Lecture #5 Hemodynamics: Capillary Exchange Flashcards
Oxygen and nutrients move out of the blood by crossing the capillary wall and entering the _____.
Interstitial Fluid (ISF)
Does the Carbon Dioxide and metabolic waste products move in the same or opposite direction?
Opposite Direction
The concentration, or ______, of capillaries in a given tissue is proportional to the tissue’s _______.
density, metabolic activity
What is the capillary bed?
Is a network of capillaries where exchange materials with the tissue cells can take place
Every tissue cell is within ______diameters from a capillary.
2-3 cell
How do the capillary cells move?
Most substance move by diffusion, which is efficient only when diffusion distances are short.
What are the routes for capillary exchange?
Intercellular clefts, endotheliail cell membranes, fenestrations.
Water and most small substances, cross capillary wall by diffusion through these pores is called _______.
Intercellular clefts
Some small molecules and gases can diffuse or be transported across the endothelial cell layer is called______.
Endothelial cell membranes
Large molecules can pass easily through the fenestrations is called _____.
Fenestrations (little window)
What are the two mechanisms used for fluid exchange?
Passive process and active process.
What materials pass through the capillary walls?
Diffusion, bulk flow, and transcytosis.
Movement of molecular or ions from a region of higher concentration to one of lower concentration until equilibrium is reached is called what?
Diffusion
Diffusion: passive or active process?
Passive
Refers to the movement of a fluid from region of higher pressure to one of lower pressure is called what?
Bulk Flow
Bulk flow: passive or active process?
Passive
Substances enter pinocyotic vesicles move to endothelial cells via endocytosis, and exit on opposite side via exocytosis is called what?
Transcytosis
Transcytosis: passive or active process?
Active
Fluid exchange between ISF and capillaries occurs primarily by _____.
Bulk flow
What two forces favor movement of fluid OUT of capillaries and into the ISF?
Blood Hydrostatic Pressure (BHP)
Pushes Fluid through capillary pores is called?
Blood Hydrostatic Pressure (BHP)
‘Pulls’ fluid out via osmosis; this pressure is very small compared to BHP is called?
Interstitial fluid osmotic pressure (IFOP)
What two forces favor movement of fluid out of ISF INTO the capillaries?
Blood Colliod osmotic pressure and Interstital fluid hydrostatic pressure
Differences in protein concentration between plasma and ISF tends to pull water from the ISF and into the capillaries is called?
Blood colloid osmotic pressure (BCOP)
Pressure exerted by interstitial fluid, but it is typically very small is called?
Interstitial fluid hydrostatic pressure (IFHP)
What is Net Filtration Pressure?
Net movement of fluid is driven by the difference between the inward and outward pressure
What is the equation for net filtration pressure?
NFP= (BHP + IFOP) - (BCOP + IFHP)
Push (Filtration) - Pull (Reabsorption)
The ____ and ____ are the principle determiner of fluid movement across the capillary wall.
BHP and BCOP
Results in a constant flow of fluid that washes over the tissue cells at the arterial end of the capillary, carrying nutrients and oxygen with it is called what?
Filtration
What results in a return of fluid to the capillary at the venous end, thereby depositing wastes in the venous system?
Reabsorption
Where does the fluid go when it does not enter the capillaries?
Lymphatic vessels and return to circulation
