Bez tytulu slajdu

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circulatory system
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• 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)
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The CVS is composed of
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the heart ( that pumps the blood into two
separated circuits the pulmonary circuit and the
systemic circuit)
the blood vascular system ( arteries,
capillaries, veins)
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General Structure of Blood Vessels

• TUNICA INTIMA
• Internal elastic lamina
• TUNICA MEDIA
• External elastic lamina
• TUNICA ADVENTITIA

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TUNICA INTIMA

• a single layer of endothelial cells
• a subendothelial layer

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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.

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TUNICA ADVENTITIA

• fibroblasts
• type I collagen fibers
• longitudinally oriented elastic fibers
• Vasa vasorum in large vessels

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Classification of arteries
Elastic ( conducting )
Muscular (distributing)
Arterioles
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Arteriole
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CAPILLARIES
are composed of a single layer of endothelial
cells , rolled into a tube, resting on a basal
lamina
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ENDOTHELIAL CELLS

• are mesenchymal origin
• each cell contains desmin and vimentin
• filaments provide structural support
• are joined together by
• zonulae occludentes and gap junctions

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• PERICYTES
• 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

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Continuous capillary
blood-brain barrier muscle tissue connective
tissue exocrine glands
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Fenestrated capillary

• With diaphragme
• endocrine glands, intestine
• Without diaphragme
• renal glomerulus

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Discontinuous ( sinusoidal) capillary
liver, spleen, bone marrow
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Functions of capillaries
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
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CAPILLARY
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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)

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• The Myocardium
• 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)

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The Epicardium
is the serous covering of the heart and forming
the visceral layer of the pericardium is
covered externally by mesothelium
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• Structures that control heartbeat
• the sinoatrial node
• internodal tracts
• the atrioventricular node
• the atrioventricular bundle of His
• Purkinje cells
• The sinoatrial node is the pacemaker
• of the heart

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Atrioventricular bundle of His
right bundle branches
left bundle branches
fascicles
PURKINJE CELLS
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• Lymphatic vessels
• 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