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WHAT IS THE HEART'S FUNCTION?

Provides the driving force for the cardiovascular system

WHAT ARE THE FUNCTIONS OF THE CARDIO SYSTEM?

1) Transport and distribute essential substances to tissues 2) Remove metabolic byproducts 3) Regulation of body temp 4) Humoral communication 5) Adjustment of O2 and nutrient supply in diff. physiologic states

ARTERIES (EFFERENT VESSELS)

Carry blood away from the heart- serves as distribution channels to organs

VEINS (AFFERENT VESSELS)

Return blood to the heart and serves as blood reservoirs

CAPILLARIES

Small vessels that interconnect the smallest arteries and veins and thin wall permits diffusion of gases, nutrients and waste b/w plasma and interstitial fluids

MEDIASTINUM

Located in thoracic cavity

BASE

Superior border which the great vessels (largest veins and arteries) are attached

APEX

Located in LEFT ventricle- the pointed tip b/w 5th & 6th rib

RIGHT BORDER

Right atrium

LEFT BORDER

Left atrium

INFERIOR BORDER

Right and Left ventricles

SUPERIOR BORDER

Great vessels/ base of heart

3 LAYERS OF THE HEART WALL

1) Epicardium 2) Myocardium 3) Endocardium

EPICARDIUM (VISCERAL PERICARDIUM)

Outer layer of heart wall

MYOCARDIUM

Middle layer of heart wall; Bulk of the heart

ENDOCARDIUM

Inner Layer of heart wall; filled with simple squamous epithelium

LAYERS OF THE PERICARDIUM

1) Fibrous pericardium 2) Serous pericardium

PERICARDIUM

Double walled sac w/c encloses the heart

FIBROUS PERICARDIUM

Outermost layer of the heart; Prevents over distention from continuous filling of heart; Anchors heart to surrounding structures

SEROUS PERICARDIUM

2 Layers: 1) Parietal layer: outermost of 2 layers, lines the internal surface of fibrous pericardium 2) Visceral Layer (Epicardium) covers and adheres closely to outer surface of heart

PERICARDIAL CAVITY

Helps diagnose disease; Found b/w partietal and visceral layers; contains serous fluid secreted by membranes

PERICARDITIS

Infection of the pericardium; inflamed surfacrs rub together producing scratching sound heard through steth.

CARDIAC TAMPONADE

Compression of the heart due to fluid accumulation in pericardial cavity; caused by traumatic injuries causing bleeding into pericardial cavity

4 CHAMBERS OF THE HEART

2 Atria (left and right) and 2 Ventricles (left and right); Each side consisting of 1 atrium, 1 ventricle, 2 valves

LANDMARKS: INTERATRIAL SEPTUM & INTERVENTRICULAR SEPTUM

Much thicker when heart is divided longitudinally

ATRIOVENTRICULAR GROOVE

Visable on heart's surface

CORONARY SULCUS

Atrial ventricular sulcus; deep groove taht marks border b/w atria and ventricles; Wraps around circum of heart; contains fat; contains coronary vessels

ANTERIOR INTERVENTRICULAR SULCUS /POSTERIOR..

Separates the left an right ventricles, shallower groove; contains large amt of fat; contains coronary vessels.

AURICLE

Broad, flattened process that resembles external ear; right auricle is Larger

ATRIA

2 left and 2 right; Upper chambers of heart; receiving chambers for blood returning to heart from both systemic circuit (rec'vd by right atria) and pulmnary circuit (rec'vd by left atria)

3 VESSELS OF THE HEART

1) Superior vena cava 2) Aorta 3) Branches of right pulmonary artery

LEFT PULMONARY ARTERY

Has 4 pulmonary veins; left and right, LV, RV, RA, LA

4 VALVES OF THE HEART

RIGHT SIDE: 1) Tricupsid Valve (RA-->RV) 2) Pulmonic Valve (RV-->PA) LEFT SIDE: 1) MItral Valve (LA-->LV) 2) Aortic Valve (VL-->Aorta)

FUNCTION OF VALVES

Regluate blood flow; Unidirectional; Prevents back flow

LEFT SIDE OF HEART

Works against higher pressure system

RIGHT ATRIUM

Blood returns here via 3 veins: Superior Vena Cava, Inferior Vena Cava, Coronary Sinus

SUPERIOR VENA CAVA (SVC)

Returns blood from the head, neck and thorax

INFERIOR VENA CAVA (IVC)

Returns blood from areas below the diaphragm

CORONARY SINUS

Collects blood draining from the myocardium itself

TRICUSPID ORIFICE

Area where the right atria pumps blood to the right ventricle

LEFT ATRIUM

Blood returns to left atrium via 4 pulmonary veins: 2 left & 2 right (best seen in posterior view of heart); returning blood is rich in O2

