Unit 1 Lecture 6 Flashcards
How does oxygen and nutrients move throughout the body?
Exits blood in capillaries and travels throughout interstitial fluid (ISF)
how does CO2 and waste travel in the body in relation to oxygen and nutrients?
in opposite directions
What is the blood flow velocity in a capillary?
0.1 cm/sec
What is true about capillary density (or thickness) and is work load?
The greater the work load (metabolic activity), the more dense the capillary
Define the term capillary bed
Network of capillaries
How far are tissue cells from capillaries?
~1-3 cell diameters
Are capillaries thin or thick?
THIN
Why is it important for capillaries to be thin and tissue cells to be close to them?
It’s easier for substances to diffuse into capillaries when they aren’t thick
What are the 3 ways that things can get into capillaries?
- Intercellular clefts
- Endothelial cell membranes
- Fenestrations
Define intercellular clefts
Pores in capillaries
What typically enters capillaries through intercellular clefts?
Water and small substances
What diffuses into capillaries through endothelial cell membranes
Some small molecules and gases
What enters capillaries through fenestrations?
large molecules
What are the 3 type of capillaries?
continuous, fenestrated and sinusoid capillaries
Where are continuous capillaries found?
Lungs, skeletal muscle, and connective tissue
Where are fenestrated capillaries found?
Kidneys, endocrine glands, and small intestine etc
Where are sinusoid capillaries found?
Liver, spleen, bone marrow and anterior pituitary gland
What is active transport?
transport across a membrane that requires energy to get into the cell
What is passive transport
transport that doesn’t require energy to enter or leave a cell
What are the 3 major ways that materials/ ions travel through cells
- Diffusion
- Bulk Flow
- Transcytosis
Define diffusion
movement of molecules/ions from HIGH concentration to LOW concentration until equilibrium is reached
Is diffusion active or passive transport?
passive
Define bulk flow
movement of a fluid from HIGH pressure to LOW pressure
Is bulk flow active or passive transport?
passive
Define transcytosis
movement where macromolecules are captured in vesicles on one side of the cell, taken across the cell, and ejected out the other side
Is transcytosis active or passive transport?
Active
Fluid exchange between ISF and capillaries mainly uses what mode of transport?
Bulk Flow
What are the 2 major forces that pushes fluid OUT of capillaries and into ISF? FILTRATION
- Blood hydrostatic pressure (BHP)
2. Interstitial fluid osmotic pressure IFOP)
What does blood hydrostatic pressure do?
pushes fluid out through the capillary
What does interstitial fluid osmotic pressure do?
PULLS fluid out via osmosis
Does interstitial fluid osmotic pressure have a higher or lower pressure compared to blood hydrostatic pressure?
Smaller pressure
What are the 2 forces that pull fluid INTO capillaries? REABSORPTION
- Blood colloid osmotic pressure (BCOP)
2. Interstitial fluid hydrostatic pressure (IFHP)
What is blood colloid osmotic pressure?
the result of differences in protein concentration between plasma and ISF, which tends to pull water from the ISF and into the capillaries
Define net filtration pressure
The difference in the net movement of fluid between the inward and outward pressures
What are the systems of outward filtration?
Blood hyrdostatic pressure
Interstitial fluid osmotic pressue
What are the systems of inward reabsorption?
Blood colloid osmotic pressure
Interstitial fluid hydrostatic pressure
What is the formula for new filtration pressure?
NFP = outward filtration - inward reabsorption
What are the major factors that determine fluid movement across capillaries?
Blood Hydrostatic pressure
Blood colloid osmotic pressure
What does capillary filtration do?
-> fluid washes over tissue cells @ the arterial end carrying nutrients and oxygen
What does capillary reabsorption do?
-> return of fluid to capillary @ venous end -> deposits wastes into venous end
Does more fluid enter or leave capillaries?
Leaves (3L/day)
Where happens to the excess fluid?
Lymphatic vessels absorb it and return it to the circulatory system
