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20 Cards in this Set
- Front
- Back
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Extrinsic controlers of arteriolar radius
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1) Neuronal - Symp keeps neruogenic tone w/ NE -
2) Hormonal - catecholamines, angiotensin, vasopressin |
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adrenal meduallary catecholamines
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- release epi (some NE) in response to symp-ex which get B1 in heart - get a-adr at high plasma levels (good for shock in ER)
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angiotensin
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from renal - increase SVR, decrease venous CPL to support MAP at or above normal
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vasopressin
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from posterior pituitary - constrictor - released w/ decreased CVP, hemmorhage, dehydration
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dq/dt (diffusion rate) =
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Perm * SA * [grad/l]
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CFR (cap filtration rate) =
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Kf[(Pc-Pisf)-(COPp-COPisf)]
where COPp and Pc are most imp |
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filtration and resorption w/
COPp and Pc |
if COPp < Pc, filtration
if COPp > Pc, resporption |
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Determinants of ultrafiltration
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1) COP (usually constant)
2) Kf (inflam can change) 3) Pc - directly related ot Pv, but constrict arterioles, decrease Pc |
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Coronary Circulation
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- all caps perfused
- determinants of O2 demand - preload, afterload, CTY, HR - determinants of Q - RV diameter, diastole P and duration (directly) |
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Control of Coronay vascular R and Q
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- Intrinsic - metabolism things like adenosine, CO2, H, NO will dilate - dominates over extrinsic
- Extrinsic - neural things like symp - gets coronary less than others (dont restrict Q!) |
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Cerebral Blood Flow determinants
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- can only increase 2X - must keep CSF, ISF, and BV constant
- Arterial P - main one - Resistance vessels - intrinsic over extrinsic like heart - Intracranial P (inverse) - Venous P not sig - Blood PCO2 (direct) |
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Pulmonary circulation and determinants
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- in series w/ L and R hearts
- low P (no filt), R - high Q, CPL - no myogenic behavior - determined by passive control, PO2, little symp nerves (NE and CATs decrease CPL so higher SV wont cause dilation) |
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SNS in primary MAP reflex
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- increase SVR (consrict) get a to constrict, b to dilate
- constrict VSM to decrease CPL - Gets SA node to increase HR - increase CTY and SV - gets adrenal cells to increase NE |
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PNS in primary MAP reflex
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mainly does HR (only gets SA, atria, and AV - NO his, purkinjie or ventricles) - via vagus that hits muscarine M2
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ABR
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- nerve endings in carotid sinus and aortic arch sense stretch - Af 9 and 10, ef symp and vagus
- increase BP, vagal discharge and decrease symp (for MAP) - takes secondes - MAP decrease -> kidney give out renin and AII, pit does vasopressin - take minutes |
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Cardio Pulmonary Low-P baroreflex (aka Henry-Gauer reflex)
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- supports ABR and regulates BV
- receptors on vena cava and R atrium - fire IRT stretch throught vagus and hit medulla - decrease CVP, and decrease vagus firing - also does ADH and renin for water and Na retention |
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Arterial Chemoreflex
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- 2 MAP reflex
- Peripheral (carotid, aortic) and central (indirect) chemoreceptors sense PO2, PCO2, and Ph and respond w/ RR and symp to change MAP |
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Cerebral Ischemic Reflex
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- 2 MAP reflex
- If MAP below 50, CBF will decrease enought to cause strong symp from medullary vasomotor center |
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Cushing Reflex
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- 2 MAP reflex
- If extravascular intracranial P increases, CBF decreases -> ischemia in medulla -> vasomotor center stium -> symp - signs are high BP, low RR and HR |
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CR stiumlation vs baroreflex stiumlation
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- if both stiumlated, baroreflex dominate
- if CR coupled to baroreflex inhibition, CR will increase symp |
