13456747
Description
Flashcards by J yadonknow, updated more than 1 year ago
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Created by J yadonknow
about 6 years ago
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| Question | Answer |
| What is vasomotion? | spontaneous oscillation in tone of blood vessel walls, independent of heart beat, innervation or respiration |
| Microcirculation capillary BV | Small arterioles - smooth muscle w/ symp. innervation. Term. arterioles - Controlled by local metabolites Pre-capillary sphincters |
| Diagram of capillary network (6) | terminal arteriole Pre-capillary spincters metarterioles true capillaries thoroughfare channels postcapillary venule |
| What is a thoroughfare channel? | Direct connection of metarteriole to venule (skips capillary) |
| Function of pericytes | Stabilise newly formed capillary Maintain BBB Regulate cerebral BF at level of individual capillary |
| What does BBB control? | Movement of ions/solutes btw. continuous capillaries and choroid plexus |
| How do they do this? | Have TJ which prevent movement of hydrophilic solutes Specialised transporters which allow controlled movement across capillary wall |
| Tissues that capillary types found in | Cont. - muscle Fen. - Endocrine gland Discontinous - bone marrow |
| Why can CO2/O2 cross continuous cap? | As they're lipophilic |
| Show a diagram of CO2 X in capillaries | Bicarbonate formation accounts for most of the difference btw. total[CO2] and dissolved [CO2]. |
| What are the four starling forces? | cHSP/iHSP BCOP/ICOP |
| How is bCOP formed? | Colloid proteins, especially albumin, insoluble and too large to cross endothelium Accounts for reabsorption of H2O |
| What happens when edema? | Low protein content BCOP low Excess fluid drained from cap. Leads to excess build-up in tissues |
| Describe fluid movement at arterial side of capillary | cHSP>> iHSF cHSP>>BCOP Net filtration as fluid forced against walls of capillary |
| Why cHSP>> iHSF? | Lymphatic vessels constantly drained into subclavian veins of the neck Low protein content so low HSP |
| What happens at venous side of capillary? | BCOP>cHSP Water drawn in |
| Which is larger, net. filtration or net absorption? | Net absorption, as cHSP > BCOP so inevitable that more fluid will be forced out than drawn back in |
| Transcytosis | Exocytosis of large lipid insoluble compounds into a lipid vesicle by endothelial cells |
| Bulk Flow | Small lipid-insoluble solutes in H2O Direction depends on net filtration pressure derived from 4 Starling Forces |
| What transport do capillaries of BBB use? | Transcellular Transport |
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