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Lecture7 circulatory system
1.
2. Indeks
12
• The circulatory system ( CS) is
composed of two components:
the cardiovascular system – CVS ( the
function is to carry blood between the
heart and the tissues)
the lymphatic system – LS ( the
function is to collect lymph and
deliver it back to the CVS)
3. Indeks
12
The CVS is composed of :
the heart ( that pumps the blood into two
separated circuits: the pulmonary circuit
and the systemic circuit)
the blood vascular system ( arteries,
capillaries, veins)
4.
5. Indeks
General Structure of Blood Vessels
♥ TUNICA INTIMA
♥ Internal elastic lamina
♥ TUNICA MEDIA
♥ External elastic lamina
♥ TUNICA ADVENTITIA
7. Indeks
TUNICA MEDIA
♥ concentric layers of smooth muscle cells
♥ some elastic fibers
♥ type III collagen
♥ proteoglycans
Capillaries and postcapillary venules do not
have a tunica media.
Pericytes replace the media.
21. Indeks
ENDOTHELIAL CELLS
are mesenchymal origin
each cell contains desmin and vimentin
filaments = provide structural support
are joined together by
zonulae occludentes and gap junctions
22. PERICYTES
Indeks
♥are mesenchymal origin
♥are located along the outside of the
capillaries and small venules
♥possess a small Golgi complex,
mitochondria, rER, microtubules
♥contain myosin, actin,and tropomyosin
and protein kinase, which are all related
to contraction
♥may differentiate into smoooth muscle
and endothelial cells- after injury
26. Functions of capillaries:
Indeks
1. Transport of gases ( O2, CO2), and
hydrophylic molecules (e.g.glucose)
2. Metabolic:
a. Production of vasoactive factors:
endothelin I- acts as hypertensive agent
b. Secretion of :
- collagen types II, IV, V,
- fibronectin, laminin ( the ExCM)
c. Antithrombogenic – prevent contact of
platelets with the subendothelial CT
d. Lipolysis- breakdown of lipoproteins
e. Inactivation- bradykinin, serotonin,
prostaglandins, norepinephrine, thrombin
29. Indeks
The Endocardium consists of:
♥ a single layer of squamous endothelial
cells
♥ a thin subendothelial layer of loose
connective tissue
♥ the subendocardial layer ( with
veins, nerves and Purkinje cells)
30.
31. The Myocardium
Indeks
♥ is the thickest of the tunics
♥ consists of cardiac muscle arranged in layers
and grouped into three populations:
1. contractile cells
2. the impulse-generating and conducting
cells
3. specialized cardiac muscle cells –
located in the atrial wall-produce peptide:
atrial natriuretic polypeptide ( cardiodilatin,
cardionatrin)
it acts on kidneys to cause sodium and
water loss ( balance of electrolytes and
blood pressure)
32. Indeks
The Epicardium
is the serous covering of the
heart and forming the visceral
layer of the pericardium
is covered externally by
mesothelium
33.
34.
35. Structures that control heartbeat
Indeks
the sinoatrial node
internodal tracts
the atrioventricular node
the atrioventricular bundle
of His
Purkinje cells
The sinoatrial node is the pacemaker
of the heart
39. Lymphatic vessels
Indeks
♥ are found in all organs
♥ are blind-ended
♥ consist of a single layer of
endothelium
♥ have no fenestrations in their
endothelial cells, no zonula
occludens between cells and
incomplete basal lamina
♥ they absorb some of electrolytes and
proteins that leave the blood
capillares
