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26 Cards in this Set

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COMPOSITION OF BODY
A. 40-50% solutes
B. 50-60% of body = water
1. %water increases with
a. increased skeletal muscle mass
b. decreased fat in body
c. decreased age
2. water is not evenly distributed throughout body
3. body is divided into fluid compartments
FLUID COMPARTMENTS OF THE BODY
A. INTRACELLULAR FLUID COMPARTMENT: cytoplasm
2/3 of all body fluids in this compartment


B. EXTRACELLULAR FLUID COMPARTMENT: outside of cells
1. 1/3 of all body fluids in this compartment
2. considered to be the "internal environment" of body
3. two subcompartments/regions
a. INTERSTITIAL FLUID (80%)
*between tissue cells *eye humors
*cochlear fluid *synovial fluid
*serous fluid *lymph
*cerebrospinal fluid *GI tract secretions

b. PLASMA (20%)
COMPOSITION OF BODY FLUIDS
A. WATER: primary component
B. SOLUTES
1. NON ELECTROLYTES: non-charged particles stable
a. bonds prevent these chemicals from breaking apart in solution
b. primarily organic compounds: glucose, lipids, creatine, urea

2. ELECTROLYTES: charged particles (ions)
a. molecules dissociate into ions (ionize) in water
b. transmit electricity
c. primarily inorganic: salts, acids, bases
d. some organic: acids, bases, proteins

3. Solutes are not evenly distributed due to various sizes, charges, and need for active transport
mechanisms.

4. EXTRACELLULAR FLUIDS VS INTRACELLULAR FLUIDS
a. EXTRA: hi in Na+, Cl-, HCO3-, organic acids
b. INTRA: hi in K+, HPO42-, proteins, Mg+
EXCHANGE BETWEEN COMPARTMENTS
A. Between ICF and ECF
1. passive and active transport of nutrients, gasses and wastes
2. active transport of ions
3. osmosis (passive)
4. Na+ movement generates most water movement (water follows sodium)

B. Between interstitial fluid and Plasma: 2 primary pressures are involved
1. OSMOTIC PRESSURE: large particles draw water towards them
2. HYDROSTATIC PRESSURE: fluid pressing against a wall/membrane
NET EXCHANGE AT CAPILLARY BEDS WITH INTERSTITIAL FLUID
: students are to review
material presented earlier in the blood vessel chapter – presented again in note form)

NFP= (HPc + OPif) - (OPc + HPif) = (forces out of capillaries) - (forces into capillaries)
REGULATED BY TWO TYPES OF PRESSURES
HYDROSTATIC PRESSURE: fluid pressing against a vessel wall

-CAPILLARY HYDROSTATIC PRESSURE (HPc) pr. in cap. forcing fluids out
of caps: varies from arterial to venous ends of cap bed
*arteriole end: HPc = 32 mmHg out of cap.
*venule end : HPc = 15 mmHg out of cap.

-INTERSTITIAL FLUID HYDROSTATIC PR. (Hpif) pr in IF forcing fluid into capillaries: negligible due to removal of fluid by lymphatic system
*Hpif = 0mmHg into cap.

b. OSMOTIC PRESSURE: due to large particles (proteins) that attract water

-CAPILLARY OSMOTIC PRESSURE (Opc) pr drawing fluid into cap due to lg
plasma proteins that could not be filtered out of cap
*OPc = 25mmHg into cap.

