Lecture 6/7 done

Question 1

What are some examples of things that must be isotonic?

Answer 1

NS solution, D5W solution, eye drops, oral rehydration solution

Question 2

Why do many drugs need to be isotonic?

Answer 2

avoid disturbance to electrolytes in body, minimize discomfrt for patient, minimize damage to delicate tissues

Question 3

What determines direction of water flow in cells?

Answer 3

concentration gradient

Question 4

What system is used to determine the isotonicity of drugs?

Answer 4

freezing point (FP) depression

Question 5

What are the key elements of FP?

Answer 5

1)a solute lowers water’s FP
2)we use FP as a scale for water’s chemical potential in a drug solution: lower the FP, lower the chemical potential
3)FP=-0.52 for blood and tears
4)make isotinic solutions by making FP=-0.52 C

Question 6

What is the normal range for FP of blood?

Answer 6

-0.51- -0.57 C

Question 7

What is osmotic ressure?

Answer 7

the pressure that stops water flow at equilibrium

Question 8

True or false: the pressence of more solute lowers the chemical potential

Answer 8

true

Question 9

What is the equation to calculate osmotic pressure?

Answer 9

pi=RTc2

Question 10

How is osmotic pressure calculated in the presence of many solutes?

Answer 10

total osmotic pressure is equal to the sum of all of its components

Question 11

WHat is osmolality?

Answer 11

indicates tonicity

Question 12

What is the eqquation for osmolality?

Answer 12

osm=change in Tf/Kf

Question 13

What is the tipical osmolality range in blood?

Answer 13

270-300 mOsm/kg