Blood vessel notes

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