Lecture 1

1.
What is the apical membrane?
The lumen side of the membrane
2.
What is an ANP?
A polypeptide hormone that causes vasodilation
3.
What are baroreflexes?
Negative feedback system (receptors) that regulate blood pressure
4.
What is ECF (extracellular fluid)?
fluid outside cells
5.
What is GFR (glomerular filtration rate)?
The volume of fluid filtered by time
6.
What is membrane potential?
The difference in voltage between the inside and outside of cells
7.
What is osmolality?
the number of osmoles per Kg
8.
What is osmolarity?
The number of osmoles per litre
9.
10.
What is osmotic pressure?
The pressure needed to resist inward flow of water
11.
What is tonicity?
The measure of osmotic pressure between two solutions.
12.
What is a hypertonic solution?
A solution with greater tonicity (osmolarity) than that with which it is being compared
13.
What is a hypotonic solution?
A solution with a lower tonicity (lower osmolarity) than that with which it is being compared.
14.
Which way does water move when ECF of a cell is hypotonic to the cell interior?
Into the cell
15.
Which receptors detect changes in BP? (3)
"Aortic and carotid baroreceptors, BV receptors in atria, endocrine cells in atria"
16.
What does the sympathetic system do to mitigate an decrease in BP? (3)
"Vasoconstriction, increase HR, increase contractility"
17.
What does the parasympathetic system do to mitigate an increase in BP? (3)
"Vasodilation, decrease HR, increase intestinal activity"
18.
How do the kidneys respond to changes in BP?
Decrease or increase the rate of filtration/sodium excretion to elicit changes in BV
19.
20.
What is negative feedback?
Where the response decreases the stimulus
21.
What are some examples of positive feedback loops? (2)
"Lutenising hormone during pregnancy, blood clotting"
22.
23.
Is higher gain or lower gain better?
greater value (could be more negative)
24.
What is the equation for determining gain?
"gain=correction/error 
25.
normal BP:
100mmHg
26.
27.
error: 100mmHg - 120mmHg
20mmHg"
28.
What are the types of ECF? (3)
"Interstitial fluid, plasma, transcellular"
29.
Where is transcellular fluid? (3)
"pleural fluid, synovial fluid, cerebral spino fluid"
30.
What is total body water for 70kg males?
60% of 70 kg: 42kg
31.
What is total body water for females?
50%
32.
What percentage of total body water is ICF?
60%
33.
What percentage of TBW is ECF?
40%
34.
What percentage of ECF is interstitial?
75%
35.
What percentage of ECF is blood plasma?
20%
36.
What percentage of ECF is transcellular fluid?
5%
37.
Are the proportions of ICF and ECF and BV different for males and females?
no
38.
How does Na+ compare between ICF and interstitial fluid?
"very high in interstitial fluid, very low in intracellular"
39.
How does K+ compare between  ICF and interstitial fluid?
"High in intracellular, low in interstitial"
40.
How does Cl- compare between  ICF and interstitial fluid?
"High in interstitial, low in cell"
41.
How does protein compare between  ICF and interstitial fluid?
"low in interstitial, higher in cell"
42.
How does osmolarity compare between  ICF and interstitial fluid?
the same
43.
How do solutes compare between  blood and interstitial fluid?
nearly the same but a little lower in blood
44.
45.
How much interstitial fluid is in the bone?
2 litres
46.
How much interstitial fluid is in dense connective tissue?
3 litres
47.
"When calculating Na+ levels, what must be taken into account?"
proteins in the plasma
48.
What are the reasons for differences in solute concentrations in ICF/ECF? (3)
"Generating gradients for: membrane potential, secondary active transport, passive diffusion "
49.
50.
How does water move? (2)
"Passive, aquaporins (bulk), through transcellular or paracellular pathways"
51.
What is osmosis?
diffusion of water from high water conc to low water conc
52.
How is osmotic pressure calculated?
Hoff’s law
53.
What does an ATPase do?
"3 Na+ out of cell, 2 K+ in through ATP energy"
54.
What is an osmole?
One mole of solute particles
55.
How much ATP does one cylce of ATP cost?
1 ATP
56.
What does hypotonic solution do to cell?
Water flows into cell
57.
What is a hypotonic solution?
One with a lower (hypo) osmolarity than the cell's solution
58.
"What happens to ECF/ICF compartments, osmolarity, and water movement when isotonic saline water is added to ECF? (2)"
"ECF compartment expands, osmolarity stays same, no movement of water"
59.
"What happens ECF/ICF compartments, osmolarity, and water movement when pure water is added to ECF? (3)"
"ECF compartment expands, osmolarity drops, movement of water out of ECF into ICF, swelling of ICF compartment as balancing of water between compartments according to number of milliosmoles. "
60.
"What happens ECF/ICF compartments, osmolarity, and water movement when salt is added to ECF? (3)"
"Osmolarity increases in ECF, water moves to ECF increasing ECF compartment, shrinking ICF compartment"
61.
What is the distribution proportions between ICF and ECF?
1/3 2/3