MITRIAL ORIFICE

Area where the left atria pumps blood to left ventricle

VENTRICLES

2 ventricles: Left and right; lower chambers of the heart, comprise most of the mass in heart; thick walled compared to atria

TRABECULAE CARNAE

Series of irregular muscle ridges in ventricular chambers (internal surfaces); includes MODERATOR BAND (right side) w/c contains portion of conducting system

PAPILLARY MUSCLES

Cone like muscle bundles assoc. w/ heart valves; attached to chordae tendineae; together anchoring valve flaps in closed position

RIGHT VENTRICLE

Forms most of heart's anterior surface; pumps blood through Pulmonary Semilunar Valve into the Pulmonary Trunk and into the lungs for gas exhange

PULMONARY SEMILUNAR VALVE

Separates the right ventricle and pulmonary trunk

PULMONARY TRUNK

First Vessel of the pulmonary circuit

LEFT VENTRICLE

Dominates inferior surface; more larger and musclular than right; more muscle nec. bec. LV pumps blood against greater pressure; Pumps blood into the systemic circuit

3 CARDIAC CIRCUITS

1) Pulmonary 2) Systemic 3) Coronary

AORTA

First vessel of the systemic circuit; needs high pressure to output to organs away from heart; Peripheral

AORTIC SEMILUNAR VALVE

Separtes the left ventricle and the right Aortic trunk

RIGHT & LEFT VENTRICLE

Pump the same volume of blood per beat

HEART VALVES

Regulate blood flow, prevent back flow; blood flow is unidirectional (from atria to ventricles to vessels);

4 HEART VALVES ENFORCE?

Unidirectional flow

CUSPS

Fibrous flaps that form Bicuspid and Tricuspid valves (AV Valves); prevents valves from opening backwards

CHORDAE TENDINEAE

Tiny white collagen cords attached to each AV valve flap; attached to papillary muscles

ATRIOVENTRICULAR (AV) VALVES

Found b/w atria and ventricle: 2 main valves: TRICUSPID & BICUSPID (MITRAL) valve; Located at base of atrio-ventricular junction; prevents backflow into atria when ventricles contract

TRICUSPID VALVE

Right AV valve

BICUSPID VALVE (MITRAL)

Left AV valve

VENTRICULAR DISTOLE

AV valves are open; allowing blood to flow into the ventricles

VENTRICULAR SYSTOLE

AV valves are closed; preventing backflow into atria

VENTRICULAR CONTRACTION

Blood pressure closes valve cusps

SEMILUNAR VALVES

Found b/w vetricle and artery; consist of 3 semilunar (half-moon shaped) cusps of thick connective tissue; arrangement of cusps prevent backflow into ventricle as ventricle relaxes

TWO SEMILUNAR VALVES

1) Aortic (LEFT) 2) Pulmonary (RIGHT); located at base of large vessels; prevent backflow into ventricles when relaxed

VALVULAR DISEASE (2 TYPES)

1)Regurgitation (insufficiency) or Prolapse; 2) Stenosis (Scarred down)

REGURGITATION (INSUFFICIENCY) PROLAPSE

1 TYPE of valvular disease; valve does not close properly; blood leaks backwards; results in reduced blood flow to organs

STENOSIS

2nd Type of valvular disease; Valve doesn't open fully, creates extra workload for heart, making heart bigger, which ultimately fails to compensate

PULMONARY CIRCUIT

Right side of heart;B/w heart and lungs: carries blood to and from gas exchange surfaces of lungs

SYSTEMIC CIRCUIT

Left side of heart; b/w heart and teh rest of the body tissues; carries blood to and from the body

CORONARY CIRCUIT

Provides nourishment ot heart muscle itself; irrigates heart; arising from base of aorta to Right coronary artery and left coronary artery to multiple cardiac arteries to capillaries to multiple cardiac veins to coronary sinus to right atrium.

MARGINAL ARTERY

1ST BRANCH: irrigates right lateral aspect of the heart (R Ventricle)

CORONARY (SYSTEM) ARTERIES

Arising from base of aorta; RIGHT & LEFT

RIGHT CORONARY

2 BRANCHES that course right side of heart

LEFT CORONARY

2 BRANCHES that course left side of heart

POSTERIOR INTERVENTRICULAR ARTERY

2ND BRANCH: Posterior descending artery (clinical name);runs to apex of heart; supplies the posterior wall of heart

CIRCUMFLEX ARTERY

2ND BRANCH: Runs along atrioventricular groove; irrigates the left atrium and the posterior walls fo the left ventricle

ANTERIOR INTERVENTRICULAR ARTERY

1ST BRANCH: Left anterior descending artery (clinical name);irrigates the interventricular septum and the anterior walls of both vetnricles

