water balance with Na, P, Cl, and pH

Water Distribution in the Body (functions-6)

- chemical reactions

- body temp & regulation

- lube & protect

- solvent & transport medium

- blood volume maintenance

- acid base balance (ABB)

changes to water during growth/aging (3)

- total water decreases

- extracellular decreases

- intracellular increases (within cell)

what factors play a role in the maintenance of fluid balance in the body

- beverages

- liquid in food

- <10% from metabolism

total about 2500ml

what are the components of extracellular fluid

interstitial fluid (intercellular)

plasma/intravascular 

lymph

transcellular fluid 

interstitial fluid =

intercellular

interstitial/intercellular fluid refers to 

fluid surrounding the cell (between cells)

What is the function of interstitial fluid?

directly bathes the cells.

What is the role of interstitial fluid?

It provides a medium for the exchange of nutrients and metabolic products to and from plasma and cells.

What is plasma?

fluid portion of the blood.

intracellular fluid %**

2/3 

extracellular fluid %**

1/3

extracellular is broken up into what 2 groups

interstitial and plasma/intravascular

interstitial fluid % of extracellular fluid **

78%

plasma/intravascular % of extracellular fluid **

22%

most of the water of the body is lost through

urine

smaller amounts of water are lost through (3)

feces, respiratory tract, and skin

AI (water)

adults women: 2.7L

adult men: 3.7L

needs based on activity & energy intake AND VARY

water movement strongly affected by ....

Na in extracellular fluid

movement between interstitial space & extracellular regulated by

osmotic pressure

formaintaintenanceoffluidbalance,movement across capillary blood vessel walls _______________, governed by _____________ & _________

separate plasma from interstitial

differences in hydrostatic pressure & colloidal osmotic pressure

maintenance in fl balance

osmosis

osmolarity

K major cation inside cells

osmosis

Movement of water across semipermeable membrane in response to differences in solute concentrations

osmolarity

solute (particle) concentration of a fl

K major cation inside cells

Na major cation in ECF

arteries maintain a

positive net filtration pressure

veins maintain a

negative net filtration preassure

where is protein found in fl balance?

within plasma & intracellular space

sustaining ECF volume is...

vital to BP & CV system functions

several hormones correct imbalances in fl & Na levels are....

vasopressin

renin-angiotensin-aldosterone system

natriuretic peptides

CV system

vasopressin is a

anti-diuretic hormone

Vasopressin is released by ____ in response to ______

hypothalamus ; slight increases in ECF osmolarity

vasopressin stimulates ...

resorption of water in kidneys & thirst

Vasopressin increases BP by ....

stimulating vasoconstriction of the arterioles

Bowmans capsule is

glomerulus capillary network

the kidney includes

Proximal & distal convoluted tubule

loop of Henle

collecting duct

Glomerulus filters...

water & solutes from the blood

_____ collects the filtrate

Bowman's capsule

Urine composition depends on

1. Filtration through which the glomerular filtrate is formed

2. resorption of filtrated into blood

3. secretion into tubules from capillaries

Renin-angiotensin-aldosterone system (RAAS) enhances ....

Na & Cl resorption

(1) Renin released when....

BP & plasma fl volume are low

(2) Renin then....

hydrolyzes angiotensinogen

angiotensin II increases BP

aldosterone promotes resorption of ___ & excretion of ____ in _____

Na

K

distal tubule

Natriuretic peptides

oppose RASS (ANP & BNP)

promote Na+ & water excretion (lowers BP & volume)

inhibits RAAS ( -> renin -> aldosterone)

Natriuretic peptides increases

GF pressure & GFR

table salt composition

40% Na, 60% Cl

processed foods account for ___ total Na, ~____ form natural sources, ~___ Na added at table/cooking, ~___ from water consumption

75%

10%

15%

<10%

Na AI 19-50yrs

1500mg

Na is the most ...

