Cardiovascular System Flashcards
(200 cards)
The CVS operates via 2 systems:
- Systemic
- Pulmonary
*united by heat
There is high pressure within the:
Left ventricle
Aorta
Systemic capillaries
Systemic circuit
There is low pressure within the:
Systemic capillaries Right atrium Right ventricle Pulmonary circulation Left atrium Left ventricle
Blood pressure is calculated by…
Pressure = Force/Area
Flow is calculated by…
Flow = (Pressure1 - Pressure2) / Resistance
Primary functions of the cardiovascular system?
Delivery of O2 to tissues and cells
Removal of by-products and CO2
Enables metabolism, growth and repair by delivering necessary components to specific parts of the body
Intercalated discs:
Interlocking of adjacent cardiomyocytes
Desmosomes:
Provide strength and anchor membranes together
Gap Junctions:
Allow for signalling with movement of ions between cells
Functional syncytium:
A single unit of electrically-coupled cardiomyoctes
*There are no gap junctions between atrial and ventricular cells.
Atrial and ventricular cells are separated by….
Non-conductive fibrous tissue that surrounds the AV valves
Purkinje fibres:
Modified muscle cells which contract depolarisation more rapidly than muscle cells
Found within ventricular walls and Bundle of His
The AV node generates primary action potentials for heart contractility. T/F
False, SA node
The rate of AP production is limited by ____
how fast Na+ leaks through HCN channels
HCN channels:
Hyperpolarization-activated cyclic nucleotide–gated channels
The AV node generates…
~40-60 AP/min
Ectopic beats:
When conduction to the ventricles causes spontaneously contraction out of sync with the atria.
Ventricular myocytes have no capacity for generating action potentials and their resting membrane potential rests at a stable level until an action potential from arrives from the bundle of His. T/F
True
Ventricular myocytes have no capacity for generating action potentials and their resting membrane potential rests at a stable level until an action potential from arrives from the bundle of His.
This initiates the…
Ventricular action potential –> increase in Ca2+ entry –> contraction of the myocyte.
- Fast Na+channels open, rapidly depolarising the cell.
- This opens L-type Ca2+>channels, as in SA node cells. This Ca2+entry initiates contraction.
- Voltage-gated K+channels open as the Na+and Ca2+begin to close, causing hyperpolarisation and bringing the membrane potential back to its resting level
The ECG measures…
the electrical activity that reaches the skin surface, initiated by a cardiac impulse
Atrial repolarisation is shown on the ECG. T/F
False
Contraction:
Sysole
Relaxation:
Diastole
Lead ll describes the positioning of…
1 lead on the right arm
1 lead on the left leg