NORZULAIKA BINTI ALIASPENGAJAR JURUPULIH PERUBATAN ANGGOTA

HAS 1033

CARDIOVASCULAR SYSTEM ANATOMY

Identify the structure of the heart and its location

Explain the pericardium and the layers of the heart wall

Identify the heart valvesRecognize blood supply to the heart.Explain the structure of arteries and veinsIdentify the common disorders of

cardiovascular system.

OUTLINE

Location of the heart

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Location of the heart small, same size as a closed fist about 12 cm long, 9 cm wide,

6 cm thick. its mass averages 250 g in

adult females 300 g in adult males it rests on the diaphragm, near the

midline of the thoracic cavity in

the mediastinum. 2/3 of the mass of the heart lies

to the left of the body's midline.

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Cont.

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Cont.

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Heart Apex: pointed end,formed by the tip of the

left ventricle (lower chamber of the heart) directed anteriorly, inferiorly

and to the left.

Base: broad portion of the heart,

opposite the apex is formed by the atria

(upper chambers of the heart) directed posteriorly, superiorly

and to the right. the site of exit and entrance

of major blood vessels.

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Cont.

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Pericardium membrane that surround and protects the heart functions: confines the heart to its post. in the

mediastinum, allowing sufficient freedom of movt. for vigorous and rapid contraction.

consists of 2 parts: fibrous pericardium serous pericardium

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Pericardiumpericardium superficial composed of a tough, inelastic, dense irregular connective

tissue functions:prevent overstretching of the heart, provides

protection and anchors the heart in the mediastinum

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Pericardiumserous pericardium deeper thinner, delicate membrane forms a double layer around the heart outer layer: parietal layer, fused to the fibrous pericardium inner layer: visceral layer (epicardium), adheres to the

surface of heart percardial fluid: thin film of fluid between the parietal and

visceral layer. function: slippery secretion of the percardial cells that

reduces friction between membrane during movt.of heart. percardial cavity: space that contains pericardial fluid.

Cont.

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Cont.

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Layers of the heart wallis composed of 3 layers: epicardium myocardium endocardium

epicardium•external layer•transparent outer layer •also known as visceral layer of serous pericardium•composed of mesothelium and connective tissue•provides smooth, slippery texture to the outermost surface of the heart.

Layers of the heart wall

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Layers of the heart wallmyocardiumconsists of cardiac muscle tissue:

striated cardiac musclecardiac muscle fibers swirl

diagonally around the heart in

interlacing bundles.constitutes the bulk of the

heartfunction: pumping action

endocardium•thin layer of endothelium overlying a thin layer of connective tissue.•function: provides a smooth lining for the chambers of the heart, covers the valves of the heart•continuous with endothelium lining of large blood vesselsa attached to the heart.

Layers of the heart wall

Cont.

Cont.

Cardiac muscle bundles of the myocardium

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Chambers4 chambers2 upper chambers: atria2 lower chambers: ventricles

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Cont.ant. surface of atriumwrinkled pouch-like structure,

called an auricle (resembles a dog's ear)Function of auricle:increases capacity of an

atrium so can hold greater

volume of blood.

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Cont.on the surface of heart:a series of grooves, called sulcisulci: contain coronary blood vessels and variable amount of fat.marks the external boundary between 2 chambers of heart

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Cont.coronary sulcusresembling the crownencircles the heart, marks boundary between the sup. atria and inf. ventricles.anterior interventricular sulcus: marks the ant.boundary between the right and left ventriclesposterior interventricular sulcus: marks the boundary between the ventricles on the post.aspect of the heart.

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Right atriumright atrium receives blood from 3 veins: superior vena cava inferior vena cava coronary sinus anterior wall: rough due to presence of muscular ridges

called pectinate muscles, extend into auricle. posterior wall: smooth

tricuspid valve: consists of 3 cups or leaflets blood passes from the right atrium into the right ventricle

Cont.

• Pectinate muscle Coronary sulcus

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Cont.

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Cont.

