❤️

Question 1

Organization of cardiovascular system

Answer 1

The Pulmonary Circuit
■ Carries blood to and from gas exchange surfaces of the lungs

The Systemic Circuit
■ Carries blood to and from the body

Question 2

Capillaries

Answer 2

“exchange vessels”
■ Exchange materials between blood and tissues
■ Dissolved gases, nutrients, wastes

Question 3

4 chambers of the ❤️

Answer 3

■ 2 for each circuit:
■ left and right:
■ ventricles and atria

1) Right atrium:
■ collects blood from systemic circuit
2) Right ventricle:
■ pumps blood to pulmonary circuit
3) Left atrium:
■ collects blood from pulmonary circuit
4) Left ventricle:
■ pumps blood to systemic circuit

Question 4

Anatomy of the ❤️

Answer 4

■ Located directly behind sternum
■ Great veins and arteries at the base
■ Base leans toward right shoulder

■ Pointed tip is apex
■ Apex points toward left hip

Question 5

Relation to thoracic cavity

Answer 5

Surrounded by pericardium
■ Between 2 pleural cavities
■ In the mediastinum

Question 6

Pericardium

Answer 6

2x lining of pericardial cavity

Question 7

2 layers of pericardium

Answer 7

1. Parietal pericardium:
   • outer layer
   • forms inner layer of pericardial sac (Fibrous pericardium)
2. Visceral pericardium:
   • inner layer of pericardium

Question 8

Structures of pericardium

Answer 8

■ Pericardial cavity:
■ Is between parietal and visceral layers (Serous pericardium)
■ contains pericardial fluid

■ Pericardial sac (Fibrous pericardium):
■ fibrous tissue
■ Protects, anchors, and prevents overfilling

Question 9

Cardiac tamponade

Answer 9

■ Fluid from pericarditis related inflammation can build up in the pericardial cavity
■ Can restrict heart movement

Question 10

3 layers of ❤️ wall

Answer 10

■ Epicardium: outer layer
■ Myocardium: middle layer
■ Endocardium: inner layer

Question 11

Epicardium

Answer 11

■ Same as the visceral pericardium
■ Covers the heart

Question 12

Myocardium

Answer 12

■ Muscular wall of the heart
■ Concentric layers of cardiac muscle tissue
■ Atrial myocardium wraps around great vessels
■ 2 divisions of ventricular myocardium

Question 13

2 divisions of ventricular myocardium

Answer 13

■ Superficial ventricular muscles: surround both ventricles

■ Deep ventricular muscles:
■ surrounds only the left ventricle
■ Makes up the intraventricular septum

Question 14

3 types of 🩸vessels

Answer 14

■ Arteries: carry blood away from ❤️

■ Veins: carry blood to heart (oxygenation?)​

■ Capillaries: networks between arteries and veins

Question 15

Atrioventricular (AV) Valves

Answer 15

■ Connect right atrium to right ventricle and left atrium to left ventricle
■ Permit blood flow in 1 direction:
■ atria to ventricles

Question 16

Vena cava

Answer 16

■ Delivers systemic circulation to right atrium

■ Superior vena cava:
■ receives blood from head, neck, upper limbs, and chest

■ Inferior vena cava:
■ receives blood from trunk, and viscera, lower extremities

Question 17

Coronary sinus

Answer 17

■ Cardiac veins return blood to coronary sinus
■ Coronary sinus opens into right atrium

Question 18

Pectinate muscles

Answer 18

■ Contain prominent muscular ridges
■ On anterior atrial wall
■ And inner surfaces of right auricle

Question 19

Right atrioventricular (AV) Valve

Answer 19

■ Also called tricuspid valve
■ Opening from right atrium to right ventricle
■ Has 3 cusps
■ Prevents backflow

Question 20

Trabeculae carneae

Answer 20

■ Muscular ridges on internal surface of the ❤️s ventricles

■ Includes moderator band (right side only):
■ ridge contains part of conducting system
■ coordinates contractions of cardiac muscle cells
■ May help prevent the heart overstretching

Question 21

Pulmonary circuit

Answer 21

■ Conus arteriosus (superior right ventricle) leads to pulmonary trunk
■ Pulmonary trunk divides into left and right pulmonary arteries
■ Blood flows from right ventricle to pulmonary trunk through pulmonary valve
■ Pulmonary valve has 3 semilunar cusps

Question 22

Left ventricle

Answer 22

■ Holds same volume as right ventricle
■ Is larger; muscle is thicker, and more powerful
■ Similar internally to right ventricle, but does not have moderator band

Question 23

Left ventricle system circulation

Answer 23

■ blood leaves left ventricle through aortic valve into ascending aorta

■ ascending aorta turns (aortic arch) and becomes descending aorta

Question 24

Left and right ventricle

Answer 24

■ Have significant structural differences
Structure of Left and Right Ventricles
■ Right ventricle wall is thinner, develops less pressure than left ventricle
■ Right ventricle is pouch-shaped, left ventricle is cone-shaped

Question 25

❤️ valves

Answer 25

■ One-way valves prevent backflow during contraction

Question 26

Regurgitation

Answer 26

■ Failure of valves
■ Causes backflow of blood into atria

Question 27

Semilunar valves

Answer 27

■ Pulmonary and aortic tricuspid valves
■ Prevent backflow from pulmonary trunk and aorta into ventricles
■ Have no muscular support

Question 28

Aortic sinuses

Answer 28

■ At base of ascending aorta
■ Prevent valve cusps from sticking to aorta
■ Origin of right and left coronary arteries
■ Blood can only flow in to coronary arteries in diastole

