Special Circulations: Cerebral, Skeletal, Splanchnic, Cutaneous Flashcards
What does autoregulation in cerebral blood flow do?
Ensures that changes in arterial pressure do not dramatically affect CBF
What causes Cushing reflex?
Reduced CBF; used to maintain flow
What do sensory nerves that run with cerebral arteries contain?
Substance P and calcitonin gene related peptide
What do substance P and CGRP cause?
Vasodilation
What do cerebral veins converge into?
Pial plexus
What prevents solutes in blood from accessing brain ECF?
Blood brain barrier
Local production of what cause vasodilation?
Adenosine, CO2, decreasing pH
What are the primary stimulus for vasodilation in SM?
Adenosine, CO2, K+
What is hyperemia?
Excess blood vessels supplying an organ
At rest what controls splanchnic circulation?
Autonomics
After a meal what controls splanchnic circulation?
CNS
What does the enteric nervous system control?
Peristalsis of the intestine; receives sensory info and sends motor from CNS
What does right sided heart failure cause?
Increased CVP and increased filtration by the liver leading to ascites
When do sympathetics cause control cutaneous blood flow?
In regulation of body core temperature
What is cutaneous flow divided into?
Apical
Nonapical
What are glomus bodies?
Arterial-venous anastomoses found in apical skin only
What controls glomus bodies?
Neural control; norepi
What is the function of glomus bodies?
Vasoconstricts in response to cold skin sensors or cold core temperature to conserve heat
Where is apical skin flow found?
Nose, lips, ears, hands and feet
What controls non-apical skin blood flow?
Norepi and acetylcholine
What is the effect of sympathetics on non-apical skin?
Ach to vasodilate
What is the triple response of cutaneous flow and what causes each?
Red reaction: increased cap perfusion from histamine
Flare reaction: spread of redness, dilation of arterioles by axon reflex
Wheal: edema from cap permeability
