BIO 202 Exam 2
List the three main functions of the lymphatic system. - answer1. Fluid recovery
-absorbs plasma proteins and fluid - 10 to 15%- (2 to 4 L/day) from tissues and returns it
to the bloodstream
---interference with lymphatic drainage leads to severe edema
2. Lipid absorption
-Lacteals in small intestine absorb dietary lipids
3. Immunity
-Fluid has to go through lymph nodes on way back to bloodstream where immune cells
stand ready
Why does it matter that the endothelium of capillaries are only one cell layer thick? -
answerSo gas exchange can occur across the membrane easily
Compare and contrast diffusion and osmosis. Draw a couple of pictures if you need to! -
answerDiffusion:
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! - answerPhil (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. - answerCHP: 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! - answer90%
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? - answerInterstitial 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. - answerIncr.
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? - answerTissue 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? - answerExercises, Bandages
Compression garments (socks/TEDS)
Pneumatic compression
Diuretics
, NO CURE
Diagram lymphatic fluid flow from a capillary to a large vein, making sure to indicate
where the pressures are highest and lowest. - answerPressure in lymphatic is always
lower than circulatory system
(HIGH) Blood capillaries -> interstitial fluid -> lymph capillaries -> lymph veins -> lymph
ducts -> large circ. veins (LOW)
Explain the general flow of lymph through the human body. Where are lymphatic
vessels absent? - answerAlways flowing towards the heart
Absent from bones, bone marrow, teeth and CNS
Explain the importance of mini-valves in lymphatic capillaries. - answerCollagen
filaments anchor flaps to connective tissue, so any increase in volume opens valves
When fluid pressure in interstitial space is greater than pressure in lymphatic capillary,
minivalves open the gate - but lymph can't leak back out because increased pressure in
lymphatic capillaries keeps gates closed
Explain the relationship between lymph nodes and cancer metastasis. - answerWhen
tissues are inflamed, lymphatic capillaries develop openings where larger debris and
particles can enter (cancer cells can then travel to other parts of the body)
Goes to lymph nodes where debris is cleansed and other particles are examined
List AND describe the mechanisms of lymph flow. - answerLymph flows at low pressure
and speed
Rhythmic contractions of lymphatic vessels
stretching of vessels stimulates contraction
Skeletal muscle pump
Valves
Rapidly flowing blood in subclavian veins, draws lymph into it
Exercise significantly increases lymphatic return
What are lacteals? Where are they found? What purpose do they serve? - answerAre
special lymphatic capillaries in small intestine
Transport lipids from digestive tract
List the primary and secondary lymphatic organs. - answerPrimary lymphatic organs:
site where T and B cells become immunocompetent (able to fight infection)
red bone marrow and thymus
Secondary lymphatic organs:
lymph nodes, tonsils, and spleen
List AND describe the two basic functions of lymph nodes. - answer1. Act as lymph
filters with macrophages destroying microorganisms and debris
2. Help activate immune system
List the three main functions of the lymphatic system. - answer1. Fluid recovery
-absorbs plasma proteins and fluid - 10 to 15%- (2 to 4 L/day) from tissues and returns it
to the bloodstream
---interference with lymphatic drainage leads to severe edema
2. Lipid absorption
-Lacteals in small intestine absorb dietary lipids
3. Immunity
-Fluid has to go through lymph nodes on way back to bloodstream where immune cells
stand ready
Why does it matter that the endothelium of capillaries are only one cell layer thick? -
answerSo gas exchange can occur across the membrane easily
Compare and contrast diffusion and osmosis. Draw a couple of pictures if you need to! -
answerDiffusion:
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! - answerPhil (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. - answerCHP: 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! - answer90%
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? - answerInterstitial 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. - answerIncr.
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? - answerTissue 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? - answerExercises, Bandages
Compression garments (socks/TEDS)
Pneumatic compression
Diuretics
, NO CURE
Diagram lymphatic fluid flow from a capillary to a large vein, making sure to indicate
where the pressures are highest and lowest. - answerPressure in lymphatic is always
lower than circulatory system
(HIGH) Blood capillaries -> interstitial fluid -> lymph capillaries -> lymph veins -> lymph
ducts -> large circ. veins (LOW)
Explain the general flow of lymph through the human body. Where are lymphatic
vessels absent? - answerAlways flowing towards the heart
Absent from bones, bone marrow, teeth and CNS
Explain the importance of mini-valves in lymphatic capillaries. - answerCollagen
filaments anchor flaps to connective tissue, so any increase in volume opens valves
When fluid pressure in interstitial space is greater than pressure in lymphatic capillary,
minivalves open the gate - but lymph can't leak back out because increased pressure in
lymphatic capillaries keeps gates closed
Explain the relationship between lymph nodes and cancer metastasis. - answerWhen
tissues are inflamed, lymphatic capillaries develop openings where larger debris and
particles can enter (cancer cells can then travel to other parts of the body)
Goes to lymph nodes where debris is cleansed and other particles are examined
List AND describe the mechanisms of lymph flow. - answerLymph flows at low pressure
and speed
Rhythmic contractions of lymphatic vessels
stretching of vessels stimulates contraction
Skeletal muscle pump
Valves
Rapidly flowing blood in subclavian veins, draws lymph into it
Exercise significantly increases lymphatic return
What are lacteals? Where are they found? What purpose do they serve? - answerAre
special lymphatic capillaries in small intestine
Transport lipids from digestive tract
List the primary and secondary lymphatic organs. - answerPrimary lymphatic organs:
site where T and B cells become immunocompetent (able to fight infection)
red bone marrow and thymus
Secondary lymphatic organs:
lymph nodes, tonsils, and spleen
List AND describe the two basic functions of lymph nodes. - answer1. Act as lymph
filters with macrophages destroying microorganisms and debris
2. Help activate immune system
