Overview/CV Anatomy

Question 1

functions of the cardiovascular system

Answer 1

• distributes dissolved gases & nutrients.
• removes metabolic waste
• contributes to systemic homeostasis by controlling temp, O2 supply, pH, ionic composition, nutrient supply
• quickly adapts to changes in conditions and metabolic demands

Question 2

what part of the heart s arranged in series? what is the purpose?

Answer 2

• right & left heart arranged “in series”
• –no direct connection between right & left
• –output of left and right sides of heart must be closely matched

Question 3

what part of the heart s arranged in parallel? what is the purpose?

Answer 3

• Systemic circulation is primarily arranged “in parallel.” This is important because…
• oxygenated blood visits only one organ system before returning to pulmonary circulation
• Changes in metabolic demand or blood flow in one organ do not significantly affect other organs
• Blood flow to different organs can be individually varied to match demand.
• –At rest, most blood directed to brain (~14%), skeletal muscle (~15%), GI system (~21%), and kidney (~22%). During exercise up to 80% to exercising muscle.
• major exception = hepatic circulation — large fraction of hepatic blood supply is via intestinal circulation

Question 4

chambers of the heart:

Answer 4

o Ventricles: the main pumping chambers
 Left ventricle: supplies higher pressure systemic circulation. Bigger and thicker. Does more work and uses more O2 than right ventricle.
 Right ventricle
o Atria: small “primer” chambers, supply the ventricles with blood. Thinner walls than ventricles.
 Left atrium
 Right atrium

Question 5

Valves of the heart: describe the valves.

Answer 5

in two sets. Tricuspid and mitral valves are between the atria and ventricles; they are attached to the papillary muscles inside ventricles by chordae tendonae. Valves are one-way and pressure-operated. Thin flaps of fibrous tissue covered by endothelium; mitral has two cusps, the rest have three. All of the valves are located on the same horizontal plane of the heart.

Question 6

Where are the following valves located: tricuspid, pulmonic, mitral and aortic

Answer 6

o Tricuspid valve: between right atrium and the right ventricle
o Pulmonic valve: between right ventricle and pulmonary artery
o Mitral valve: between left atrium and left ventricle
o Aortic valve: between left ventricle and aorta.

Question 7

Major vessels of the heart:

Answer 7

o Vena cava (superior and inferior): inlet vessels into right atrium.
o Pulmonary artery: outlet vessel from right ventricle.
o Aorta: outlet valve from left ventricle—main blood supply to body

Question 8

Describe the blood flow pathway through the heart

Answer 8

eoxygenated blood returns from systemic circulation via the superior and inferior vena cavae, passively enters the right atrium (no valve). Right atrium contracts, increased pressure pushes open the tricuspid valve, blood enters the right ventricle. The right ventricle contracts, pushes open the pulmonic valve, blood enters pulmonary circulation via pulmonary arteries.
• Oxygenated blood returning from the lungs enters the left atrium via the pulmonary vein. The left atrium contracts, pushes open the mitral valve, and blood enters the left ventricle. The left ventricle contracts, pushing open the aortic valve, and blood enters systemic circulation via the aorta.

Question 9

Aorta: describe and size

Answer 9

single outlet from heart; d=2.5 cm

Question 10

Arteries : describe and size

Answer 10

thick walled, resist expansion, d=0.4 cm

Question 11

Arterioles: describe and size

Answer 11

relatively thicker walls (more vascular smooth muscle); d = 30 um.
o Primary site of regulation of vascular resistance and blood flow

Question 12

Capillaries: define and size

Answer 12

smallest vessels—walls are just a single layer of epithelium thick, approximately the same size as RBCs, which travel through in a single-file; d = 6 um

Question 13

Venules/Veins: define and size

Answer 13

thin walls relative to diameter compared to equivalent-sized arteries (but still some smooth muscle), not much elasticity; d = 20um—0.5cm
o One-way valves compensate for lower pressure in venous system to ensure blood flow is only in one direction.

Question 14

Vena cava: define and size

Answer 14

input to heart; d=3 cm

Question 15

arrangement of the microcirculation

Answer 15

• Microcirculation: defined as vasculature from the first-order arterioles to the venules.
• Capillaries are the site of gas, nutrient, and waste exchange. Blood flow through capillary beds is determined by the pressure gradient, and is highly regulated via constriction/dilation of arterioles and precapillary sphincters.
• Movement of substances between capillaries and tissue is driven by concentration and pressure gradients.

Question 16

function of the lymphatic system

Answer 16

Pathway for fluid and large molecules to move from interstitial space to blood