Chapter 18 Heart Flashcards
Atria
Small, upper spaces of the heart; right and left paired atria
Ventricles
Large, lower spaces of the heart; right and left paired ventricles
Pulmonary circulation
- Right side of heart
- Thin muscle wall
- Chamber slightly smaller
- Lower pressure
Systemic circulation
- Left side of heart
- Thick muscle wall
- Chamber slightly larger
- High pressure
Artery
Takes blood away from the heart
Vein
Takes blood toward the heart
Deoxygenated
Oxygen-poor
- Arteries of pulmonary circulation
- Veins of systemic circulation
Oxygenated
Oxygen-rich
- Veins of pulmonary circulation
- Arteries of systemic circulation
Pulmonary arteries
-Carry deoxygenated blood from heart to lungs
Pulmonary veins
-Carry oxygenated blood from lungs to heart
Capillary bed
Where gas exchange occurs in lungs and body tissues
Aorta
- Into which the left ventricle discharges blood
- From which all systemic arteries diverge to supply the body tissues
Parietal pleura
-lines the internal surface of the fibrous pericardium
Pericardium
-Double-walled fibroserous sac which encloses the heart
Superior vena cava
-From with the right atrium receives relatively oxygen-poor blood
Fibrous pericardium
- Composed of dense connective tissue
- Lined by the serous parietal pericardium
Epicardium
-closely applied to the heart muscle (also called the visceral epicardium)
Myocardium
- walls of the heart
- composed primarily of cardiac muscle
Endocardium
-thin serous endothelium which lines the ventricles
Pectinate muscles
-Bundles of muscle tissue that form the ridges in the walls of the atrium
Papillary muscle
- Small bundles of cardiac muscle that project from the myocardial wall
- From which the chordae tendineae originate
Chordae tendineae
-tiny white collagenic cords that anchor the cusps of the to the ventricular wall
Trabeculae carnae
-irregular ridges of muscle that mark the internal walls of the ventricular chambers
Bicuspid valve
-Separates the left atrium and ventricle
Tricuspid valve
-Separates the right atrium and ventricle
Semilunar valves
- Composed of three pocketlike cusps
- guard the base of the two large arteries leaving the ventricular chambers
Ligamentum arteriosum
-fibrous remnant of the ductus arteriosus
Intercalated discs
Areas where the cells interdiditate
Desmosomes
- contained in the intercalated discs
- prevent adjacent cells from separating during contraction
Pacemaker potential
-slow depolarization due to opening of Na+ channels and closing of K+ channels
SA node
- located in the right atrial wall
- generate impulses
AV node
- located in the inferior portion of the interatrial septum
- impulses pause here
Pacemaker
the SA node
Internodal pathway
-the pathway that electrical impulses follow
Atrioventricular bundle
-connects the atria to the ventricles
Purkinje fibers
- depolarizes the contractile cells of both ventricles
- also known as the contractile cells of both ventricles
Interventricular septum
-separates the ventricles
EKG
Electrocardiograph; shows electricity in the heart
P wave
Atrial depolarization initiated by the SA node
QRS complex
Ventricular depolarization and atrial repolarization
T wave
Ventricular repolarization
SV
Stroke volume; SV=EDV-ESV
EDV
End diastolic volume; blood that collects in the ventricle during diastole
ESV
End systolic volume, blood that remains in the ventricle after it has contracted
Preload
Degree of stretch of the heart muscle before contraction; affects EDV
Contractility
Contractile strength at a given muscle strength; increases with Ca2+ influx
Afterload
Back pressure exerted by arterial blood; the pressure the ventricles must overcome to eject blood from the heart
Secondary messenger system
- With norepinephrine, cAMP system to catalyze and activate protein kinases
- Affects SR to release Ca2+
- Increased actin-myosin interaction
- increases contractile force
Norepinephrine
Increases heart contractility via a cyclic AMP second-messenger system
Tachycardia
Heart hurry
-Above 100/min
Bradycardia
Slow heart
-Under 60/min
Congestive heart failure
-Pumping efficiency so low that tissue needs are not met
Coronary atherosclerosis
Fatty buildup that clogs the coronary arteries; impairs blood and oxygen delivery
Myocardial infarction
Heart attack; dead cells replaced with noncontractile scar tissue
Dilated cardiomyopathy
-Ventricles stretched out and “flabby”
Pulmonary congestion
When the left side of the heart fails, blood vessels in the lungs become engorged; suffocation
Peripheral congestion
When right side of the heart fails; edema
Edema
Swelling in the tissues due to excess fluid
Ventricular septal defect
Superior part of the interventricular septum fails to form
Coarcation of the aorta
A part of the aorta is narrowed, increasing the work load on the left ventricle
Tetralogy of fallot
Multiple defects
- Pulmonary trunk too narrow
- Ventrical septal defect
- Aorta opens from both ventricles
- Wall of right ventricle thickened
