Test I (SECTION II) Mechanism of Control of Cardiovascular and respiratory Systems Flashcards
Chemoreceptor
controller of oxidation to the brain, located in aortic/carotid body
Mechanism that controlls Heart Rate
neurohormone & CNS (medulla) regulation
Parasympathetic Vagus Control
neurotransmitter: acetylcholine
vagal control is dominant at rest
sympathetic cardioacceleration neurotransmitters
epinephrine & norepinephrine
Baroreceptor influences
sympathetic discharge indirectly proportional to firing rate
parasympathetic discharge is directly proportional to firing rate (SLIDE)
Atrial Stretch receptors
SLIDE
Chemoreceptor Influences
Main f(x): protect brain from poor perfusion (SLIDE)
Stroke Volume regulated by
Frank Starling Mechanism (more in, more out)
Cardiac output’s main determinant
Body O2 needs
autoregulators for cardiac output
intrinsic change in preload, after load and SV
extrinsic hormonal influences
Blood Pressure influenced by:
total peripheral resistance
chemoreceptor influences
Cardiac Output
Blood Volume
GFR
glomerular filtration rate
Dehydration
loss of body water and associated electrolytes
Causes of Dehydration
gastroenteritis (Vomitting/diarrhea) disease (yellow fever, cholera) excessive alcohol consumption (SLIDE) prolonged exercise without fluid replacement diabetes (hyperglycemia) (SLIDE) shock (blood loss due to injury)
Signs and Symptoms of Dehydration
SLIDE
Treating Dehydration
sip small amounts of water
drink carbohydrate/electrolyte solutions
consider IV for intense core temp.
Skeletal muscle Flow mechanisms
locally auto-regulated
vasodilator metabolites
myogenic response
Vasodilator Metabolites
usually overrides adrenergic neurohormone control
mediated by vasodilator metabolite buildup/removal (SLIDE)
Myogenic response
involves stretch activated Ca channels
negative feedback control (SLIDE)
Systemic blood flow during exercise
sympathetic ouflow & circulating catecholamines
redistribution of blood flow during max exercises
sympathetic ouflow & circulating catecholamines
alpha activation leads to vasoconstriction in non-exercising tissue
redistribution of blood flow during max exercises for: brain, heart, muscle, skin, kidneys, viscera, various other parts
NC in brain heart: increase Muscle: increase (largest) Skin: increase Kidneys: decrease Viscera: decrease (largest) Various other parts: decreas
Minute ventilation =
tidal volume x respiratory rate
generally controlled via central chemoreceptors in medulla-pons respiratory center
Dominant influence on respiration
central chemoreceptors in medulla-pons respiratory center