abundant EC cation

____ on bone surface to be released w/ ___

30% ; hyponatremia

major source is table salt, 1tsp = _____mg

2300

DV for food labels

2400mg

Na linked with ___ in some

HTN

_______ of ingested Na is absorbed, little excreted in ____

95-100% ; feces

Na Absorption initiates from the ___ (__), ___ & ___

stomach (Cl), SI & colon

Na absorption pathway utilizes

Na/glucose co-transport system through the SI

the _____ pathway works in the SI & proximal colon (sodium)

Na/Cl electroneutral

_____ Na absorption occurs in the colon

electrogenic

for blood transport, _____ are kept within a tight range similar to K & Ca

serum Na concentration

For transport in blood, what hormones/enzymes regulate

vasopressin

aldosterone-atrial-natriuretic

renin

angiotensin II

key function of Na: +ions in the ECF to maintain....

osmotic pressure

key function of Na: ___ is the main regulatory hormone associated w/ Na balance

aldosterone

key function of Na: key for retaining ___

body water

key function of Na: Na participates in ....

nutrient absorption

muscle contraction

conduction of nerve impulses

key function of Na: Na creates ...

an electrical potential charge (muscle contraction/conduction)

Na interaction w/ Ca

- high Na = high Ca requirements

- Na influences Ca excretion

Na deficiency

- V/D

- excessive perspiration (lose 2-3% body wt)

- depletion of Na

- cramps, dizziness, shock, coma

- kidneys conserve Na

___-___ of Na intake added to food by individuals

1/3 - 1/2

___-___ of Na added to food by manufacturers

1/2 - 2/3

Na needs

body needs:

minimum:

AI:

DV:

typical intake:

Body needs 100mg/d

Minimum 500mg/d

AI 1500mg/d

DV 2400mg/d

typical intake 3500mg/d

Salt sensitive adults

10-15% adults

high Na leads to high BP

Salt sensitive guidelines

1-1.5g Na/d

all individuals recommended <2.5g/d

K is a ___ in the ICF (intracellular fl) & ___% found inside the cell

+ion ; 95-98%

higher K sources are associated w/

natural & unprocessed foods

K used for

salt substitutes

higher intakes are associated w/

lowering (normalizing) BP

____ of K consumed is absorbed

90%

K absorption takes place primarily in ....

SI, some in colon

K absorption regulated by

aldosterone & kidneys

K passive or facilitated via ___ of the mucosal cell by the ____

apical membrane; K+/H+ ATPase pump

exchange IC __ for luminal ___

H+ ; K+

to enter blood, K ____ in the cell & diffuses across the cell membrane via ____ & maintained by ___

accumulates ; K channel ; Na/K ATPase pump

___ & ____ influence K transport & concentrations

Insulin & catecholamines (epinephrine, norepinephrine, dopamine)

Functions of K

Fluid & electrolyte balance

• Maintenance of pH

• nerve-impulse transmission

• Muscle contraction (smooth and cardiac)

• Decreases urinary excretion of calcium (DASH diet)

K DV

4700mg

Minimum requirement & typical intake of K

minimum; 2000mg/d

typical; 2000-3000mg/d

excess K excreted by

kidneys

K toxicity

Hyperkalemia (high serum K)

- diuretics

- Loss of appetite, cramps, confusion, constipation, irregular heart beat

K deficiency

- alcoholics, anorexia, bulimia

- Loss of appetite, cramps, confusion, constipation, irregular heart beat

Hypokalemia (low serum K)

Cl is the most abundant

-ion for ECF

Cl most important function

electrolyte balance

Cl is obtained from ___ & high intake may ___

salt ; high BP

Cl is a major electrolyte in relation to ...

shift that moves Cl in opposite to bicarbonate across membrane

Cl is absorbed in the

SI & colon

Cl absorbed through ____ (follows __)

Na+ glucose cotransport system (Na)

_______ and the ______ also have chloride accompanied to maintain electric neutrality

Electroneutral co-transport ; electrogenic sodium absorption

Cl formation via

hydrochloric acid

Cl released via _____ to destroy ____

WBC ; foreign substances

Exchange anion for HCO3 in ____, ; contribute to ___

RBC: Cl shift

Cl plays a role in

nerve function (depolarization of ion channels)

Excess Cl is excreted via

GI, kidneys, skin