Physiology - Specialised circulations Flashcards
what two intrinsic factors control vascular resistance ?
a. autoregulation, mechanical compression
b. nervous , hormonal
c. perfusion pressure, mechanical compression
c. nervous and autoregulation
a.autoregulation, mechanical compression
the ability of an organ to maintain blood flow despite changes in perfusion pressure in the abscence of extrinsic factors is known as?
a. mechanical compression
b. autoregulation
c. regulatory mechanisms
b.autoregulation
sympathetic activation to the heart results in..
a. vasodilation
b. vasoconstriction
a.vasodilation
increased metabolic activity
vasodilation> SNS vasoconstriction
how much of the cardiac output us dedicated to the coronary blood flow?
a. 10%
v. 5%
c. 2%
d. 15%
v.5%
what condition is most significant in patients with coronary artery disease due to low coronary flow reserve?
a. heart failure
b. tachycardia
c. bradycardia
d. MI
b.tachycardia
true or false local metabolism increase eg lactic acid , hypoxia,k+ leads to vasodilation in skeletal muscle?
a. true
b. false
a.true
Sympathetic noradrenergic vasoconstrictor nerves act on which receptors?
a. a adrenoceptors
b. b2 adrenoceptors
a.a adrenoceptors
adrenaline acts on which receptor in skeletal muscle?
a. a adrenoceptors
b. b2 adrenoceptors
b. b2 adrenoceptors
which nerves are active at the start of excercise and can cause fainting?
a.Sympathetic noradrenergic vasoconstrictor nerves
bparasympathetic noradrenergic vasoconstrictor nerves
c. Sympathetic cholinergic vasodilator nerves
d. Parasympathetic cholinergic vasodilator nerves
c.Sympathetic cholinergic vasodilator nerves
which function does the splanchnic system serve?
a. capacitance
b. conduit
a.capacitance
which nerves act on the splanchnic system in hypotension/ ecercise to increase SV and CO?
a.Sympathetic vasoconstrictor nerves
bparasympathetic noradrenergic vasoconstrictor nerves
c. Sympathetic cholinergic vasodilator nerves
d. Parasympathetic cholinergic vasodilator nerves
a.Sympathetic vasoconstrictor nerves
true or false blood flow through the lungs = cardiac output
a. true
b. false
a.true
which is true of the pulmonary circulation?
a. low compliance and flow, low resistance and pressure
b. high compliance and flow, low resistance and pressure
b.high compliance and flow, low resistance and pressure
what happens to pulmonary vessels in hypoxic conditions to allow for V/Q matching?
a. vasoconstriction
b. venoconstriction
c. vasodilation
a.vasoconstriction
hypothalamus output to sympathetic NS makes up the nervous control of BF to which organ?
a. brain
b. skin
c. lungs
d. splanchnic system
b.skin
decreased O2 in the cerebral blood flow leads to..
a. vasoconstriction
b. venoconstriction
c. vasodilation
c.vasodilation
what happens when MAP in th brain <60 mmHg?
a. syncope
b. stroke
c. oedema
a.syncope
what happens when MAP in th brain <160 mmHg?
a. syncope
b. stroke
c. oedema
c.oedema
how is blood flow in the brain controlled?
a. neural and metabolic
b. metabolic and myogenic
b.metabolic and myogenic
what happens to cerebral vessels when MAP increases?
a. constrict
b. dilate
a. constrict
what happens to cerebral vessels when MAP decreases?
a. constrict
b. dilate
b.dilate
what does functional hyperaemia refer to?
a.active regions of brain giving more sympathetic output
b. inactive regions of the brain receiving increased blood flow
c. active regions of the brain recieving increased blood flow
d. active regions of the brain recieving more sympathetic tone
c.active regions of the brain recieving increased blood flow
what effect does increased intracranial pressure have on cerbral BF?
a. increase
b. decrease
b.decrease
bv compressed
what does an increase in brain volume lead to?
a. oedema
b. hydrocephalus
c. blockage in venous drainage
a.oedema
what does an increase in CSF lead to?
a. oedema
b. hydrocephalus
c. blockage in venous drainage
b.hydrocephalus
what does an increase in cerebral blood volume lead to?
a. oedema
b. hydrocephalus
c. blockage in venous drainage
c.blockage in venous drainage
true or false in stressfu circumstances bf to heart and brain is maintained , reductions occur to other organs
a. true
b. false
a.true
which of these does not act as a defence against venous pooling?
a. baroreceptors
b. muscle pump
c. RAAS
d. Cardiac output
d.Cardiac output
how does fainting occur?
standing up 400ml pools in leg veins fluid accumulation in interstitium decreased venous return decreased SV.CO and BP decreased cerebral BP decreased JVP\decreased cerebral blood flow fainting
what does cerebral BP reduce to in fainting?
a. 30-40 mmhg
n. 20-40 mmhg
c. 40-50 mmhg
n.20-40 mmhg
when cerebral blood flow decreases and paco2 increases what happens to vascular resitance to increase blood flow?
a. increase
b. decrease
b.decrease
what is the correct order of steps for helping someone who has fainted?
a. turn head to side, place horizontally head below heart and legs raised, loosen tight clothing, apply cold moist towel to face and neck, keep warm
b. place horizontally head below heart and legs raised,turn head to side, loosen tight clothing, apply cold moist towel to face and neck, keep warm
c. loosen tight clothing,place horizontally head below heart and legs raised,turn head to side, loosen tight clothing, apply cold moist towel to face and neck, keep warm
b. place horizontally head below heart and legs raised,turn head to side, loosen tight clothing, apply cold moist towel to face and neck, keep warm
