Body fluid compartments

Question 1

What is the water percentage in baby, male and female?

Answer 1

baby-80%
male-60%
female-50%

Question 2

What percentage of water is gained from metabolism?

Answer 2

10%

Question 3

What percentage of water is lost in urine and faeces?

Answer 3

Urine-60%

Faeces- 40%

Question 4

What are the 4 different sources of water to the body? How much water does each source supply?

Answer 4

1. Ingested water (2 liters)
2. Liver and pancreatic secretions ( 2 liters)
3. salivary gland secretions (1.5 liters)
4. Stomach and small intestines secretions (3.5 liters).

Question 5

What are the 3 different sources of water loss in the body? How much water does each source loose?

Answer 5

Small intestines absorbs ~ 8.5 liters
Colon (400ml)

feces (100 ml)

Question 6

Where is most of the water in the body located?

Answer 6

Intracellular fluid (40%)= other, plasma, interstitial 
Extra (20%)

Question 7

Which ions are high in the extracellular fluid and plasma? Which is the major cation and anion?

Answer 7

In order
Na+ Cation
Cl- Anion
HC0- 3 Anion

Question 8

Which ions are high in the intracellular fluid?

Which is the major cation and anion?

Answer 8

K+ Cation
PO4 3- Anion
Protein anions (also a little in plasma)

Question 9

What is the normal plasma osmolality?

What is the normal urine osmolality?

Answer 9

280-300 mOsm/Kg

500and 800 mOsm/Kg (24h urine test)
Randon- 50-1400

Question 10

What is the effect of hydro-static pressure?

Answer 10

Moves water moves from the blood plasma into the interstitial fluid

Question 11

What is the effect of osmotic pressure?

Answer 11

Moves water from interstitial fluid into the blood plasma

Question 12

Which two compartments make up extracellular fluid?

Answer 12

Interstitial fluid

Blood plasma

Question 13

What does the blood plasma have which may effect osmotic pressure?

Answer 13

plasma proteins (protein ions)

Question 14

Why does active transport require energy?

Answer 14

Because it is going against the concentration gradient

Question 15

What is an aquaporine?

Answer 15

Membrane protein water channels

Question 16

How is water and osmolality of the ECF controlled by the CNS/ brain?

Answer 16

The hypothalamic thirst center involves

Subfornical Organ (SFO)
and
Organum Vasculosum of the lamina terminalis (OVLT)

both have extensive vasculature and lack of a normal blood brain barrier (BBB)
This allows them to link the CNS and peripheral blood flow

Question 17

What happens when the hypothalamic thirst center is damaged?

Answer 17

Partial or total loss of a desire to drink

Question 18

What stimulates the sensation of thirst?

Answer 18

increase in plasma osmolality (1-2%)

or decrease in plasma volume (10-15%)

Question 19

Where is the thirst centre located, what is used to monitor it, and where are impulses relayed to in the brain?

Answer 19

anterior hypothalamus
osmoreceptors
cerebral cortex (conscious)

Question 20

Describe how information in the blood is relayed to the hypothalamus

Answer 20

Baroreceptors in blood vesseles are innervated by the vagus and glossopharangeal nerve..

Information passes using these nerves to the vasomotor centre in the medulla oblongata

It travels up to the paraventricular and supraoptic nucleus in the hypothalamus.

The osmoreceptros then stimulate the posterior pituitary which when required will stimulate ADH production

Question 21

What is ADH? Where is it released from, what does its release depend on and what effect does it have?
(hormonal regulation of low plasma level)

Answer 21

Antidiurectic hormone

Posterior pituitary

Released when plasma osmolality increased (sensed by osmoreceptors and hypothalamus)

Released when plasma volume decreases (sensed by baroreceptors in the great veins and right atrium)

It causes the cells of the collecting duct and distal tubules to be more permeable to water. And increases the insertion of aquaporins

Question 22

What is aldosterone? What releases it? Why is it released? And what effect does it have?
(hormonal regulation of plasma osmolality)

Answer 22

Hormone
Released from Adrenal cortex
when NA+ is low or k+ is high.

