Cardiovascular System Flashcards
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 Histamine
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 c
HCN channels:
Hyperpolarization-activated cyclic nucleotide–gated channels
The AV node generates…
~40-60 AP/min
~40-60 AP/min
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:
Systole
Relaxation:
Diastole
Lead ll describes the positioning of…
1 lead on the right arm
1 lead on the left leg