Question 29

Carditis

Answer 29

■ An inflammation of the ❤️

■ Can result in valvular heart disease (VHD):
■ From the build up of scar tissue
■ e.g., rheumatic fever

Question 30

Fibrous skeleton

Answer 30

■ 4 bands around heart valves and bases of pulmonary trunk and aorta
■ Stabilize valves
■ Electrically insulate ventricular cells from atrial cells

Question 31

Coronary circulation

Answer 31

-Coronary arteries and cardiac veins
-Supplies 🩸 to muscle tissue of heart

Question 32

Coronary arteries

Answer 32

■ Left and right
■ Originate at aortic sinuses
■ High blood pressure, elastic rebound force blood through coronary arteries between contractions

Question 33

Right coronary artery

Answer 33

■ Supplies blood to:
■ right side of ❤️
■ portions of both ventricles
■ cells of sinoatrial (SA) and atrioventricular nodes
■ marginal arteries (surface of right ventricle)
■ posterior interventricular artery

Question 34

Left coronary artery

Answer 34

■ Supplies blood to:
■ left ventricle
■ left atrium
■ interventricular septum

■ 2 main branches:
■ circumflex artery
■ anterior interventricular artery

Question 35

Arterial anastomoses

Answer 35

■ Interconnect anterior and posterior interventricular arteries
■ Stabilize blood supply to the ❤️

Question 36

Great cardiac vein

Answer 36

■ drains blood from area of anterior interventricular artery into coronary sinus

Question 37

Anterior cardiac vein

Answer 37

■ empties into right atrium

Question 38

Posterior cardiac vein, middle cardiac vein, and small cardiac vein:

Answer 38

■ empty into great cardiac vein or coronary sinus

Question 39

Cardiac muscle cells

Answer 39

■ Intercalated discs:
■ interconnect cardiac muscle cells
■ secured by desmosomes
■ linked by gap junctions
■ convey force of contraction
■ propagate action potentials

Question 40

Characteristics of cardiac muscle cells

Answer 40

1. Small size
2. Single, central nucleus
3. Branching inter-connections between cells
4. Intercalated discs

Question 41

Structure of cardiac tissue

Answer 41

■ Cardiac muscle is somewhat striated with light and dark cross bandings

■ The striped or striated pattern is due to:
■ alternating dark, (A bands) and light, (I bands)

Question 42

Characteristics of cardiocytes

Answer 42

■ Unlike skeletal muscle, cardiac muscle cells (cardiocytes):
■ have an extensive system of short, wide T tubules which are filled with extracellular rich fluid
■ Rely on extracellular Ca2+ for contraction

■ Individual muscle cells:
■ have no triads
■ have SR with no terminal cisternae
■ are aerobic (high in myoglobin, mitochondria)
■ have limited capacity for regeneration
■ terminate in thickened structures known as intercalated discs

Question 43

Intercalated discs

Answer 43

Are specialized contact points between cardiocytes

Question 44

Functions of intercalated discs

Answer 44

■ Join cell membranes of (cardiac muscle cell) cardiocytes using gap junctions and desmosomes
■ Maintain structure
■ Enhance molecular and electrical connections
■ Conduct action potentials

Question 45

Energy source of cardiocytes

Answer 45

■ At rest fatty acids (60%), glucose (35%) and small amounts of lactic acid can be burned AEROBICALLY (as long as sufficient oxygen is available to the muscle) to meet long term ATP needs.
■ ATPs can be used to sustain power stroking
■ Cardiiocites also use creatine kinase to produce ATP

■ During exercize cardiocytes use more lactic acid which is produced by active skeletal muscles
■ It is converted to pyruvic acid by the enzyme Lactate dehydrogenase (LDH)

Question 46

Coordination of cardiocytes

Answer 46

■ Cardiac muscle cells form Functional Syncytia which means a multi-nucleated mass of cells. These cells are:
■ Mechanically
■ Chemically
■ Electronically Connected

■ Because the myofibrils from adjoining cells are essentially locked together, they all pull together for max. efficiency

■ are arranged into 2 Syncytia
■ an atrial syncytium and
■ a ventricular syncytium
■ separated by a band of connective tissue

Question 47

❤️beat

Answer 47

■ A single contraction of the heart
■ The entire heart contracts
■ first the atria
■ then the ventricles

Question 48

2 types of cardiac muscle cells

Answer 48

■ Conducting system:
■ controls and coordinates heartbeat

■ Contractile cells:
■ produce contractions

Question 49

Conducting system

Answer 49

■ The cardiac cycle begins with action potential at sinus (sinusatrial node(SA))node
■ transmitted through conducting system
■ produces action potentials in cardiac muscle cells (contractile cells)

■ A system of specialized cardiac muscle cells:
■ initiates and distributes electrical impulses that stimulate contraction

■ Automaticity or autorythicity:
■ cardiac muscle tissue contracts automatically (no cns stimuli needed)

Question 50

Structures of conducting system

Answer 50

■ Sinoatrial (SA) node
■ Atrioventricular (AV) node
■ Conducting cells

Question 51

Conducting cells

Answer 51

■ Interconnect SA and AV nodes
■ Distribute stimulus through gap junctions in intercalated discs in cardiac muscle

■ In the atrium:
■ internodal pathways

■ In the ventricles:
■ AV bundle and bundle branches

Question 52

Pacemaker (autohythmic) cells

Answer 52

■ Pacemaker potential (#1)
■ Have unstable resting membrane potentials due to opening of slow Na+ channels
■ Continuously depolarize
■ Never flat line

■ Depolarization (#2)
■ At threshold, Ca2+ channels open
■ Explosive Ca2+ influx produces the rising phase of the action potential

■ Repolarization
■ results from inactivation of Ca2+ channels and opening of voltage-gated K+ channels