2nd Year Concepts Flashcards
Which baroreceptors measure stretch due to BP? Where are they located?
High pressure baroreceptors. Located in carotid sinus (main) and aortic arch
Which baroreceptors measure stretch due to volume? Where are they located?
Low pressure baroreceptors. Located in walls of atria and great venous vessels
Describe the bainbridge reflex.
Low pressure receptors in right atriat (detect increase in volume: increased BP)-> message via vagus to CNS -> Sympathetic messaging to myocardium = Increased HR
Describe effect of decreased BP on high pressure Baroreceptors
Decreased BP->Decreased firing of baroreceptors -> CNS->Increased SNS output (Periph. Vasoconstriction, increased contractility, increased HR) and decreased PNS (Increase HR) -> Increased Pressure
What is the myogenic reflex?
Arteriolar smooth muscle responding to passive stretch due to increased BP by myogenically increasing tone (resistance). Opposite happens with a decrease in stretch.
How does the Frank-Starling mechanism occur?
SV is directly linked to end-diastolic volume. As EDV increases, the heart pumps out a greater volume of blood in response, increasing SV.
How is the Frank-starling Law related to headwise G-force?
Acceleration forces blood pooling in lower body and away from the heart. This decreases venous return and therefore EDV. Frank starlings law referes to EDV having a positive relationship with SV, therefor SV decreases in this case.
How is MAP affected by headwise G-force?
Blood to lower body-> Decreased Venouse return -> decreased EDV -> Decreased SV -> Decreased CO -> Decreased MAP
What is a consequence of difficulty breathing on venous return when affected by headwise g-force?
Lack of abdomino-thoracic pump (breathing muscles help create intrathoracic pressure gradient that increases SV
What is Charles Law?
When the pressure on a sample of a dry gas is held constant, the Kelvin temperature and the volume will be in direct proportion (V/T=K)
What is Daltons Law?
Each gas in a mixture exerts its own pressure as if all the other gases were not present.
What is Henrys Law?
The quantity of a gas dissolving in a liquid is proportional to its partial pressure and solubility coefficient
What is Boyles Law
The equation states that the product of pressure and volume is a constant for a given mass of confined gas and this holds as long as the temperature is constant. PV =K
