22328467
Description
Flashcards by Evian Chai, updated more than 1 year ago
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Created by Evian Chai
over 5 years ago
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| Question | Answer |
| What is included in the microcirculation? | 1. Terminal arterioles 2. Capillaries 3. Post-capillary venules |
| What are atrioventricular anastomoses's, and what is their role in temperature regulation? | 1. Wide vessels found in dermis 2. Vasoconstrict to prevent heat loss when SNS increases 3. Vasodilate in response to lowered SNS shunts blood to dermal plexus and promotes heat loss |
| What is the tone of the terminal arterioles controlled by? | No innervation, local factors determine |
| How was capillaries/post capillary venules able to constrict without SM? | Pericytes |
| How is excess fluid/protein absorbed and transported back? What route does it take back to blood? What do microorganisms get transported to? | 1. Absorbed by lymphatic capillaries 2. Returns to blood via subclavian vein 3. Lymph glands |
| What are the three types of capillaries? Where are they found? | 1. Continuous - Skeletal muscle, myocardium, skin, lung, connective tissue 2. Fenestrated - Kidney, intestine, mucosa, joints 3. Discontinuous - Bone marrow, spleen, liver |
| Continuous capillaries: - Continuous thin layer of ...cells surrounded by membrane - .... for quick and easy exchange of gas and solutes - ...within endothelial cells that limit passage of substances - ... that can cause constriction or relaxation | 1. 1-3 endothelial cells 2. Small diffusion distance 3. Tight junctions 4. Pericytes |
| Fenestrated capillary: - Endothelium perforated by ... (Except glomerulus) - ....within endothelium that allows .... to go through more easily | 1. Fenestrations 2. Small holes, water |
| Discontinious capillary: - ....gaps - Located in places where ... - Basement membrane has .... to allow cells to go through - that show the gaps | 1. Large endothelial 2. Cells need to be transported 3. Small gaps 4. Small invaginations |
| How do gases move across capillary walls? What is their rate of diffusion? | Move across the plasma membrane via diffusion Fast |
| How do small solutes (eg. salts) move across the capillary wall? What is their rate of diffusion? | 1. Intercellular junctions 2. Fenestrae when present Fast diffusion |
| How does water move across the capillary wall? What is their rate of diffusion? | 1. 90% by intercellular junctions 2. 10% via water channels in the plasmalemma Fast |
| How do proteins move across the capillary wall? What is their rate of diffusion? | 1. Transcytosis (taken in vesicles) Very slow, carried by water |
| What is the purpose of the blood brain barrier? What is blocked? What is freely transported? | 1. Prevent diffusion of hydrophilic solutes into brain to maintain constant extracellular composition 2. salts, glucose, amino acids, etc. need transport processes 3. Gases |
| What is filtration? | Movement of water across capillary wall |
| What are the two determinants of fluid filtration? | 1. Hydrostatic pressure (driving force out) - more pressure at arterial than venous side 2. Oncotic pressure - opposes hydrostatic pressure - more proteins inside capillary, so some water drawn back in |
| How does standing impact pressure in the capillaries? | 1. Increase pressure in lower region, increased filtration (eg. feet swelling) 2. However reflexes quickly cause vasoconstriction, decrease the increase 3. This causes net fluid absorption |
| How does high venous pressure impact filtration? (common in heart failure) | 1. High filtration rate overwhelms lympathic system, leading to oedema |
| What is the structure of the lymphatic system, starting from fluid from blood capillary going to the lymphatic capillary? | 1. Lymphatic capillary 2. Afferent Lympathic 3. Lymph node 4. Efferent Lympathic 5. Thoracic duct 6. Subclavian vein |
| How does a decreased oncotic pressure gradient lead to oedema? What is this caused by? | Increased fluid leaves microcirculation, leads to local swelling This is caused by inflammation, wherein histamine induces vasodilation/increased flow OR break in tight junctions allowing proteins to leave |
| What causes increased hydrostatic pressure and how does this lead to oedema? | Congestive heart failure increases Central Venous Pressure due to decreased CO This increases pulmonary/systematic pressure in capillary More fluid leaves capillary |
| What is Elephantiasis and what does it cause? | 1. a nematode worm impairs lympathic system so fluid cannot be removed 2. Oedema |
| What is Starling's Equation? | (hydrostatic Pressure in capillary-hydrostatic pressure in interstitium)- (oncotic pressure in capillary-oncotic pressure in interstitium) |
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