BIO 202 EXAM 2 COMPREHENSIVE QUESTIONS
AND ANSWERS GRADED A+ PREPARATION
◉ Why does it matter that the endothelium of capillaries are only
one cell layer thick?
Answer: So gas exchange can occur across the membrane easily
◉ Compare and contrast diffusion and osmosis. Draw a couple of
pictures if you need to!
Answer: Diffusion:
Mixing of two or more substances from an area of high
concentration to an area of low concentration to distribute an equal
amount throughout
Perfume in a room
Osmosis:
Diffusion of WATER through a selectively permeable membrane
from a solution of low solute concentration (high water potential) to
a solution with high solute concentration (low water potential)
◉ Describe what osmotic pressure is. Now, explain why hydrostatic
pressure is. Stop! If you don't understand this, then take some time
to go over it again, or else the lymphatic system won't make sense!
,Answer: Phil (albumin/protein in blood) swims through the
capillary - water hangs out with Phil no matter where in the
capillary he is
Phil did not change as he moved through the capillary - he stayed the
same and the water followed him
The osmotic (pulling) pressure is water being pulled into the
capillary
Hydrostatic (pushing) pressure is pushing water out of the capillary
by the pressure in BVs created by the heart - Capillary like a garden
hose with tiny holes in it (doesn't have holes)
Osmotic pressure doesn't change across the capillary because Phil is
the same everywhere
Hydrostatic does change - drops as you get further from the heart -
lowers as you go from arteriole to venule
Filtration - water out of capillaries
Absorption - water into capillaries
◉ Diagram the relationship between CHP, IFHP, COP, and IFOP at the
arteriole and venule end of a capillary.
Answer: CHP: Circulatory Hydrostatic pressure - In capillary - by
heart = CHP (chip) that pushes fluid out
IFHP: Intersitial Fluid Hydrostatic Pressure - pressure by the fluid
that is in the fluid around capillaries (not much - mostly
insignificant)
,COP: Circulatory Osmotic Pressure - pull
IFOP: Interstitial Fluid Osmotice Pressure - trying to pull water out
of the capillary - not that strong - protein trying to pull water out
◉ Does filtration actually ever exactly equal reabsorption? Explain!
Answer: 90% reabsorbed
The interstitial fluid keeps building and building
Lymphatic system deals with remaining 10% that was never
reabsorbed
◉ What exactly is interstitial fluid? Where does it go if it is not
reabsorbed into the capillary?
Answer: Interstitial fluid - space around capillaries filled with fluid
If the capillary does not re-absorb the fluid, the lymphatic system
takes it
◉ List AND describe some causes of edema which were discussed in
class.
Answer: Incr. Capillary filtration (incr. capillary BP or permeability)
Poor venous return
Congestive heart failure - pulmonary edema
, Insufficient muscular activity
Kidney failure (water retention, hypertension)
Histamine makes capillaries more permeable
Decr. Capillary reabsorption
Hypoproteinemia (oncotic pressure blood albumin) cirrhosis,
famine, burns, kidney disease
Obstructed lymphatic drainage
◉ What can edema lead to?
Answer: Tissue necrosis - dead tissue as result of blood vessels
getting smooshed
Pulmonary edema
suffocation
Cerebral edema
headaches, nausea, seizures and coma
Circulatory shock
excess fluid in tissue spaces causes low blood volume and low BP
◉ How is edema treated?
Answer: Exercises, Bandages
Compression garments (socks/TEDS)
Pneumatic compression
AND ANSWERS GRADED A+ PREPARATION
◉ Why does it matter that the endothelium of capillaries are only
one cell layer thick?
Answer: So gas exchange can occur across the membrane easily
◉ Compare and contrast diffusion and osmosis. Draw a couple of
pictures if you need to!
Answer: Diffusion:
Mixing of two or more substances from an area of high
concentration to an area of low concentration to distribute an equal
amount throughout
Perfume in a room
Osmosis:
Diffusion of WATER through a selectively permeable membrane
from a solution of low solute concentration (high water potential) to
a solution with high solute concentration (low water potential)
◉ Describe what osmotic pressure is. Now, explain why hydrostatic
pressure is. Stop! If you don't understand this, then take some time
to go over it again, or else the lymphatic system won't make sense!
,Answer: Phil (albumin/protein in blood) swims through the
capillary - water hangs out with Phil no matter where in the
capillary he is
Phil did not change as he moved through the capillary - he stayed the
same and the water followed him
The osmotic (pulling) pressure is water being pulled into the
capillary
Hydrostatic (pushing) pressure is pushing water out of the capillary
by the pressure in BVs created by the heart - Capillary like a garden
hose with tiny holes in it (doesn't have holes)
Osmotic pressure doesn't change across the capillary because Phil is
the same everywhere
Hydrostatic does change - drops as you get further from the heart -
lowers as you go from arteriole to venule
Filtration - water out of capillaries
Absorption - water into capillaries
◉ Diagram the relationship between CHP, IFHP, COP, and IFOP at the
arteriole and venule end of a capillary.
Answer: CHP: Circulatory Hydrostatic pressure - In capillary - by
heart = CHP (chip) that pushes fluid out
IFHP: Intersitial Fluid Hydrostatic Pressure - pressure by the fluid
that is in the fluid around capillaries (not much - mostly
insignificant)
,COP: Circulatory Osmotic Pressure - pull
IFOP: Interstitial Fluid Osmotice Pressure - trying to pull water out
of the capillary - not that strong - protein trying to pull water out
◉ Does filtration actually ever exactly equal reabsorption? Explain!
Answer: 90% reabsorbed
The interstitial fluid keeps building and building
Lymphatic system deals with remaining 10% that was never
reabsorbed
◉ What exactly is interstitial fluid? Where does it go if it is not
reabsorbed into the capillary?
Answer: Interstitial fluid - space around capillaries filled with fluid
If the capillary does not re-absorb the fluid, the lymphatic system
takes it
◉ List AND describe some causes of edema which were discussed in
class.
Answer: Incr. Capillary filtration (incr. capillary BP or permeability)
Poor venous return
Congestive heart failure - pulmonary edema
, Insufficient muscular activity
Kidney failure (water retention, hypertension)
Histamine makes capillaries more permeable
Decr. Capillary reabsorption
Hypoproteinemia (oncotic pressure blood albumin) cirrhosis,
famine, burns, kidney disease
Obstructed lymphatic drainage
◉ What can edema lead to?
Answer: Tissue necrosis - dead tissue as result of blood vessels
getting smooshed
Pulmonary edema
suffocation
Cerebral edema
headaches, nausea, seizures and coma
Circulatory shock
excess fluid in tissue spaces causes low blood volume and low BP
◉ How is edema treated?
Answer: Exercises, Bandages
Compression garments (socks/TEDS)
Pneumatic compression
