pracentation ku saabsan electrolytes plancy oo aan kajeediyay Bosaso University Fucalt of Clinical Medicine Madada Antomy And Physiology Kurtun Medical Clinic

1. Anatom
y
&
Physiology
UNIVERSIT
Y OF
BOSASO
Bosaso, Puntland State
of Somalia

2. UNIVERSITY OF
BOSASO
 Faculty: Clinical Officer
 Subject: Anatomy & Physiology
 Assignment: Fluid, Electrolyte Balance
 Semester: Two

3. Prepared by
GROUP 6
ΩMohamud Mohamed
Hassan
ΩMohamud Abdullahi
Mohamed
ΩShariif Hassan Abdi
ΩYusuf Aymoy Abdulle
ΩAbdullahi Omar
ΩAli Omar Abukar

4. Fluid, Electrolyte
Balance

5. Body Fluids & Fluid Compartments
Figure 26.1
 Approximately 60% of body weight is H2O.
 Fluid Compartments
 Intracellular fluid (ICF): fluid within the cells
 Extracellular fluid (ECF): fluid outside the cells
 Plasma
 Interstitial fluid (IF)
ICF IF

6. What are electrolytes?????
 An electrolyte is a substance that produces an
electrically conducting solution when dissolved in
water. Electrolytes carry a charge and are essential
for life. All higher forms of life need electrolytes to
survive.
 In our bodies, electrolytes include sodium (Na+
),
potassium (K+
), calcium(Ca2+
), bicarbonate (HCO3
-
),
magnesium (Mg2+
), chloride (C1-
), hydrogen phosphate
(HPO4
2-
) and hydrogen carbonate (HCO3
-
).

7. Body Fluids
 Composition (solutes):
 Electrolytes
 chemical compounds that dissociate in H2O to form ions –
salts, acids, bases
 anything with a charge
 Nonelectrolytes: do not dissociate in H2O (glucose,
lipids, creatinine, urea, etc.)

8. Body Fluids
 Osmosis: the diffusion of a solvent (such as
water) across a semipermeable membrane
 From a less concentrated solution (H2O moves out).
 Toward a more concentrated solution (H2O moves in).
 The solvent (H2O) moves down its concentration
gradient.
 Osmotic activity is based on the number of
particles in solution.

9. Osmotic Activity
 Electrolytes have a greater potential for
osmotic activity than nonelectrolytes
NaCl  Na+
+ Cl-
2 particles
MgCl2  Mg2+
+ 2 Cl-
3 particles
Glucose  Glucose 1 particle
 Electrolytes have the greatest ability to
cause fluid shifts.

10. Electrolyte Concentration
 Electrolyte concentration is an expression of the
number of electrical charges in 1 liter
[expressed as milliequivalents per liter (mEq/L)]
 mEq/L = ion concentration (mg/L) x charge
atomic weight
 Normal plasma levels:
 Na+
: 3300 mg/L x 1 = 143 mEq/L
23
 Ca2+
: 100 mg/L x 2 = 5 mEq/L
40

11. Body Fluids
 Comparison of extracellular
fluid (ECF) and intracellular
fluid (ICF)
 ECF: increased Na+
and
increased Cl-
 ICF: increased K+
and
increased HPO4
2-
Figure 26.2

12. Fluid movement
 Movement between plasma and interstitial fluid (IF) across
capillary membranes
 Hydrostatic pressure in the capillaries pushes fluid into the IF
 Oncotic pressure returns fluid to plasma
 Lymphatic system returns the small remainder to the blood
 Exchanges between IF and ICF occur across the selectively
permeable cell membranes
 H2O flow is conducted both ways
 Ion movement is controlled and restricted
 Ion transport is selective by active transport
IFICF
Figure 26.1

13. Water Balance and ECF Osmolality
 H2O sources / losses
 Sources:
 Intake (~2500 ml/day)
 Metabolic H2O : H2O produced by cell metabolism
 Losses:
 Insensible loss: vaporizes from lungs and skin
 Losses in perspiration and feces
 Urinary losses (~60%)
Figure 26.4

14. Regulation of intake / output
 Intake: Thirst is regulated by the hypothalamic thirst center
 Sensory feedback from dry mouth stimulates the thirst center
 Hypothalamic osmoreceptors lose H2O into hypertonic ECF and
stimulate the thirst center
 Angiotensin II stimulates the thirst center
 Output:
 Kidneys: make short term adjustments to compensate for low intake
 Obligatory H2O loss
 Insensible loss + Sensible loss in urine yields a daily minimum of
500ml
 With a normal diet the kidneys must excrete 900-1200 mOsm of
solute daily
Figure 26.5

15. Figure 26.5

16. Water Balance: Conservation
 ADH
 H2O reabsorption in collecting duct
 Hypothalamic osmoreceptors sense ECF osmolality
and regulate ADH release
 Large decreases in BP trigger ADH release via
signals from baroreceptors
 ADH acts directly and via stimulation of Renin-
Angiotensin system

17. Figure 26.6

18. Disorders of H2O Balance
 Dehydration: H2O loss and/or electrolyte imbalance
 Hypotonic hydration: H2O intake with inadequate
electrolytes; marked by hyponatremia
 Edema: accumulation of fluid in the interstitial space
 Hypoproteinemia: loss of colloid osmotic pressure H2O
leaves plasma, enters IF
 Any event that increases plasma  IF movement or
hinders IF  plasma return

19. Electrolyte Balance: Role of Na+
 Na+
is the most abundant cation in the ECF
 Na+
is the only ECF ion with significant osmotic effect
 Cell membranes are relatively impermeable to Na+
 [Na+
] across the cell membrane may be altered
 Na+
has the primary role in control of ECF volume and
H2O distribution

20. Electrolyte Balance: Role of Na+
 ECF total Na+
content may change but [Na+
] remains stable
because of shifts in water content
 A change in the [Na+
] in plasma will effect; plasma volume,
BP, intracellular fluid volume and interstitial fluid volume.

21. Regulation of Na+
balance
 Regulation of Na+
balance is linked to BP and blood volume
 65% of Na+
is reabsorbed in the PCT
 25% of Na+
is reabsorbed in the ascending limb of the loop of
Henle
 10% remains in DCT and collecting duct filtrate

22. Aldosterone
 ↑ aldosterone :
 Virtually all Na+
is actively
reabsorbed in DCT & collecting
duct (H2O follows Na+
if ADH is
present)
 Renin-Angiotensin system is the
most important trigger of
aldosterone release
 Aldosterone effect occurs slowly
(hours to days)
 Changes in blood will feedback
to modulate the effect of
aldosterone.

23. Cardiovascular Baroreceptors:
Blood Pressure Homeostasis
 Decreased BP leads to:
Constriction of afferent arterioles
Activation of the renin angiotensin system
Release of aldosterone
Release of ADH
Conservation of Na+
Conservation of blood volume
Increased thirst

24. Maintenance of Blood Pressure Homeostasis