Body Fluids and Compartments (physiology)

Question 1

Which solvent drives the folding of proteins?

Answer 1

Water

Question 2

True or false:
Infants have low extracellular volume of water.

Answer 2

False, they have low intracellular volume and high extracellular volume.

Question 3

What may be the reason why infants have a low intracellular volume?

Answer 3

It may be bcs they have high body fat.

Question 4

Approximately how many kg of water will a person weighing 70kg have?

Answer 4

40kg

Question 5

Two compartments that have aqueous solution in the human body

Answer 5

The intracellular and extracellular compartments

Question 6

List 4 subdivisions of the extracellular compartment.

Answer 6

-Plasma
-Interstitial fluid
- Lymph
- Transcellular fluids

Question 7

What is transcellular fluid?

Answer 7

Fluid found in epithelial lined compartment. E.g, the cerebrospinal fluid.

Question 8

How does the interstitial fluid form?

Answer 8

When plasma is being filtered along the capillary membrane.

Question 9

Explain how interstitial fluid enters the lymphatic vessels.

Answer 9

The pressure of the interstitial fluid is higher than that of the lymphatic vessel, it enters in the gaps.

Question 10

Explain the two processes, as well as the pressure that drives them:
A. Filtration
B. Reabsorption

Answer 10

A. Movement of fluid from the capillaries to tissues, it is driven by hydrostatic pressure.
B. Movement of fluid from the tissues to the capillaries, it is driven by osmotic pressure.

Question 11

Differentiate btwn hydrostatic pressure and osmotic pressure.

Answer 11

Hydrostatic pressure is the pressure applied by blood confined within the blood vessel.
Osmotic pressure is the pressure applied by the proteins in the blood vessel.

Question 12

What do we call the pressure exerted by blood against the wall of a capillary?

Answer 12

Capillary hydrostatic pressure.

Question 13

How do we calculate the net filtration pressure?

Answer 13

Net filtration pressure = Capillary hydrostatic pressure (CHP) - Blood colloidal osmotic pressure (BCOP)

Question 14

List the electrolytes that are mostly in the intracellular compartment

Answer 14

Potassium, Magnesium, Phosphate and Sulphate.

Question 15

What separates the interstitial fluid and intracellular environment?

Answer 15

Semi-permeable plasma membrane

Question 16

What facilitates the transport btwn ECF and ICF of all charged and polar molecules?

Answer 16

Protein channels or pumps

Question 17

What is the diff btwn passive diffusion, facilitated diffusion and active transport.

Answer 17

Passive diffusion- Not selective, does not require ATP.
Facilitated diffusion- uses protein channels and carrier proteins, does not require ATP.
Active transport- moves molecules against their concentration gradient, required ATP.

Question 18

What is the diff btwn uniporter, symporter and antiporter?

Answer 18

Uniporter- Transport one molecule at one go.
Symporter- Transport two molecules at one go, to the same direction.
Antiporter- Transport two molecules which goes to opposite side at one go.

Question 19

Differentiate btwn the two types of glucose transporters

Answer 19

Sodium dependent glucose transporter (SGLUT)
-Active transport
- Found in renal tubules and intestinal epithelia.
-Uses a sodium gradient for energy.

Sodium independent glucose transporter (GLUT)
-Passive transport
- Glut 4 is insulin dependent.

Question 20

Function of/note about:
1. SGLUT
2. GLUT 1
3. GLUT 2
4. GLUT 3
5. GLUT 4

Answer 20

1. Resp for absorption(intestines) and reabsorption(renal tubules) of glucose.
2. Pancreas- Important for gauging blood glucose levels in humans.
   Liver- Important for bi-directional transport of glucose when influences by hormones.
3. Liver- Resp for bi-directional transport of glucose with respect to hepatic glucose metabolism.
4. Has high affinity for glucose.
5. Expression is regulated by insulin.

Question 21

Explain how the SGLUT transporter works. (3)

Answer 21

• Sodium potassium pump, pumps sodium out of the renal tubules and potassium in.
  -This decreases the concentration of sodium in the proximal tubules.
  -Sodium will diffuse from the lumen of the kidney to the proximal tubule, glucose will move along with it via the SGLUT.

Question 22

What is the difference between osmolality and osmolarity?

Answer 22

Osmolality is osmoles of solute per kg of a solvent while with osmolarity it is per litre of a solvent.

Question 23

Receptors that detect changes in:
A. Osmotic pressure
B. Blood pressure

Answer 23

A. Osmoreceptors
B. Baroreceptors

Question 24

How is osmolality regulated, for example when we have a high osmolality?

Answer 24

• Decreased saliva and dry mouth.
• Osmoreceptors detect this change and stimulates the hypothalamus.
• Causes increased thirst.
• Person drinks water.
• Water moistens mouth, throat, stretches the stomach, intestines.
• Absorption of water in the GI tract.
• Osmolality decreases.

Question 25

What are the functions of angiotensin 2? (2)

Answer 25

Causes thirst and vasoconstriction.

Question 26

List and explain how the water volume receptors work.

Answer 26

V1A- Found on smooth muscle of blood vessels, they cause vasoconstriction (raises arterial BP). V1B- Found in pituitary corticotrope cells, they increase ACTH release. V2- Found in the cells of collecting ducts of kidneys, causes increased water reabsorption (also raises arterial BP).

Question 27

How does ADH increases water reabsorption?

Answer 27

It inserts aquaporins on the cell membranes which increases the flow of water out of the tubule.

Question 28

Normal osmolality levels in plasma

Answer 28

285-295 mOsm/kg

Question 29

What do we call the syndrome caused by excess vasopressin?

Answer 29

Syndrome of inappropriate ADH secretion (SIADH)

Question 30

What are the causes of SIADH? (5)

Answer 30

Pituitary tumours Other malignancies Nervous system disorders Some drugs Pulmonary diseases

Question 31

What characterises the SIADH? (2)

Answer 31

Decreased water excretion. Decreased plasma osmolality.

Question 32

Which tests are taken to diagnose SIADH? (3)

Answer 32

- Measure serum and urine osmolality and sodium concentration. - Renal function test. - Test for adrenal insufficiency.

Question 33

Treatment for SIADH (5)

Answer 33

- Restricted water intake. - Hypertonic saline solution - Vasopressin antagonists - Tolvaptan - Diuretics

Question 34

What does insufficient vasopressin cause?

Answer 34

Diabetes insipidus

Question 35

What characterises Diabetes insipidus? (3)

Answer 35

- Polyuria, polydipsia and plasma hyperosmolality.

Question 36

Two types of diabetes insipidus (4)

Answer 36

Central- Pituitary trauma, alcohol abuse. Nephrogenic- genetic inactivation of v2 receptor or aquaporin channel protein, or kidney disorders.

Question 37

What are the tests perfomed to diagnose diabetes insipidus? (3)

Answer 37

- Measure 24 hour urine volume and plasma osmolality. - Water deprivation test- they will lose water at a greater rate and there will be an increase in plasma osmolality. - Desmopressin is used to distinguish btwn central and nephrogenic.

Question 38

Treatments for diabetes insipidus (4)

Answer 38

- Increased water intake - Desmopressin - Thiazide diuretics - Low salt diets