The document summarizes the cardiovascular system, including the five types of blood vessels - arteries, arterioles, capillaries, venules, and veins. It describes how blood flows from the heart through arteries and arterioles to capillaries, then through venules and veins back to the heart. It also discusses how certain veins function as blood reservoirs and how the circulatory system is regulated through nervous system control and blood pressure.

1. Chapter 16 Cardiovascular System- Vessels

2. Types of Vessels
• There are 5 types of blood vessels.
• Arteries - take blood away from heart-
aorta and pulmonary trunk
• arterioles - medium sized
• capillaries - microscopic vessels in tissues

3. Types of Vessels
• venules - small veins
• veins - take blood back to heart
• arteries --> arterioles --> capillaries -->
venules --> veins

4. Blood Reservoirs
• Because veins carry so much blood,
certain veins function as blood reservoirs,
or holders of blood.
• The main areas are veins of the
abdominal organs.
• This blood can be diverted quickly to other
parts of the body when needed such as
skeletal muscles.

5. Arteries and Arterioles
• Lumen -hollow space thru which blood
flows
• Inner layer of endothelium- simple
squamous
• Middle layer of smooth muscle and elastic
tissue
• Outer layer of elastic and collagen fibers

6. Nervous System Control
• Vasoconstriction - sympathetic nervous
stimulation causes contraction of muscle and
decrease in diameter of lumen
• Vasodilation - decrease in stimulation of SNS
causes relaxation of muscle and increase in
diameter of lumen

8. Veins and Venules
• Veins return blood from the body to the
heart-deoxygenated blood
• Middle and inner layers thinner than
arteries
• contain valves which prevent backflow of
blood
– varicose veins caused by repeated pressure
from backflow which pushes vein walls out

9. Venous Return
• Due to pressure
from
– heart contractions
– skeletal muscle
pump
– respiratory pump
• diaphragm moves
down and
decrease thoracic
pressure and
increasing
abdominal
pressure

10. Capillaries connect
arteries and veins.
This is where oxygen
is exchanged with
the body.

11. Capillaries
• Microscopic with
blood flow when
tissue active
• movement of
substances into and
out of tissue cells

12. Capillary exchange
• Simple Diffusion

13. Bulk Flow
• bulk flow - passive process of movement
of large numbers of particles in same
direction

14. Bulk Flow
–filtration - water and solutes flow from
capillary into interstitial fluid
–reabsorption - water and solutes flow
from interstitial fluid back into capillary
–autoregulation - tissue control of flow by
vasodilation and vasoconstriction

15. Blood Pressure
• Pressure exerted on walls of vessels
• vascular resistance is opposition to
blood flow and affects BP
–size of blood vessel lumen (inner
space)
–blood viscosity (thickness)
–total blood vessel length

16. • regulation
–cardiovascular center
–hormonal
• Systolic – pressure when heart contracts
• Diastolic – pressure when heart relaxes
• Sphygmomanometer – blood pressure
cuff
• Which number should be higher? Why?

19. Systemic
• Systemic circulation- includes the aorta
that carries oxygenated blood from the left
ventricle to the body and the veins and
venules that carry deoxygenated blood
back to the right atrium

20. Pulmonary
• Pulmonary circulation- the flow of
deoxygenated blood from the right
ventricle to air sacs in the lungs and the
return of oxygenated blood to the left
atrium

23. Vocabulary
• Artery
• Arteriole
• Capillary
• Capillary exchange
• Venule
• Vein
• Blood pressure
• Systemic circulation
• Pulmonary circulation