Fundamentals of Anatomy & Physiology: Chapter 20 Flashcards

Carries blood to and from gas exchange surfaces of lungs

• Carries blood to and from the body
• Blood alternates between pulmonary circuit and systemic circuit

• Arteries
• Veins
• Capillaries

Carry blood away from heart

Carry blood to heart

• Networks between arteries and veins
• Exchange materials between blood and tissues
• Materials include dissolved gasses, nutrients, waste products

• Right atrium
• Right Ventricle
• Left Atrium
• Left Ventricle

Collects blood from the systemic circuit

Pumps blood to pulmonary circuit

Collects blood from pulmonary circuit

Pumps blood to systemic circuit

• Divides atria and ventricles
• Part of the external anatomy of the heart

• Seperates left and right ventricles
• Part of external anatomy of the heart
• Contain blood vessels of cardiac muscle

• Thin walled
• Expandable outer auricle (atrial appendage)
• Each has pectinate muscles (ridges) anteriorly
• left and right separated by interatrial septum

• inferior, thick walls, lined with trabeculae carneae (muscle ridges)
• left and right separated by interventricular septum
• Left ventricle 3x thicker than right
• Left has same volume as right
• Left is round, right is crescent

Line the ventricles and make the contraction of the heart as a whole.

Separates atria

Seperates ventricles

Between the atria and ventricles

• Atrioventricular valve on between the right atria and the right ventricle
• Has 3 cusps (flaps)

• Atrioventricular valve between the left atria and left ventricle
• Has 2 cusps (flaps)

Attached to chordae tendineae from papillary muscles on ventricle wall

The contraction of papillary muscles

Cusps hang loose, allowing the ventricles to fill with blood

• Between ventricles and arteries
• 3 cusps, no chordae tendineae or muscles
• forced open by blood from ventricular contraction
• snap closed to prevent backflow

• Epicardium
• Myocardium
• Endocardium

• Outer Layer
• Covers the heart
• Visceral pericardium

• Middle Layer
• Muscular wall of the heart
• Concentric layers of cardiac muscle tissue
• Atrial myocardium wraps around great vessels
• Two divisions of ventricular myocardium

• Inner Layer
• Simple squamous epithelium

Valve function deteriorates to extent that heart cannot maintain adequate circulation

leaky valve

• Murmur of the left AV valve
• Cusps don't close properly
• Blood regurgitates back into left atrium

• Decreased pumping efficiency due to diseased valves or damaged muscle
• Blood backs up
• fluid leaks from vessels and collects in lungs and tissues

Heart muscle cells

• Uses actin and myosin sliding filaments to contract
• rich in mitochondria, resists fatigue but dependent on aerobic respiration
• cells connected by intercalated discs

• connect cells in Cardiac Muscle Tisse
• consists of desmosomes and gap juntions
• convey force of contraction
• propagate action potentials

• Found in the fetal heart
• 25% of blood bypasses the lungs directly to the left atrium
• Closes at birth

Scar left after the foramen ovale closes at birth

• Found in fetal heart
• connects pulmonary trunk to aorta
• 90% of blood bypasses lungs
• Closes at birth

Scar left after the Ductus arteriosus closes after virth

Failure of either the foramen ovale or the ductus arteriosus to close after birth. Causing poor oxygenation of blood.

• Blood supply to the heart
• Supplies blood to muscle tissue of heart via coronary arteries or coronary veins

• Originate at base of ascending aorta
• Branch to capillary beds for diffusion

Blood returns via cardiac veins that join to form coronary sinus whic empty into right atrium

Single contraction of the heart

Cardiac muscle tissue contracts automatically

• Conducting system
• Contractile Cells

• Controls and coordinates heartbeat
• SA node
• AV node
• Conducting cells

• AV bundle
• Bundle Branches
• Purkinje fibers

Connect nodes and myocardium, run down interventricular septum and around apex

Produce contractions that propel blood

Right atrium wall near superior vena cava

Inferior portion of interatrial septum above tricuspid valvle

1. SA node activity and atrial activation begin
2. Stimulus spreads across the atrial surfaces and reaches the AV node
3. There is a 100 msec delay at AV node then atrial contraction begins 150 msec
4. The impulse travels along the interventricular septum within the AV bundle and the bundle branches to the Purkinje fibers, and via the moderator band, to the papilary muscles of the right ventricle. 176 msec
5. The impulse is distributed by the Purkinje fibers and relayed throughout the ventricular myocardium. Atrial contraction is completed. Ventricular contraction begins 225 msec

Atrial depolarization (contract)

Ventricular depolarization (contract)

Ventricular repolarization (relax)

• The period between the start of one heartbeat and the beginning of the next
• Includes both contraction and relaxation

1. Systole
2. Diastole

• Atrial systole
• Atrial diastole
• Ventricular systole
• Ventricular diastole

Ventricular pressure exceeds vessel pressure opening the semilunar valves and allows blood to leave the ventricle.

The amount of blood ejected is during ventricular ejection

SV= SYSTOLIC - DIASTOLIC

The volume pumped by left or right ventricle in one minute

CO= HR X SV