SPPS 241 - Internal Heart

describe the interatrial septum

separates right and left atria

smaller and thinner than the interventricular septum and has mostly smooth surface

prevents mixing of deoxygenated blood with oxygenated blood

describe fossa ovalis

slight depression in interatrial septum, just superior to opening of IVC

derived from embryonic foramen ovale — shunt that allows blood to bypass the fetal lungs

acts as a one-way valve that permits flow from right to left

describe tricuspid valve

between right atrium and right ventricle

prevents deoxygenating blood from flowing backwards into right atrium during systole

describe interventricular system

separating the right and left ventricles

thicker than the interatrial septum and forms muscular medial wall of each ventricle

describe chordae tendineae

tendinous cords that tether the leaflets of the atrioventricular valves to the walls and septum of the ventricles

what happens if chordae tendineae get disrupted?

prolapse or retrograde displacement of the valves into the atria with consequent regurgitation, or retrograde flow of blood from ventricle into atrium

describe papillary muscles

specialized muscular projections of ventricular walls connected to chordae tendineae

contract to take up slack in chordae tendineae and maintain tension and prevent tricuspid prolapse as ventricle shrinks during systole

describe pulmonic valve (or pulmonary valve)

surround opening of right ventricle into pulmonary trunk

describe interatrial septum

look into left atrium

between left and right atrium

describe auricle of left atrium

pooling of blood in the auricle of the left atrium increases risk of clot formation

describe mitral valve

surrounds opening between left atrium and left ventricle

closes during systole, prevent oxygenated blood from flowing backwards from left ventricle into left atrium

describe aortic valve

surrounds opening of left ventricle into aorta

Identify each of the great vessels and heart chambers the blood cell passes through, in order

1. Deoxygenated Blood Pathway (Body to Lungs):

• Superior/Inferior Vena Cava: Receives blood from the body.

• Right Atrium: Chamber receiving the blood.

• Tricuspid Valve: Allows blood to flow into the right ventricle.

• Right Ventricle: Chamber that pumps blood to the lungs.

• Pulmonary Valve: Allows blood to exit into the pulmonary artery.

• Pulmonary Artery: Carries blood to the lungs.

• Lungs: Oxygenates the blood.

2. Oxygenated Blood Pathway (Lungs to Body):

• Pulmonary Veins: Returns blood to the left atrium.

• Left Atrium: Chamber receiving oxygenated blood.

• Mitral (Bicuspid) Valve: Allows blood to flow into the left ventricle.

• Left Ventricle: Chamber that pumps blood to the body.

• Aortic Valve: Allows blood to exit into the aorta.

• Aorta: Main artery distributing blood to the body.

What path would the blood cell take in a developing fetus?

1. Placenta to Fetus: Oxygen-rich blood enters via the umbilical vein.

2. Heart Entry: Oxygenated blood enters the right atrium

3. Atrial Shunt (Foramen Ovale): Most oxygenated blood moves directly from the right atrium to the left atrium, bypassing the lungs.

4. Ductus Arteriosus: Because the lungs are not functional, most blood in the pulmonary artery is diverted through the ductus arteriosus directly into the descending aorta.