Pump it up
True or false: cardiac output (CO) changes only when both SV or HR are changed.
False, CO increases/decreases in response to either HR or SV OR both being changed
What is the name of the graphic recording of the electrical activity of the heart?
ECG or EKG
What are the three main waves/complexes found in an ECG?
P-wave
QRS complex
T wave
What are the three types of capillaries?
1. continuous capillaries
2. fenestrated capillaries
3. sinusoid capillaries
What are the three determinants of resistance in blood vessels?
1. blood viscosity
2. blood vessel length
3. blood vessel diameter
What is the cardiac output equation? ** bonus point: explain what each variable means
CO (amount of blood pumped out by each ventricle in 1 min) = HR (beats/min) x SV (volume of blood pumped each heartbeat)
What does it mean if a cell is depolarizing?
The cell is starting to get more positive, typically due to open sodium channels causing influx of sodium
Explain what is happening when you see a P-wave on an ECG?
depolarization of the SA node and atria
What are the two types of circulation?
1. pulmonary circulation (heart to lungs and back to heart)
2. systemic circulation (long loop to all parts of body and back to heart)
What is a typical/normal BP?
<120/<80 mm Hg
What are the 3 main factors that affect stroke volume (SV)?
Preload: stretched cardiac muscle to help w/ venous return
Contactility: contraction strength at given muscle length (increases = lower end systolic vol.)
Afterload: the amount of pressure the ventricle must overcome to eject blood
what is the pacemaker of the heart?
The SA (sinoatrial) node
Explain what is happening at the QRS complex in an ECG?
venticular depolarization and atrial repolarization
True or false: most veins carry blood away from the heart.
False, most veins carry unoxygenated blood to the heart (except for the pulmonary vein, oxygenated)
What are the three main factors regulating blood pressure?
1. Cardiac output (CO)
2. peripheral resistance (PR)
3. blood volume
Define the following two conditions:
1. Tachycardia
2. Bradycardia
1. abnormally fast HR (>100 beats/min)
2. abnormally slow HR (less than 60 beats/min)
Define this term: gap junctions
relating to conduction of the heart, allow ions to pass from cells (allows the heart to have effective pumping)
Explain what is happening at the T-wave in an ECG?
ventricular repolarization
What controls the rate of blood flow?
extrinsic (sympathetic NS & hormone control) and intrinsic (autoregulation) controls
What is MAP and how is it maintained?
MAP = mean arterial pressure and is maintained by altering blood vessel diameter (alters resistance)
What are some examples of things that can regulate heart rate (HR)?
ex. ANS (sympathetic = emotions/physical stress, norepinephrine release speeds up HR & contractility) (parasympatheic = vagal tone at rest, dominant influence which decreases HR abt 25 beats/min)
Chemicals (hormones & ion concentrations)
Age, gender, exercise, body temp, etc.
explain the 5 steps of electrical conduction in the heart as simple as you can.
1. SA node makes impulses
2. impulse pauses at the AV node
3. the AV bundle connects atria to ventricles
4. bundle branches conduct impulses through the interventricular septum
5. subendocardial conducting network (Purkinje fibers) depolarizes contractile cells of both ventricles
The SA node is the pacemaker of the heart with an inherent rate of around 100 bpm.However, it is tempered by the ANS to around 75 bpm on average. If so, what is likely exerting its effect more - the parasympathetic or sympathetic nervous system?
parasympathetic
What are the two types of valves found in the heart that help control blood flow?
1. Atrioventricular (AV) valve (between atria & ventricle)
2. Semilunar valves (between major arteries and ventricles to prevent backflow)
Where is systemic pressure highest?
near the aorta