Mastering A&P & study guide for chap 27

________ promotes water reabsorption at the kidneys and stimulates thirst.

ADH

How do kings regulate when pH when PCO2 is high? When PCO2 is low?

As PCO2 increases carbonic acid concentration increases as PCO2 decreases less carbonic acid is formed

Dehydration

Develops when water loss is greater than water gain. Mild dehydration is when body mass decreases by 2%. Causes excessive perspiration, vomiting, diarrhea, inadequate water consumption. Treatment is hydrate with plain water.

What is an electrolyte and it's function? Which actions/anions are common in ECF & ICF?

Function: control osmosis of water between fluid compartments. When cells move solutes water follows between compartments via osmosis. They maintain acid base balance. Carry electrical current they allow neurons to conduct action potentials. Na+ are main cations in ECF K+ are main cations in ICF Cl- are main anions in ECF HPO4- are main anions in ICF

The two organs that play an important role in maintaining acid-base balances are the

Lungs and kidney

How do the lungs respond to metabolic acidosis?

Lungs increase respiratory rate

What does metabolic acid-base disorder result from?

Results from generation of organic/fixed acids or conditions affecting HCO3- concentration in the ECF. Caused by metabolic acidosis from lactic acidosis ketacidosis impaired H+ excretion it severe HCO3- loss. Metabolic alkalosis results from elevated HCO3- concentrations.

What does respiratory acid-base disorders result from?

Results from imbalance of CO2 generated in tissues and CO2 excretion at lungs. Caused by abnormal CO2 levels in ECF. Respiratory acidosis caused by hypoventilation and respiratory alkalosis caused by hyperventilation.

role of aldosterone

Secretes by adrenal cortex in response to the rising K+ or Na+ levels in blood and activation of RAA pathway which drops blood volume and blood pressure. Promotes the reabsorption of Na+ and CI- in DCT and collecting duct water follows via osmosis. This results in a small volume of concentrated urine.

Acid

Substance that dissociates to release H+ strong acids dissociate completely in solution releasing a lot of H+ and cause a decrease in pH.

base (alkaline)

Substance that dissociates to release OH- or take up H+ bases may be strong or weak. Strong bases dissociate in solution releasing OH- and cause increase in pH.

Intracellular fluid (ICF) is found only within

cells of the body

The two major subdivisions of the ECF are the

interstitial fluid and plasma

Which of the body compartments has the greatest volume?

intracellular fluid

Excess hydrogen ion is eliminated from the body largely by

kidneys

The carbonic acid-bicarbonate buffer system functions mainly to

limit ECF pH changes caused by metabolism

Hypoventilation leads to

respiratory acidosis

If a hypertonic sodium chloride solution is injected into a patient's vein, this will cause a shift of water from __________ and cause cells to __________.

the ICF to the ECF; shrink

In clinical estimates, _____ of total body water is in the ICF and ____ in the ECF

two-thirds; one-third

Calcium reabsorption by the kidneys is promoted by the hormone

parathyroid hormone

What percentage of the total body mass of an adult is composed of water?

55-60%

The normal pH range for ECF is

7.35 to 7.45

pH of ECF

7.35-7.45

If a person loses 750 mg/day of sodium in urine, sweat, and feces, to remain in electrolyte balance, he or she will need to consume at least ____ daily

750 mg of sodium ion

What is the role of antiduretic hormone?

Aka vasopressin increases osmolarity of body fluids stimulate ADH secretion from posterior pituitary. ADH promotes insertion of aquaporins into cells of collecting duct of kidneys and water moves from renal tubule to blood. This results in small volume of very concentrated urine. Stimulates thirst center in hypothalamus.

Role of Natriuretic Peptides

Blood volume increases stretch receptors in walls of heart are activated. Stretching in atria results in release of ANP stretching of ventricle results in release of BNP. Both promote excretion of Na+ and Cl- water follows via osmosis. This results in high concentration of dilute urine (decreases blood volume)

A substance that can release or absorb a hydrogen ion is know as a(n) ____

Buffer

What is the kidneys response to alkalosis caused by the removal of H+?

Conserve H+ and secrete HCO3-

Overhydration

Develops when water gain is greater than water loss. Caused by large intake of plain water, endocrine disorder, renal failure, etc.

Two fluid compartments in the body

Intracellular fluid- fluid inside cells (Cytosol) two thirds of body fluid. Extracellular fluid- fluid outside of cells. One third of body fluids. 80% of ECF is interstitial fluid found between tissue cells 20% of ECF is plasma.

protein buffer system

Most important buffer in ICF and blood plasma. Depends on amino acids of plasma proteins. If pH increases -COOH of amino acid dissociates and releases H+ if pH decreases amino group -NH2 combined with H+ becomes ammonia.

Exchange between the two main subdivisions of ECF occurs primarily at the

capillaries

What is the most abundant anion in the intracellular fluid?

Phosphate

phosphate buffer system

Phosphate ions act as important buffers of ICF. Dihydrogen phosphate H2PO4- acts as a weak acid and buffers are strong bases. Mono hydrogen phosphate ion (HPO42-) acts as a weak base buffers strong acids

Two barriers between fluid compartments

Plasma membrane- separates ICF from surrounding interstitial fluid selectively permeable. Exchange occurs through simple diffusion and osmosis. It's an active transport proteins embedded in membrane serve as pumps. Blood vessel wall- separate interstitial fluid from blood plasma. Only capillaries permit exchange of water and solutes.

The principal cation in intracellular fluid is

Potassium

Sources of water gain vs. water loss

Water gain: absorption via GI tract drinking (1200 ml a day and eating 1000 ml a day) cellular metabolism- water created via ECT during cellular respiration Water loss: kidneys (urine) GI tract (feces) Skin (sensible and insensible perspiration) Lungs (water vapor)

carbonic acid-bicarbonate buffer system

When there is an excess of H+ HCO3- acts as a weak base producing a weak acid. Carbonic acid dissociates into H2O and CO2 exhaled from the lungs.

Which hormone plays a central role in determining the rate of sodium reabsorption and potassium secretion?

aldosterone

When the pH rises above 7.45, a state of ____ exists

alkalosis

Which of these is not a component of the extracellular fluid compartment?

blood cells

Alkalosis

blood pH above 7.45 due to accumulation of bases of the loss of acids overexcitability of CNS and PNS neurons

Acidosis

blood pH below 7.35 due to an accumulation of bases of the loss of acids depression of synaptic transmission in CNS

A drop in blood pH will be compensated for by __________.

excreting more hydrogen ions and fewer bicarbonate ions

Hyperventilation usually leads to a substantial ____ in the partial pressure of _____ in body fluids

fall; carbon dioxide

A rise in the partial pressure of carbon dioxide will cause a __________ in pH and a __________ in blood bicarbonate levels.

fall; rise

Which of the following is a renal response to acidosis?

increasing secretion of hydrogen ions

What happens to pH when Pco2 increases above 45 mm Hg?

pH will fall below 7.35

A person who consumes large amounts of sodium bicarbonate ("baking soda") to settle an upset stomach risks

metabolic alkalosis

Which hormone(s) is released by heart muscle in response to excessive chamber volume?

natriuretic peptides

Water molecules move across cells by

osmosis

pH

pH is a measure of H+ solution indicating acidity or alkanity of a solution. Acids: 0-6 Neutral solutions: 7 Basic solutions: 8-14 A solution with a pH of 4 is 100X more acidic than a pH of 6. Acidity increases moving towards zero alkanity increases moving towards 14.