heart2

Question 1

Types of Vessels

Answer 1

• heart - elastic artery - muscular artery - arteriole - continuous capillary
• fenestrated capillary - venule - medium size vein - large vein - heart

Question 2

Change in Size of Arteries?

Answer 2

• near heart: most change in pressure so lots of elastic fibers
• muscular arteries: less elastic fibers, more smooth muscles to preciesly control diameter and thus direction of blood fkiw
• drop in pressure: venous side has thinner vessel walls

Question 3

Structure of Capillaries - two types? influence?

Answer 3

• continuous capillary and fenestrated capillary
• incluence rate at which exchange will occur

Question 4

Continuous vs. Fenestrated Capillary?

Answer 4

• continuous: wall made of squamous endothelial cells, no smooth muscle, no CT, so small it could just be a single layer of endothelial cells wrapped around itself
• fenestrated: fenestra = window/doorway, instead of simple epithelial cells, there are holes to get more rapid exchange from open channels

Question 5

Answer 5

Question 6

Answer 6

Question 7

Answer 7

Question 8

Cardiac Cycle - Atrial Systole and Diastole? (steps 1 and 2)

Answer 8

• atrial contraction forces a small amount of additional blood into relaxed ventricles
• atrial systole ends, atrial diastole geins: relaxes as ventricle contracts which will close AV valves

Question 9

Cardiac Cycle - Step 3/4 - Ventricular Systole

Answer 9

• first phase: ventricular contraction pushes AV valves closed, but not enough pressure to open semilunar valves
• second phase: venticular pressure rises and exceeds pressure in arteries - semilunar valves open, blood is ejected

Question 10

Cardiac Cycle - steps 5/6 - ventricular diastole

Answer 10

• early: ventricle relax, pressure in v drops, blood flows back against semilunar valve cusps, forces them closed, blood flows into relaxed atria
• late: all chambers are relaxed, ventricles fill passively

Question 11

Conduction System - Sinoatrial node?

Answer 11

• found in Right Atrium, where it meets the superior vena cava
• aka pacemaker
• will spontaneously depolarize
• rate can be modulated with nervous/hormonal/drug input
• because of gap junctions, will spread out through atrium but can’t get to ventricle because of disk of CT

Question 12

Conduction System - Atrioventricular node?

Answer 12

• between right atrium/ventricula
• when depolarizing input hits it from atrium, it depolarizes
• impulses sent through bundle of his, which will devide into left and right then travel down to apex to Purkinje fibers

Question 13

Conduction System - Bundle of his and Purkinje fibers?

Answer 13

• BoH: specialized for conduction, branches into left and right bundle branches
• Purkinje fibers: heart contracts at apex up to base
• if it contracts base to apex, blood would flow the wrong way

Question 14

Answer 14

Question 15

Cardiac Muscle - gap junctions?

Answer 15

• gap junctions on one cell will align perfectly with next cell - holes for metabolites to pass through
• allows ions to pass from one cell to the next, so depolarization spreads out like a wave
• branching and pores allows heart to beat - depolarize cells in one region, but heart is branched so it spreads out in a wave

Question 16

Cardiac Muscles - papillae? composition?

Answer 16

• papillae: lots of surface area to hold them together - intercalated disks
• single nucleus, cells join end to end

Question 17

Heart Valves

Answer 17

• all valves are on the same plane
• atria and ventricles are separated by connective tissue, in which valves are embedded

Question 18

Ventricular Diastole - valves?

Answer 18

• diastole = relaxed
• Right AV/tricuspid and left AV/mitral/bicuspid OPEN
• aortic and pulmonary semilunar valves closed

Question 19

Ventricular systole - valves

Answer 19

• systole - contraction
• right and left AV vavles closed
• aortic and plumonary semilunar valves open

Question 20

Coronary Sulcus, Anterior Interventricular Sulcus

Answer 20

• coronary: runs around division b/w atriums and ventricles
• anterior IV: depression/indentation where septum is
• dperession covered with fat, not really seen

Question 21

Coronary Sinus

Answer 21

• posterior of heart
• veins draining heart will all be traced here, then goes into right atrium
• rest of body drains into vena cava, then to right atrium

Question 22

Pericardium - parts?

Answer 22

• parietal pericardium: fibrous, outer body wall
• visceral pericardium, aka epicardium: sits tightly against heart
• fibrous attachment to diaphragm from parietal pericardium