Cardiovascular Anatomy Baru

8/2/2019 Cardiovascular Anatomy Baru

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Dr. Dini Sri Damayanti,M.Kes


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Helps maintain homeostasis by

Circulating blood to the lungs (thepulmonary circuit)and then to the other tissues of the body (systemic

circuit)


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Heart

Blood vessels

Arteries

Capillaries

Veins


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Size of a closed fist

Shape

Apex: Blunt rounded

point of cone Base: Flat part at

opposite of end ofcone

Located in thoraciccavity inmediastinum


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Generating blood pressure Routing blood

Heart separates pulmonary and systemiccirculations

Ensuring one-way blood flow Heart valves ensure one-way flow

Regulating blood supply Changes in contraction rate and force match

blood delivery to changing metabolic needs


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Visceralpericardium: layer next to cardiacmuscle

Parietalpericardium: layer around the outside

Pericardial cavity: between the visceral andparietal layers

contains 10 to 20 mL of lubricating fluid


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Also called the epicardium

Composed of a simple squamous epithelium (aserous membrane that produces pericardial

fluid) and a thin layer of areolar connectivetissue


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Fibrous pericardium outside, composed of denseirregular tissue (pericardial sac)

Serous pericardium inside (produces pericardial

fluid), a simple squamous epithelium plus alayer of areolar tissue


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Three layers of tissue

Epicardium: This serous membrane of smoothouter surface of heart

Myocardium: Middle layer composed of cardiacmuscle cell and responsibility for heartcontracting

Endocardium: Smooth inner surface of heart

chambers


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Four chambers 2 atria

2 ventricles

Auricles Major veins

Superior vena cava

Pulmonary veins

Major arteries Aorta

Pulmonary trunk


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Four chambers

Right atrium

Right ventricle

Left atrium Left ventricle


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Relatively thin myocardium, ridges calledpectinate muscles

L and R atria separated by

interatrial septum Atrial myocardium forms a single functional

unit called the atrial syncytium (depolarizationspreads throughout all myocardial cells)


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Trabeculae carneae: muscular ridges found oninner surface of ventricles (helps ensure mixingof blood?)

Left ventricle: inverted cone shape Right ventricle: shaped like a pouch

Ventricular syncytium, interventricular septum


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4 valves, located infibrous skeleton betweenatria and ventricles

2 atrioventricular valves (AV valves)

Right AV valve = tricuspid valve Left AV valve = bicuspid v. = mitral v.

2 semilunar valves Pulmonary semilunar valve

Aortic semilunar valve


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Atrioventricular valves, prevent blood flowingback into atria during ventricular contraction

Tricuspid valve = right AV valve

Bicuspid valve = mitral valve = left AV valve


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Attached to edges of AV valves are chordaetendineae (dense regular CT)

Papillary muscles pull on chordae tendineae

during ventricular contraction to hold valveclosed against the high pressure in theventricles


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Between ventricles and the large blood vesselsthat leave the ventricles (pulmonary trunk,aorta)

3 flaps each, no chordae tendineae or papillarymuscles needed


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Composed of specialized cardiac muscle cellsthat carry electrical impulses but do notcontract

Sinoatrial node (SA node) Internodal pathways

Atrioventricular node (AV node)

Atrioventricular bundle (AV bundle,

bundle of His) Bundle branches, Purkinje fibers


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Each heartbeat is called a cardiac cycle.

When the heart beats, the two atriacontract together, then the two ventriclescontract; then the whole heart relaxes.

Systole is the contraction of heartchambers; diastole is their relaxation.

The heart sounds, lub-dup, are due to theclosing of the atrioventricular valves,followed by the closing of the semilunarvalves.


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The SA(sinoatrial) node, orpacemaker,initiates the heartbeat and causes the atriato contract on average every 0.85 seconds.

TheAV(atrioventricular) node conveys the

stimulus and initiates contraction of theventricles.

The signal for the ventricles to contract

travels from the AV node through theatrioventricular bundle to the smallerPurkinje fibers.


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A cardiac control centerin the medullaoblongata speeds up or slows down theheart rate by way of the autonomic

nervous system branches:parasympathetic system (slows heart rate)and the sympathetic system (increasesheart rate).

Hormones epinephrine andnorepinephrine from the adrenalmedulla also stimulate faster heart rate.


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Consists of plate offibrous connectivetissue between atriaand ventricles

Fibrous rings aroundvalves to support

Serves as electricalinsulation between

atria and ventricles Provides site for

muscle attachment


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Elongated, branching cells containing 1-2 centrally located nuclei

Contains actin and myosin myofilaments

Intercalated disks: Specialized cell-cell contacts

Desmosomes hold cells together and gap junctions allow actionpotentialsElectrically, cardiac muscle behaves as single unit


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The cardiovascular system has three typesof blood vessels:

Arteries (and arterioles) carry bloodaway from the heart

Capillaries where nutrient and gas

exchange occur Veins (and venules) carry blood

toward the heart.


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Arteries and arterioles take bloodaway from the heart.

The largest artery is the aorta.

The middle layer of an artery wallconsists of smooth muscle that canconstrict to regulate blood flow and

blood pressure. Arterioles can constrict or dilate,

changing blood pressure.


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Capillaries have walls only one cell thick toallow exchange of gases and nutrients withtissue fluid.

Capillary beds are present in all regions of the

body but not all capillary beds are open at thesame time.

Contraction of a sphinctermuscle closes off a

bed and blood can flow through anarteriovenous shunt that bypasses the capillarybed.


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Venulesdrain blood from capillaries,

then join to form veins that take bloodto the heart.

Veins have much less smooth muscle

and connective tissue than arteries. Veins often have valves that prevent

the backward flow of blood when

closed. Veins carry about 70% of the bodys

blood and act as a reservoirduring

hemorrhage.


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The cardiovascular system includestwo circuits:

1) Pulmonary circuit which circulates

blood through the lungs, and

2) Systemic circuit which circulates

blood to the rest of the body.3) Both circuits are vital to

homeostasis.


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Thepulmonary circuit begins with thepulmonary trunk from the rightventricle which branches into twopulmonary arteries that take oxygen-poor blood to the lungs.

In the lungs, oxygen diffuses into theblood, and carbon dioxide diffuses outof the blood to be expelled by the

lungs. Fourpulmonary veins return oxygen-

rich blood to the left atrium.


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The systemic circuit starts with theaorta carrying O2-rich blood from theleft ventricle.

The aorta branches with an arterygoing to each specific organ.

Generally, an artery divides into

arterioles and capillaries which thenlead to venules.


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The vein that takes blood to the vena cava oftenhas the same name as the artery that deliveredblood to the organ.

In the adult systemic circuit, arteries carryblood that is relatively high in oxygen and

relatively low in carbon dioxide, and veinscarry blood that is relatively low in oxygen andrelatively high in carbon dioxide.

This is the reverse of the pulmonary circuit.


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The coronary arteries serve the heartmuscle itself; they are the firstbranch off the aorta.

Since the coronary arteries are sosmall, they are easily clogged,leading to heart disease.

The hepatic portal system carriesblood rich in nutrients fromdigestion in the small intestine to theliver, the organ that monitors thecomposition of the blood.


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Cardiovascular Anatomy Baru

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