CARDIAC VEINS

Collects venous blood (venous return); joined together making the Coronary Sinus w/c empties blood into the RA

CORONARY SINUS

5 tributaries: 1) The Great Cardiac Vein 2) Middle Cardiac Vein 3) Small Cardiac Vein 4) Posterior Cardiac Vein 5) Anterior Cardiac Vein

THE GREAT CARDIAC VEIN

Found in anterior interventricular sulcus; drains blood supplied by anterior interventricular artery

MIDDLE CARDIAC VEIN

Found in posterior interventricular sulcus; drains blood from the posterior interventircular artery

SMALL CARDIAC VEIN

Found along the right inferior margin; drains the posterior surface of the right atrium and ventricle

POSTERIOR CARDIAC VEIN

Drains blood supplied by the circumflex artery

ANTERIOR CARDIAC VEIN

Drains the anterior surface of the circumflex ventricle; empties directly into the right atrium

WHICH SIDE WORKS HARDER?

Left side; if coronary is blocked it is the most alarming situation

CONDUCTING SYSTEM

In a single cardiac contraction/ heartbeat, the entire heart contracts in series; frist atria then ventricles

2 TYPES OF CARDIAC MUSCLE CELLS

1) Conducting Cells (Autorhythmic Cells) 2) Contractile Cells

CONDUCTING CELLS (AUTORHYTHMIC CELLS)

Controls and coordinates heartbeat

CONTRACTILE CELLS

Produce the powerful contractions that propel blood

INTRINSICALLY

Force of contraction controlled by heart tissue itself

EXTRINSICALLY

Force of contraction controlled through the influences of nerve signals, hormones and other blood-borne substances

AUTOMATICITY

Cardiac muscle tissue contracts automatically

SINOATRIAL NODE (SA NODE)

Pacemaker; located in the posterior wall of the right atrium; communicates with AV node

TURBULENCE

Swirling action that disturbs smooth flow of liquid

TOTAL PERIPHERAL RESISTANCE (TPR)

The combined resistance of all blood vessels within the systemic circulation

RESISTANCE VESSELS

Small arteries and arterioles

MEAN ARTERIAL PRESSURE (MAP)

The driving force for blood flow

MEDULLA OBLONGATA

Adjusts cardiac output and peripheral resistance

CARDIOACCELERATORY CENTER

Contains sympathetic neurons w/c release norepinephrine onto the cardiac cells; increases heart rate and increases heart's contractile strength; projects to SA and AV nodes and bulk of myocardium

CARDIOINHIBITORY CENTER

Contains parasympathetic neurons; releasing acetylcholine onto cardiac cells; decreasing heart rate but NO change in heart's contractile strength; projects via vagus nerve, CNX to SA & AV nodes

PARASYMPATHETIC & SYMPATHETIC NEURONS

At rest both release neurotransmitters onto the heart, but parasympathetic neurons release more

EPINEPHRINE

Hormone released by adrenal medulla

THYROXINE

Hormone released by thyroid gland; increases metabolic rate, increases heartrate

4 PHASES OF CARDIAC CYCLE

1) Ventricular Filling 2) Isovolumetric Contraction 3) Ventricular Ejection 4) Isovolumetric Relaxation

VASOMOTOR CENTER

1) Vasoconstriction 2) Vasodilation

VASOCONSTRICTION

Controlled by adrenergic nerves

VASODILATION

Controlled by cholinergenic nerves

ADH

Targets kidney; Increases water reabsorption, blood volume, blood pressure

ANGIOTENSINOGEN

Produced by liver; Angiotensin I (ACE)(produced by Renin) to Angiotensin II causing vasoconstriction; Increases ADH secretion, Increases Aldosterone secretion

ALDOSTERONE

Produced by kidney; increases sodium reabsorption, blood volume, blood pressure

VENTRICULAR FILLING

Blood filling ventricle, AORTIC valve CLOSED, MITRAL valve OPEN

ISOVOLUMETRIC CONTRACTION

1st Heart sound (LUBB); Ventricle contracting but volume not changing. SL & AV valves CLOSED

VENTRICULAR EJECTION

Blood ejected from ventricle; AORTIC valve OPEN; MITRAL (AV) valve CLOSED

ISOVOLUMETRIC RELAXATION (DISTOLE)

2nd Heart sound (DUBB); Sl & AV valves CLOSED

ABSOLUTE REFRACTORY PERIOD

Period in w/c u cannot stimulate another/ propagate action potential

SYSTOLIC PRESSURE

Contraction; peak of contraction/ peak arterial pressure; Average = 120 mmHg

DIASTOLIC PRESSURE

Relaxation: lowest arterial pressure; Average = 70-80 mmHg

BLOOD VOLUME

Quanitity of blood in cardiovascular system; varies from Male 5-6 L and Femals 4-5 L

