Cardiovascular System

Question 1

Pulmonary Arc

Answer 1

Elastic aa: heart –> lungs

Elastic vv: lungs –> heart

Question 2

Systemic Arc

Answer 2

Heart –> elastic aa. –> muscular aa. –> arterioles –> terminal vascular bed
Terminal vascular bed –> venules –> muscular vv. –> elastic vv. –> heart

Question 3

Lymphatic system

Answer 3

Afferent system

Tissue fluid –> lymph vessels –> lymph channels –> elastic vv –> heart

Question 4

Vascular tubular wall

Answer 4

3 layers and 3 fiber types

elastic fibers, smooth muscle fibers, collagen

Question 5

Tunica intima

Answer 5

endothelium, basal lamina, subendothelial CT, and some smooth ms.
Orientation is parallel to long axis of vessel
Avascular
IEL = outermost portion of TI in large aa & vv

Question 6

Tunica media

Answer 6

Predominantly sm. ms. in muscular vessels and elastic in elastic vessels
Collagenous fibers are admixed w/sm. ms. or elastic fibers
Arranged concentrically (perpendicular to long axis of vessel)
EEL = outermost part of layer
Vasa vasorum and nervi vasorum - supply outer half of tunic (inner half supplied by TI)

Question 7

Tunica adventitia

Answer 7

Connective tissue - collagen and elastic fibers
Parallel to long axis of vessel
Vasa vasorum and nervi vasorum are present - usually @ junction b/t TM and TA

Question 8

Elastic arteries

Answer 8

conduct blood away from the heart
thick tunica media
indistinct IEL & EEL

Question 9

Elastic veins

Answer 9

thicker tunica adventitia
TI & TM receive nourishment from the lumen via foot processes that extend from endothelial cells via myoendothelial [gap] junction to sm. ms of innter TM

Question 10

Muscular arteries

Answer 10

Very thick TM comprised primarily of smooth ms.
TI and IEL may appear scalloped in tissue sections
IEL and/or EEL may be present

Question 11

Muscular veins

Answer 11

Smooth ms. in TM
Collagen may predominate w/smaller amounts of sm. ms intermixed
IEL and/or EEL may be present

Question 12

Lymph vessels

Answer 12

thin walls
indistinct tunics
lumen contain precipitate or lymphocytes (but no RBCs like in aa/vv)

Question 13

Arterioles

Answer 13

regulating/resistance vessels
small muscular AA
1-3 layers of smooth ms. comprising TM
small IEL present
EEL absent
regulate blood into terminal vascular bed
paired w/a nearby venule

Question 14

Venules

Answer 14

returning vessels
indistinct TM and TA
collect blood from terminal vascular bed
coalesce into progressively larger vv

Question 15

Arteriovenous anastomoses

Answer 15

thick muscular wall
sm. ms. adjacent to TI is oriented longitudinally & appears epitheloid
Remainder of sm. ms. in TM is comprised of circularly arranged sm. ms.
Can open or close to regulate blood clow to certain capillary beds
in skin, digestive tract, erectile tissue

Question 16

Terminal vascular bed

Answer 16

May have pericytes (perivascular cells) - can differentiate into fibroblasts, sm. ms. and mast cells
Pericytes located within the vessel’s basement membrane - appear to bulge on outside of vessel

Question 17

Terminal arteriole

Answer 17

TM comprised of a single layer of sm. ms.

TA absent

Question 18

Capillaries

Answer 18

Simplest members of vascular system
Thin TI surrounded by basement membrane
Lumen can only admit a single RBC
How metabolites gain acess to and waste products leave CT

Question 19

Continuous capillary

Answer 19

No interruptions in continuity of their endothelial cells
wall is uniform in thickness
tight junctions present
in ms. - contains pinocytotic vesicles for transport of materials across wall
Neural caps and blood-brain barrier lac pinocytotic vesicles
basement membrane still intact

Question 20

Fenestrated capillary

Answer 20

pores scattered thruout walls of endothelium
wall is attenuated where cytoplasm is absent
finestrae are present for mvmnt of materials
in metabolically active tissues (kidney and intestine)
basement membrane still intact

Question 21

Discontinuous capillary - sinusoids

Answer 21

lumens large enough to allow passage of several RBCs
thin walled vessels w/irregular caliber
wall is finestrated
basal lamina is either discontinuous or entirely missing
in endocrine glands and organs w/phagocytic cells associated w/endothelium such as liver

Question 22

Lymph capillary

Answer 22

resemble blood caps, but carry lymph
similar to finestrated caps
lack basal lamina
lack pericytes 
end blindly
prominent in gut where they collect FA and glycerol for transport to blood

Question 23

Postcapillary venule

Answer 23

most permeable part of terminal vascular bed
site of inflammatory response (can become leakier w/this response)
similar structure to capillary
lumen diameter can accomodate 2 to 3 RBCs
can have associated pericytes

Question 24

blood (venous) sinuses)

Answer 24

in erectile tissue
large, round irregularly shaped vessels
for pooling of blood
lack smooth ms. (usually)

Question 25

venous portal system

Answer 25

capillary bed situated b/t two veins

venous drainage for GI tract - then empty into hepatic vv

Question 26

arterial portal system

Answer 26

capillary bed situated b/t two arterioles

example: afferent & efferent arterioles in renal capillary beds