Introduction to Heart Anatomy

Pre-lecture content

heart function + location

the pump that drives the movement of blood around the cardiovascular system

• located in thoracic cavity, posterior to sternum and on the superior surface of the diaphragm

• pointed apex facing down, forward, and to the left

different between right and left side chambers

• right side chambers more anterior (right atrium + ventricle)

• left side chambers more posterior (left atrium + ventricle)

pericardium

supports + anchors heart in thoracic cavity; fibrous sac

• fibrous pericardium (outermost)

• serous pericardium

fibrous pericardium

• outermost layer of dense CT

• attaches to central tendon of diaphragm and sternal ligaments to anchor

serous pericardium

• parietal: lines cavity wall

• pericardial cavity: space between parietal and visceral pericardium that is filled with serous fluid

• visceral: lines the heart

layers of the heart wall deep to pericardium

1. epicardium

2. myocardium

3. endocardium

epicardium

superficial layer made of visceral pericardium; underlying CT layer contains coronary vessels, nerves, and fat

myocardium

middle layer, made of cardiac muscle; important for impulse generation, propagation, and endocrine secretion

endocardium

deep layer, made of single layer squamous cells; subendocardial layer- loose CT with Purkinje fibers for conduction

cardiac muscle

in the myocardium; contraction of heart chambers

structural characteristics:

• striated involuntary muscles

• uni or bi nucleate cells

• branched cells

• contain intercalated discs

  • constant communication between cells by gap junctions

  • desmosomes hold muscle cells together

left ventricle

pump for systemic circuit; high pressure to get blood all over the body

right ventricle

pump for pulmonary circuit; doesn’t need as much pressure; does not need to pump as hard as left

great vessels

bring blood back to the heart or take blood away from the heart

arteries

carry blood away from heart (usually O2 rich)

veins

carry blood back to heart (usually oxygen poor)

chambers

receive and pump blood (atrium and ventricle)

atrium

receives blood

ventricle

pumps blood out of heart

right atrium

blood from vena cavas and coronary sinus

right ventricle

pumps blood toward lungs

left atrium

blood from the pulmonary veins

left ventricle

blood toward systemic tissues via the aorta

valves

separate ventricles and atria to prevent backflow of blood

right atrioventricular valve (tricuspid)

3 cusps; separate right atrium from ventricle

left atrioventricular valve (bicuspid)

2 cusps; separate left atrium from ventricle

semilunar valves

separate ventricles from circuits

pulmonary semilunar valve

connects right ventricle and pulmonary trunk to pulmonary arteries to lungs

aortic semilunar valve

blood is pumped from left ventricle into systemic circuit via aorta