END DIASTOLIC VOLUME (EDV)

Volume of blood in ventricle before systole; 120 ml (normal)

END SYSTOLIC VOLUME (ESV)

Volume of blood left in ventricle at the end of systole; 50 ml (normal)

EJECTION FRACTION

The % of blood ejected per heart beat; ratio b/w EDV/ESV; avg= 70 ml (60-65% avg)

STROKE VOLUME

The amount of blood pumped out of each ventricle during a single beat (cycle) during the Ventricular Ejection phase; SV (70)= EDV (120) - ESV(50)

CARDIAC OUTPUT (CO)

Amount of blood pumped by each ventricle in one minute; CO =HRxSV; any change in EDV, ESV, HR affects CO

LEFT & RIGHT SIDE OF HEART

Have identical stroke volumes;What's happening on the left side is also happening on the right; only differ. is pressure involved

LEFT VENTRICLE

Must contract harder to open SL valve becuz systemic circuit is under higher pressure than pulmonary circuit

LV SV > RV SV

Blood would back up in the systemic circuit

LV SV < RV SV

Blood would back up in the pulmonary circuit

FRANK-STARLING LAW OF THE HEART

Ensures that the SV are equal in both LV & RV; more cardiac muscle is stretched w/in phisological limits the more forcibility it will contract (rubberband analogy)

HEART RATE (HR)

The # of cardiac cycles per minute (systolic/diasolic); Autonomic NS; MALE avg= 64-72/min; FEMALE avg= 72-80/min;

BLOOD PRESSURE

Force generated against arterial walls per unit of area in mm Hg

PRELOAD

Amount the ventricles are stretched; greater the EDV= the greater the preload;

AFTERLOAD

Amount of tension the contracting ventricle must produce to force open the SL valve and eject blood; afterload increases, SV decreases; Aortic blood pressure

CONTRACTILITY

The contractile force of the heart; CALCIUM IONS; the more Ca2+ the more forceful the contraction

CONDUCTING SYSTEM (ACTION POTENTIAL AUTORHYTHMICICTY; SA NODE)

1) Prepotential; K+ channels begin to close, Ca2+ begin to open 2) Depolarization Phase: Ca2+ channels OPEN (upstroke) K+ channels CLOSED, CALCIUM INFLUX 3) Repolarization Phase: Ca2+ channels CLOSED, K+ channels OPEN, POTASIUM EFFLUX

CONTRACTING SYSTEM (ACTION POTENTIAL)

1) Depolarization Phase: Na+ OPEN, K+ begin to CLOSE, Ca+ begin to OPEN; SODIUM INFLUX 2) Plateau Phase (early repolarization): Na+ channels CLOSE; Some K+ OPEN, Ca+ OPEN (producing plateau by slowing further repol.) CALCIUM INFLUX 3) Repolarization: Ca+ channels CLOSED, Many K+ OPEN; POTASSIUM EFFLUX

FUNCTIONS OF VESSELS

Carry blood,exchange,transport,regulate BP, direct blood flow

3 MAJOR TYPES OF VESSELS

1) Arteries 2) Capillaries 3) Veins

ARTERIES

Take blood AWAY from heart

CAPILLARIES

Smallest and most numerous single celled, simple squamous; permits exchange, provides direct acces to cells, Connects arteries and veins

VEINS

Take blood TOWARD heart; Contains valves to ensure blood flow in one direction;conduit; carrying deoxygenated blood from tissues to RA; Reservoir

3 TYPES OF ARTERIES

1) Elastic 2) Muscular 3) Arterioles

ELASTIC ARTERIES

Aorta, Carotid, Illiac; Thick medial layer; Elastin and Smooth muscle cells; Serves as blood reservoir (accmodates SV); Acts as a recoil system when ventricles relax

MUSCLUAR ARTERIES

Femoral; Serves as distributing channels; large lumen to wall thickness; Large lumen minimizes the pressure drop

ARTERIOLES

Has largest amount of smooth muscle; valves of the circulation; controls volume of blood flow to various vessels beds; Site of major pressure drop in Cardio syst. Thick layer smooth muscle; Narrow lumen; control of flow via smooth muscle tone

STRUCTURE OF BLOOD VESSELS

1) Tunica Interna (Intima); INNERMOST 2) Tunica Media; MIDDLE 3) Tunica Externa (Adventitia); OUTERMOST

3 TYPES OF CAPILLARIES

1) Continuous (most common) 2) Fenestrated (more porous; permeable) 3) Sinusodial ( Greatest Permeablity)

VEINS VS. ARTERIES

Veins have Valves Arteries don't

VEIN VALVES

Folds of tunica intimia; prevents backflow; compression pushes blood toward heart

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