Download Circulatory system

Circulatory system
General outline
Heart
Blood vascular system
Arteries
Capillaries
veins
Lymphatic capillaries
Lymphatic vascular system Lymphatic vessel
Lymphatic ducts
Capillaries
A single layer of endothelial cells
 LM
basement membrane
A few connective tissue (pericytes)
Continuous capillary
 EM
Fenestrated capillary
Sinusoid
Capillaries
Continuous C.
Fenestrated C.
Sinusoid
Continuous capillary:
 distributed in muscle tissue, brain, lung and
connective tissue, etc.
 endothelial cell: large number of pinocytotic
vesicles, no pores, exist cell junctions
between the endothelia
 basement membrane: integrity
Continuous
capillary
Fenestrated capillary:
 distributed in the kidney glomerulus, mucosa
of gastrointestine, some endocrine glands
 endothelial cells: present abundant pores, have
or haven’t diaphragm on them
 basement membrane: continuous
Fenestrated
capillary
Sinusoid:
 distributed in liver, spleen, and some
endocrine glands
 a greatly enlarged diameter
 endothelial cell: intercellular clefts are large
between cells, many pores without diaphragm
 absence of a continuous basement membrane
Sinusoid
Artery
 transport blood from heart to capillaries
 according to their size, structure
and function
are classified
Large artery
Medium-sized artery
Small artery
arteriole
Medium-sized artery:
 muscular artery
Tunica intima
Endothelium
Subendothelial layer: LCT
Internal elastic lamina: clear
Tunica media: contain 10~40 layers of circular
smooth muscle
External elastic lamina
Tunica adventitia
LCT: contain vasa vasorum
Medium-sized artery
Large artery:
 elastic artery
 subendothelial layer is thicker with a few
smooth muscles
 tunica media is thick, contains a lot of circular
elastic membrane
 internal and external elastic lamina are not
distinguished
 tunica adventitia are thiner
Large artery
Small artery:
 muscular artery and peripheral resistance
vessel
 internal elastic lamina is clear, while
external elastic lamina is not distinguished
 the media contains 3~9 layers of smooth
muscles
Vein
 large lumen, thin wall, irregular
 internal and external elastic lamina are not clear
 tunica media is thin, with a few elastic fibers and
smooth muscles
 tunica adventitia is thick
 some veins have valves
Heart
 a muscular organ that contracts
rhythmically
 pump blood through the circulatory
system
The wall of heart
Endothelium
 endocardium Subendothelial layer
Subendocardial layer
 myocardium: thickest layer, consists of
cardiac muscle
LCT: contain adipose tissue
 epicardium
Methothelium
Impulse generating and conducting
system of the heart:
 Pacemaker cells: heartbeat generating
 Purkinje cells (bundle cell):
distributed in subendocardial layer,
larger than cardiac muscle cells
 Transitional cells: transmit impulse
Purkinje cell
Cardiac cell