122 final ch12

Define colloid
a substance with large molecules that attract and hold water

uniformly distributed

does not settle

ex. protoplasm of a cell

Define solution
stable mixture of 2 substances

made up of solute, and solvent

Define suspension
Large particles that float in a liquid

Dispersion depends on physical agitation

Define solubility
ease at which a solute dissolves into a solvent
What are factors that influence solubility?
Nature of the solute

Nature of the solvent

Temperature

Pressure

How does temperature influence solubility?
Solubility increases with temperature for solids.

for gases, solubility varies inversely (more gas dissolves in a liquid at lower temperature)

How does pressure influence solubility?
for gases, pressure and solubility are directly related

solids and liquids are not greatly affected

Define dilute
a small amount of solute (a weak solution)

Most solutions in the body are dilute

Define saturated
maximum amount of solute in a solution at a constant temperature
Define super saturated
more solute that solution
Define osmotic pressure
forced produced by solvent particles under certain conditions
What is a semipermeable membrane?
a membrane that allows passage of solvent molecules, but not solute
(diffusion)
What drives particles through a semi-permeable membrane?
osmotic pressure
What influences osmostic pressure
(volume, temperature)
osmotic pressure depend on the number of particles in a solution, but not their charge. (2% solution has twice the amount of osmotic pressure as a 1% solution)

inversely proportional to the volume of a solvent

Varies directly with temperature

Define “tonicity”
osmotic pressure exerted by a solution
How many liters of water does a 150lb man
have?
40L (10.5 gals)
25L inside the cells (6.6 gals)
15L outside the cells (3.9 gals)
Isotonic

Solutions that have equal tonicity

 

(normal saline 0.9%)

Hypertonic
Solutions that have greater tonicity
For example, a 2% NaCl solution
Will draw water out of the cells
Hypotonic
Solutions that have less tonicity
For example, 0.45% NaCl
• Will fill the cells with water
Cation
positive charged + ion
Anion
negetive charged – ion
electrolyte
chemical substance that dissociates into ions when placed into a solution, becoming capable of conducting electricity
Acid
compound that yields H+ (protons)
when placed in an aqueous solution

compound that donates H+

base
compound that yields hydroxyl ions
(OH-) when placed in an aqueous solution

A substance that can inactivate an acid;

Any compound that accepts a H+

What are the seven major electrolytes
– Sodium (Na+)
– Chloride (Cl-)
– Bicarbonate (HCO3-)
– Potassium (K+)
– Calcium (Ca++)
– Magnesium (Mg++)
– Phosphorus (P)
How is water distributed in the body.
intra-cellular (2/3 total body water)
extra-cellular (1/3 total body water)
What 3 sub-compartments is extra-cellular divided into?
intra-vascular water (plasm)5% of body weight

interstitial water 15% of body weight

transcellular fluid (mucus, digestive juices)

Describe the characteristics of water in the human body.
45-80% of body weight is water (depending on age,
weight, gender)
– Lean people have greater water content
– Obese people have less water content
– Men have higher percentage of water than females
(females have higher percentage of adipose tissue)
– Total % body water in infants/children is higher than in
adults (+/- 80% of TBW in newborns is water)
what are prominent electrolytes found in extracellular fluid.
calcium Chloride (Cl-) Bicarbonate (HCo3)
What are prominent electrolytes found in the intracellular fluid

potassium (K+) magnesium (Mg2+) Phosphate (HPo4,2-) Sulfate (SO4,2+)

 

(the cells pms, when theres an eletrolyte imbalance)

How is water lost from the body?
through the skin, kidneys, lungs, and GI tract

water lost from in infant can be twice that of an adult

how much water needs to be replenished in a patient with a fever.
for each degree over 99 (over 24 hours) an additional 1000 ml is required
how much water can be lost through the respiratory tract.
ave/day 200 ml – max/day 1500 ml
Describe the movement of fluids and solutes between capillaries and the interstitial space.

when hydrostatic pressure is greater fluid moves from capillaries to interstitial space.

 

When osmotic pressure is greater, fluid flows from interstial space to capillaries

What is hydrostatic pressure.
pressure exerted by a fluid at equilibrium at a given point within the fluid, due to the force of gravity
Describe factors that affect hydrostatic pressure and what tendency does it have on fluids.
BP, blood volume, gravity
Discuss capillary colloidal osmotic pressure.
“pulling pressure” into a vessel; depends on protein concentration in liquid; higher protein content sucks more fluid into vessel; proteins cannot get out, drawing water towards capillaries
A balance between hydrostatic and osmotic pressure does what?
Keeps water in appropriate compartment
water makes up what % of an individuals body weight?
45-80, depends on weight age gender and adipose tissue
What is the the function of the lymphatic system with regards to fluid movement.
help remove excess fluid from interstitial spaces; very low pressure

how does the alveolar interstitial areas of the lung remain relatively dry.

 

hydrostatic pressure

simple diffusion removes excess fluids from interstitial spaces to lymphatic channels (prevents edema)
What is the NORMAL RANGE FOR SERUM SODIUM
136 – 145 mEq/L
HOW IS SODIUM REABSORPTION IN KIDNEY IS REGULATED:
governed by aldosterone
WHAT IS THE MOST PROMINENT ANION IN BODY
(CL-) *usually excreted with K+ as KCl
NORMAL RANGE FOR SERUM CHLORIDE
98 – 106 mEq/L
NORMAL RANGE FOR BICARBONATE
22 – 26 mEq/L
ROLE OF BICARBONATE IN ACID BASE HOMEOSTASIS
HCO3 is the primary means for transporting CO2 from tissue to the lungs
how do the kidneys react to acute respiratory acidosis and alkalosis.
in acidosis they retain or produce HCO3 to buffer the additional acid caused by CO2 retention in alkalosis the opposite occurs
List the most prominent cation in the intracellular compartment.
Potassium (K+), 98% found in cells

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