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Cont.interatrial septum a thin partition between right and left atrium fossa ovalis: a prominent feature of septum, oval depression the remnant of the foramen ovale

Cont. Interatrial septum Fossa ovalis

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Cont. foramen ovale an opening in the interatrial septum of the fetal heart that

directs blood from the right to left atrium in order to bypass the nonfuctioning fetal lungs

closes soon after birth

Cont.

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Right ventricle forms most of ant.surface of the heart the inside contains series of ridges formed by raise bundles

of cardiac muscles fibers called trabeculae carnae. the cups of tricuspid valve are connected to tendonlike

cords called chordae tendineae. chordae tendineae connects to trabeculae carneae called

papillary muscles. interventricular septum: separate the right ventricle with

left ventricle. pulmonary valve: blood from right ventricle pass through a

large artery, pulmonary trunk (carries blood to the lungs for oxygenation).

Cont.

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Left atrium left atrium receives blood from the lungs through 4

pulmonary veins from inside, consists a smooth posterior wall anterior wall: smooth because the ridged pectinate muscles

are confined to the auricle of the left atrium. bicuspid (mitral) valve: blood from the left atrium passes into left ventricles. has 2 cups mitral refers to its resemblance to a bishop's miter (hat),

which is two-sided.

Cont.

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Cont.

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Left ventricle forms the apex of the heart contains trabeculae carneae and chordae tendinae:

anchors the cups of the bicuspid valve to papillary muscles. aortic valve: blood passes from the left ventricle into the

largest artery of the body (ascending aorta) Blood flows into: Ascending aorta Coronary arteries: branch from ascending aorta, carry

blood to the heart wall. Arch of the aorta Descending aorta

Carry blood throughout the body

Cont.

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Cont. Ductus arteriosusA temporary blood vessel during fetal lifeFunction: shunts blood from the pulmonary trunk into aorta to bypass the nonfunctioning fetal lungsCloses after birthLeave a remnant called ligamentum arteriosum (connects the arch of the aorta and pulmonary trunk.

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Cont.

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Cont.

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Myocardial thickness and function

The thickness of 4 chambers varies according to amount of work each chamber has to perform.

Atria: The walls are thinner than ventricles because need only

fewer cardiac muscle tissue

Ventricles: The walls are thicker because need to pump blood greater

distances

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Cont.

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Cont.

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Cont. Right ventricle:

Pumps blood a short distance to the lungs (pulmonary circulation)

Left ventricle:

Pumps blood to all parts of the body (systemic circulation) Right and left ventricles eject equal volumes

of blood simultaneously Left ventricle works harder than right

ventricle to maintain the same rate of blood flow. Muscular wall of left ventricle is

thicker than the right ventricle.

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Cont.

Heart valves The contraction of chambers of the heart, will forces valves

to open Blood flow through the valves The contraction and relaxation of each chambers result

pressure differences across the valves Contraction: valves open Relaxation: valves close Function: ensure one-way flow of blood Opening of valves to let blood

through them. Closing of valves to prevent

blood backflow

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Atrioventricular valves Between atrium and ventricle 2: tricuspid and bicuspid valves

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Cont.

Cont.Contraction of atrium wall.

Increase blood pressure

Forces AV valve to open

Atrial blood flow through AV valve into ventricle

The pointed ends of the cups project into the ventricle

Papillary muscles relax

Chordae tendineae slack

Blood from higher pressure in atria moves into lower pressure in ventricle15/04/23

Cont.

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Cont.Contraction of ventricle wall

The pressure of ventricular blood drives the cups upward

Close the valve opening

contraction of papillary muscles

Pulls on and tightens chordae tendineae

Prevents the valve cusps from pushing up into atria

The damage of AV valves or chordae tendineae will cause the backflow of blood into atrium during ventricle contraction.

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Semilunar valves Near to the origin of pulmonary trunk and aorta 2: Pulmonary and aortic valves Each consists of 3 semilunar (half moon shaped) cups. The cups attach to the artery wall by their outer margins The margins project into lumen of the artery Function: prevent arterial blood from flowing back into heart Permit blood to flow in 1 direction (from ventricles to

arteries)

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Cont. Ventricles contract

Increase ventricular blood pressure

Blood flow through semilunar valves

Into pulmonary trunk and aorta

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Cont.

