HE 22 Cardiovascular I

Question 1

Endothelium Function

Answer 1

1. exchange and adhesion
   - jxnl complexes, GJ, HemiDm FA, BL
2. Syntehtic and Secretory
   - vascular tone +/- (NO-vasorelaxant)
   - inflammatory rxns-extravasation/diapedesis
   - angiogenesis
   - blood coagulation and thrombus (clot) form

*simple squamous in orientation of vessel

Question 2

von WIllebrand Factor

Answer 2

vWF

stored in endothelium, released and secreted to underlying CT

Question 3

Weibel Palade bodies

Answer 3

release vWF into blood upon injury
-vwf can be part of the clotting factor, or secreted constitutively for repair, but also stored in case of injury for fast release.

Question 4

Comparison of Medium Veins and Muscular artery considering
Pressure
Diameter
Shape
Thickness
   TM
   TA
IEL
Valves

Answer 4

Medium Vein Muscular Artery
low pressure High pressure
Wider Smaller
Irregular Regular
Less thick Very Thick
less well developed More well developed
most developed Less well developed
only in large veins Present
Present None

Question 5

Elastic Arteries (largest)

Answer 5

pulmonary trunk, aorta, BC trunk, subclavian

conduct blood

facilitate continuous movement along vessels

• TM composed of 40-70 layers of Fenestrated elastic laminae made by SMC’s.
• difficult to distinguish from IEL but it is present

Vaso Vasorum Present

Question 6

Large Veins

Answer 6

Subclavian, BC veins, SVC, IVC, iliac veins

conduct blood, return all blood to heart

low pressure

TI & TM hard to delineate, small

TA very well developed, collections of longitudinally arranged SMC
-Vaso Vasorum

Question 7

Medium Veins

Answer 7

Axillary, ITV, ICV, CV

less SMC’s than musc. arteries, TA proportionally the thickest layer, need more VV for Oxygen delivery to tissue

more irregular lumen shape

NO IEL

often seen near Muscular artery, unlike large

Question 8

Muscular Arteries

Answer 8

Axillary, ITA, ICA, CA

thick muscularies, 5-40 layers SMC countable by stacked nuclei (cells in spiral pattern)
-prominent IEL EEL
-VV
GAP jxns spread signal-const/dilate
-where are the nerves?

often seen near medium vein unlike elastic arteries

Question 9

Valves and dysfunction

Answer 9

extensions of tunica intima

have a core of subendothelial CT covered by endothelium

Vericose veins: incompetent veins (pooling in legs)

Question 10

Arterioles characteristics

Answer 10

last artery before capillary

TI & TA THIN, TM 1-4 SMC

• may have IEL. NO EEL
• lumen D increase of decrease to control vascular resistance / lumen size/ blood flow and systemic blood pressure.

leads to Precapillary sphincter

• smallest arteriole, one layer SMC
• directly controls amount of blood in caps

Question 11

venules

Answer 11

start as post capillary venules

• NO SMA, just endothelial lining, BL, pericytes(STEM CELLS)
• site of fluid extravasation in response to histamine as inflam, allergic, immune response from MAST CELLS

Lead to Venules

• compared to arterioles thinner alls and irregular larger lumen
• TM, ONE more layer of SMC

look at a summary slide

Question 12

Type I capillaries

Answer 12

Continuous

smallest lumen 6-8 microns

endothelial jxnl complexes, pinocytotic vesicles

BL cont and complete

located in skin/bone/muscles/heart

Question 13

Type II capillaries

Answer 13

fenestrated

larger (medium)

jxnl complexes- FENESTRA- windows with small diaphragm that can control opening

BL cont and complete

endocrine organs, GI tract, intestines, stomach, kidney

Question 14

Type III capillaries

Answer 14

sinusoidal

largest in Diameter with irregular shape

fewer jxnl complexes, large pores, gaps

BL discount and can be absent

sinusoids: Bone Marrow (hematapoeisis: blood cell creation) liver, spleen, fluid and cell migration out of BV

Question 15

Pericytes

Answer 15

Stem Cell of cap and post capillary vessels.

for support and poromote stability

as mesenchymal cell can derive endothelial cells and SMC

form JXNL COMPLEXES WITH ENDOTHELIUM

activated in injury for would healing.