-INTERSTITIAL FLUID OSMOTIC PRESSURE (OPif)
pr drawing fluid out of cap to dilute protein in IF (lo [prot.])
*OPif = 3mmHg out of cap.
NET FILTRATION PRESSURE
pr driving blood fluid loss
NFP = pressures out of capillaries - pressures into capillaries

pr out: (arteriole end) HPc + OPif=32 + 3 = 35 mmHg
(venule end) HPc + OPif = 15 + 3 = 18 mmHg

pr in: same for arteriole and venule ends:
HPif + OPc = 0 + 25 = 25 mmHg

NFP arteriole end = 35 mmHg - 25 mmHg = 10 mmHg out of capillaries
NFP venule end = 18 mmHg - 25 mmHg = -7 mmHg out (or +7 mmHg into capillaries)
WATER BALANCE
balance intake, output & movements
A. WATER INTAKE: usually 2500 ml/d: easy to regulate
1. 60% from beverages
2. 30% from food
3. 10% metabolic water: from glycolysis, Kreb's, ETC


B. STIMULATING WATER INTAKE: THIRST MECHANISM
1. decreased plasma volume OR hi osmolarity of plasma
2. dry mouth
3. hypothalamic thirst center
4. thirsty
5. drink
WATER BALANCE
WATER OUTPUT: usually = intake
1. 68% SENSIBLE WATER LOSS: 60% urine, 8% perspiration
2. 28% INSENSIBLE WATER LOSS: thru skin, respiration
3. 4% lost thru feces and used in digestion

D. REGULATING WATER OUTPUT
1. OBLIGATORY WATER LOSS: amount of water you will lose every day no matter how
much you try to conserve ( insensible loss, fecal loss, sensible loss)

2. increases in other types of water loss will decrease urine output

3. 30 minute lag time between fluid input & urine output

4. HORMONES play a big role in regulation of output
a. ADH (dec.) c. ANF (inc.)
b. ALDOSTERONE (dec.) d. RENIN (dec.)
ELECTROLYTE BALANCE
A. ELECTROLYTES: cations (+) and anions (-) which transmit electrical current through water
1. some electrolytes are essential minerals
2. as seen earlier, concentrations of electrolytes are not equal between compartments
3. Na+ is the primary electrolyte involved in water balance

B. INTAKE: thru diet, metabolic activities (catabolic)


C. OUTPUT: thru perspiration, urine, feces
. REGULATION OF ELECTROLYTES
1. HORMONES
a. PTH, CT - Ca+
b. TH - I
c. aldosterone, ADH, estrogen, progesterone, glucocorticoids - Na+

2. Hormonal regulation of Na+
* 90-95% of electrolytes in ECF are NaCl or NaHCO3 -related
* wherever Na+ goes, water will follow, and vice versa (if possible!)
* negative ions will follow the movement of Na+
RENIN-ANGIOTENSIN-ALDOSTERONE
low [solutes] in blood or lo blood volume ->JG cells secrete RENIN into blood->
helps convert angiotensinogen -> angiotensin II ->stimulates ALDOSTERONE ->
increase Na+ reabsorption from urine ->may cause increased water retention if ADH is
present
ADH
hi [Na+] in blood or hi osmolarity in ECF ->stimulate osmoreceptors in hypothalamus ->
stimulates posterior pituitary to release ADH ->influences DCT and CD to increase water
reabsorption->dec. urine production, inc. blood vol, dec. osmolarity
ANF
Hi BP -> atria release ANF -> inhibits Na+ and H2O retention by inhibiting: RENIN,
ADH, ALDOSTERONE, and causing vasodilation
ESTROGENS AND GLUCOCORTICOIDS
act like aldosterone to inc. Na+ reabsorption
PROGESTERONE
blocks aldosterone, dec. Na+ reabsorption
REGULATION OF ELECTROLYTES
ACTIVE TRANSPORT BY KIDNEY TUBULES

4. ELECTRIC AND CONCENTRATION GRADIENTS
a. [hi] -> [lo]
b. opposite charges attract, like charges repel
. ACID-BASE BALANCE
A. pH SCALE: 0 7 14
acidic neutral basic (alkaline)
HI [H+] LO [H+]

1. [H+] affects protein structure and thus affects the rate of most reactions!

2. NORMAL VENOUS BLOOD pH = 7.35 - 7.40
a. BELOW 7.35 = ACIDOSIS
b. ABOVE 7.40 = ALKALOSIS

3. NORMAL ICF pH = 7.0
. ACID-BASE BALANCE
A. pH SCALE: 0 7 14
acidic neutral basic (alkaline)
HI [H+] LO [H+]

1. [H+] affects protein structure and thus affects the rate of most reactions!

