and veins, are termed

capacitance vessels

right side of the heart generates a systolic pressure of approximately how much

25 mmHg

The left side of the heart generates systolic pressures of approximately how much

120 mmHg

cardiac output formula

CO = HR X SV

this is the volume ejected by left ventricle on each contraction

stroke volume