4. kidney functions A WET BED .
A – maintaining ACID-base balance
W – maintaining WATER balance
E – ELECTROLYTE balance
T – TOXIN removal
B – BLOOD Pressure control
E –ERYTHROPOIETIN making
D – Vitamin D metabolism.

5. FLUID, Electrolyte, and
Acid-Base Balance

6. Introduction
Electrolytes serve various purposes, such as conduction of electrical impulses along cell membranes in neurons and muscles,
Stabilizing enzyme structures, and
Releasing hormones from endocrine glands.

7. IONS IN PLASMA
Contribute to the osmotic balance that controls the movement of water between cells and their environment.
Imbalances of these ions can result in various problems in the body, and therefore their concentrations are tightly regulated.

8. HORMONES HAVE A VERY Important Role in This control
ADH , Aldosterone and Renin/ angiotensin control the water and electrolytes balance and exchange between the renal filtrate and the renal collecting tubule.
Calcium and phosphate are regulated by PTH, calcitrol, and calcitonin.

9. IMPORTANT ELECTROLYTES
Electrolytes in living systems include sodium, potassium, chloride, bicarbonate, calcium, phosphate, magnesium, copper, zinc, iron, manganese, molybdenum, copper, and chromium.
In terms of body functioning, six electrolytes are most important: sodium, potassium, chloride, bicarbonate, calcium, and phosphate.

10. Roles of Electrolytes
These six ions help in nerve excitability, endocrine secretion, membrane permeability, buffering body fluids, and controlling the movement of fluids between compartments.
These ions enter the body through the digestive tract.
More than 90 percent of the calcium and phosphate that enters the body is incorporated into bones and teeth, with bone serving as a mineral reserve for these ions.
In the event that calcium and phosphate are needed for other functions, bone tissue can be broken down to supply the blood and other tissues with these minerals.
Phosphate is a normal constituent of nucleic acids high energy molecules, phosphate buffer system

11. Excretion of ions
occurs mainly through the kidneys, with lesser amounts lost in sweat and in feces.
Excessive sweating may cause a significant loss, especially of sodium and chloride.
Severe vomiting or diarrhea will cause a loss of chloride and bicarbonate ions.
Adjustments in respiratory and renal functions allow the body to regulate the levels of these ions in the ECF.

12. Fluid and Electrolyte Balance
Fluids constitute ~50%–60% of total body composition in which Minerals are dissolved and forming electrolytes
Fluid compartments
Intracellular fluid (ICF)
Extracellular fluid (ECF)

13. Body composition and Fluid Compartments
Distribution of body solids and fluids in an average lean , adult female and male

14. Changes in Water Content with Age
Water content-varies with gender, body mass and age. The percentage of body weight is composed of water. It is generally greater in men than women because men tend to have more lean body mass than women. Fat cells contain less water than an equivalent volume of lean tissue.
One liter of water weights 2.2 lb (1kg). Therefore body weight change is an excellent indicator of overall fluid volume loss or gain. If a pt. D
rinks 240 ml (8oz) there will be a weight gain of 0.5lb (0.24kg), an adult who is fasting might lose 1-2 lbs per day, most in fluids.
Thus, infants and elderly are at a higher risk for fluid related problems than young adults

15. Body Fluid Compartments
In lean adults, body fluids constitute 55% of female and 60% of male total body mass
Intracellular fluid (ICF) inside cells
About 2/3 of body fluid
Extracellular fluid (ECF) outside cells
Interstitial fluid between cell is 80% of ECF
Plasma in blood is 20% of ECF
Includes lymph, cerebrospinal fluid, synovial fluid, aqueous humor, vitreous body, endolymph, perilymph, and pleural, pericardial, and peritoneal fluids

16. Adult males Adult females Other body fluids (≤1%)
Total body composition of adult males and females
WATER 60%
ECF
ICF
Intracellular fluid 33%
Interstitial fluid 21.5%
Plasma 4.5%
Solids 40% (organic and inorganic materials)
Other body fluids (≤1%)
Adult males
SOLIDS 40%
WATER 50%
ECF
ICF
Figure 24 Section 1.1 Fluid and Electrolyte Balance
Intracellular fluid 27%
Interstitial fluid 18%
Plasma 4.5%
Other body fluids (≤1%)
Solids 50% (organic and inorganic materials)
Adult females
SOLIDS 50% 16

17. The solid components of a 70-kg (154-pound) individual with a minimum of body fat
(31.5 kg; 69.3 lbs) Kg
Figure 24 Section.1.2 Fluid and Electrolyte Balance
Proteins
Lipids
Minerals
Carbohydrates
Miscellaneous 17

