Lecture 10: Intro to Cardiovascular System

Question 1

Parts of the CVS

Answer 1

Heart (pump), Blood vessels (pipes), Blood (fluid)

Question 2

Functions of the CVS

Answer 2

• Transport nutrients to and remove
  waste from cells
• Transport hormones
• Body temperature regulation

Question 3

List the steps of the pulmonary and systemic circulation in order (including valves)

Answer 3

Superior/Inferior vena cava –> Right atrium–> Tricuspid (atrioventricular) valve –> Right ventricle –> Pulmonary (semilunar) valve –> Pulmonary Artery –> Lungs –> Pulmonary Vein –> Left atrium –> Bicuspid/Mitral (atrioventricular) valve –> Left ventricle –> Aortic (semilunar) valve –> Aorta –> Body

Question 4

What is the composition of blood?

Answer 4

Plasma (55%)
Hematocrit/RBC (45%)
Buffy coat (<1%)

Question 5

What is the composition of each type of artery and vein?

Answer 5

Large artery- many layers of smooth muscle and connective tissue

Arteriole- smooth muscle cells, endothelium

Capillary- endothelial cells

Venule- endothelium, connective tissue

Large vein- few layers of smooth muscle and connective tissue

Question 6

What is compliance?

Answer 6

The pressure-volume relationship

𝐶 =∆𝑉/∆P
Compliance of veins = 20 x compliance of arteries

Veins: high slope, large volume of blood –> pressure does not change much
Arteries: small slope, small volume change with high pressure change

*Most of the blood at any one time is in the veins

Question 7

Flow equation

Answer 7

𝑄 = ∆P/R

Question 8

Poiseuille’s Law

Answer 8

Factors that determine resistance to flow

R =𝟖𝜼𝑳/𝝅𝒓^4

**Radius plays an important role in resistance

Question 9

Equations for flow, pressure, and resistance in SERIES

Answer 9

1. Flow through each segment must be equal
   ▪ 𝑄𝑡𝑜𝑡𝑎𝑙 = 𝑄𝐴 = 𝑄𝐵 = 𝑄𝐶
2. Pressure difference is additive
   ▪ ∆𝑃𝑡𝑜𝑡𝑎𝑙 = ∆𝑃𝐴 + ∆𝑃𝐵 + ∆𝑃𝐶
3. Total resistance is the sum of the individual resistances
   ▪ 𝑅𝑡𝑜𝑡𝑎𝑙 = 𝑅𝐴 + 𝑅𝐵 + 𝑅𝐶

Question 10

Equations for flow, pressure, and resistance in PARALLEL

Answer 10

1. Pressure difference is equal
   ▪ ∆𝑃𝑡𝑜𝑡𝑎𝑙 = ∆𝑃𝐴 = ∆𝑃𝐵
2. Flow is additive
   ▪ 𝑄𝑡𝑜𝑡𝑎𝑙 = 𝑄𝐴 + 𝑄𝐵
3. Inverse of the total resistance is the sum of inverses of the
   individual resistances
   ▪𝟏/𝑹𝒕𝒐𝒕𝒂𝒍=𝟏/𝑹𝑨+𝟏/𝑹𝐵

Question 11

Flow velocity

Answer 11

𝑣 =𝑄/A

*Capillaries have the lowest
flow velocity

Question 12

Bernoulli’s Equation

Answer 12

Total energy per unit volume is constant

𝑝1 + 1/2𝜌𝒗1^2 + 𝜌𝑔ℎ1 = 𝑝2 + 1/2𝜌𝒗2^2 + 𝜌𝑔ℎ2

Which means

𝐸𝑡𝑜𝑡𝑎𝑙/𝑉 = 𝐸𝑙𝑎𝑡𝑒𝑟𝑎𝑙/𝑉 + 𝐸𝑘𝑖𝑛𝑒𝑡𝑖𝑐/𝑉 + 𝐸𝑔𝑟𝑎𝑣𝑖𝑡𝑦/V

Question 13

Reynold’s number

Answer 13

Tells you the propensity of laminar (layered) flow to become turbulent flow

Nr=rhodv/eta