Cardiovascular System (Chapter 6) Flashcards
Roles of the CV system
- work with all organs and systems
- deliver oxygen and fuel
- remove waste
- circulate hormones and immune components
- regulate temp and acid-base
What does blood flow determine
max capacity for sustained work
Vessels from largest to smallest
- arteries
- arterioles
- capillaries
- venules
- vein
Circulation routes
pulmonary - heart to lungs
peripheral/systemic - heart to whole body
Name the 4 chambers
2 atria’s and 2 ventricles
Name the 4 valves and where they are in the heart
Atrioventricular
tricuspid - right atrium to ventricle
bicuspid - left atrium to ventricle
Semilunar
pulmonary - right ventricle
aortic - left ventricle
Pericardium
tough, membranous sac (encloses the heart)
Blood flow though the heart
- enters right atrium from vena cave
- pumped though tricuspid into right ventricle
- pumped though pulmonary valve into pulmonary artery
- goes to lungs
- enters after lungs though pulmonary veins into left atrium
- pumped though bicuspid into left ventricle
- pumped though aortic valve into aorta
- goes to whole body
2 coronary arteries
- branch off of aorta and on outside of heart
- blood is fully oxygenated
- high BP
Myocardium (heart muscle) contraction and force generation
- high mitochondrial density
- extensive capillary network
- aerobic energy for contraction
Myocardium (heart muscle) intercalated disc
- spread impulse to contract
- transfers AP to adjoining cells
- syncytial contraction (simultaneously)
Myocardium (heart muscle) AP
- long and slow
- Ca+ is stored on outside of cell
Myocardium (heart muscle) thickness
thick chamber wall = great force (contraction)
Myocardium (heart muscle) and regular physical training and chronic hypertension
- inc left ventricle wall thickness and mass
Cardiac cycle (heart beat)
- systole (contraction phase)
- diastole (relaxation/filling phase)
- “lub-dub” sound is valves closing
Bradycardia
< 60 bpm
Normal heart rate
60-100 bpm
tachycardiac
> 100 bpm
Extrinsic Control
nervous system input from medulla oblongata
Extrinsic Control: PSNS
- dec HR
- vagus nerve to SA and AV nodes
- release of acetylcholine limits both
Extrinsic Control: SNS
- inc HR
- cardiac accelerator nerve to SA and AV
- release of norepinephrine speeds both
Extrinsic Control: endocrine glands
- epinephrine from adrenal gland speed HR and inc contractility
Intrinsic Control
- nodes, AV bundle, and bundle branches
Intrinsic Control: sinoatrial (SA nodes)
- pacemaker
- AP starts on own and spreads to all cells
Intrinsic Control: atrioventricular (AV node)
- delays impulse by 1/10th of a sec allowing atria to fill and then contract before ventricle
Intrinsic Control: purkinje fibers
- spreads impulse to contract ventricles
Electrocardiogram
- graphical representation of the hearts electrical activity (intrinsic)
- electrodes are placed on skin record depolarization and repolarization of cardiac muscle fibers
Electrocardiogram axis’s
- y-axis: vertical height of a wave shows amount of electrical activity
- x-axis: horizontal length of the wave represents time
Electrocardiogram circuits
- created between the electrodes and called “leads”
- different angles though the heart
- positive and negative pole
Electrocardiogram circuit poles
- electrical flow towards positive pole = positive deflection
- electrical flow towards negative pole = negative deflection
- the more direct the stronger the deflection
- EKG waves describe each deflection
P wave
depolarization of atria
QRS complex
depolarization of ventricle
Q: septal wall
R: ventricle
S: purkinje fibers
T wave
repolarization of ventricle
proper intrinsic control
duration and intervals between waves
Sinus rhythm
all the waves are present and within time limits
ST depression
- sign of ischemia
- limited blood supply to cardiac muscles causing ST to be sloped (not flat)
Arterial fibrillation
- other cells (not SA node) triggers contraction = atria spasm
- causes inefficient pumping with left over blood in
atria
- causes inefficient pumping with left over blood in
- EKG will have irregular QRS, no P wave, inc HR
Cardiac Arrest
loss of heart function due to dysrhythmia (random rhythm)