Cardio Vascular System(Circulatory system)Ajith SominandaDepartment of Anatomy1Lecture outlineWhy a circulatory system ?Arrangement of the CVSVascular tree-Gross AnatomyCVS histology

Circulatory system; Why?

Amoeba in motion

Need of a circulatory system

3Circulatory system; Why?

Evolution of circulatory system4

Circulatory system; Why?An essential Co/ordinator of other system5Functions of circulatory systemTransport of materials and cells by continuous movement of blood GasesNutrientsWaste productsComponents of immune and endocrine systemThermoregulation

6Components of human circulatory systemBlood vascular system (closed) HeartArteries and arterioles (conduction / distributing vessels)Capillaries (exchange vessels)Venules and veins (capacitance vessels)

Lymph vascular system (open)LymphaticsLymph nodes

Pulmonary circulationHeart: left chambers (oxygenated blood)Heart: right chamber s (De-oxygenated blood)Conducting vessels

ArteriolesExchange vessels(Capillaries)VenulesLymph nodesLymphaticsCapacitance vessels(Veins)Distributing vessels

Recalling AL & high school knowledgeWorking classification 7Vascular tree- Gross anatomyOverall arrangement

Aorta(2-2.5 cm)Large and medium size arteries(100-200)Arterioles(4 * 106 )(Upper gut /celiac trunkMiddle and lower parts by messentric vesselsLower end of aorta give rise to common iliac arteries and enters the pelvic cavityThen supplies pelvis and perineal region internal illiac arteries 13Branching patterns of arterial treeTerminal branches

Co-lateral branches

End-to-end anastomosisVaginal artery-ovarian arteryLeft gastro epiploic arteriesUlnar artery and superficial palmar branch of radial artery

Anastomosis by convergenceVertebral arteries forming basilar artery

Transversal anastomosisBetween anterior cerebral arteriesBetween radial and ulnar at wristBetween posterior tibial and peroneal arteries

Anastomosis of arteries

Venous system

Superficial veinsDeep veinsVenae comitantesValves & Venous drainage

Venous system: problems

Failed superficial veins: VaricositiesObstructed deep veins: Deep vein thrombosis (DVT)

CVS HistologyGeneral arrangement of cardio-vascular tissues (CARDIO VASCULAR TUBE) Tunic = coat Tunica externa / adventitia

Tunica media

Tunica intima Vasa vasorum(Vessels of vessels)Nervi vasorum(Nerves of vessels)Has three-layered structure19General arrangement of cardio-vascular tissuesHeartArteriesCapillariesVeinsNote the changes occurring in the wall of the structuresMuscular wall shows the greatest variationBlood pressure of 120 in major arteries to 0 once returned to right atrium

20Structure for Function !The heart is a (muscular) pump !

Heart is a pump< theconceptSpecial pump,probably the best pump that pump continuously from 3rd week of |IUL till death.21HeartEndocardium (Tunica intima)

Myocardium (Tunica media)

Epicardium / viceral pericardium (Tunica adventitia)Cardiac wall consists of three layers:

Endothelium (single layer of flattened epithelial cells)Sub-endothelial connective tissueHeart

EndocardiumTunica intima23Consists of cardiac muscle fibers (Cardiocytes) arranged in a network Syncytium

Cardiocytes have central nucleus and are connected by junctional complexes intercalated discs

Mitochondria and sarcoplasmic reticulum are abundant in cytoplasm

Muscle contractions are Strong , continuous and inherent

Heart Myocardium

Recall foundation moduleConnected by intercalated disc24Heart Cardiocyte-Ultra structure

Transverse junctional complexes (Intercalated discs)StriationsLongitudinal junctional complexes(GAP junctions)

Heart EpicardiumConsists of flattened epithelium (Mesothelium) that secretes serous fluid into pericardial space

Epithelium is supported by Sub-endothelial connective tissues

Contains coronary vasculature

HeartArteriesCapillariesVeinsArterial tree Arteries conduct and distribute blood to periphery

Blood pressure

Vascular anatomy

High pressure tubal system for conduction of blood to peripheryLow pressure tubal system for drainage of bloodExchange systemStructural adaptation for Function !Why elastic tissues are more in EAsSo for muscular arteries28Conform to the three-layered tissue arrangement

Main types of vessels in arterial systemLarge elastic arteries(Aorta , Brachiocephalic, common carotid, subclavian & common iliac arteries)

Medium-sized muscular arteries(Intercostal, axillary, radial arteries)

Arterioles

Arterial tree Elastic arteries Tunica media contains large amounts of fenestrated sheaths of elastin and lesser amounts of collagen and smooth muscle cells

Tunica adventitia contains collagen tissues

Arterial tree Muscular arteriesTunica intima has three layers:EndotheliumSub endothelial connective tissuesInternal elastic lamina (sheath of elastin)

Tunica media has thick layer of smooth muscle cellsLarger vessels have external elastic lamina

Arterial tree ArteriolesArterioles are final branches of arterial system that regulate blood flow to capillary bed

Tunica media has concentric layers of smooth muscles

Innervated by sympathetic nerves and control the vascular tone

Arterial tree

Arterioles and micro circulation Arterial tree

ArteriloesVenuleSympathetic nervePre-capillary spincters

Circulation when regulated due to functional demand blood either goes through capillary bed or through shunts33Continuation of endotheliumNo smooth muscle and adventitial layersOccasion pericytes are found

Capillaries: the exchange compartment

Capillaries: different typesContinuous

Fenestrated

Discontinuous

Q: List the sites where different capillary types are foundVenous system Veins & venulesVenules (Post capillary, Muscular & Collecting venules)

CapillariesVeins Has relatively Large lumen & thinner wall Elastic and muscular components are much less prominent compared to arteriesActs as reservoirs of blood; Capacitance vessels

36Lymph vascular system Reuptake excess tissue fluid that accumulates in ECS

Similar to venous system

Things that are good to read (know) !Formation of EdemaThickening of arterial walls i.e. Arteriosclerosis & AtherosclerosisEndothelium and inflammationEndothelium and blood coagulationBiology of vessel formation and tumors (tumor angiogenesis )ReferencesWheaters functional histologyHistology and cellbiology by Abraham L KierszenbaumGrays AnatomyWWW.

The ENDThank you