Lecture 12

Question 1

Define the term “electrolyte.” Give several examples of electrolytes in the body. Give two examples of why maintaining balance of electrolytes is important.

Answer 1

Electrolytes are inorganic compounds, aka salts, that dissociate into ions. Important for maintaining homeostasis and fluid balance

Question 2

What is the average osmolarity of extracellular fluid and intracellular fluid?

Answer 2

The average osmolarity of extracellular fluid and intracellular fluid are both 300. They are equal because most plasma membranes are permeable to water.

Question 3

What electrolytes have higher concentration in intracellular fluid?

Answer 3

Potassium and phosphate

Question 4

What electrolytes have higher concentration in extracellular fluid?

Answer 4

Sodium, Calcium and Chloride

Question 5

Which fluid compartments are most similar in their concentrations of individual electrolytes? Which are most dissimilar?

Answer 5

Concentrations of electrolytes are very similar in IF and plasma.

Concentrations of individual electrolytes are dissimilar in Extracellular Fluid and Intracellular Fluid.

Question 6

What is the most common electrolyte imbalance?

Answer 6

Sodium. Often due to dehydration.

It is the main solute in Extracellular Fluid consisting of 90% of the osmolarity.

Question 7

List three reasons why maintaining sodium balance in the body is important.

Answer 7

osmoregulation

electrical activity of neurons and muscle cells

cotransport of K+/Ca2+/glucose/AAs

Question 8

How is it that ions are typically gained and lost in the body?

Answer 8

Gained through eating and lost through urine, feces, and sweat.

Question 9

Hypernatremia

Answer 9

To much extracellular sodium.

Causes: Diabetes insipidus, dehydration, hyper secretion of Aldosterone.

Effects: Increased blood plasma, pressure, volume, and thirst. Edema

Question 10

Hyponatremia

Answer 10

Not enough sodium in extracellular fluid.

Causes: not enough dietary sodium, to much water intake, and hyperglycemia

Effects: same as hypotonic hydration

Question 11

What is the most dangerous electrolyte imbalance?

Answer 11

Potassium because it can effect the electrical activity of heart.

Question 12

Hypokalemia

Answer 12

Not enough potassium in the extracellular fluid. K

Question 13

Describe the mechanism that results in hyperpolarization of excitable cells due to hypokalemia.

Answer 13

More potassium has to leak out to maintain action potential. Has to pull positive charged ions from cell making it more negative thus lowering its action potential

Question 14

fast hyperkalemia

Answer 14

Fast increases in ECF K+ causes resting membrane potentials to be closer to threshold, and excitable cells to be hyper excitable.

Causes: Crushing injury, transfusions with old blood, hemolytic anemia, and lethal injection.

Effects: Cardiac arrhythmias and hyper excitable cells.

Question 15

Slow Hyperkalemia

Answer 15

Opposite effect of fast.

Causes: aldosterone hyposecretion, renal failure, and chronic acidosis.

Affects: H+ displaces K+ in cells and Principal cells can secrete H+ instead of K+ while reabsorbing Na+
Muscles become inactive because voltage gated Na+ channels close.

Question 16

Three reasons that calcium balance in the body is important.

Answer 16

Bone formation, muscle contractions, blood clotting, exocytosis of neural transmitters, second messenger systems.

Question 17

Why is it that extracellular levels of calcium are high, while intracellular levels of calcium are low, and at the same time extracellular levels of phosphate are low, and intracellular levels are high?

Answer 17

Because if they were both high in the same compartment calcification would occur.

Question 18

Hypercalcemia

Answer 18

To much calcium in the extracellular fluid.

Causes: Hyperparathyroidism, Hypothyroidism, immobilization, or boneless due to cancer.

Effects: decreased permeability of excitable cell’s plasma membranes to sodium, cardiac arrhythmia, classification of soft tissue, fatigue, constipation, confusion.

Question 19

Hypocalcemia

Answer 19

Not enough calcium in extracellular fluid.

Causes: Hypoparathyroidism, Hyperthyroidism, Vitamin D deficiency, and pregnancy.

Effects: Increased permeability of sodium in excitable cells. spasms of larynx and osteoporosis.

Question 20

pH of intracellular and extracellular fluid

Answer 20

Extracellular fluid 7.35-7.45

Intracellular fluid 7

Question 21

Why is acid-base balance important?

Answer 21

Enzyms activity by maintaining the proper shape of proteins

Electrical gradients because H+ can displace intracellular K+

Question 22

Acids in our body

Answer 22

Carbonic Acid, Lactic Acid, Fatty Acid, Sulfuric Acid, Phosphoric Acid, Amino Acid, HCL, and Ketone Bodies

Question 23

Factors that can affect Acid-Base balance

Answer 23

Acidic = high protein or wheat diet. Diarrhea
Basic = Vegetarian diet. Chronic vomiting or antacids.

Question 24

What buffer systems regulate pH balance?

Answer 24

Chemical buffers - Fast acting but will run out. least effective. only good for short term.

Physiological Buffers- Reparatory and Urinary.

Question 25

Carbonic Acid – Bicarbonate buffer system

Answer 25

Extracellular fluid

Binds H+ to bicarbonate when acidic this is catalyzed by carbonic anhydrase

Question 26

Phosphate buffer system

Answer 26

Intracellular fluid

Dihydrogen Phosphate can remove a H+
Monohydrogen phosphate can add a H+

Question 27

Protein buffer system

Answer 27

Intra and extracellular. Best chem buffer.

Carboxyl group use a H+ and become carboxylate.

Amine group can accept a H+ forming amino ion

Histones can neutralize H+

Question 28

How effective is the respiratory system at balancing pH, relative to the chemical buffers? How quickly does the respiratory system accomplish this?

Answer 28

3x more effective than chemical buffers. It can take minutes to effectively buffer

Question 29

How effective is the renal system at balancing pH, relative to the respiratory system? How quickly does the renal system accomplish this?

Answer 29

It is much more effective than the respiratory system but can take hours to days to effectively buffer

Question 30

What mechanisms does the renal system use to balance pH?

Answer 30

Intercalated A cells: Secret H+ and absorb bicarbonate

Intercalated B cells: Secret bicarbonate and absorb H+

Takes place in the DCT and collecting system of the nephrons in the kidneys

Question 31

Two negative effects of acidosis on the body

Answer 31

Inside of cells become hyper polarized

Depressed nervous system

Question 32

two negative effects of alkalosis on the body

Answer 32

increased resting membrane potential

muscle spasms and respiratory paralysis

Question 33

Respiratory Acidosis

Answer 33

Causes: Hypercapnia decreased CO2 levels, COPD, hypoventilation

Effects: Damage to muscles or nerves. Damage mylination

Question 34

Respiratory Alkalosis

Answer 34

Hypocapnia, increased CO2 levels caused by hyperventilation.

Question 35

Metabolic acidosis

Answer 35

The production of H+ from other sources or the loss of too much bicarbonate.

Kidney diseases that affect intercalated A cells, lactic acid build up, heart failure, anaerobic fermentation, tissue hypoxia, chronic diarea, leto acidosis

Question 36

Metabolic alkalosis

Answer 36

Periods of frequent vomiting or bicarbonate antacids