CH 27 Study Guide

What are electrolytes?

are minerals in the body that carry an electric charge and are essential for various physiological functions, including maintaining fluid balance, muscle contraction, and nerve signaling.

What two main fluids make up the ECF?

interstitial fluid and plasma.

What fluid makes up the ICF?

primarily composed of cytosol, the fluid found inside cells.

List three principal ions found in the ECF.

sodium (Na+), chloride (Cl-), and bicarbonate (HCO3-).

List three principal ions found in the ICF.

potassium (K+), magnesium (Mg2+), and phosphate (PO4^3-).

What negatively charged organic molecule is found in large quantities in the ICF?

proteins

Which fluid compartment (ICF or ECF) is monitored for changes and composition of body fluids?

ECF

No receptors directly monitor fluid or electrolyte balance. What two parameters are monitored by receptors?

blood osmolarity and blood volume.

Which pituitary hormone promotes water retention by the kidney?

antidiuretic hormone (ADH), also known as vasopressin.

What two important effects occur when ADH release is increased?

it causes increased water reabsorption in the kidneys and constriction of blood vessels, leading to increased blood pressure.

Which corticosteroid hormone regulates sodium and water balance by signaling sodium reabsorption by the kidney?

aldosterone

Which corticosteroid hormone is secreted in response to increased potassium ions or decreased sodium ions in blood that reaches the adrenal cortex?

aldosterone

Which two hormones are released from cardiac cell walls in response to stretching?

atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP).

The release of natriuretic peptides reduces thirst and blocks the release of ADH and aldosterone.

What is the result?

reduces thirst, blocks the release of ADH and aldosterone, and promotes diuresis, leading to decreased blood volume.

Define diuresis

is the increased production of urine by the kidneys, often leading to the excretion of excess water and electrolytes.

What step in aerobic glucose metabolism generates water within the cells?

the electron transport chain, where oxygen acts as the final electron acceptor.

Describe sensible

is the visible loss of sweat from the skin

Describe insensible perspiration

is the continuous loss of water through the skin and respiratory tract that is not noticeable.

What is edema

is the abnormal accumulation of fluid in the interstitial spaces of tissues, leading to swelling.

Define fluid shift

refers to the movement of water between the intracellular and extracellular compartments in response to changes in osmotic or hydrostatic pressure.

What is hypernatremia?

is a condition characterized by elevated sodium levels in the blood

What is hyponatremia?

low sodium levels in the blood.

What is the principal cation in the ECF?

sodium (Na+)

What is the principal cation in the ICF?

potassium (K+)

Imbalances in which electrolyte causes the most common problems?

Sodium (Na+)

Imbalances in which electrolyte are less common, but more dangerous?

potassium (K+)

Aldosterone-sensitive ion pumps reabsorb which ion from the nephron’s tubular fluid in exchange for which ion in the peritubular fluid?

sodium (Na+) from the nephron's tubular fluid in exchange for potassium (K+) in the peritubular fluid.

What is hyperkalemia?

a condition characterized by elevated potassium levels in the blood

What is hypokalemia?

characterized by low potassium levels in the blood.

Severe cardiac arrhythmias and muscle spasms are caused by which disorder?

hypokalemia

Muscular weakness and paralysis are caused by which disorder?

hyperkalemia

What is the normal pH range of the ECF?

between 7.35 and 7.45

What blood pH is considered a state of acidosis?

pH below 7.35

What blood pH is considered a state of alkalosis?

pH above 7.45

List three mechanisms that contribute to acid-base balance.

buffer systems, respiratory regulation of carbon dioxide, and renal regulation of bicarbonate and hydrogen ions.

Which general category of acids in the body affects blood pH?

volatile acids, such as carbonic acid, and fixed acids, such as sulfuric and phosphoric acids.

Which acid spontaneously forms from carbon dioxide and water?

