Lecture 2: Water and electrolyte balance

Question 1

Define electrolyte

Answer 1

Compound that when dissolved in water or another solvent, forms or dissociates into ions. Cations (+) and Anions (-)

Question 2

Define non-electrolyte

Answer 2

Uncharged, eg glucose

Question 3

what are the factors of body fluid on cell metabolism/function

Answer 3

Body fluid volume, distribution , composition and osmolality

Question 4

Body Fluid Volume facts
what % is body fluid?
What organs have the MOST and LEAST body fluid?

Answer 4

The total body fluid, or total body water, in an adult man averages approximately 60% of his body weight.

Brain and kidneys have the highest proportions of water, which composes 80–85 percent of their masses. Teeth have the lowest proportion of water, at 8–10 percent.

Question 5

Body fluid distribution areas and how much of the body weight does this take?

Answer 5

1. Intracelluar fluid
   40% bw

2.Extracelluar fluid
20% bw
- interstitial fluid = 15%
-plasma = 5%

Question 6

What is intracellular fluid?

Answer 6

Thisfluidis located within the cell membrane and contains water, electrolytes and proteins.

Question 7

What is extracelluar fluid?

Answer 7

fluids that exists outside of cells of the organism but sealed within the body cavities and vessels. Eg Blood

Question 8

What is interstitial fluid?

Answer 8

thin layer offluidwhich surrounds the body’s cells.

Question 9

What is transcelluar fluid?

Answer 9

small compartment that represents all those body fluids which are formed by the secretion of epithelial cell which includes cerebrospinal, pleural, pericardial, peritoneal.

Question 10

What is fluid movement controlled by?

Answer 10

1. Oncotic pressure/colloid osmotic pressure
2. Hydrostatic pressure
3. Osmosis

Question 11

What is solute movement is controlled by?

Answer 11

Active and Passive transport

Question 12

What are the three forms of osmosis?

Answer 12

1. Isotonic
   The solutions being compared have equal concentration of solutes.

2.Hypotonic
The solution with the lower concentration of solutes.
(dilute, swollen RBC)

3.Hypertonic
The solution with the higher concentration of solutes.
(concentrated, shurken RBC)

Question 13

Define Osmotic Pressure

Answer 13

Osmotic pressure is the pressure exerted to prevent the movement of free solvent molecules across a semi-permeable membrane into a region of high solute concentration.

Question 14

Define Oncotic Pressure

Answer 14

Form of osmotic pressure induced by the proteins, notably albumin, in a blood vessel’s plasma (blood/liquid) that displaces water molecules, moving water back into the circulatory system

Question 15

Define hydrostatic pressure

Answer 15

The force exerted by a fluid against a wall, causes movement of fluid between compartments.

Question 16

How does blood show hydrostatic pressure

Answer 16

The hydrostatic pressure of blood is the pressure exerted by blood against the walls of the blood vessels by the pumping action of the heart.o

Question 17

Hydrostatic vs Oncotic

Answer 17

Thekey differencebetween them is thathydrostatic pressure is the pressure developed by solutes dissolved in water working across a selectively permeable membranewhileOncotic pressure is a part of the osmotic pressure created by the larger colloidal solute components.

Question 18

Active vs passive transport

Answer 18

The movement of some solutes between compartments is active (low conc to high conc), which consumes energy and is an active transport process, whereas the movement of other solutes is passive (high to low conc), which does not require energy.

Active transport allows cells to move a specific substance against its concentration gradient through a membrane protein, requiring energy in the form of ATP

Question 19

Define Osmolality

Answer 19

an estimation of the osmolar concentration of plasma and is proportional to the number of particlesper kilogram of solvent

Question 20

Mechanisms that regulate body fluid (4)

Answer 20

Sensation of thrist
Antidiuretic hormone
Aldosterone
The natriuretic peptide family

Question 21

Sensation of thirst initiated by …

Answer 21

Initiated by the osmoreceptors in hypothalamus that are stimulated by increase in osmotic pressure of body fluids

Also stimulated by a decrease in the blood pressure through the receptor of baroreceptor.

Question 22

Where is Antidiuretic hormone (ADH) produced and location and function

Answer 22

ADH is produced in neuron cell bodies in supraoptic and paraventricular nuclei of the hypothalamus and stored in posterior pituitary in response to increase sodium.

Function
Promote the reabsorption of water in the collecting duct.

Question 23

Aldosterone location and function

Answer 23

Hormone secreted from the zona glomerulosa cells of adrenal cortex

Function
Stimulates kidneys
Retain sodium
Retain water
Excrete potassium

Question 24

The natriuretic peptide family;

what are the 4 peptides?

Answer 24

Atrial natriuretic peptide (ANP)

Brain natriuretic peptide (BNP)

C-type natriuretic peptide (CNP)

Urodilatin

Question 25

Dehydration affect on the brain

Answer 25

In the short term, cerebral shrinkage is mitigated somewhat by movement of extracellular ions into cerebral cells, causing an osmotic intracellular shift of water (water leaves brain) leading to acute changes in memory and attention.

Loss of water from the ECF causes anincrease
in osmolality, which, in turn, causes movement of water from the ICF to the ECF, thus lessening the increase.

Question 26

Factors that shift potassium in or out of cells and description

Answer 26

Insulinconcentrations
Insulinmoves potassium into cells; high concentrations ofinsulinthus lower serum potassium concentration.

Beta-adrenergic activity
Beta-adrenergic agonists, especially selective beta 2-agonists, move potassium into cells, whereas beta-blockade and alpha-agonists promote movement of potassium out of cells.

Acid-base status
Acutemetabolic acidosiscauses potassium to move out of cells, whereas acutemetabolic alkalosiscauses potassium to move into cells.

Question 27

Why women have less water than men if they are the same weight?

Answer 27

The water content of adipose (fat) tissue is less than that of muscle, while women have more adipose tissue at the effect of feminine hormone.

Question 28

Major extracellular and major intracellular ion

Answer 28

Extracellular: Sodium
Intracellular: Potassium