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Human Phys: Integrated cardio

Terms in this set (26)

Hypovolemia
-decrease in intravascular volume due to:
hemorrhage
GI loss (diarrhea, vomiting)
loss from capillaries to interstitium ( burns, anaphylaxis)
renal loss
Circulatory changes from hypovolemia
-decrease in central and peripheral pressure
-decrease in venous return
-decrease in cardiac volume and stroke volume
-arterial hypotension
-reduced blood flow to the cutaneous, splanchnic, and renal circulations
blood loss of atleast 20%
atrial pressure and cardiac output decrease
compensatory response to preserve MAP (fast acting) Baroreceptor reflex
-hypotension
-decreased stretch of baroreceptor
-reduced afferent nerve activity to brain
-increase SNS to heart and peripheral vessel resistance
compensatory response to preserve MAP (fast acting) Chemoreceptor reflex
-hypotension
-impaired perfusion of carotid body
-increased afferent activity to brain
-increase ventilation
-increase SNS activity to the heart and peripheral resistance vessels
Compensatory response to preserve MAP (fast acting) Cardiopulmonary receptor
-hypovolemia
-decrease stretch of atrial receptor
-increase SNS to heart and peripheral resistance vessels
-increase vasopressin
-decrease ANP
compensatory response to preserve MAP (fast acting)
CNS ischemic response
-hypotension
-decrease cerebral perfusion
-ischemia of cardiovascular centers
-Increase SNS to peripheral resistance vessels (at 50% blood loss)
Intermediate compensatory response to preserve MAP: Epinephrine
-increase SNS to adrenal medulla
-increase secretion
-stimulate heart and peripheral resistance vessels
Intermediate compensatory response to preserve MAP:
Renin-Angio-Aldo
-stimulated by hypotension
-increase SNS activity to JG cells
-peripheral vasoconstriction
-increased vascular volume
Intermediate compensatory response to preserve MAP:
Vasopressin
-more than 30% loss
-decreased stretch of atrial receptors
-decreased afferent nerve activity to CNS
-increase vasopressin
-peripheral vasoconstriction
-increased vascular volume
Intermediate compensatory response to preserve MAP:
Capillary fluid shift (500 mL)
-reduced capillary hydrostatic pressure, favors absorption from interstitium to vascular compartment
-increased vascular volume
Intermediate compensatory response to preserve MAP:
Hepatic glycogenolysis
-increased plasma osmolality (20 mOsm)
-water moles from intracellular compartment to extracellular compartment
during hypovolemic shock..
-increase TPR
-decrease organ flow
Long term compensatory response to preserve MAP:
renal fluid system
-hypotension
-enhanced renal absorption of Na+ and water
-increased extracellular fluid volume
Intermediate compensatory response to preserve MAP:
Hepatic albumin synthesis
-increase plasma oncotic pressure
-favors absorption from interstitium to vascular component
-increased vascular volume
Intermediate compensatory response to preserve MAP:
enhanced thirst
Angiotensin II and hypotension
Hypovolemic shock
-can be fatal
-symptoms:
pale skin
cold, sweaty
rapid weak pulse
constricted veins
reduced urine output
MAP normal or low
rapid shallow breathing
mental confusion
inadequate blood flow to peripheral tissues
Non-progressive (compensated) shock
-under 25% of blood loss
-compensation return MAP without outside theraphy
Progressive shock
-severe hypovolemia (over 30% blood loss for 3-4 hours)
-worse until death without therapy shock
-circulatory system deteriorates
-reduced SNS vasoconstrictor outflow
-deleterious positive feedback cycles
Irreversible shock
-30-40% blood loss
-compensatory mechanism exhausted
-no therapy is beneficial
Nonprogressive compensation
-baroreceptor
-release catecholamine
-active renin
-ADH release
-results in tachycardia, peripheral vasoconstrictor, conserve renal fluid
Progressive effects
-wide spread tissue hypoxia
-lactate acidosis
-vasodilation blood pooling
-declined CO
-oligouria
Irreversible effects
-widespread cell injury
-further decreased myocardial contractility
-anuria tubular necrosis
-ischemic bowl, may lead to leakage of bacterial flora
-fluid in lungs (ARDs)
Movement to upright position
-gravity causes shift in blood volume from central to legs
-venous return reduced
-venous pooling
Dynamic exercise
-increase O2 delivery to skeletal muscles
-increase CO2 and ventilation
-metabolic functional vasodilation in active musculature
-the less SVR the more O2 intake
Increased baroreflex
=decreased TPR
=increase Cardiac Output
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