Carbonic acid (H2CO3)

What molecule has the molecular formula H2CO3?

carbonic acid

What molecule has the molecular formula HCO3-?

bicarbonate

The partial pressure of which gas is the most important factor affecting blood pH.

carbon dioxide

PCO2 is ____ proportional to blood pH.

indirectly

When CO2 increases in the blood, PCO2 increases. What effect does it have on blood pH?

it causes a decrease in blood pH, resulting in acidosis.

When CO2 decreases in the blood, PCO2 decreases. What effect does it have on blood pH?

it causes an increase in blood pH, resulting in alkalosis.

What is a buffer and what is its function?

is a substance that helps maintain a stable pH in a solution by neutralizing acids or bases, thus preventing significant changes in pH.

Which two major buffer systems buffer the ICF?

the protein buffer system and the phosphate buffer system.

Which two major buffer systems buffer the ECF?

the bicarbonate buffer system and the protein buffer system.

Which major buffer system is the most important in the pH regulation of the ECF?

bicarbonate buffer system

Which buffer system’s primary role is to prevent pH changes in the ECF caused by metabolic and fixed acids?

bicarbonate buffer system

Define respiratory compensation.

is the process by which the respiratory system adjusts the rate and depth of breathing to help maintain the acid-base balance in the body, primarily by regulating carbon dioxide levels in the blood.

During respiratory compensation, what is the effect on blood pH when respiratory rate increases?

raises blood pH back toward a normal, more alkaline state

During respiratory compensation, what is the effect on blood pH when respiratory rate decreases?

blood pH decreases, becoming more acidic

Define renal compensation.

is the process by which the kidneys help maintain acid-base balance by excreting or retaining hydrogen ions (H+) and bicarbonate (HCO3-) in response to changes in blood pH.

During renal compensation, what would occur to blood pH if more H+ is excreted from the body?

blood pH increase becoming alkaline

What would happen if more H+ are retained by the kidneys?

blood pH decrease becoming acidic

What is the primary molecule that causes respiratory acid-base disorders?

carbon dioxide

What are the primary molecules that cause metabolic acid-base disorders?

bicarbonate (HCO3-) and hydrogen ions (H+).

Define hypercapnia

is a condition characterized by an elevated level of carbon dioxide (CO2) in the blood.

Which acid/base imbalance is caused by hypoventilation?

respiratory acidosis

What three diseases/medical conditions result in chronic respiratory acidosis?

Chronic obstructive pulmonary disease (COPD), severe asthma, and obesity hypoventilation syndrome

How does the body compensate for a state of respiratory acidosis?

increasing renal excretion of H+ and reabsorbing bicarbonate (HCO3-) to raise blood pH.

What respiratory condition develops when respiratory activity lowers the blood carbon dioxide to below-normal levels?

Hypocapnia

Define hypocapnia

a condition characterized by a reduced level of carbon dioxide (CO2) in the blood.

Which acid/base imbalance is caused by hyperventilation

respiratory alkalosis

How does the body compensate for a state of respiratory alkalosis?

decreasing renal excretion of H+ and increasing bicarbonate (HCO3-) excretion to lower blood pH.

Which acid/base imbalance is caused by lactic acidosis or ketoacidosis?

Metabolic acidosis

Which acid/base imbalance is caused by chronic diarrhea or glomerulonephritis?

Metabolic acidosis

How does the body compensate for a state of metabolic acidosis?

increasing respiratory rate to expel CO2 and decrease acidity.

Which acid/base imbalance is caused by alkaline tide?

Metabolic alkalosis

How does the body compensate for a state of metabolic alkalosis?

decreasing respiratory rate to retain CO2 and increase acidity.

What are the aging effects of glomerular filtration rate? What is the result of this?

a decreased glomerular filtration rate (GFR), which can lead to reduced kidney function and impaired fluid and electrolyte balance.

What are the aging effects on ADH and aldosterone? What is the result of this?

decreased sensitivity to antidiuretic hormone (ADH) and aldosterone, resulting in impaired water retention and electrolyte balance.