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CAPILLARY EXCHANGE - Coggle Diagram

- - - - LEAD TO :-
        
        ARTERIOLAR VASODILATION
        
        Increase exchange between blood & tissue to support increased metabolic activity
        
        Increased capillary blood flow
        
        Increase conc gradient for these material between blood & tissue
        
        Increase delivery of O2 --- more rapid removal of CO2 & metabolites
        
        RELAXATION OF PRECAPILLARY SPHINCTERS
        
        Increase no of open capillaries
        
        Decrease diffusion distance fr cell to open capillary
        
        Increase capillary surface area available for exchange
        
        Increase exchange between blood & tissue to support increased metabolic activity
  - - - CLOSE
        
        Blood bypass the capillary bed & flow only via metarteriole
  - - - FUNCTION
        
        Primary resistance vessels
        
        Determine distribution of CO
        
        Connects artery to capillary
        
        Helps control blood flow into capillary -- by vasoconstration // vasodilation
      - TYPE OF WALLS
        
        Thinner wall than artery
        
        Have 3 layers
        
        Endothelial lining
        
        Smooth muscle tissue
        
        Connective tissue
      - FEATURES
        
        HIGHLY MUSCULAR
        
        WELL INNERVATED WALLS
        
        SMALL RADII
    - - FEATURES
        
        VERY THIN WALLED
        
        LARGE TOTAL CROSS-SECTIONAL AREA
      - FUNCTION
        
        Determine distribution of extracellular fluid between plasma & interstitial fluid
        
        Allow nutrients / gases / waste to be exchange between blood & tissue fluid
        
        Site of exchange
        
        Connects arteriole to venule
      - TYPE OF WALL
        
        Single layer of SQUAMOUS EPITHELIUM
      - OPENINGS
        
        Thin slits -- where endothelial cells overlap
      - EXCHANGE PROCESS
        
        O2 dissolve in MUCOUS LAYER -- diffuse thru alveolar & capillary walls
        
        O2 binds to HB in RBC --> form oxyhaemoglobin
        
        HCO3- ions in blood plasma converted back to CO2 --> diffuse thru barrier
        
        CO2 exchaled
    - - FUNCTION
        
        Passageway fr heart to organs
        
        Pressure reservoir
        
        Carries blood under high pressure fr heart to arterioles
      - TYPE OF WALLS
        
        THICK WALLS
        
        STRONG WALLS W/ 3 LAYERS
        
        Smooth muscle & Elastic connective tissue
        
        Outer layer of connective tissue
        
        ENDOTHELIAL LINING
      - FEATURES
        
        HIGHLY ELASTIC WALLS
        
        LARGE RADII
        
        THICK
    - - FEATURES
        
        Thin walled compared to arteries
        
        Highly distensible
        
        Large radii
      - FUNCTION
        
        Blood reservoir
        
        Carries blood under low pressure fr venule to heart
        
        Passageway to heart fr organs
        
        Valves prevent backflow of blood
      - TYPE OF WALLS
        
        Middle layer more poorly developed
        
        Thinner wall than artery
        
        Some hve flaplike valves
    - - FUNCTION
        
        Connects capillary to vein
      - TYPE OF WALLS
        
        Thinner wall than in arteriole
        
        Less smooth muscle
        
        Less elastic connective tissue
- - - - Depends on conc gradient
      - SUBSTANCES:-
        
        GLUCOSE
        
        AMINO ACIDS
        
        CO2
        
        Diffuse fr body cells --> IF --> blood
        
        HORMONES
        
        O2
        
        Diffuse fr blood --> IF --> body cells
    - - Small quantity of materials -- cross CAPILLARY WALLS
      - Substances in blood plasma --> endothelial cells
        
        BY ENDOCYTOSIS
        
        Then enclosed w/in tiny pinocytic vesicles
        
        Move across cell --> exit on other side
        
        BY EXOCYTOSIS
      - METHOD SUITABLE FOR :-
        
        Large lipid insoluble molecules -- which cant cross capillary wall
        
        ANTIBODIES / PROTEINS
        
        Pass fr maternal circulation --> fetal circulation by transcytosis
        
        INSULIN HORMONE
        
        Enter bloodstream via transcytosis
    - - WHAT IS ??
        
        Passive process
        
        Large no of ions // molecules // particles in fluid move together in same direction
        
        Vol of protein free plasma filters out of capillary mixes w/ surrounding interstitial fluid -- then reabsorbed
        
        Continues as long as pressure difference exist
      - FUNCTION
        
        To regulate relative volume of blood & intrerstitial fluid
      - FILTRATION
        
        Promoted by :-
        
        BLOOD HYDROSTATIC PRESSURE
        
        INTERSTITIAL OSMOTIC PRESSURE
        
        blood hydrostatic pressure -- pushed fluid OUT OF capillaries
        
        movement of solutes / fluids --- fr blood capillaries ---> IF
        
        Fluid exits capillaries d/t hydrostatic pressure > blood colloidal osmotic pressure
      - REABSORPTION
        
        Blood colloid osmotic pressure PULLS FLUID INTO capillaries
        
        Fluid enters capillaries d/t hydrostatic pressure < blood colloidal osmotic pressure
        
        movement of solutes / fluids -- fr IF --> blood capillaries
        
        Promoted by :-
        
        BLOOD COLLOID OSMOTIC PRESSURE
        
        BASICALLY !!
        
        Pressure PUSH FLUID OUT OF CAPILLARIES >>> pressure that PULL FLUID INTO CAPILLARIES
        
        FLUID MOVES FR CAPILLARIES --> IF
        
        FILTRATION !!
        
        Pressure PUSH FLUID OUT OF IF INTO CAPILLARIES >>> pressure PULL FLUID OUT OF CAPILLARIES
        
        FLUID MOVES FR IF --> CAPILLARIES
        
        REABSORPTION !!!
      - REABSORPTION = FILTRATION = NET FILTRATION PRESSURE (NFP)
        
        NFP = ( BHP + IFOP ) - ( BCOP + IFHP )
        
        Indicates -- direction of fluid movement
      - STARLINGS LAW
        
        Vol of fluid / solutes reabsorbed AS LARGE AS vol filtered
        
        excess fluid filtered
        
        go to lymphatic capillaries --> back into blood
        
        few plasma proteins that escape fr blood into IF
      - TYPES OF PRESSURE
        
        INTERSTITIAL FLUID HYDROSTATIC PRESSURE [ IFHP ]
        
        PUSH fluid fr IF --> capilaries
        
        INTERSTITIAL FLUID COLLOID OSMOTIC PRESSURE [ IFOP ]
        
        PUSH fluid fr IF --> capillaries
        
        BLOOD COLLOID OSMOTIC PRESSURE [ BCOP ]
        
        PULL fluid fr IF --> capillaries
        
        BLOOD HYDROSTATIC PRESSURE [BHP]
        
        Push fluid OUT of capillaries --> IF
- - - - Abnormal increase in interstitial fluid volume
    - - Excess filtration
        
        High capillary bp --> more fluid to be filtered out of capillaries
        
        Increase permeability of capillaries --> allows some plasma proteins to escape --> increase IFOP
      - Inadequate reabsorption
        
        Inadequate synthesis // loss of plasma proteins due to :-
        
        liver disease
        
        burns
        
        malnutrition
        
        kidney disease
        
        Decreased conc of plasma proteins --> lower BCOP