P5 - Fluids and Vascular Disorders Part 3 Flashcards
how is blood flow controlled by heart and nervous system (3)
- baroreceptors
- left atrial volume receptors
- Osmoreceptors in hypothalamus
role of epinephrine in blood distribution
- acts on B2 receptors -> vasodilation -> increase flow
role of norepinephrine in blood distribution
- acts on A receptors -> vasoconstriction -> reduce flow
vasodilation causes
- hyperemia
- engorgement of arterioles and capillaries
- increased metabolic activity
congestion of vessels
- passive engorgement of vascular bed
- decreased outflow
right-sided heart failure causes what kind of congestion
- hepatic
obstruction of venous outflow as a result of (4)
- neoplastic mass
- inflammatory mass
- displacement of organ
- fibrosis resulting from healed injury
nutmeg liver
- alternating tan (normal) and red (congested) areas
- hypoxia in centrilobular areas
left-sided heart failure causes what kind of congestion
- pulmonary
vessel occlusion results in
- acute infarction of dependent tissue
venous infraction due to
- congested intestinal loops that impinge on vessels and veins
pathogenesis after prolonged ischemia
- ATP degraded to adenosine (potent vasodilator to relieve ischemia) -> blood return causes fluid to move into interstitium -> high tissue pressure -> compression of veins (inhibits local blood return) -> blood vessel hemorrhage -> TF released secondary hemostasis and thrombosis
progression of infraction (tan infracts)
- become tan and pale over time as cells swell and tissue becomes necrotic and blood is forced out of infracted area
types of sock (3)
- cardiogenic
- hypovolemia
- blood maldistribution
cardiogenic shock
- myocardial infraction
- dilated or hypertorphic cardiomyopathy
- outflow obstruction
hypovolemia shock
- low volume due to hemorrhage or fluid loss
types of blood maldistribution shock (3)
- anaphylactic
- neurogenic
- septic
anaphylactic shock
- histamine and other vasoactive mediators released -> vasodilation
- increased vascular permeability
- smooth muscle contraction
neurogenic shock
- electrochock -> autonomic discharges
septic shock
- due to infectious pathogens
stages of shock (3)
- nonprogressive
- progressive (cardiac damage)
- irreversible
clinical signs of chock (6)
- hypotension
- weak pulse
- tachycardia
- hyperventilation with pulmonary rales
- reduced urine output
- hypothermia
nonprogressive stage of shock
- compensatory mechanisms counter decreased blood volume and peripheral pressure
progressive stage of shock
- cardiac damage leads to decreased output, blood pooling and tissue hypoperfusion
irreversible stage of shock
- anaerobic metabolism inhibits cellular enzymes for energy production
- multiorgan failure