1. Chapter 9 Circulatory system

2. ---Closed tubular system
---Blood circulatory or cardiovascular S
---Lymph vascular S

3. The cardiovascular S
heart
artery
vein
capillary

4. 1. Capillaries 1) LM: endothelium: basement membrane: pericyte:
/flattened with processes
/function:
i.  support
ii. undifferentiated cell

6. endothelial cell:
processes –microvilli-like, finger-liked
vesicle
/60-70nm, constitute about 25-35% of total volume
/transendothelial channel
function: transport large molecules and storage of membrane (for enlarge, enlongated, pore-formed and microvilli)

7. EM: classification ①Continuous capillary: ---Structural feature:
endothelial cell:
-more vesicles
-tight junction
basal lamina: complete
---Distribution: CT, MT, lung and CNS

8. ---Structural feature:
② Fenestrated capillary
---Structural feature:
endothelial cell: -have fenestrae or pore (60-80nm in D, with 4-6 nm diaphragm)
basal lamina: complete
---Distribution: gastrointestinal tract, endocrine gland and renal glomerulus

9. ③Sinusoid capillaries (enlarge capillary)
---Structural feature:
endothelium: gap, pore
basal lamina: incomplete or no (absent)
---Distribution: liver, spleen and bone marrow

11. 2. Artery ---large A: aorta, pulmonary trunk
---medium-sized A: all named A, the diameter > 1mm (radial A, ulnar A)
---small A: 300um<D<1mm

12. Medium-sized A – muscular A ---Tunica intima endothelium
subendothelial layer: CT
-collagenous F
-elastic F
-smooth muscle
internal elastic membrane: wave-liked, pink-colored band- elastin

13. ---Tunica media: thickest layer
smooth muscle: layers of, circularly
elastic F: produced by SM
collagenous F: produced by SM
---Tunica adventitia:
LCT –with small BV-vasa vasorum, NF and LV
external elastic M

15. 2) Large A: elastic A
---Structural features:
a. Tunica intima is thick, and internal elastic M is not prominant
b.   Tunica media: consists of layers of elastic membrane, CF and SM

16. Large A SM
elastic M

17. 3) Small A:
---large SA:
internal EM
3-4 layers SM
no external M
---small SA:
no internal M
1-2 layers SM

19. 2. Veins ---three type ---correspond with A except for LV
---three layers

20. ---structural features:
a. larger diameter, thinner walls- collapsed
b.  no internal and external elastic membrane, so the boundaries between three tunica are not very clear
c. contains more CT, less smooth M, SM are arranged in bundles
d.   vein valve:
/infolding of tunica intima
/semilunar-liked
/prevent back flow of blood

22. 4.      Heart
---atrium(right and left)
---ventricle (right and left)

23. The wall of heart E SE endocardium subendocardial layer myocardium
epicardium

24. 1) The wall of heart
---endocardium:
endothelium
subendothelial layer: more dense CT- contain fibroblast, CF, EF, SM
subendocardial layer: LCT, with BV, N and conducting S- Purkinje fiber

25. ---myocardium:
cardiac M:
a.    atrial muscle:
/atrial granules: um in D, contain atrial natriuretic polypeptide or cardionatrin
b.   ventricular M: thick, long, branches
LCT: rich in capillaries
*atrioventricular fibrous annulus: DCT

26. ---epicardium: visceral layer of pericardium- serous membrane:
mesothelium
LCT: more fat cell- subepicardial layer
---cardiac valve:
formed by infolding of endocardium: endothelium + DCT
prevent the back flow of blood

27. 2) Conducting S
① components:
---sinoatriol node (SA node): located in epicardium of right atrium
---atrioventricular node (AV node) and bundles (AV bundles): located in subendocardial layer
---network of Purkinje fiber:

28. ② three types of cells
a. pacemaker cell ( P cell):
mainly distributed in SA and AV node
small, fusiform or polygonal in shaped
enclosed by DCT
less organelle: myofibril, plasmalemmal vesicles and more glycogen

29. b. transitional cell:
mainly distributed in periphery of SAN or AVN and AV bundle
The structure is between pacemaker cell and cardiac M
thinner and shorter than CM
more myofibril than P cell

30. c. Purkinje cell:
mainly constitute AV bundle and branches
shorter, boarder than CM, with 1-2 centrally located nuclei
rich in mitochondria, glycogen, less myofibril
well-developed intercalated disks