18. Daily Water Gain and Loss

19. Figure 24.1.1 Fluid balance exists when water gains equal water losses19

20. Sources of Body Water Gain and Loss
Fluid balance related to electrolyte balance
Intake of water and electrolytes rarely proportional
Kidneys excrete excess water through dilute urine or excess electrolytes through concentrated urine
Body can gain water by
Ingestion of liquids and moist foods (2300mL/day)
Metabolic synthesis of water during cellular respiration and dehydration synthesis (200mL/day)
Body loses water through
Kidneys (1500mL/day)
Evaporation from skin (600mL/day)
Exhalation from lungs (300mL/day)
Feces (100mL/day)

21. Regarding Cells ,the basic unit of life we know that
Human cells dwell in salt water.
Their well-being depends on the ability of the body system to regulate the salinity of ECF.
By controlling water intake and excretion, the osmoregulatory system normally prevents the plasma sodium concentration from going outside its normal range (135 to 145 mmol per liter).
Failure of the system to regulate within this range exposes cells to hypotonic or hypertonic stress.

22. The plasma sodium concentration affects cell volume.
The term “tonicity” describes the effect of plasma on cells
— Hypotonicity makes cells swell and
___Hypertonicity makes them shrink.

23. Fluid balance ICF and ECF compartments balance Vary in composition
Are at osmotic equilibrium
Loss of water from ECF is replaced by water in ICF
= Fluid shift
Occurs in minutes to hours and restores osmotic equilibrium
Dehydration
Results in long-term transfer that cannot replace ECF water loss
Homeostatic mechanisms to increase ECF fluid volume will be employed

24. The major factors that affect ECF volume
Water absorbed across digestive epithelium (2000 mL)
Water vapor lost in respiration and evaporation from moist surfaces (1150 mL)
ECF
Metabolic water (300 mL)
Water lost in feces (150 mL)
ICF
Water secreted by sweat glands (variable)
Figure Fluid balance exists when water gains equal water losses
Plasma membranes
Water lost in urine (1000 mL) 24

25. Mineral balance Mineral balance
Equilibrium between ion absorption and excretion
Major ion absorption through intestine and colon
Major ion excretion by kidneys
Sweat glands excrete ions and water variably
Ion reserves mainly in skeleton

26. and ion excretion (primarily at the kidneys)
Mineral balance, the balance between ion absorption (in the digestive tract)
and ion excretion (primarily at the kidneys)
Ion Absorption
Ion Excretion
Ion reserves (primarily in the skeleton)
Ion absorption occurs across the epithelial lining of the small intestine and colon.
Sweat gland secretions (secondary site of ion loss)
Ion pool in body fluids
Kidneys (primary site of ion loss)
Figure Mineral balance involves balancing electrolyte gains and losses
ICF
ECF 26

27. Figure 24.2.2 Mineral balance involves balancing electrolyte gains and losses27

28. Water and sodium balance
Sodium balance (when sodium gains equal losses)
Relatively small changes in Na+ are accommodated by changes in ECF volume
Homeostatic responses involve two parts
ADH control of water loss/retention by kidneys and thirst
Fluid exchange between ECF and ICF

29. The mechanisms that regulate sodium balance when sodium concentration in the ECF changes
ADH Secretion Increases
Recall of Fluids
The secretion of ADH restricts water loss and stimulates thirst, promoting additional water consumption.
Because the ECF osmolarity increases, water shifts out of the ICF, increasing ECF volume and lowering ECF Na concentrations.
Rising plasma sodium levels
Osmoreceptors in hypothalamus stimulated
If one consumes large amounts of salt without adequate fluid the plasma
Na concentration rises temporarily.
HOMEOSTASIS RESTORED
HOMEOSTASIS DISTURBED
Decreased Na levels in ECF
Increased Na levels in ECF
HOMEOSTASIS
Normal Na concentration in ECF
Start
Water balance depends on sodium balance, and the two are regulated simultaneously 29

30. The mechanisms that regulate sodium balance when sodium concentration in the ECF drops
HOMEOSTASIS
Start
Normal Na concentration in ECF
HOMEOSTASIS DISTURBED
HOMEOSTASIS RESTORED
Decreased Na levels in ECF
Increased Na levels in ECF
Osmoreceptors in hypothalamus inhibited
Water loss reduces ECF volume, concentrates ions
ADH Secretion Decreases
Figure Water balance depends on sodium balance, and the two are regulated simultaneously
As soon as the osmotic concentration of the ECF drops by 2 percent or more, ADH secretion decreases, so thirst is suppressed and water losses at the kidneys increase.
Falling plasma sodium levels 30

31. Water and sodium balance
Sodium balance (continued)
Exchange changes in Na+ are accommodated by changes in blood pressure and volume
Hyponatremia (natrium, sodium)
Low ECF Na+ concentration (<136 mEq/L)
Can occur from overhydration or inadequate salt intake
Hypernatremia
High ECF Na+ concentration (>145 mEq/L)
Commonly from dehydration

