Blood Vessels II

Question 1

What type of intermediate filaments does an endothelial cell have?

Answer 1

Desmin and vimentin

Question 2

What do endothelial cells secrete in their basal lamina?

Answer 2

1. Type I, III, IV, V collagens
2. Fibronectin and laminin
3. Coagulants and anticoagulants

Question 3

What is the average lifespan of an endothelial cell?

Answer 3

150-180 days

- relatively slow renewing

Question 4

Is intact endothelium thrombogenic?

Answer 4

no0o

Question 5

What do endothelial cells share their basal lamina with?

Answer 5

Pericytes

Question 6

Is a pericyte’s nuclei heterochromatic or euchromatic?

Answer 6

Heterochromatic

Question 7

What are the functions of pericytes?

Answer 7

1. some capable of contraction to regulate blood flow

2. can be stem cells for endothelial and smooth muscle cells after injury

Question 8

What are the most common type of capillaries?

Answer 8

Continuous capillaries

Question 9

Where are continuous capillaries found?

Answer 9

• Muscle system
• nervous system
• connective tissue
• exocrine system
• pancreas

Question 10

How would you describe continuous capillaries?

Answer 10

• endothelial cells are sealed by tight junctions

- permit the passage of small molecules

Question 11

Where are fenestrated capillaries found?

Answer 11

• pancreas
• intestines
• endocrine glands

Question 12

What is unique about the fenestrated capillaries found in the renal glomerulus?

Answer 12

-there is not a diaphragm

Question 13

What are the size of a typical fenestrae?

Answer 13

60-80 nm

Question 14

How would you describe fenestrated capillaries?

Answer 14

Continuous, but thin endothelium and basal lamina, covered by a diaphragm
-specialized for rapid exchange

Question 15

Where are sinusoidal capillaries found?

Answer 15

-endocrine glands

Question 16

Where are discontinuous sinusoids found?

Answer 16

• liver

- bone marrow

Question 17

Where are venous sinusoids found?

Answer 17

• spleen

Question 18

How would you describe a sinusoid?

Answer 18

• irregular blood channels that conform to the shape of the structure they line
• large gaps btwn endothelial cells permits enhanced exchange btwn blood and tissue

Question 19

In which structure are the diaphragms larger, Discontinuous sinusoids or fenestrated capillaries?

Answer 19

discontinuous sinusoids

Question 20

Small pores of capillaries:

1. what are their size
2. where are they found
3. what do they allow to pass

Answer 20

1. 9-10 nm
2. occluding junctions (tight)
3. water and small hydrophilic molecules

Question 21

Large pores of capillaries:

1. what are their size
2. what occurs through them

Answer 21

1. 50-70 nm

2. transcytosis by vesicles

Question 22

Which are more numerous - veins or arteries?

Answer 22

veins - 70% of total volume

Question 23

Which has more vasa vasorum and lymphatics - veins or arteries?

Answer 23

veins

Question 24

which has more collagen and less elastic substance and smooth muscle - veins or arteries?

Answer 24

veins

Question 25

In what size veins are valves in? what composes a valve?

Answer 25

small and medium veins | -infolding of intima with an elastic core

Question 26

Describe a large vein: 1. Intima 2. Media 3. Adventitia

Answer 26

1. Intima - Continuous Endothelium and basal lamina - Subendothelial CT (no internal elastic lamina) 2. Media – frequently incomplete or absent - CT, SM 3. Adventitia – largest, 95% of thickness - SM in long bundles – defining feature - Well developed vasa vasorum and lymphatic’s

Question 27

Describe a medium and small vein: 1. Intima 2. Media 3. Adventitia

Answer 27

1. Intima - Continuous endothelium and basal lamina - Complete internal elastic laminae only found in veins of the leg - some valves 2. Media – poorly developed except in the limbs - CT fibers - 2-3 layers circumferential SM 3. Adventitia – thickest tunic, no smooth muscle Collagen layers with fibroblasts, lymphatic’s, vasa vasorum, elastic fibers

Question 28

Describe a venule: 1. Intima 2. Media 3. Adventitia

Answer 28

1. Intima - Endothelium 2. Media - Sparse CT, few SM 3. Adventitia - Some Collagen

Question 29

How would you compare venules to arterioles?

Answer 29

1. larger diameter | 2. no smooth muscle

Question 30

What are some functions of venules?

Answer 30

- allow exchange | - leukocyte emmigration

Question 31

In response to what two subtances, can venules become leaky?

Answer 31

histamine and serotonin

Question 32

What is the diameter of pericytic venules and what do they resemble?

Answer 32

1. 10-50 microns | 2. resemble large capillaries

Question 33

what is the function of muscular venules?

Answer 33

-receive blood from pericytic venules and accompany arterioles

Question 34

Describe the adventitia of muscular venules?

Answer 34

1-2 layers of smooth muscle and thin adventitia

Question 35

What are portal systems?

Answer 35

- carry blood from one capillary to another

Question 36

What are 3 examples of portal systems?

Answer 36

1. hepatic portal vein btwn intestines and liver 2. hypophyseal portal veins of the pituitary 3. efferent arterioles of the renal cortex

Question 37

What are arteriovenous anastomoses?

Answer 37

- direct cross connections btwn arterioles and venules - allows bypass of a capillary bed - smooth muscle cells form a sphincter which regulates blood flow

Question 38

How would you describe lymphatic vessels?

Answer 38

- large lumens, thin walls, irregular shapes - similar to veins but more irregular - branch parallel to capillaries and veins

Question 39

What is the basal lamina of lymphatic vessels like?

Answer 39

-discontinuous or absent

Question 40

How are lymphatic vessels held open?

Answer 40

elastic anchoring filaments

Question 41

Are RBCs found in lymphatics?

Answer 41

N0OO0O