Transcript iphy 3430 10-25

IPHY 3430 10-25-11
Exchange of materials in capillaries
Diffusion
Bulk Flow
Diffusion:
When the blood reaches the capillaries, many
nutrients, O2, and metabolic end products
diffuse out/in (down concentration gradients)
between the blood and cells.
Cellular utilization or production of materials
causes diffusion gradient to exist between blood
and cells.
Bulk Flow
Plasma (minus most plasma proteins)
is moved by bulk flow out of the capillaries,
moving all water soluble materials to the cells,
and then most of the water is restored back to
the circulation, carrying wastes.
Forces:
Capillary blood pressure (outward)
Plasma colloid osmotic pressure (inward)
beginning
BP = 37
end
COP = 25
37-25 = 12 out
COP = 25
BP = 17
25-17 = 8 in
Lymph circulation picks up the rest
unabsorbed “water” containing wastes, ions, etc
from extracellular fluid space
loose plasma proteins
loose red blood cells
cell debris
pathogens
cancer cells
Lymph flow caused by:
1. Skeletal muscle contraction
2. Smooth muscle contraction in
walls of lymph vessels
3. SNS stimulation to walls of lymph
vessels
Excretory System
Roles:
remove wastes
balance body water content
balance body ionic content
balance acid-base balance
Kidney also regulates RBC’s and secretes
renin as part of regulation of blood pressure
Kidney: by regulating blood water, ionic and
H+ content, can regulate extracellular fluid and
cell water, ionic and H+ content
blood
Extracellular
fluid
Water, ions
and H+
If blood water drops, increase blood ion content, and withdraw
water from extracellular tissues, and then water would leave cell
Plus,…
1. adrenal gland (aldosterone)
2. hypothalamus and posterior
lobe of the pituitary
(vasopressin)
3. Heart atrium (atrial natriuretic
factor)
Fig. 14-3, p. 504
Glomerular filtration
55- (30 + 15) = 10 mm Hg
blood
BP = 55 
COP = 30 
Bowman’s Capsule 15 
How glomerular filtration can be
varied:
Increased blood pressure
65- (30 + 15) = 20 mm Hg
blood
BP = 65 
COP = 30 
Bowman’s Capsule 15 
How glomerular filtration can be
varied:
Dehydration
55- (35 + 15) = 10 mm Hg
blood
BP = 55 
COP = 35 
Bowman’s Capsule 15
Materials filtered into Bowman’s
capsule
Water
Ions
glucose, amino acids
wastes (NH3, urea, etc)
a few plasma proteins
everything else in plasma
hopefully no cells