Properties of Cardiovascular Sys

Question 1

Discuss the purpose of the cardiovascular system.

Answer 1

• Transport nutrients to tissues
• Transport waste away from tissues
• Transport hormones
• Maintain tissue fluid environment

Question 2

List the vascular components of the systemic and pulmonary circulation.

Answer 2

• Arteries: transport blood under high pressure to tissue
  
  • Strong vascular walls
  • High velocity blood
• Arterioles: last small branches of arteries
  
  • Control conduits: release blood to capillaries
  • Strong muscular walls that can close or dilate
  • Alters blood flow to tissues based on need
• Capillaries: exchange fluid, nutrients, electrolytes, hormones b/t blood & interstitial fluid
  
  • Capillary pores allow exchange
• Venules: collect blood from capillaries
• Veins: transport blood back to heart
  
  • Reservoir for extra blood
  • Low pressure w/ thin walls

Question 3

Describe the pressures in the various chambers of the heart and vascular system.

Answer 3

• Aorta: avg 100mmHg
• Arteries: 120mmHg systolic 80mmHg diastolic
• Thru systemic circulation falls to 0mmHg at vena cavae (empties to RT atrium)
• Systemic capillaries: 35-10mmHg fxn 17mmHg
• Pulmonary:
  
  • Arteries: 25 systolic and 8 diastolic (mean: 16mmHg)
  • Capillaries: mean 7mmHg

Question 4

Define the relationship between perfusion pressure, cardiac output, and total peripheral resistance.

Answer 4

• Blood flow determined by:
  
  • Pressure difference at 2 ends
  • Vascular resistance: result of friction
  • F=ΔP/R
• Flow controlled by need
  
  • Active tissues increase blood flow to increase nutrient supple
  • Micro vessels dilate or constrict to control blood flow to specific tissues
• Cardiac output: amt of blood pumped into aorta each min
  
  • Controlled by sum of all local tissue flows
  • Increased inflow to heart increases CO by pumping it back out
• Arterial pressure regulation is independent
  
  • Nervous sys acts if pressure falls below 100mmHg
    
    • Increase force of contractions
    • Contract veins to pump blood from reservoir
    • Constrict arteries
  • Kidneys regulate pressure via hormones

Question 5

Discuss the volume flow of blood in each section of the cardiovascular system.

Answer 5

-Volume flow (F) must stay the same in each segment.
-Velocity (v) inversely proportional to vascular cross sectional area (A)
v=F/A

Question 6

Differentiate between blood flow and blood velocity as related to cross sectional area.

Answer 6

v=F/A

• Volume of blood flow remains constant
• Velocity of blood changes inversely w/ cross sectional area
• As area increases velocity decrease and vice versa

Question 7

Describe the relative volumes of each part of the cardiovascular system.

Answer 7

• Systemic: blood flow to all tissues except lungs.
  
  • 84% of total blood volume
  • 64% in veins, 13% in arteries, 7% in arterioles & capillaries
• Pulmonary: blood flow thru the lungs
  
  • 9% total blood volume