Ventricles relax

Blood flows back toward heart

The cups are filled with back-flowing blood

Semilunar valves close

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Cont.

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Blood supplies: arteries and veins

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Structure of arteries and veins

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Structure of vessels

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Arteries

Carry blood away

from the heart to

other organs. The wall consists

of 3 coats or tunics: Tunica interna Tunica media Tunica externa

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Tunica interna

The inner most coat Closest to lumen Lumen: hollow space that blood flows. Composed of a lining of simple squamous epithelium called: Endothelium Basement membrane Layer of elastic tissue called the internal elastic lamina

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Tunica media The middle coat Consists of plenty of elastic fibers and smooth muscle fibers

As a result: Arteries have high compliance Their walls stretch easily or expand without tearing in

response to a small increase in pressure. Arranged in rings around the lumen

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Cont.

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Tunica externa The outer coat Composed of elastic and collagen fibers The external elastic lamina: composed of elastic tissue Separates between tunica externa and tunica media.

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Cont.

the smooth muscle of blood vessels are innervated by sympathetic neurons of the autonomic NS.

3 conditions: Vasoconstriction Vasodilatation Vasospasm

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Cont.

Vasoconstriction

Increase in sympathetic stimulation

Stimulates smooth muscle’s contraction

Squeeze the vessel wall

Narrows the lumen

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Cont. Vasodilatation

Decrease in sympathetic stimulation/presence of chemicals such as nitric oxide,H+ lactic acid

Stimulates smooth muscle’s relaxation

Increase diameter of the lumen

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Cont.

Vasospasm

The damage of artery and arteriole

Smooth muscle contracts

Vasospasm of vessel

Limit the blood flow through the damaged blood vessel

Reduce blood loss in the small vessels.

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Elastic arteries

The largest-diameter arteries Contain of elastic fibers in their tunica media As a result: The stretching of elastic walls to accommodate the blood

from heart Store mechanical energy as pressure reservoir Then, the ventricles relax As a result: Artery walls recoil Forces the blood onward toward the smaller arteries The blood still moves through arteries even during

ventricles relaxation.

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Cont.

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Functions: Propel blood onward while the ventricles relax Conducting arteries: conduct blood from the heart to

muscular arteries Examples: aorta and brachiocephalic, common carotid,

subclavian, vertebral, pulmonary and common iliac arteries

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Cont.

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Muscular arteries

Medium-sized arteries Tunica media consist more smooth muscle and fewer

elastic fibers Functions: For greater vasoconstriction and vasodilatation to adjust

the rate of blood flow Distributing arteries: distribute blood to various regions of

the body Examples: brachial artery in the arm and radial artery in

the forearm.

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Arterioles

Muscular arteries small arteries arterioles smaller arteries that deliver blood to capillaries and regulate

resistance Near to arteries have: Tunica interna: same with arteries Tunica media: composed of smooth muscle and very few

elastic fibers Tunica externa: composed mostly of elastic and collagen

fibers The smallest arterioles Closest to capillaries Their tunics have little more than a layer of endothelial cells

surrounded by a few scattered smooth muscle fibers.

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Cont.

Delivery of blood

1)Vasoconstriction

Contraction of arteriole’s smooth muscle

Increases resistance

Decreases blood flow into capillaries supplied by arterioles

2)Vasodilatation

Relaxation of arteriole’s smooth muscle

Decreases resistance

Increases blood flow into capillaries supplied by arteriole

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Cont.

Changes of blood pressureVasoconstriction:

Increases blood pressureVasodilatation:

Decreases blood pressure

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Cont.

2)Regulating resistanceResistance: Opposition to blood flowDue to friction between blood vessel and inner walls of blood vesselsSmaller diameter of blood vessel greater frictionAlso known as resistance vesselsThe changes of diameter cause:VasoconstrictionVasodilatationDecrease blood pressureIncrease blood pressure

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Cont.

