Chapter 18 The Heart Flashcards
1
Q
Pulmonary and Systemetic Circuts
A
- Pulmonary Circut) Blood pumps to lungs to remove CO2 and pick up O2
- Right Atrium) Recives blood returning from systemic citcut and delivers to Right ventricle
- Right Ventricle) Pumps blood through the pulmonary Circut.
- Systemic Circut) Pumps blood through the body to deliver O2 and picks up CO2 for the lungs
- Left Atrium) recives blood from pulmonary circut and moves it to the Left ventricle
- Left Ventricle) Pumps blood through the systemic circut.
2
Q
Size, Location and Orentation
A
- About the size of a fist (One pound or so)
- Location
- In mediastinum; between second and fith ribs intercostal space
- Superior surface of diaphragm
- 2/3 of the heart is left of midsternal line
- Base (Posterior Surface) leans toward right shoulder
- Apex) Points toward the left hip
3
Q
Pericardium
A
Double-Walled sac that surrounds the heart
- Superficial Fibrous pericardium) protects heart, anchors surrounding structures, prevents overfilling
- Serous Pericardium (two layers)
- Parietal layer) Lines surface of fibrous pericardium
- Visceral layer (epicardium) on external surface of heart
- Seperated by pericardial Cavity (decreases friction)
4
Q
Pericardial Homestatic Imbalance
A
- Pericardiatis) Inflammation of pericardium
- Pericardial Frictin Rub) creaking sound caused
- Cardiac Tamponade) Excess fluid compresses heart
- Limited pumping ability
- Fluid is drawn from cavity.
5
Q
Layers of the Heart Wall
A
- Epicardium) Visceral (organ) layer of serous pericardium
- Myocardium) Circular bundles of cadriac muscle cells
- Teathered to one another (cardiac skeleton)
- Anchors muscle fibers, supports vessels and calves, keeps AP on specific paths
- Endocardium) continous with lining of blood vessels
- lines heart chambers
6
Q
Atria
A
- Receiving chambers of the heart
- small, thin-walled chambers
- Do not pump blood
- Auricles) Increase atrial volume
- Right Atrium) recives deoxygenated blood from the body
- Anterior portion is smooth walled
- Containes ridges formed by pectinate muscles
- Superior (above diaphragm) and Inferior (below diaphragm) Vena Cava’s and Cornary Sinus (cornary veins) empty blood into the Right artium
- Left Atrium) recives oxygnated blood from lungs
- Mostly smooth muscles with few pectinate muslces
- Four pulmonary veins return blood from the lungs (2 right 2 left)
7
Q
Ventricles
A
- The Pumping chambers of the heart
- Make up most of the hearts volume
- Right Ventricle) most of the anterior surface
- Pumps blood into pumonary trunk
- Left Ventricle) Posteroinferior surface
- Pumps blood into the aorta (largest artery in body)
- Trabeculae Carneae) ridges of muscle on ventricular walls
- Papillary Muscles) Project into the venticular cavity
- Achor chordae tendinae mucles that control valves
- Features
- Thicker walls than atria
8
Q
Heart Valves
A
- Atrioventricular valves) located between atria and ventricles
- Tricuspid Valves) Between Right artium and aorta
- made of 3 cusps (lips)
- Mitral valvue) Between Right artium and aorta
- made of 2 cusps
- Chordae muscles anchor cusps to valves
- Tricuspid Valves) Between Right artium and aorta
- Semilunar (SL) valves
- Pulmonary Semilunor valve) Between right ventricle and pulmonary trunk
- Aortic Semilunar valve) Between left ventricle and aorta.
9
Q
Blood Pathway
A
10
Q
Cornary Circulation
A
Functional Blood suply of the heart itself
- Cornary Artieries
- Both Left and Right
- Arise from base of aorta and supply blood to heart
- Encirrcle heart in coronary sulcus
- Cornary Veins
- Colelct blood from capliary beds
- Cornary Sinus) empties into right atrium (merges with cardiac veins)
11
Q
Cardiac Muscle Cells
A
- Striated, Branched, and connected. have one central nucleus and tons of mitochondria.
- Intercalated Discs) connecting juction between cardiac cells
- Demosomes hold cells togehter and prevent seperation
- Gap junctions allow ions to pass from cell to cell
- Allows heart to be a functional syncytium
- Contraction of Muscle cells is through the action of an Action potential
- Some heart muscle cells are self excitable
- Contractile cells) responsible for contraction
- Pacemaker cells) noncontractile; initate deploraztion and do not need nervous stimulation
- Heart contacts as a unit
12
Q
Cardiac Rythym) Conduction System
A
- AP for heart contraction is iniated by pacemaker cells
- have unstable reting membrane potentials called pacemaker potentials (prepotentials)
- Three steps of an AP
- Pacemaker potential) Inside is more positive (K+ down, Na+ up)
- Depolarization) Ca2+ floods in and causes AP
- Repolarization) K+ floods back in and cell becomes more negative
13
Q
Sequence of Heart Excitation
A
- Sinoatrial (SA) Node
- Pacemaker of heart in right atrial wall
- Depolarizes faster than myocardium so it sets the pace for contraction (sinus rhythm)
- AtrioVentricular (AV) Node
- Delays impulse appozimately .1 of a sec
- Allows atrial contraction before ventricular contraction
- Atriventricular (AV) Bundle
- Eletrical connection between atria and ventrile
- Right and Left Bundle Branches
- Splits into two pathways
- Carry impulses to the apex of the heart
- Subendocardial conducting network (Punkije Fibers)
- Complete pathway and extend into ventricle walls and out of apex
*
- Complete pathway and extend into ventricle walls and out of apex
14
Q
Extrensic innervation of Heart
- Medulla Oblongota
- sympathetic) Up rate and force
- Parasymptahtetic) down rate and force
- Cardioaccelratory Center) Stimulares heart to increace rate and force
- Cardioinhibitory Center) Parasympathetic signals to decrease rate.
A
15
Q
Eletrocardiograph Readings
A
- Singular
- P wave) Depolarization of SA node and Atria
- QRS Complex) ventricular depolarization and atrial repolarization
- T wave) Ventrical repolarization
- Compelxes
- P-R interval) Begining of atrial extiation to begining of ventricular extitation
- S-T segment) entire ventricular myocardium depolarized
- Q-T interval) beginning of ventricular depolarization through ventricular repolarization.
