Chp 19: The cardiovascular system: blood vessels

Question 1

Arteries

Answer 1

carry blood away form heart

Question 2

Capillaries

Answer 2

narrowest blood vessels, site of exchange of water, gases, nutrients, hormones

Question 3

Veins

Answer 3

Carry blood toward heart

Question 4

largest artery, largest vein

Answer 4

aorta, vena cava

Question 5

3 tunics of blood vessels

Answer 5

Tunica externa: loosely woven collagen fibers, larger lumen valves
Tunica media: mostly circularly arranged smooth muscle cells and sheets of elastin
Tunica intima: innermost; contains endothelium (simple squamous epithelium that lines lumen of all vessels)

Question 6

Elastic arteries

Answer 6

largest arteries
2.5 to 1 cm
ex// aorta and its major branches
aka “conducting arteries”
high elastin content dampens surge of blood pressure
elastic arteries stretch during ventricular contraction and recoil during ventricular relaxation

Question 7

Muscular (distributing) arteries

Answer 7

Lie distal to elastic arteries
Diameter: 1 cm to .3 mm
Includes most named arteries
Unique features: internal and external elastic laminae

Question 8

Arterioles

Answer 8

smallest arteries
deliver blood to capillaries
vasoconstriction/vasodilation

Question 9

Capillary beds

Answer 9

site of exchange

Question 10

Metarterioles

Answer 10

Emerge from arterioles and supplies group of capillaries

Question 11

Thoroughfare channel

Answer 11

Arise from metarterioles, contain no smooth muscle, allow blood to bypass capillary

Question 12

Continuous capillaries

Answer 12

Most common
“continuous” b/c their endothelial cells are connected by tight junctions with gaps between neighboring cells called intercellular clefts ( less permeable, just large enough to allow limited passage of fluids and small solutes)
Muscles, connective tissue, lungs and skin

Question 13

Fenestrated capillaries

Answer 13

Plasma membranes have many holes, found wherever active capillary absorption or filtrate formation occurs
Renal glomeruli, intestinal villi, choroid plexuses, ciliary process, endocrine glands

Question 14

Sinusoids

Answer 14

Very large fenestrations, allow large molecules and blood cells to pass between blood and surrounding tissues
Discontinuous endothelium and basement membrane
liver,bone marrow, spleen

Question 15

Veins

Answer 15

formed by venules
Have thinner tunica interna and media, thicker tunica externa
Less elastic tissue and smooth muscle
Low pressure system

Question 16

Venous valves

Answer 16

Thin folds of tunica interna prevent back flow

Question 17

Venous “pumps”

Answer 17

Respiratory pump: pressure changes created during breathing
Muscular pump: contraction of skeletal muscles “milk” blood
Vasoconstriction of veins under sympathetic control