chapter 16- Exam 2 Flashcards
what is the importance of microciruculation
- Important in the transport of nutrients to tissues
* Site of waste product removal
what are arterioles
Small precapillary resistance vessels (10-15μ) composed of an endothelium surrounded by one or more layers of smooth muscle cells
what are the arterioles rich in
Richly innervated by sympathetic adrenergic fibers → vasoconstrict
what do the arterioles regulate
systemic vascular resistance
what are terminal arterioles
metarterioles
what is a metarterioles
precapillary sphincter can be found here
what are precapillary sphincter
no muscular coat, but smooth muscle fibers encircle the vessel at intermittent points
what is a capillary
Composed of single layer of endothelial cells surrounded by a basement membrane
how big are capillaries
Diameter of capillaries is 4-9 microns
—-Rbc ~6-8 microns
how does soulte and water move acorss capillaries
intercellular cleft
plasmalemmal vesicesl
what is an intercellular cleft
space between cells
how do substances transfer across membranes
diffusion
what is diffusion
Most important means by which substances are transferred between plasma and interstitial fluid
what is lipid solubel
substances diffuse directly through cell membrane of capillaries (I.E.CO2, O2)
what is lipid insoluble
substances such as H2O, Na, Cl, glucose cross capillary walls via intercellular clefts
what enhances diffusion across capllaires
differences across capillary enhances
how do water soluble and non lipid soluble move in the body
through the pores
what is the width of capillary intecellular slits
is 6 to 7 nanometers
what is the permeability of capillarys pores
for different substance it will vary according to their molecular diameters
***** capillaries in different tissues have difference in their permeability
what help determine the permeability
the capillary form!!
what are some types of capillaires
Continuous
Fenestrated - kidney
Discontinuous - liver
what is the most common capillary tissue
continuous
– muscle, skin, lung, connective and nervous tissue
what does BM mean abbreviation
Basement membrane (BM)
what does ICJ mean abbreviation
Intercellular junction (ICJ)
what does V mean abbreviation
Vesicles (V)
what does OF mean abbreviation
Open fenestrae (OF)
what does DF mean abbreviation
Diaphragmmed fenestrae (DF)
what does G mean abbreviation
Gap (G)
what is continous tissue
Endothelial cells are continuous, and only allow small substances like water and ions to diffuse through intercellular clefts
what is fenestrated tissue
some have diaphragms – allow small substances and limited protein
Some with no diaphragms – slit pores (kidney)
what is discontinuous tissue
**found in the live
***also called sinusoid
large openings
what do pores have in different organs
they will have special characteristics to meet the peculiar need of the organ
what are liver pores ( pore characteristics )
Large openings so almost all dissolved substances of the plasma, including the plasma proteins, can pass from the blood into liver
what are gastrointestinal pores ( pore characteristics )
Midway between those of the muscles and those of the liver
what are glomerular pores ( pore characteristics )
- Numerous small oval windows called fenestrae
- **Allow large amounts of very small molecular and ionic substances
- *****But not large molecules of the plasma proteins
-To filter through the glomeruli
what is an example of filtration
the kidney
what is the 1st step of kidney filtration
First, filtered substance passes through fenestra in the capillary endothelium (red)
what is the 2nd step of kidney of filtration
Next, pass across the glomerular basement membrane (tan)
- *****BM has collagen fibrils and other structural proteins
- ****This creates small pores that exclude based onsize
what is the last step of kidney filtration
Finally, pass through thefiltration slits (blue and green)
where does substances go when they move from the capillareis
then they enter the interstitium then the cel
what is the interstitium
the space between the cells
what is interstital fluid
fluid in the space between the cells
what are two major types of solid structures in interstitium
collagen fibers
proteoglycan filaments
what is Proteoglycan filaments
—coiled molecules composed of hyaluronic acid
—-Highly Polar – so they attract water
what does the fluid look like in the interstitium
in the form of gell ( fluid proteoglycan mixtures and there is very little free fluid under normal conditions
what is movment across the capillary determined by!!
balance of the forces
look at slide
14– there is some other forces
look at slide
15!!
need to know this pic and the equation
what is capillary hydrostatic pressure
Pc
tends to force fluid outward through the capillary membrane
what creates ↑ Pc
↓arteriole resistance
↑venous pressure
what is flow equal to
pressure / resistance
what is Interstitial fluid pressure
(Pif)-
opposes filtration when value is positive
what is Plasma colloid osmotic pressure
opposes filtration causing osmosis of water inward through the membrane
what is Interstitial fluid colloid pressure
- promotes filtration by causing osmosis of fluid outward through the membrane
what is the net fluid movement across the capillary equation
NFP = ([Pc – Pif] – [Πc – Πif])
what do the capillary hydrostatic pressure number looks like NORMAL
17mmgh ( lower numbers)
what do the Interstitial fluid pressure numbers look like NORMAL
in most tissues is -3 (Encapsulated organs have positive interstitial pressures (+5 to +10 mmHg))
what does a negative interstitial fluid pressure mean
is caused by pumping of lymphatic system
what Colloid osmotic pressure is caused by
presence of large proteins
what are proteins
they are colloids
–Microscopic insoluble particles dispersed in the solvent (plasma, interstitial fluid)
what is the interstitial colloid osmotic pressure numbers look like NORMAL
is about 8 mmhg
what is the plasma colloid osmotic pressure numbers look like NORMAL
about 28 mmhg
what is the osmotic pressure inside the capillary principally determined by
plasma proteins that are relatively impermeable
what is colloid
particle dispersed in a liquid
what is colloid osmotic pressure made up of
75%- albumin
25%- golbulins
how much of the filtered fluid is reabosrbed on the venous end
90%
how much of the filtered fluid is returned to circulation via lymphatics
10%
go to slide
28-33 to look at equations
what is an accessory route for proteins
lymphatic
** a place were the proteins form the interstitial space can to back to the blood
what is important in preventing edem
lymphatic
where can the lymphatics be found
which takes lymph that is derived form interstitital fluid to flows in to the lymphatics
how does the lymphatic help the GI Tract
major route for absorption of nutrients
is the lympth part of immune system
yes
how does the lymphatics work as a pump
=Smooth muscle filaments in lymph vessel cause them to contract
=External compression also contributes to lymphatic pumping
look at slide
36 at the graphs
