Blood Vessels

Front 1

Tunica intima

Back 1

innermost layer of vessels
made of
1.endothelium and basal lamina
2. subendothelial CT (longitudinally oriented) made of fibroblasts and Collagen I
3. internal elastic lamina

Front 2

Tunica Media

Back 2

Circular layer of smooth muscle cells, each sm. mm cell surrounded by basement membrane, and mixed with reticular fibers (Coll. III) and proteoglycans
also has:
-elastic laminae
-external elastic lamina

Front 3

Tunica adventitia

Back 3

1. elastic and collagenous CT (longitudinal) w/fibroblasts, collagen I, and elastic fibers

2. Blood vv (vasa vasorum), nerves, lymphatics

Front 4

3 Basic types of arteries

Back 4

1. elastic (conducting)- often close to heart where high P (aorta, pulm a.)
2. Muscular (distributing)- downstream of elastic (eg, named aa- hepatic , renal)
3. Arterioles- located w/in organs or tissues

Front 5

Elastic arteries

Back 5

Relatively thick intima (20% in aorta)
Media forms bulk of wall (40-70 elastic laminae in aorta)
Adventitia is thin

prominent vasa vasora and lymphatics

structure of them fcns to smooth out pressure diff. between systole and diastole

Front 6

Muscular Arteries

Back 6

thin intima w/prominent internal elastic membrane
thick media- mostly smooth muscle, external elastic lam. less evident
adventitia is 1/2 to 2/3 of media, w/ vasa, nn, and lymphatics

fcns to distribute blood to body

Front 7

Arterioles (<100microm. diam)

Back 7

wall thickness~to size of lumen
very thin intima (lg art. may have IEL)
Media- 1-5 layers of sm. musc., w/EEL in lg arterioles
Adventitia- very thin, mostly collagenous fibers

Reduces pressure before blood enters capillaries and also maintains blood pressure of system

Front 8

Artery/vein shape differences

Back 8

A: circular w/crinkled IEL
V:deformed w/smooth IEL

Front 9

Artery/vein wall thickness differences

Back 9

A: very thick
V: thin for the same diameter

Front 10

Artery/vein media/adventitia differences

Back 10

A: media prominent
V: adventitia prominent

Front 11

Norepinephrine

Back 11

delivered via sympathetic fibers
causes vasoconstriction via alpha1 receptors on the SMC

Outer SMC are innervated, then excitation is spread via gap jcns

Front 12

Epinephrine

Back 12

delivered via circulation
causes vasodilation via beta2 receptors on SMC

Transmitter is diffused across SMC layer

Front 13

General structure of capillaries
-EC setup
-cytoplasm characteristics
-between ECs?

Back 13

-endothelial tube of 1-3 cells + basal lamina
-thin cytoplasm w/pinocytotic vesicles (eg, caveolae) and microfilaments to allow shape change)
-cell junctions

Front 14

cell junctions of capillaries

Back 14

-intercellular clefts (15-20 nm) and/or
-tight junctions (fascia or occludens)
-gap jcns

Front 15

Continuous capillaries
-characteristics
-where are they found
-important for what aspect of cerebral circulation?

Back 15

-continuous layer of cytoplasm (via tight jcns)
-continuous basement membrane
-pinocytotic vesicles for bidirectional exchange
-found in muscle, CT, nervous system, exocrine glands
-blood-brain barrier (zonula occludens w/few pinocytotic vesicles)

--found where macromolecular transport not that important

Front 16

Fenestrated capillaries w/diaphragms

Back 16

-cytoplasmic openings called fenestrae (60-80nm) closed off by diaphragm (not a cell membrane)
-continuous basement membrane
-allows more rapid movement between blood and tissues
-found in viscera, endocrine glands

Front 17

Fenestrated capillaries w/o diaphragms

Back 17

thickened basement membrane
only found in renal glomerulus

Front 18

Sinusoids
-characteristics
-found where
-their function

Back 18

-irregularly shaped, very thin walls, large lumen
-discontinuous cytoplasm (fenestrae w/o diaphragms)
-basement membrane often discontinuous
-allows free exchange of particles and cells (bact, erythrocytes)
-found in liver, spleen, bone marrow

Front 19

Pericytes

Back 19

pleuripotent mesenchymal stem cells surrounding capillaries and small venules

-enclosed in basement membrane
-contractile fcn
-can differentiate into SMC, fibroblasts

Front 20

Terminal arterioles

where can they open into?

Back 20

sm. arterioles regulating flow into capillary beds
-open into true capillaries w/precap. sphincter
-metarterioles- larger than cap., w/sm. muscle, bypasses capp

Front 21

Arteriovenous anastamoses

Back 21

direct connections between aa/vv systems w/ flow through vessels larger than capillaries
-important for heat conservation in skin

Front 22

post-capillary venules

Back 22

-similar structure to capillaries
-exhibit migration of leukocytes between ECs (diapedesis)

this causes: enhanced migration of cells and fluid in inflammation

high endothelial venules are found in lymph nodes-- fcn for lymphocyte homing

Front 23

endocardium

Back 23

-endothelium + basal lamina
-subendothelial layer of dense CT (fibros, SMCs, elastic fibs)
-subendocardium w/looser irregular CT (continuous w/CT around cardiac mm)

subendocardium contains branches of impulse-conducting system and blood vv

Front 24

myocardium

Back 24

thickest layer
-cardiac m + basal lamina in spiralling sheets; attached to fibrous skeleton of heart (dense CT, tendency toward cartilage formation)
-delicate, loose CT (Collagen I & III) w/ blood vv, lymphatics, nn fibers

Front 25

epicardium

Back 25

-simple squamous mesothelium (secretes serous fluid) lined w/collagenous CT
-looser subepicardial CT w/blood vv, lymphatics, nn (and some adipose)

Front 26

Differences between atria/ventricles: thickness of endocardium

Back 26

atrium > ventricles

(endocardium thickness inversely proportional to myocardium thickness)

Front 27

Atria/vent difference- thickness of myocardium

Back 27

LV > RV >> atria

Front 28

Atria/vent differences- Atrial natriuretic factor (ANF)

Back 28

found atrial myocytes, stored in granules
secreted in response to increased distension
converted to active peptide in blood
signals kidney to natriuresis and diuresis (loss of NaCl and water)

Front 29

A/V valve structure

Back 29

folds of endocardium are reinforced w/core of dense CT and are attached to cardiac skeleton (prevents dilation of A-V outlets)

chordae tendinae- dense CT cords from papillary muscles of ventricles to ventricular surface of each leaflet
-parallel bundles of collagen fibers
-covered w/endothelium

Front 30

Semilunar valve structure

Back 30

similar to A/V valves but thinner and no chordae

thickened at free margin and at nodule where cusps meet

Front 31

SA node location

Back 31

right hand wall of SVC and RA

Front 32

AV node location

Back 32

lower interatrial septum

Front 33

AV bundle (of His) location

Back 33

in interventricular septum, then branches into right and left bundle branches in subendocardium of respective ventricles (purkinje fibers)

Front 34

nodal cell structure

Back 34

fine caliber
extensive branching and anastamosing pattern
few myofibrils
probably connected via gap jcns

Front 35

Purkinje fiber sturcture

Back 35

large caliber
myofibrils around periphery
large quantities of glycogen
gap jcns