32. Water and sodium balance
Sodium balance (continued)
Exchange changes in Na+ are accommodated by changes in blood pressure and volume (continued)
Increased blood volume and pressure
Natriuretic peptides released
Increased Na+ and water loss in urine
Reduced thirst
Inhibition of ADH, aldosterone, epinephrine, and norepinephrine release
Decreased blood volume and pressure
Endocrine response
Increased ADH, aldosterone, RAAS mechanism
Opposite bodily responses to above

33. The mechanisms that regulate water balance when ECF volume changes
Responses to Natriuretic Peptides
Combined Effects
Increased Na loss in urine
Reduced blood volume
Increased water loss in urine
Rising blood pressure and volume
Natriuretic peptides released by cardiac muscle cells
Reduced thirst
Reduced blood pressure
Inhibition of ADH, aldosterone, epinephrine, and norepinephrine release
Increased blood volume and atrial distension
HOMEOSTASIS RESTORED
HOMEOSTASIS DISTURBED
Figure Water balance depends on sodium balance, and the two are regulated simultaneously
Falling ECF volume
Rising ECF volume by fluid gain or fluid and Na gain
HOMEOSTASIS
Start
Normal ECF volume 33

34. The mechanisms that regulate water balance when ECF volume changes
HOMEOSTASIS
Start
Normal ECF volume
HOMEOSTASIS DISTURBED
HOMEOSTASIS RESTORED
Falling ECF volume by fluid loss or fluid and Na loss
Rising ECF volume
Decreased blood volume and blood pressure
Endocrine Responses
Combined Effects
Increased renin secretion and angiotensin II activation
Figure Water balance depends on sodium balance, and the two are regulated simultaneously
Increased urinary Na retention
Decreased urinary water loss
Increased aldosterone release
Falling blood pressure and volume
Increased thirst
Increased ADH release
Increased water intake 34

35. Potassium imbalance Potassium balance (K+ gain = loss)
Major gain is through digestive tract absorption
~100 mEq (1.9–5.8 g)/day
Major loss is excretion by kidneys
Primary ECF potassium regulation by kidneys since intake fairly constant
Controlled by aldosterone regulating Na+/K+ exchange pumps in DCT and collecting duct of nephron
Low ECF pH can cause H+ to be substituted for K+
Potassium is highest in ICF due to Na+/K+ exchange pump
~135 mEq/L in ICF vs. ~5 mEq/L in ECF

36. The major factors involved in potassium balance
Factors Controlling Potassium Balance
Approximately 100 mEq (1.9–5.8 g) of potassium ions are absorbed by the digestive tract each day.
Roughly 98 percent of the potassium content of the human body is in the ICF, rather than the ECF.
The K concentration in the ECF is relatively low. The rate of K entry from the ICF through leak channels is balanced by the rate of K recovery by the Na/K exchange pump.
When potassium balance exists, the rate of urinary K excretion matches the rate of digestive tract absorption.
The potassium ion concentration in the ECF is approximately 5 mEq/L.
Figure Disturbances of potassium balance are uncommon but extremely dangerous
KEY
 Absorption
The potassium ion concentration of the ICF is approximately 135 mEq/L.
Renal K losses are approximately 100 mEq per day
 Secretion
 Diffusion through leak channels 36

37. The role of aldosterone-sensitive exchange pumps in the kidneys in determining the potassium concentration in the ECF
The primary mechanism of potassium secretion involves an exchange pump that ejects potassium ions while reabsorbing sodium ions.
Tubular fluid
ECF
The sodium ions are then pumped out of the cell in exchange for potassium ions in the ECF. This is the same pump that ejects sodium ions entering the cytosol through leak channels.
KEY
Figure Disturbances of potassium balance are uncommon but extremely dangerous
 Aldosterone sensitive exchange pump
 Sodium-potassium exchange pump 37

38. Distal convoluted tubule
Events in the kidneys that affect potassium balance
Under normal conditions, the aldosterone-sensitive pumps exchange K in the ECF for Na in the tubular fluid. The net result is a rise in plasma sodium levels and increased K loss in the urine.
Distal convoluted tubule
When the pH falls in the ECF and the concentration of H is relatively high, the exchange pumps bind H instead of K. This helps to stabilize the pH of the ECF, but at the cost of rising K levels in the ECF.
Collecting duct
Figure Disturbances of potassium balance are uncommon but extremely dangerous 38

39. Potassium imbalance Disturbances of potassium balance
Hypokalemia (kalium, potassium)
Below 2 mEq/L in plasma
Can be caused by:
Diuretics
Aldosteronism (excessive aldosterone secretion)
Symptoms
Muscular weakness, followed by paralysis
Potentially lethal when affecting heart

40. Potassium imbalance Disturbances of potassium balance (continued)
Hyperkalemia
Above 8 mEq/L in plasma
Can be caused by:
Chronically low pH
Kidney failure
Drugs promoting diuresis by blocking Na+/K+ pumps
Symptoms
Muscular spasm including heart arrhythmias

41. THANKS

42. Sodium NA At.No. 11 Atomic mass 22.98

43. SODIUM Alkali metal Highly reactive,
Found in combined state, mostly as Salt.

44. The body needs a small amount of sodium to help maintain normal blood pressure and normal function of muscles and nerves.