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Capillaries Microscopic vessels Connect arterioles to venules Are found near every cell in the body Composed of only a single layer of endothelial cells and a

basement membrane. No tunica media and externa. Only one cell thick: materials pass through them easily. The number varies according to metabolic activity of the

tissue they serve Examples: High metabolic rate: muscles, liver, kidneys, NS. Lower metabolic rate: tendons, ligaments. Absent in fewer tissues, all covering and lining epithelia,

cornea and lens of eye and cartilage15/04/23

Cont. Function: exchange of nutrients and wastes between the

blood and body cells through the interstitial fluid Also known as exchange vessels The exchange occurs through the walls of capillaries and

the beginning of venules. Branching network of capillaries increase the surface area

for exchange materials

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Cont.

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Metarteriole

A vessel that emerges from an arteriole to supply a network of 10 to 100 capillaries

Forms a capillary bed The proximal: Is surrounded by scattered smooth muscle fibers Contraction and relaxation regulate blood flow through the

capillary bed The distal: Has no smooth muscle fibers Is called thoroughfare channel. Blood flow through it bypasses the capillary bed

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Precapillary spchinters

Rings of smooth muscle at point where capillaries branch from arterioles

Function: control blood flow through the capillary bed During relaxation: open- blood flows into capillary bed During contraction: close- blood flows through

thoroughfare channel, bypasses capillary bed

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Cont.

VasomotionIntermittent contraction and relaxationDue to chemicals released by endothelial cells; nitric acidBlood flow intermittently through a capillary bed due to alternating contraction and relaxation of smooth muscle metarterioles and precapillary sphinctersOnly 25 % through a capillary bed.

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Types of capillaries

3 types: Continuous capillaries Fenestrated capillaries sinusoids

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Continuous capillaries

Most of the capillaries Can be founded in skeletal and smooth muscle, connective

tissues and the lungs. The plasma membrane of endothelial cells form a

continuous tube that is interrupted by intercellular clefts, gaps between neighboring endothelial cells.

Intercellular clefts: Allows diffusion of water and small solutes Prevent loss of larger substances such as formed elements

and plasma proteins

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Fenestrated capillaries

Can be founded in kidneys, villi of the small intestine, choroid plexuses of the ventricles in the brain, ciliary processes of the eyes and endocrine glands.

The plasma membrane of endothelial cells have many fenestrations.

Fenestrations: small pores that give them greater permeability than continuous capillaries

Functions: Allow quick exchange of fluids and solutes

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Cont.

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Sinusoids

Wider and more winding than other capillaries Are found in liver, spleen, endocrine glands. Endothelial cells have large fenestrations Have incomplete or absent plasma membrane Have large intercellular clefts: allow proteins and blood

cells to pass from a tissue into the bloodstream Example: new formed blood cells enter the bloodstream

through sinusoid of red bone marrow.

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Cont.

Blood flows in sequence From the heart-arteries-arterioles-capillaries-venules-veins-

heart In some parts of body, body passes from one capillary

network into another through a vein called a portal vein. Portal system: a blood circulation through portal vein. Forms second capillary location. Example: liver (hepatic portal circulation) and pituitary

gland (hypophyseal portal system).

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Cont.

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Venules The united of capillaries which forms small venules Smallest venules are to closest capillaries Consists of: Tunica interna of endothelium Tunica media: has only a few scattered smooth muscle

fibers and fibroblasts. The walls: very porous and the site where phagocytic white

blood cells emigrate from the bloodstream into an inflamed or infected tissue

Venules forms larger vessels called veins Veins contains tunica externa characteristics of veins

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Veins

Consists of 3 coats: Tunica interna: thinner than arteries Tunica media: much thinner than arteries, little smooth

muscle and elastic fibers. Tunica externa: the thickest layer, consists of collagen and

elastic fibers. Lack of external and internal elastic laminae Not designed to withstand high pressure The lumen is larger than arteries More thinner than arteries: collapsed ( flattened) when

sectioned.

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Cont.

Have valves Thin folds of tunica interna Form flaplike cusps They project into lumen of the veins, pointing toward heart Function:o Prevent backflow of bloodo In the veins, low blood pressure, result blood returning to

the heart to slow and back up.

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Cont.

