19.1- 19.6 Blood Vessels

Question 1

Delivery system that begins and ends at heart
Work with lymphatic system to circulate fluids

Answer 1

Blood vessels

Question 2

Carry blood away from heart
Oxygenated except for pulmonary circulation and umbilical vessels of fetus

Answer 2

Arteries

Question 3

Carry blood towards heart
Deoxygenated except for pulmonary circulation and umbilical vessels of fetus
“Visit heart”
Thinner wall compared to artery

Answer 3

Veins

Question 4

Direct contact with tissue cells; Directly serve cellular needs
Smaller than veins

Answer 4

Capillaries

Question 5

In all vessels; Central blood-containing space, surrounded by wall

Answer 5

Lumen

Question 6

Innermost layer of a vessel; contains the endothelium which lines lumen of all vessels; Continuous with endocardium
Slick surface reduces friction

Answer 6

Tunica intima

Question 7

Layers of a blood vessel; 3 in vessels
1. Tunica intima
2. Tunica media
3. Tunica externa

Answer 7

Tunics

Question 8

size of arteries sheet

Question 9

Simple squamous layer of epithelium that lines lumen of all vessels
Located in Tunica intima

Answer 9

Endothelium

Question 10

Connective tissue basement membrane
Found only in vessels larger than 1 mm
Located in Tunica intima

Answer 10

Subendothelial layer

Question 11

Second layer in all vessels; Composed of mostly smooth muscle and sheets of elastin
Bulkiest layer in arteries
Responsible for maintaining blood flow and blood pressure
Sympathetic nerve fibers innervate layer controlling its size

Answer 11

Tunica media

Question 12

Decrease in lumen diameter

Answer 12

Vasoconstriction

Question 13

Increase in lumen diameter

Answer 13

Vasodilation

Question 14

Outermost layer of wall of vessel; Composed mostly of loose collagen fibers; Thicker in veins than in arteries
Aka - Tunica adventitia
Infiltrated with nerve fibers and lymphatic vessels (vasa vasorum)

Answer 14

Tunica externa

Question 15

System of tiny blood vessels found in larger vessels; Nourish outermost external layer (Tunica externa)

Answer 15

Vasa vasorum

Question 16

Type of artery; Thick walled with large, low-resistance lumen
Elastin found within; Allows for continuous blood flow/ pressure reservoirs that expand and recoil as blood is ejected from heart
Aka - Conducting arteries
Ex.Aorta and its major branches + Pulmonary arteries

Answer 16

Elastic arteries

Question 17

Type of artery; Account for most named arteries
Elastic arteries give rise to these
Have thickest tunica media
Active in vasoconstriction
Aka - Distributing arteries

Answer 17

Muscular arteries

Question 18

Smallest type of artery; Changing diameters change resistance to blood flow
Aka - Resistance arteries
Large ____ contain all 3 tunics, smaller ones only smooth muscle
Control flow into capillary beds via vasodilation and vasoconstriction of smooth muscle
Lead to capillary beds

Answer 18

Arterioles

Question 19

Exchange vessels that are microscopic
Only single RBC can pass through at a time
Exchange gasses, nutrients, wastes, hormones between blood and interstitial fluid
Do not supply: Cartilage, epithelia, cornea and lens of eye

Answer 19

Capillaries

Question 20

Spider shaped stem cells that help to stabilize capillary walls, control permeability, and play a role in vessel repair

Answer 20

Pericytes

Question 21

Gaps joined by tight junctions in all capillary endothelial cells

Answer 21

Intercellular clefts

Question 22

Least permeable and most common capillary; Abundant on skin, muscles, lungs, and CNS
Often have associated pericytes

Answer 22

Continuous capillaries

Question 23

Ferry fluid across the endothelial cel in continuous capillaries

Answer 23

Pinocytotic vesicles

Question 24

Have fenestrations (pores) which increase permeability
Occur in areas of active filtration or absorption, and areas of endocrine hormone secretion
Fenestrations covered by thin diaphragm made of glycoproteins

Answer 24

Fenestrated capillaries

Question 25

Number increases during absorption in fenestrated capillaries

Answer 25

Fenestrations

Question 26

Most permeable capillary and occur in limited locations Occur in liver, spleen, and adrenal medulla Allows for large cells to pass through cell walls

Answer 26

Sinusoidal capillaries

Question 27

Interwoven network of capillaries between arterioles and venules

Answer 27

Capillary bed

Question 28

Flow of blood through bed from arteriole and venule

Answer 28

Microcirculation

Question 29

Branch off of arteriole that further branches into 10-20 capillaries from capillary bed

Answer 29

Terminal arteriole

Question 30

Where capillaries drain into

Answer 30

Postcapillary venule

Question 31

What regulates the amount of blood entering capillary bed

Answer 31

Chemical conditions Arteriolar nerve fibers

Question 32

Capillaries found in serous membranes that hold the intestines in place Aka - Mesenteric capillary bed

Answer 32

Special capillary beds

Question 33

Channel that directly connects arteriole with venule Bypasses true capillaries Consists of metarteriole and thoroughfare channel

Answer 33

Vascular shunt

Question 34

Cuff of smooth muscle surrounding each true capillary that branches off metarteriole Acts as valve regulating blood flow into capillary bed Controlled by local chemical conditions

Answer 34

Precapillary sphincter

Question 35

Capillaries unite to form ______ Consist of endothelium and few pericytes Very porous, allow fluids and WBCs into tissues Larger venules have one or two layers of smooth muscle cells

Answer 35

Venules

Question 36

Formed when venules converge, carry blood to heart Large lumen and thin walls make veins good storage vessels Blood pressure lower than in arteries, so adaptations ensure return of blood to the heart

Answer 36

Veins

Question 37

Prevent backflow of blood Most abundant in veins of limbs

Answer 37

Venous valves

Question 38

Flattened veins with extremely thin walls Composed only of endothelium Ex. Coronary sinus of heart and dural sinuses of the brain

Answer 38

Venous sinuses

Question 39

Another name from for veins Blood reservoirs Contain up to blood supply

Answer 39

Capacitance vessels

Question 40

Dilated and painful veins due to incompetent leaky valves Due to: Heredity Ex. Prolonged standing in one position, obesity, or pregnancy, elevated venous pressure

Answer 40

Varicose veins

Question 41

Special cross connection between adjacent channels, tubes, fibers, or other parts of a network

Answer 41

Anastamosis

Question 42

Interconnections of blood vessels

Answer 42

Vascular (circulatory) anastamosis

Question 43

Provide alternate pathways to ensure continuous flow, even if one artery is blocked Common in joints, abdominal organs, brain, and heart Not in: Retina, kidneys, spleen

Answer 43

Arterial anastomosis

Question 44

Shunts in capillaries

Answer 44

Arteriovenous anastomosis