45. REQUIREMENT
Estimated safe and adequate daily dietary intake Infants 0 – 0.5 yrs 115 – 350mg 0.5 – 1.0yr 250 – 750mg Children 1 – 3 yrs 325 – – 6 yrs 450 – – 10 yrs 600 – – 2700 Adults 1100 – 3300

46. Infants requirement is low because of
Small lean body mass
Composition of feces
Cutaneous losses
Minimum requirement for infants and young children
is about 58 mg/day.

47. Dietary sources Bread Cheese salad egg nuts spinach whole grain
Table salt “NaCl”, added to food
Bread Cheese salad egg
nuts spinach whole grain
In all foods even water.
2.5 grams of salt contain 1gm of Na

48. Human milk contains about 160mg/litre Cows milk contains about 483mg/litre

49. Absorption and Metabolism
Sodium is readily absorbed from ileum
Very little is excreted in feces except in diarrhea

50. Adults maintain sodium balance with little more than What is required by infant.
Kidneys maintain its balance in blood (Homeostasis) under the influence of a hormone “Aldosterone” on renal tubules.
When intake is decreased, aldosterone secretion Increases resulting in decrease of urinary excretion of sodium.

51. Sweat is another major route of Sodium loss
20-50mg/L

52. Distribution 1/3rd of Na is in inorganic portion of skeleton
2/3rd in ECF and is osmoticaly active
(water soluble and exchangeable)

53. Contd.
Total body content = 3800 – 4000 meqt (165 – 174 mg)
ECF = 1750 meqt (76 mg)
Soft tissues = 400 meqt (17.4 mg)
Bone = 1850 meqt (80 mg)

54. Distribution in body / tissue
Whole blood = 70 meqt/L (161 mg/dl)
Plasma = 143 meqt/L (330 mg/dl)
Cells = 37 meqt/L (85 mg/dl)
Muscle tissue = 26 – 70 meqt/L (60 – 160 mg/dl)
Nerve tissue = ~ 140 meqt/L (312 mg/dl)

55. Functions Major cation of ECF
Regulates Acid base balance, in conjunction with Cl / HCO3
It maintains the osmotic pressure of body fluids and protects severe fluid loss from body.
It preserves normal irritability of muscle and permeability of cells.

56. Ions Contributing to Resting Potential
Sodium (Na+)
Chloride (Cl-)
Potassium (K+)
Negatively charged proteins (A-)
synthesized within the neuron
found primarily within the neuron

57. The Neuron at Rest
Ions move in and out through ion- specific channels
K+ and Cl- pass readily
Little movement of Na+
A- don’t move at all, trapped inside

58. Deficiency Diseases or Symptom
When on normal diet  No hyponatermia
Normal range in plasma is 135 – 145 meqt/L
Hyponatermia is mostly secondary to
Injury
Illness (G/E)
Burns
Use of diuretics

59. Deficiency Diseases or Symptom
Adrencorcortical insufficiency (Addison’s disease)
Chronic Renal disease resulting in poor re-absorption of sodium
Cirrhosis / CCF –  serum sodium level, without reduction in total body content of Na.

60. fall in tonicity as well as total volume of plasma Leading to
Severe deficiency results in
fall in tonicity as well as total volume of plasma
Leading to
Muscular cramps  Extremities and abdomen
Headache
Nausea
Dry skin
Reduce sweating
Low urine out put having high specific gravity.

61. These are the conditions When Kidneys respond
Complete re-absorption of filtered sodium
Sodium excretion may fall to 20 meqt. / day or less.

62. Serum Sodium and adrenocortical function:
Hypo-adrenalism 113 meq/L
(Addison’s disease)
Hyper-adrenalism 150 meq/L
(Cushing syndrome)
Normal 135 – 145 meq/L

63. Toxicity Diseases or Symptoms
Hyper natremia may occur as a result of
Rapid administration of sodium salt
Hyper active adrenal cortex
Administration of Cortisone or deoxy cortisone
Dehydration excessive loss of water (Diabetes insipidus)
May cause rise in blood pressure in susceptible individually.