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Vascular (venous) sinus

A vein with a thin endothelial wall No smooth muscle to alter its diameter Surrounded by connective tissue No support from tunica media and tunicae externa Example:

1)Dural venous sinuses, supported by the dura ,ater (convey deoxygenated blood from brain to heart)

2)Coronary sinus

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Cont.

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Blood reservoirs

Blood volume at rest: is about 64% in systemic veins and venules 13% in systemic arteries and arterioles 7% in systemic capillaries 9% in pulmonary blood vessels 7% in heart chambers The largest portion of blood volume is in systemic veins and

venules. As a result: Function as blood reservoirs if the need of blood arises Venoconstriction:

1)Constriction of veins

2)Reduces the volume of blood in reservoirs

3)Allows blood to flow to skeletal muscles.15/04/23

Cont.

During hemorrhage:Blood volume and pressure decreaseVenoconstriction helps to counteract the drop of pressureExample: veins in abdominal organs ( liver and spleen) and veins of the skin.

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Cont.

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Blood supply to the heart

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Arterial supply to heart

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Venous drainage of the heart

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Common disorders in CV anatomy

Septal defects:

1)Atrial septal defects

2)Ventricular septal defects Valvular heart disease:

1)Mitral valve insufficiency

2)Pulmonary valve stenosis

3)Pulmonary valve incompetence

4)Aortic valve stenosis

5)Aortic valve insufficiency

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Common disorders in CV anatomy

Atrial septal defects (ASD)A congenital anomaly of the interatrial septum, usually incomplete closure of the oval foramen.These small openings cause no hemodynamic abnormalities.Large ASDs allow oxygenated blood from the lungs to be shunted from the left atrium through the ASD into the right atrium.It causes enlargement of the right atrium and ventricle Dilation of pulmonary trunk.Overloading of blood in the pulmonary vascular systemHypertrophy of the right atrium and ventricle and pulmonary arteries.

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Cont.

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Cont.

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Cont.Ventricular septal defects (VSD)The membranous part of the IVS develops separately from the muscular partHas a complex embryological originVSDs always occur at this site above.Also occurs in the muscular part.Almost 125% of all forms of congenital heart diseaseThe size varies from 1 to 25 mm.It causes a left to right shunt of blood through the defect A large shunt increases pulmonary blood flow and causes severe pulmonary disease.Examples: hypertension and cardiac failure.

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Cont.

Valvular heart diseaseDisorders involving the valves of the heart disturb the pumping efficiency of the heart.Causes stenosis ( narrowing) or insufficiency.Stenosis: the failure of a valve to open fully, slowing blood flow from a chamber Insufficiency: also known as regurgitation, the failure of the valve to close completely, usually owing to nodule formation on ( or scarring or contraction of ) the cusps As a result, the edges of cusps do not meet or align.

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Cont.

Mitral valve insufficiencyAlso known as mitral valve insufficiencyIt is an insufficiency or incompetent valve with one or both leaflets enlarged, redundant or “ floppy” and extending back into the left atrium during systole.It causes blood regurgitation into the left atrium when the left ventricle contracts, produces murmur.Common condition and occurs mostly in young females.Pt. suffers chest pain and fatigue.Murmur: abnormal sound from the heart

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Cont.

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Cont.Pulmonary valve stenosisThe valve cusps are fused, forming a dome with a narrow central opening

Pulmonary valve incompetenceResults in a backrush of blood under high pressure into right ventricle during diastole

Aortic valve stenosisThe most frequent valve abnormalityCaused by rheumatic fever and degenerative calcificationCauses extra work for the heart resulting in left ventricular hypertrophy.

Aortic valve insufficiencyResults in aortic regurgitation (backrush of blood into left ventricle)Produces heart murmur and collapsing pulse (forcible impulse that rapidly diminishes.

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Cont.

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References Frank H. Netter.( 2011). Atlas of Human Anatomy. 5th

Edition. Saunders Elsevier. Gerard J. Tortora, Gail W. Jenkins. (2007). Anatomy and

Physiology. John Wiley & Sons. Keith L. Moore & Arthur F. Dalley. (2006). Clinically

Oriented Anatomy. 5th edition. Lippincott Williams & Walkins.

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THANK YOU

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