2. NORMAL VENOUS BLOOD pH = 7.35 - 7.40
a. BELOW 7.35 = ACIDOSIS
b. ABOVE 7.40 = ALKALOSIS

3. NORMAL ICF pH = 7.0
REGULATION OF NORMAL pH LEVELS
1. CHANGE pH IF CHANGE RESPIRATORY RATE/FUNCTION
carbonic anhydrase
CO2 + H2O <--------------------> H2CO3 <-> H+ + HCO3-

a. increase [H+] -> respiratory acidosis (slow or shallow breathing, obstructions)

b. decrease [H+] -> respiratory alkalosis (fast or deep breathing, anxiety)
CHANGE pH IF CHANGE OTHER METABOLIC RATES/FUNCTIONS
a. increase [H+] -> metabolic acidosis
increased alcohol consumption
loss of HCO3- due to diarrhea
increased lactic, phosphoric, uric acid
increased ketone bodies due to diabetes

b. decreased [H+] -> metabolic alkalosis
excess antacid consumption
constipation
vomiting (loss of H+ from stomach)
. BUFFERS HELP TO MAINTAIN CONSTANT pH
1. combination of a weak acid & the salt of a weak acid (like a weak base) that bind H+ or
release H+ to convert stronger acids & bases into weaker acids and bases to prevent large
swings in pH

2. acidity reflects concentration of FREE H+ in solution

3. DEFINITIONS:
STRONG ACID: dissociates completely in water into H+ and an anion -> big pH change

WEAK ACID: dissociates partially in water -> little pH change, prevents pH change

STRONG BASE: dissociate easily into OH- and cation ties up free H+ -> H2O: big pH change

SALT OF A WEAK ACID (WEAK BASE): dissociate in water: tie up H+, less pH change,
prevent pH change

SALT: in water, will completely dissociate into a cation and an anion (neither H+ nor OH-)
THREE MAIN BUFFER SYSTEMS IN BODY
IN BODY: work together to maintain constant pH, all
essentially work the same way
a. PROTEIN BUFFER SYSTEM
b. PHOSPHATE BUFFER SYSTEM
c. BICARBONATE BUFFER SYSTEM *this is the only important ECF buffer
. BICARBONATE BUFFER SYSTEM
H2CO3 = weak acid of system (carbonic acid)
NaHCO3 = salt of weak acid (weak base) of system (sodium bicarbonate)
in water, these will partially dissociate and act as buffers against strong acids and bases:

a. if add a strong acid, NaHCO3, the "weak base" will act to neutralize the strong acid

strong "weak salt weak
acid base" acid
HCl + NaHCO3 -> NaCl + H2CO3
HI + NaHCO3 -> NaI + H2CO3


b. if add a strong base, H2CO3, the weak acid, will act to neutralize the strong base

strong weak water "weak
base acid base"
NaOH + H2CO3 -> H2O + NaHCO3
KOH + H2CO3 -> H2O + KHCO3
. NECESSITY OF BUFFERS
1. if venous blood pH falls below 7.0 or rises above 8.0 for any length of time ->
DISFUNCTION AND DEATH

2. ACIDOSIS causes decreased nerve transmission in CNS -> DISORIENTATION & DEATH

3. ALKALOSIS causes increased excitability of neurons in CNS and PNS -> MUSCLE
SPASMS, CONVULSIONS, DEATH
COMPENSATION
: physiological responses of lungs, kidneys, and buffers to restore homeostasis

A. RESPIRATORY COMPENSATION: starts within minutes of imbalance, maximal compensation by
lungs within hours

B. METABOLIC COMPENSATION (kidneys): starts within minutes, maximal compensation by
kidneys within a few days

C. BUFFER COMPENSATION: starts immediately, continues as long as have unused buffers available