6.1 - Structures of the Heart Flashcards
Structures in the Heart Wall
1) Pericardium
- double-walled sac that encloses the heart
2) Epicardium - outermost layer
- provides protection and minimizes friction between the heart and pericardial sac
3) Myocardium
- composed of cardiomyocytes that contract to generate force to pump through circulation
4) Endocardium - innermost layer
- composed of connective tissue and endothelial cells
Chambers
Right chamber
- low pressure system
- pump deoxygenated blood into lungs
Left chamber
- high pressure system
- pump oxygenated blood into body
Atria VS. Ventricles
Atria
- smaller and thinner walled
Ventricles
- thicker walled
What are the 3 Great Vessels
1) Superior and Inferior Vena Cava
- blood from body drains into R atrium
2) Pulmonary Artery
- pumps from R ventricle into lungs
3) Aorta
- pumps from L ventricle into body
Function of Valves
- maintain unidirectional flow ensuring blood moves properly through the heart
Atrioventricular Valves
- tricuspid and mitral valve
- AV Valves OPEN during relaxation/diastole (allows blood to flow from atria to ventricles)
- LUB sound: AV valves closing at beginning of systole
Semilunar
- Pulmonic and aortic
- Semilunar valves OPEN during systole (ventricles contract and allow blood to flow into pulmonary artery and aorta)
- DUB sounds: SL valves closing before diastole
Valves To Assess for Cardiac Assessment
All Pigs Eat Too Much
1) Aortic - R 2nd intercostal space, sternal border
2) Pulmonic - L 2nd intercostal space, sternal border
3) Erb’s Point - 3rd intercostal space,
4) Tricuspid - L 4th intercostal space, sternal border
5) Mitral Valve - L 5th intercostal space, mid-clavicular line
Path of Blood Flow
Deoxygenated
1) Body
2) Superio/Inferior Ven Cava
3) right atrium
4) tricuspid valve
5) Right ventricle
6) Pulmonic valve
7) Pulmonic artery
8) Lungs
Oxygenated
1) Lugs
2) Pulmonary veins
3) L atrium
4) mitral valve
5) L ventricle
6) aortic valve
7) aorta
8) systemic circulation
Endocarditis
Cause
- inflammation of hearts inner lining (endocardium)
- bacterial infxn: strep, staph
- risk factors: prosthetic valves, IV use
Patho
- turbulent blood flow damages endothelium
- exposed matrix allows plts and fibrin to deposit
- Bacteria adhere to damaged site = vegetation (fibrin, bacteria, plts)
Changes
- VEGETATION
- emboli - fragments from vegetation can break off
- valve damage
S&S
- heart murmur (valve damage)
- petechia (spots on skin from emboli)
Pericarditis
Cause
- inflammation of pericardium
- viral infxns
- post-myocardial infraction
Patho
- Viral: virus affects pericardial cells = inflammatory response = increased cap permeability = fluid accumulation in pericardial space
- Autoimmune: immune system attacks itself, similar inflammatory process and fluid accumulation
Changes
1)Acute pericarditis
- pericardial effusion (fluid accumulation)= cardiac tompanade (heart fils with blood)
2) Chronic
- pericardial fibrosis and thickening (constrictive pericarditis)
S&S
- pleuritic chest pain
- friction rub
Complications
- pericardial effusion
- tompanade
- Becks triad: hypotension, jugular venous distention, muffle heart sounds)
Aortic Dissection
- tear in aorta causing blood flow bw aortic wall
Cause
- connective tissue disorders that weaken aortic wall
- hypertension (pressure weakens aortic wall)
- astherosclerosis (hardened arteries damage wall)
Patho
- tear in inner layer (intima) creates a false lumen
- can go toward the heart (proximal) or abdomen (distal)
- dissection tears through outer layer (adventitia) and causes a rupture
Changes
- false lumen
- obstructed arterial branches (expanding lumen compresses branches) = ↓ blood to organs
- regurgitation = LV overload
S&S
- tearing chest/back pain
- unequal BP bw arms
- aortic valve regurgitation
- aortic rupture =death
Left Ventricular Hypertrophy
Thickened wall of L ventricle
Cause
- hypertension: chronic pressure increases workload
- aortic stenosis: narrowed aortic valve increased pressure of LV
- hypertrophic cardiomyopathy - genetic thickening of myocardium
Patho
- chronic pressure overload = muscle walls thicken/fibrosis = diastolic dysfunction
Changes
- thickened left wall
- fibrotic tissue
- impaired blood flow causes angina or myocardial infraction
S&S
- risk of heart failure, stroke, arrhythmia
- chest pain, SOB
Down Syndrome and Atrioventricular Septal defects
Cause
- down syndrome
Patho
- abnormal development of endocardial cushions (in fetal development) = impaired fusion of atria/ventricular septa and AV valves
Changes
- failure of septal formation = openings bw atria and ventricle = left to right blood shunting
- malformation of valves causes single AV valve = regurgitation (backflow) of blood
Types
1) complete AVSV
- complete failure of endocardial cushions
- single AV valve
2) partial ASV
- incomplete fusion
- seperate AV Valves
S&S
- partial: asymptomatic
- complete: pulmonary congestion, R heart failure
- heart murmurs
- tachypnea, tachycardia, S3 gallop
Biscuspid Aortic Valve
Cause
- congenital defect where heart has 2 leaflets instead of 3
Patho
- premature degeneration due to mechanical stress
- regurgitation: blood leaks back into ventricle
- aortic stenosis: abnormal valves predisposes it to calcification and narrowing
Changes
- LVH if aortic valve is stenosed
- aorta can enlarge bc of altered blood flow through valve
- bicuspid aortic valve is vulnerable to degradation, calcification, and fibrosis
S&S
- aortic stenosis
-regurgitation
Aortic Stenosis
Cause
- narrowed aortic valve impairs blood flow from L ventricle to aorta
- age-related Ca buildup
- bicuspid aortic valve
Patho
- calcification/thickened valves = narrowed valve = ↑ resistance on LV = LVH = heart failure
Changes
- narrowed aortic valve
- LVH
- enlarged aorta bc of turbulent blood flow
S&S
- angina (chest pain)
- syncope (fainting)
- dyspnea (SOB)
Mitral Valve Prolapse
Cause
- mitral valve leaflets bulge into L atrium during contraction
- connective tissue disorders
- ischemic heart disease
Patho
- thickened/elongated leaflets bulge(prolapse) into atrium = backflow (regurgitation) into L atrium
- regurgitation causes L atrial enlargement
Changes
- bulging leaflets
- dilation of L atrium and L ventricle (working harder to accommodate regurgitation)
S&S
- USUALLY BENIGN and asymptomatic mitral regurgitations: palpitations, fatigue, SOB
- atrial fibrillation (atrial dilation)
- infective endocarditis (abnormal valve structure)
