Chaptser 18

Question 1

pulmonary circuit

Answer 1

-The right side receives oxygen-poor blood from
tissues
§ Pumps blood to lungs to get rid of CO2,
pick up O2,

Question 2

systemic circuit

Answer 2

-The left side receives oxygenated blood from
lungs

Question 3

Right atrium

Answer 3

§ Receives blood returning from systemic circuit

Question 4

Left atrium

Answer 4

§ Receives blood returning from pulmonary circuit

Question 5

Right ventricle

Answer 5

§ Pumps blood through pulmonary circuit

Question 6

Left ventricle

Answer 6

§ Pumps blood through systemic circuit

Question 7

Location of heart

Answer 7

– In mediastinum between second rib and fifth intercostal space
– On superior surface of diaphragm
– Two-thirds of heart to left of midsternal line
– Anterior to vertebral column, posterior to sternum

Question 8

Pericardium

Answer 8

the double-walled sac that surrounds the heart; made up of two layers

Question 9

Superficial fibrous pericardium:

Answer 9

functions to protect, and anchor heart to surrounding structures, and prevent overfilling

Question 10

Superficial fibrous pericardium:

Answer 10

functions to protect, and anchor heart to surrounding structures, and prevent overfilling

Question 11

Parietal layer

Answer 11

lines internal surface of fibrous pericardium

Question 12

Visceral layer (epicardium)

Answer 12

on external surface of heart

Question 13

pericardial cavity (decreases friction)

Answer 13

Two layers separated by fluid-filled

Question 14

Three layers of heart wall

Answer 14

-Epicardium: a visceral layer of serous pericardium
– Myocardium: circular or spiral bundles of contractile cardiac muscle cells
§ Cardiac skeleton: crisscrossing, interlacing layer of connective
tissue
– Endocardium: innermost layer; is continuous with endothelial lining of blood vessels

Question 15

Atria

Answer 15

the receiving chambers
– Small, thin-walled chambers; contribute little to propulsion of blood

Question 16

Right atrium

Answer 16

receives deoxygenated blood from body
§ Anterior portion is smooth-walled
§ Three veins empty into right atrium:
– Superior vena cava: returns blood from body regions above the
diaphragm
– Inferior vena cava: returns blood from body regions below the
diaphragm
– Coronary sinus: returns blood from coronary veins

Question 17

Left atrium

Answer 17

eceives oxygenated blood from lungs
§ Four pulmonary veins return blood from lung

Question 18

Ventricles

Answer 18

the discharging chambers
– Make up most of the volume of heart
– Trabeculae carneae: irregular ridges of muscle on ventricular walls
– Papillary muscles: project into ventricular cavity
§ Anchor chordae tendineae that are attached to heart valves
– Thicker walls than atria
– Actual pumps of heart

Question 19

Heart Valves

Answer 19

• Ensure unidirectional blood flow
  through heart
• Open and close in response to
  pressure changes

Question 20

• Two major types of valves

Answer 20

– Atrioventricular valves located
between atria and ventricles
– Semilunar valves located
between ventricles and major
arteries

Question 21

trioventricular (AV) valves

Answer 21

prevent backflow into atria when ventricles contract
– Tricuspid valve (right AV valve): made up of three cusps and lies between right
atria and ventricle
– Mitral valve (left AV valve, bicuspid valve): made up of two cusps and lies between
left atria and ventricle
– Chordae tendineae: anchor cusps of AV valves to papillary muscles that function
to:
§ Hold valve flaps in closed position
§ Prevent flaps from everting back into atria

Question 22

semilunar (SL) valves

Answer 22

prevent backflow from major arteries back into ventricles
– Open and close in response to pressure changes
– Each valve consists of three cusps that roughly resemble a half moon
– Pulmonary semilunar valve: located between right ventricle and pulmonary trunk
– Aortic semilunar valve: located between left ventricle and aorta

Question 23

Incompetent valve

Answer 23

Blood backflows so heart repumps same blood over and over

Question 24

Valvular stenosis

Answer 24

§ Stiff flaps that constrict opening
§ Heart needs to exert more force to pump blood

Question 25

Angina pectoris

Answer 25

Thoracic pain caused by fleeting deficiency in blood delivery to myocardium
– Cells are weakened