Week 3 (ch. 12 CVS Disorders) Flashcards
Heart function
The pump for both systems and pulmonary circulations
Left ventricle: anatomy and function
LV is thicker
Eject blood into extensive systemic circulation
How many valves in the heart?
4 valves - ensure one way blood flow
Describe the conduction system of the heart
- Ensure both atria and ventricles contract as desired for efficient filling and emptying
- originates at SA node
- conduction impulses produce electrical activity picked by up electrodes = electrocardiography
- abnormal variations (arrhythmia or dysthymia) may indicate acute problems
Cardiac Control Center: where is it location?
Medulla of the brain
Cardiac Control Center: function
Controls heart rate and force of contraction
Baroreceptors
Detect change in BP
Cardiac Control Center: what does it response through and how
SNS
- increased HR (tachycardia) and contractility
- any stimulation of the SNS (stress, fever, exercise, pain)
PSNS
- decrease HR (bradycardia)
Coronary Circulation: Right and left coronary arteries —> part of what
Systemic circulation
- many small branches extend from these arteries to supply the myocardium and endocardium
** cardiac muscles requires constant supple of o2 but have limited storage ability. Any BF interference affects heart function
Coronary Circulation: Right and left coronary arteries —> where are they
They branch off aorta immediately distal to the aortic valve
Left coronary artery divides into what
Left anterior descending or inter-ventricular artery, Left circumflex artery
Right coronary artery branches into what?
Right marginal artery, Posterior inter-ventricular artery
What is the cardia cycle coordinated by?
Conduction system
Systole: cardiac contract
Diastole: cardiac relaxation
Describe how heart moves through ventricles and atria, starting with Atria relaxed, filling with blood
- Atria relaxed, filling with blood (diastole?)
- AV valves open
- Blood flows into ventricles
- Atria contract, remaining blood forced into ventricles (systole?)
- Atria relax
- Ventricles contract
- AV valve closes
- Semilunar valves open
- Blood into aorta and pulmonary artery
- Ventricles relax
Heart sounds: “lubb-dub”
Heart with stethoscope
“Lubb” = closure of AV valves, ventricular systole
“Dub” = closure of semilunar valves, ventricular diastole
Heart sounds: murmurs - cause
Caused by incompetent valves or hole in septum
Heart sounds: pulse
Indicates heart rate
Pulse deficit
Difference in rate between apical and radial pulses
What is BP
Pressure of blood against the systemic arterial walls
What does BP depend on
Cardiac output and peripheral resistance
Peripheral resistance
Force opposing blood flow
Systolic pressure
Diastolic pressure
Higher number
- pressure entered by blood when ejected from LEFT VENTRICLE
Lower number
- pressure that is sustained when ventricles are relaxed
Pulse pressure
Difference between systolic and diastolic BP
Does LOCAL vasoconstriction affect systemic BP
No