Cellular Physiology I

A patient with a body w of 65kg was injected with 10ml of a 1% (w/v) solution of Evans blue. After 10min, the blood was sampled and found to contain 0.037 mg/ml of the dye. (a) What is the plasma V? (b) If the hematocrit is 45%, what is the blood V? (c) Are these values within the normal range?

A patient was given an intravenous infusion of 10g 14C-labeled inulin and 10 ml of 3H2O. After 90min, the plasma c of inulin was 0.3mg/ml and of 3H2O was 0.18 μl/ml. Over the same period, 5.2g of inulin and 2.26ml of 3H2O were excreted in the urine. Calculate (a) the total body water, (b) the excell V, and (c) the incell V. (d) Assuming the patient is a normal adult male, what is his approx body w?

A miner with body w of 75kg loses 4L of sweat during the day. (a) If the sweat contained 50mmol/L of NaCl, what would be the osmolality of the body fluids after he finished work? (b) If he replaces the lost fluid by drinking pure water, what would be the osmolality of the tissue fluid? (The initial osmolality of the body fluids is 290 mOsm/kg of NaCl and initially total body water accounted for 60% of his body w)

What % of body w does water account for?

How is the body water distributed between compartments?

Which molecules can freely cross the cell membrane?

What does the rate of diffusion depend on?

What is the osmotic pressure? What does it depend on?

Calculate the osmolarity of the following:
a. 58.4g NaCl(Mr=58.4) in 1L water
b. 8.77g NaCl in 1L water
c. 18.03g urea(Mr=60.1) 1L water
d. 1mg/ml of glucose(Mr=180.2) in water
e. 45g of albumin(Mr=69000) in 1L water

If 29.2g NaCl(Mr=58.4) were dissolved in 1L of water what would be the osmolarity?
b) Calculate the osmolality of the same quantity of NaCl present in 1kg of NaCl solution (specific gravity of solid NaCl is approx 2.2)

If, in a sample of blood, there are approx 6.15g NaCl/L of plasma and solids make up 5.5% of plasma by w, what is the osmolality contributed by the NaCl(Mr=58.4)?

Why is it convenient to use osmolality as opposed to osmolarity?

What is the osmotic pressure (in kPa) exerted by a solution of 9g NaCl in 1L of water at body T (310K)? (R=8.314Jmol-1K-1)

What is the osmotic p of a solution of 50g albumin in 1L water at body T (310K)?

If red cells were isolated from the blood and placed in solutions of the follwoing compositions, would they swell, shrink, or stay approx the same size?
a) 0.9g NaCl/100ml (0.9% saline solution)
b) 7.5g NaCl/L
c) 10.5g NaCl/L
d) 18g urea/L

What are the main contributors to the plasma osmolality?

What is the difference between iso-osmotic and isotonic?

What determines direction of solute transport across membrane?

How does the diffusion rate changes as c gradient increases in facilitated diffusion?

How can you distinguish between ion channels and carrier proteins mediated transport?

what are the 3 different types of carrier protein?

What is the difference between primary and secondary active transport? Give examples of both and their importance.

Which transport mechanisms depend on Na+ gradient?

What is the difference between constitutive and regulated exocytosis?

What are the 3 types of endocytosis and their differences?

Which important adaptation prevents the free flow of fluid to the lower regions of the body due to gravity?

How is the ultrafiltrate of interstitial fluid formed? Where is the filtration essential?

How are extracellular signals translated into intracellular signals that regulate vesicle secretion in regulated excocytosis?

Gases such as oxygen and carbon dioxide cross the plasma membrane by:

Ions can cross the plasma membrane by:

A substance can be accumulated against its electrochemical gradient by:

The principal intracellular cation is:

The following are examples of active transport:
a. Na+ pump
b. Cl--HCO3- exchange
c. Na+-Ca2+ exchange
d. Na+-linked glucose uptake by enterocytes
e. Na+-H+ exchange

The Na+ pump:
a. Exchanges intracellular Na+ for extracellular K+
b. Requires ATP
c. Directly links Na+ efflux with K+ influx.
d. Is an ion channel
e. Can be inhibited by metabolic poisons.
f. Is important in maintaining const cell V

Secretion:
a. Always involves membrane vesicles
b. May be triggered by rise in incell Ca2+
c. Provides means of inserting proteins into plasma membrane

10. Endocytosis is used by cells to:
a. Ingest bacteria and cell debris
b. Retrieve elements of the plasma membrane after exocytosis
c. Take up large molecules from the extracellular space