Chapter 19 Flashcards
(51 cards)
What is a closed system?
What gets pumped out gets pumped back
What are the 3 major types of blood vessels?
Artery, capillary, and vein
What is an artery?
Carries blood away from heart
What is the capillary?
Exchange nutrients and waste
What is a vein?
Carries blood towards the heart
What are the 3 tunics vessels are made of?
Tunica intima, media, and externa
Properties of the tunica intima?
Lines lumen wall.
Simple squamous endothelial layer.
Forms smooth layer (decrease in friction).
Subendothelial layer: basement membrane.
Present in al l vessels; thin flat layer.
Properties of the tunica media?
Thickest layer.
Smooth muscle and elastin connective tissue.
Vasoconstrict or vasodilate.
Epinephrine.
Not present in all vessels.
Properties of the tunica externa?
Outermost layer.
Loose collagen connective tissue.
Nerves and lymph vessels.
Vasa vasorum: blood vessels that carry nutrients.
What does the lymphatic system do?
Takes fluid lost from capillaries and brings back to cardiovascular system
How does blood get around restricted blood vessels?
Anastomoses
What are anastomoses?
Very prominent in capillaries.
Alternate pathways.
What are collateral channels?
Natural bypass; when artery develops second route to get them from point A to point B
What is the distribution of blood in the cardiovascular system when at rest?
Systemic arteries and arterioles: 15%
Pulmonary blood vessels: 12%
Heart: 8%
Capillaries: 5%
Systemic veins and venules: 60%
Properties of elastic (conducting) arteries?
Thick-walled arteries near the heart.
Large lumen: low-resistance to flow.
Contain elastin.
Smooth out large blood pressure fluctuations.
Serve as pressure reservoirs.
Always blood in the blood vessels.
Properties of muscular arteries?
Distal to elastic arteries; deliver blood to body organs.
Have thick tunica media with more smooth muscle.
Active in vasoconstriction.
Branching off aorta.
Can withstand high pressures.
Properties of arterioles?
Smallest arteries; lead to capillary beds.
Control flow into capillary beds (resistance vessels).
Resistance vessels.
Greatest resistance in cardiovascular system.
Branch and branch and branch.
Have all 3 tunics.
Properties of capillaries?
Smallest blood vessels.
Thin tunica interna (only).
Nutrient exchange takes place here.
Large surface area.
3 structural types.
What is the biggest elastic artery?
Aorta
Properties of continuous capillaries?
Abundant in the skin and muscles.
- endothelial cells provide uninterrupted lining.
- adjacent cells are connected with tight junctions.
- clefs allow small things to pass through.
Continuous capillaries of the brain:
- tight junctions completely around the endothelium.
- thick basal lamina.
- blood-brain barrier: continuous capillary with tons of tight junctions; restricts crossing of fluids and nutrients.
Properties of fenestrated capillaries?
Found wherever capillary absorption occurs.
Endothelium with pores.
Greater permeability
Properties of sinusoids?
Leaky, fenestrated capillaries with large lumens.
Liver, bone marrow, lymphoid tissue, and some endocrine organs.
Allow large molecules to pass between blood and surrounding tissues.
Very large clefts.
What are capillary beds?
Microcirculation of interwoven networks of capillaries
What does a precapillary sphincter do?
Prevent blood flow into the capillaries when constricted
