Sarah Heart Flashcards
What is dromotropism?
Speed at which conducting electrical current.
What is chronotropism?
Heart rate contractility (frequency of heart cell contraction)
What is inotropism
Force of contraction
What is DCI?
Speed of conduction
Frequency of cell contraction
Force of contraction
Steps of Calcium cardiac contraction
depolorisation leads to Ca influx from outside cell influx in through voltage gated ion channels leads to activation is sarcoplasmic reticulum leading to calcium in sytosol increased. This then then goes to 1 or 2 places.
Either back into ATP production
OR
It will go across the channel to import Na into the cell. One Ca molecule brings in three Na.
This happens in cardiac muscle only, not skeletal muscle contraction (where actin and myosin bind with calcium to form cross bridges).
What is the MAP set point?
93 mmHg (negative feedback loop works to this).
CO =
HR x SV
What organ is long term volume and iron control?
Kidney!
What two things control resistance?
Diameter of vessels and viscosity
What does too-high cell count lead to?
Higher pressure and increased CO
Why do RBC have negative charge?
To pass through capillary
RBC disease effecting equine and feline?
ROULEAUX
Change in protein concentration and shape and charge. Stack up, cannot perfusion through capillaries.
What does lumps, bumps and trunks cause?
Turbulence, which creates resistance, thus equations do not take this into account and only assume smooth flow.
What is velocity?
Inversely proportional to the total cross section area in parallel
This means all capillaries need to be counted together. Pressure needs to stay constant, but at each capillary it has to slow down, so there are many many capillaries, to maintain the arteriole pressure.
What is the dilution technique?
Old gold standard to measure CO. Inject saline into the heart, and measure with sensor downstream. Invasive.
