CHAPTER 16: ANTIHYPERTENSIVES- Intro Flashcards
automaticity is…
the cells within the heart’s electrical system can generate action potential WITHOUT being excited by external stimuli
short answer:
- spontaneously generate ATP without stimulus
conductivity is…
specialized cells of the heart can conduct an impulse rapidly through the system so MUSCLE cells of heart are stimulated at approx SAME TIME
periods of cardiac cycle: diastole vs cardiac cycle
diastole: period of rest, blood RETURNED to heart by veins
(atrial fill with blood)
systole: period of contraction, blood pumped OUT of heart (ventricles pump)
blood flow through pulmonary circulation
right side of heart sends blood to lungs, CO2 and waste removed from blood, O2 picked up by red blood cells
blood flow through systemic circulation
left side of heart sends oxygenated blood OUT to all cells in body
arteries vs veins
arteries are the resistant vessels (diameter determines how much pressure)
veins are the capacity vessels (high ability/capacity to STORE blood)
fluid shift within the cells: 3 types of pressure
(HP) Hydrostatic Pressure: driving force of heart pushes fluid OUT of capillary
(OP) Oncotic Pressure: pressure exerted by plasma proteins pulls fluid INTO capillary
Filtration Pressure: Net force on fluid, determined by balance between HP and OP
what is pos and neg filtration?
positive filtration is fluid LEAVING capillaries (HP)
negative filtration is fluid ENTERING capillaries (OP)
how does fluid shift within cells
goes from arterial end (+ pressure), fluid pulled out of capillary, back into capillary, and then into venous end where fluid is reduced (- pressure)
what is heart failure?
the heart is unable to perform its proper functions:
blood backs up and system becomes congested
- the fluid lost in tissues HP>OP
what are signs of HF/heart failure?
pulmonary edema- left heart fails
(fluid in interstitial spaces)
peripheral and abdominal edema- right heart fails
(right side gets blood from periphery)
systemic arterial pressure: hypotension vs. hypertension
pressure created by left ventricle contraction during systole
hypotension: reduced BP, caused by loss of blood volume or from heart muscle failure
(dec BV, dec BP)
hypertension: high BP, caused by neurostimulation of blood vessels or increase volume in system
(SNS stimulation, inc BP, inc BV)
what determines blood pressure?
blood VOLUME!
venous pressure
- what is it
- what can it result in
the pressure in veins which may rise above normal
- heart not pumping effectively
- result in backup or congestion of blood/decreased outflow
may see cyanosis or hypoxia
congestion in veins: cyanosis or hypoxia
cyanosis: bluish discoloration of skin from poor circulation/ poor oxygenation of blood
hypoxia: no sufficient amount of O2 in tissues