It targets Na+/K+ ATPase and epithelial Na+ channel. Causes absorption of Na+

Question 23

Hormonal regulation of high blood plasma-

What is ANP? What releases it? When is it released? What effect does this have?

Answer 23

Atrial natriuretic peptide

Released from cardiac atria
when blood volume inceases (stretches atria)

brings blood volume back to normal- increased Na+ excretion so increased urination

Question 24

What is the function of Antidiuretic hormone (ADH) or vasopressin

Answer 24

makes cells of collecting duct & distal tubule permeable to water.

Question 25

What is the function of Angiotensin II and Aldosterone

Answer 25

promote the urinary reabsorption of Na+ and Cl- (as well as water, by osmosis) when dehrydrated.

Question 26

What is the function of Atrial natriuretic peptide (ANP)

Answer 26

promote excretion of Na+ and Cl- followed by water excretion to decrease blood volume.

Question 27

When does dehydration occur and what are its symptoms?

Answer 27

When water intake is not enough to cover water loss over a long period of time so water is lost from the plasma and interstitial fluid. Symptoms- weight loss, confusion, fever

Question 28

Which condition can cause excess urine loss/ dehydaration?

Answer 28

Type 1 and Type 2 diabetes | excess sugar increases osmolality and prevents water reabsorbtion

Question 29

What type of kidney abnormalities can cause dehydration

Answer 29

Under developed kidneys (young) | Declined kidney function (old)

Question 30

What is water intoxication?

Answer 30

``` Too much water drunk too fast or complete blockage of urine production. This dilutes the bodies fluids. Na+ in ECF is reduced So osmotic shift of water into cells causing cellular swelling (convulsions, coma,death) ```

Question 31

What is the word to describe a low sodium concentration in the blood? Which party drug can cause this?

Answer 31

Hyponatraemia | Ecstasy- drink too much water

Question 32

What is oedema?

Answer 32

The swelling of the tissues due to accumulation of fluid in the ECF

Question 33

What are the 4 main causes of oedema? State any associated conditions

Answer 33

1. increased capillary hydro-static pressure- so fluid leaves capillaries (cirrhosis portal hypertension) 2. loss of plasma proteins (sever malnutrition) 3. Obstruction of lymphatic circulation) 4. Increased capillary permeability (inflammation)

Question 34

What is the consequence of lactose malabsorbtion?

Answer 34

Osmotic diarrhea

Question 35

Which are the major solutes which contribute to osmolality?

Answer 35

Na+, Cl-, Glucose & urea

Question 36

What are solutes? What are the different classes of solutes? What fits into each category?

Answer 36

Solutes: molecules in solution (eg salts) • Classification: – Electrolytes – inorganic salts (ie: Na+, K+, Cl-) , all acids and bases and some proteins – Non electrolytes – examples include glucose, lipids, creatinine, and urea

Question 37

Which type of solute has the greatest osmotic power?

Answer 37

Electrolytes

Question 38

Describe what is osmotic pressure?

Answer 38

the process that controls the movement of solvents (water) across a membrane. Movement will occur when there are differences in osmotic pressure across a membrane.

Question 39

What are the two definitions of osmotic pressure? Which is most often used?

Answer 39

Osmolarity- solute concentration as the number of osmoles of solute per litre of solution Osmolality: is the measure of the osmoles (Osm) of solute per kilogram (Kg) of solvent Osmolality is most often used

Question 40

Can osmolarity and osmolality be changed? I so by what?

Answer 40

Osmolarity can by pressure or tempertaure | Osmolality can not- per unit mass

Question 41

What happens to urine when ADH is high and when it is low? Which medical condition can cause ADH release?

Answer 41

Low ADH levels produce dilute urine and reduced volume of body fluids • High ADH levels produce concentrated urine prolonged fever, excessive sweating, vomiting, or diarrhea, severe blood loss

Question 42

Where is most water reabsorbed? How much is absorbed here?

Answer 42

Proximal tubule | 80%

Question 43

What is the most common cause of portal hypertension?

Answer 43

Cirrhosis

Question 44

Where will you find barereceptors? | Where will you find osmoreceptors?

Answer 44

Great veins Right atria Hypothalamus