Ch. 21 (heart) SG

Question 1

Heart location

Answer 1

anterior chest wall, posterior to sternum in the pericardial cavity

Question 2

pericardial sac

Answer 2

formed by the parietal pericardium and the fibrous pericardium; contains pericardial fluid which serves as a lubricant reducing friction from heart beats

Question 3

3 histological layers of the heart

Answer 3

epicardium (outer), myocardium (thickest), and the endocardium (inner); epicardium is aka the visceral pericardium (pericardial sac)

Question 4

Cardiac muscle tissue

Answer 4

much smaller than skeletal muscle fibers; they resemble skeletal muscle fibers though because both have myofibrils, sarcomeres (which produce striations), dependent on aerobic respiration, short t-tubules, they contract without instructions from the NS, and they have intercalated discs

Question 5

Skeleton of the heart

Answer 5

an extensive connective tissue that encircle the heart; layers composes of dense bands of fibroelastic tissue; functions consist of stabilizing valves of the heart, distributing forces of contraction, providing physical support for the cardiac muscle cells, providing elasticity

Question 6

4 chambers of the heart

Answer 6

2 atriums and 2 ventricles

Question 7

right atrium

Answer 7

receives oxygen-poor blood thru the sup. vena cava and the inf. vena cava; separated from other atrium by interatrial septum

Question 8

right ventricle

Answer 8

oxygen-poor blood from right atrium goes into this ventricle thru the right atrioventricular (AV) valve; blood goes thru pulmonary trunk then the pulmonary arteries

Question 9

left atrium

Answer 9

blood comes thru pulmonary capillaries which is now oxygen rich and goes thru pulmonary veins; blood goes to left ventricle via the left AV valve

Question 10

left ventricle

Answer 10

blood leaves it from the aortic valve into the ascending aorta then the aortic arch then the descending aorta (thickest wall of any chamber - thicker so that it can develop enough pressure to force blood around the entire systemic circuit)

Question 11

Right AV valve

Answer 11

tricuspid valve; made of connective tissue

Question 12

Left AV valve

Answer 12

bicuspid valve; has only a pair of cusps

Question 13

Function of valves

Answer 13

helps prevent or stop blood flow thru the heart

Question 14

mitral valve prolapse

Answer 14

the mitral valve cusps do not close proper which causes regurgitation which causes surges and swirls known as a heart murmur

Question 15

Primary function of Right side of heart

Answer 15

receives oxygen poor blood from the body and sends it to the lungs

Question 16

Primary function of left side of heart

Answer 16

collect oxygenated blood from the lungs and then pump it to the rest of the body

Question 17

major arteries in heart

Answer 17

coronary arteries which come off the base of the ascending aorta; the left coronary artery has atrial, and ventricular branches while the right one has a circumflex branch along with the other two types that were on the left one

Question 18

Cardiac veins

Answer 18

they deliver venous blood to the coronary sinus which drains into the right atrium

Question 19

Conducting system of the heart

Answer 19

the stimulus for contraction is generated by pacemaker cells at the Sa node; impulses follow 3 paths (internodal) thru the atrial walls to reave the AV node; after a delay the impulses are conducted to the bundle of His and then on to the bundle branches (purkinje fibers) and the ventricular myocardial cells; all this is done so the atria contract together before the ventricles and that the ventricles contract from the apex to the base

Question 20

Heart innervation

Answer 20

heart rate is established by pacemaker cells of the SA (sinoatrial) node but it can be modified by the ANS; innervated by the glossopharyngeal and vagus nerves (norepinephrine increases haert rate while ACh decreases heart rate and force of contractions)

Question 21

foramen ovale

Answer 21

oval opening in the interatrial septum (separates the two atriums) during the fifth week of embryonic development till birth; permits blood flow directly from right to left atriums;

Question 22

Fossa ovalis

Answer 22

a small depression that is located at the site where the foramen ovale closes in the adult heart