7. Cell Membrane Structure/function A

Front 1

Define cell homeostasis

Back 1

Maintainence of the cell's normal structures and functions by the integrated action of many complementary negative feedback regulatory mechanisms

Front 2

2 Requirements for maintaining cell homeostasis:

Back 2

1. Regln of extra/intracellular chemical environments by membrane-bound structures & mechanisms
2. Constant input of metabolic energy

Front 3

Is the cell in an equilibrium or steady state?

Back 3

Steady state

Front 4

Concentration of sodium
-plasma
-protein free plasma
-interstitium
-cell

Back 4

plasma =142
protein free plasma =153
interstitium = 145
cell = 15

Front 5

Concentration of potassium
-plasma
-protein free plasma
-interstitium
-cell

Back 5

plasma = 4.4
protein free plasma = 4.7
interstitium = 4.5
cell = 120

Front 6

Concentration of calcium
-plasma
-protein free plasma
-interstitium
-cell

Back 6

plasma = 1.2
protein free plasma = 1.3
interstitium = 1.2
cell = 10^-7

Front 7

Concentration of chloride
-plasma
-protein free plasma
-interstitium
-cell

Back 7

plasma = 102
protein free plasma = 110
interstitium = 116
cell = 20

Front 8

What is the concentration of magnesium
-Plasma
-Protein free plasma
-Interstitium
-Cell

Back 8

-Plasma = 0.6 (ionized)
-Protein free plasma = 0.6
-Interstitium = 0.55
-Cell = 1

Front 9

How is magnesium functionally important?

Back 9

It serves as an enzyme co-factor in many biochemical reactions

Front 10

What is the functional importance of chloride?

Back 10

To preserve electroneutrality for Na especially in plasma/ISF.

Front 11

What is the concentration of Chloride in
-Plasma
-ISF

Back 11

Plasma = 102 mM
ISF = 116 mm

Front 12

What is the function of bicarbonate?

Back 12

To buffer plasma, ISF, and Cellular pH via renal and respiratory systems.

Front 13

3 Ways to express average plasma protein concentration:

Back 13

-7 g/dl
-1 mM
-14 mEq/L

Front 14

Why are solute concentrations different in ISF vs. plasma?

Back 14

Because of plasma proteins

Front 15

2 Ways that plasma proteins alter ion concentration in ISF:

Back 15

1. Occupy 7% plasma volume
2. Proteins are net negative

Front 16

How does the 7% volume of proteins in plasma alter ion concentration?

Back 16

Ions are dissolved in only 93% of the volume of plasma; when protein is removed it allows for there to be more solute so ion conc. increases.

Front 17

How does the net neg charge of proteins affect ion concentration?

Back 17

-Proteins hang onto cations, so the plasma conc of anions is higher than cations

Front 18

Normal plasma concentration of Glucose:
(mM or mg/dl)

Back 18

-5.5 mm
-85-90 mg/dl

Front 19

What is the normal pH of
-Plasma
-Intracellular

Back 19

Plasma = 7.4
Cell = 7.2

Front 20

What is the normal Plasma osmolality?
-per kg of water
-per liter of plasma

Back 20

290/kg H2O
274/L Plasma

Front 21

Normal concentration range of oxygen:

Back 21

35-45 mm HG

Front 22

Normal concentration range of CO2

Back 22

35-45 mm Hg

Front 23

Normal concentration range of Sodium in ECF

Back 23

138-146 mM

Front 24

Normal concentration range of Potassium

Back 24

3.8-5.0 mM

Front 25

Normal concentration range of Calcium

Back 25

1.0 - 1.4 mM

Front 26

Normal concentration range of Chloride in ECF

Back 26

103-112 mM

Front 27

Normal concentration range of Bicarb ion in ECF

Back 27

24 - 32 mM

Front 28

Normal concentration range of Glucose in ECF

Back 28

75-95 mg/dl

Front 29

Normal temperature range of ECF:

Back 29

98 - 98.8
(37)

Front 30

Normal pH range of ECF:

Back 30

7.3-7.5

Front 31

2 Ways that Hypokalemia can occur:

Back 31

-net loss from body
-altered distribution in body

Front 32

4 ways that K+ can be lost from the body:

Back 32

1. Kidney tubules
2. GI tract
3. Skin
4. Inadequate diet intake

Front 33

3 reasons why K+ would be lost at the kidney tubules:

Back 33

-Diuretics
-Tubular disorder
-Hyperaldosteronism

Front 34

2 reasons why K+ would be lost at the GI tract:

Back 34

-Vomiting
-Severe diahrrea

Front 35

2 reasons why K+ would be lost via the skin:

Back 35

-Severe burns
-Strenuous exercise induced dehydration

Front 36

3 mechanisms by which K+ can be distributed abnormally in the body:

Back 36

-Alkalosis in the cell
-Catecholamine surge
-Excessive insulin dose

Front 37

Why does alkalosis cause a hypokalemic state in plasma?

Back 37

K+ gets exchanged transcellularly for H+ to increase plasma pH

Front 38

How does a catecholamine surge induced by acute body stress cause hypokalemia?

Back 38

It causes cellular uptake of K+ by the Na/K atpase

Front 39

Why would excessive administration of insulin result in hypokalemia?

Back 39

If used for treating Diabetic Ketoacidosis it involves transcellular uptake of K+ for H+

Front 40

4 consequences of Hypokalemia:

Back 40

1. Slowing of cardiac APs -> cardiac arrythmia
2. Cell memb hyperpolarization
(reduced excitability/functn)
3. Muscle weakness/paralysis
4. Inactive K+depend enzymes

Front 41

2 Types of HYPERkalemia:

Back 41

-Chronic
-Acute

Front 42

What are 5 causes of acute hyperkalemia?

Back 42

-Massive cell breakdown
-Massive trauma
-Burns
-GI bleeding
-Chemotherapy

Front 43

What can cause massive intravascular hemolysis?

Back 43

Transfusion mismatch

Front 44

Why does GI bleeding cause hyperkalemia?

Back 44

Cells lyse and that's followed by absorption of K-rich blood by liver.

Front 45

Why does chemotherapy cause hyperkalemia?

Back 45

Destroys cells - potassium spills out.

Front 46

What is the major cause of chronic hyperkalemia?

Back 46

Chronic renal disease with impaired excretion at the collecting ducts.

Front 47

3 Major consequences of hyperkalemia:

Back 47

1. Myocardial arrythmia
2. Cell memb depolarization
3. Muscle weakness and paralysis

Front 48

Why does Hyperkalemia cause myocardial arrythmia?

Back 48

Because it leads to ventricular arrythmia and fibrillation.

Front 49

Why does hyperkalemia cause muscle WEAKNESS and PARALYSIS?

Back 49

Because it increases NMJ excitability and activity and wears out the cells.