1. Functional Organization of the Cardiovascular System

2. Objectives
Describe the functional organization of cardiovascular system
List the functions of cardiovascular system.
Describe the main function of arteries, capillaries and veins
Describe the flow of blood through the chambers of the heart and through the systemic and pulmonary circulations.
Compare and contrast the systemic and pulmonary circulation.

3. Functional Organization of Cardiovascular system
HEART
(PUMP)
VESSELS
(DISTRIBUTION
SYSTEM)
Blood

4. Functions of Cardiovascular System:
I. Primary (main) function of the heart:
♥ Acts as a muscular pump:
in order to maintain adequate level of blood flow
throughout CVS by pumping blood under press into
vascular system.
♥ Responsible for the mass movement of fluid in
body.

5. Functions of Cardiovascular System (continued)
II. Secondary functions:
1. Transportation:
 delivers O2 to tissues, & brings back CO2 to lungs.
 carries absorbed digestion products to liver & tissues.
 carries metabolic wastes to kidneys to be excreted.
 distribution of body fluids.
2. Regulation:
 Hormonal: carries hormones to target tissues to produce their effects.
 Immune: carries antibodies, leukocytes (WBCs), cytokines, & complement
to aid body defense mechanism against pathogens.
 Protection: carries platelets, & clotting factors to aid protection of the body
in blood clotting mechanism.
 Temperature: helps in regulation of body temperature, by diverting blood to cool or warm the body.

6. Anatomy of the heart:
Positioned between two bony structures – sternum and vertebrae
(CPR)
Hollow, muscular organ.

7. Heart: Two sided pump

9. Vena cava
pulmonary veins
Pulmonary
trunk
(Aorta)

12. Atrium: weak primer pump for the ventricle
Ventricle: the main pumping force
 
Rt. Ventricle Lt. ventricle
Pulmonary circulation Systemic circulation

13. Blood Flow Through and Pump Action of the Heart

14. Pulmonary circulation
systemic circulation
Pulmonary circulation
Starts at left ventricle
Ends at right atrium
Receives blood from left side of heart
Carries blood between heart and other organ systems
Blood perfusing the organ systems is oxygenated
Part of the blood go to different organ systems
High pressure, high resistance
Starts at right ventricle
Ends at left atrium
Receives blood from right side of heart
Carries blood between heart and lungs
Blood perfusing the lungs is partially deoxygenated
All blood flows through lungs
Low pressure, low resistance

15. Valves of the heart: ♥ 2 atrioventricular (AV) valves:
■ One way valves.
■ Allow blood to flow from
atria into ventricles.
■ Tricuspid (Rt) & Mitral
(Lt).
♥ 2 semilunar valves :
■ One way valves.
■ At origin of pulmonary artery
& aorta.
■ Pulmonary (Rt) & Aortic (Lt).
■ Open during ventricular
contraction.

16. Heart Valves One way flow in heart is ensured by heart valves
Valves open & close passively
- open  by forward P by blood
- close  by backward P by blood

17. Atrioventricular Valve Function

18. Semilunar Valve Function

19. No valves between atria and veins
Reasons
Atrial pressures usually are not much higher than venous pressures
Sites where venae cavae enter atria are partially compressed during atrial contraction

20. The fibrous skeleton of the heart
Serves 3 roles:
A mechanical base: atria anchored above and ventricles below
Perforated by 4 apertures, each containing a valve
Insulates the ventricles

21. Vascular Tree Closed system of vessels Consists of Arteries
Carry blood away from heart to tissues
Arterioles
Smaller branches of arteries
Capillaries
Smaller branches of arterioles
Smallest of vessels across which all exchanges are made with surrounding cells
Venules
Formed when capillaries rejoin
Return blood to heart
Veins
Formed when venules merge

22. Arteries
Function:
Rapid transit passage-ways for blood from heart to tissues
Pressure reservoir
Structure of arterial wall
Plentiful of elastic fibers….high compliance

23. Arteries as a Pressure Reservoir

24. Arterioles (resistance vessels)
Very small arteries that delivers blood to capillaries
Structure
Very little elastic tissue but thick layer of smooth muscle
Function Regulating blood flow from arteries to capillaries by regulating resistance according to tissue metabolic needs.

25. Capillaries Microscopic vessels that connects arterioles to venules
Structure
Single wall layered vessels (endothelial cells)
Undergoes extensive branching
Maximized surface area and minimized diffusion distance
Velocity of blood flow through capillaries is relatively slow
Provides adequate exchange time
Function:
Exchange of nutrients and wastes between blood and tissue cells

26. Capillaries cont.
Under resting conditions many capillaries are not open
Capillaries surrounded by precapillary sphincters
Contraction of sphincters reduces blood flowing into capillaries in an organ
Relaxation of sphincters has opposite effect

27. Veins Carry blood from tissues to heart Structure: Thin wall
Less smooth muscle and considerable amount of collagen
Less elastic fibers
Function:
Passage ways back to heart
Blood reservoir (capacitance vessels)