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Regulatory Mechanism - characteristic or function

Bicarbonate buffer system
-Referred to as the alkaline reserve


Protein buffer system
=The most common buffer system in cells

Phosphate buffer system
- Uses Na2HPO4 as a weak base

Buffer system

Bicarbonate buffer system
-Referred to as the alkaline reserve


Protein buffer system
=The most common buffer system in cells

Phosphate buffer system
- Uses Na2HPO4 as a weak base

Electrolyte balance

Aldosterone
The hormone that regulates sodium and potassium levels


Calcitonin
Its antagonist is parathyroid hormone


Hyponatremia
. A condition that results from water intoxication


Hyperkalemia
An excess amount of potassium in the ECF

Aldosterone

The hormone that regulates sodium and potassium levels

Calcitonin

Its antagonist is parathyroid hormone

Hpyonatremia

A condition that results from water intoxication

Hyperkalemia

An excess amount of potassium in the ECF

Electrolytes - location

Na+
. Most abundant positive electrolyte in extracellular fluid

K+
Most abundant positive electrolyte in intracellular fluid

Cl-
Most abundant negative electrolyte in extracellular fluid


HPO4-
Most abundant negative electrolyte in intracellular fluid


Mg2+
Least abundant positive electrolyte in extracellular fluid

Dehydration

When water output exceeds intake over a period of time resulting is in negative fluid balance

Hypotonic Hydration

When the ECF osmolality starts to drop as a result of overhydration

Edema

An atypical fluid accumulation in the interstitial space, leading to tissue swelling

Hyponatremia

Low ECF Na+

Buffer systems

Bicarbonate buffer system
Strong acid (HCl) buffered by weak base (NaHCO3)

Phosphate buffer system
Strong acid (HCl) buffered by weak base (Na2HPO4)

Protein buffer system
Strong acids (HCl) buffered by amine groups (—NH2 group)

Buffer systems - products

HCl + NaHCO3 = H2CO3 + NaCl

NaOH + H2CO3 = NaHCO3 + H2O

HCl + Na2HPO4 = NaH2PO4 + NaCl

NaOH + NaH2PO4 = Na2HPO4 + H2O

Metabolic acidosis

Severe diarrhea; renal disease; untreated diabetes mellitus; starvation; excess alcohol ingestion

Metabolic alkalosis

Vomiting; selected diuretics; ingestion of excessive amount of sodium bicarbonate; constipation; excess aldosterone

Respiratory acidosis

ny condition that impairs gas exchange or lung ventilation; rapid, shallow breathing; narcotic or barbiturate overdose or injury to brain stem

Respiratory alkalosis

. Hyperventilation; brain tumor or injury

Electrolytes - descriptions

Na+
Major extracellular cation

K+
Major intracellular cation

Cl-
Major extracellular anion

HPO42-
. Major intracellular anion

Acidosis

Acidosis results in increasing levels of Hydrogen
Acid is H+.

Potassium Chloride

Currently, many states perform capital punishment (execution) using potassium chloride injection. Why would this kind of an injection cause death?

Increased K+ results in disruption of the electric potential of cardiac tissue.

KCl initially would decrease membrane potential and then reduce excitability.

Blood pH

Normal arterial blood pH averages between 7.35 and 7.45.

Parathyroid

enhances release of calcium from bone.

PTH activates osteoclasts.

Hyponatremia

The condition in which sodium levels are too low

"Hypo" means low, and "natrium" is Latin for sodium.

Body water

The largest percentage of body water is located in Intracellular fluid

The largest percentage of body water is located in the intracellular fluid, which is known as the cytosol.

Cytosol

The largest percentage of body water is located in the intracellular fluid, which is known as the cytosol.

Intracellular fluid

The largest percentage of body water is located in the intracellular fluid, which is known as the cytosol.

Urine

Urine accounts for roughly 60% of the body's water loss.

Electrolyte - sodium

The most prevalent electrolyte in the extracellular fluid is sodium.

Kidney - fixed acids

The only organ of the body that can remove excess fixed acids is the kidney. Fixed acids are also called metabolic acids.

Metabolic acids

The only organ of the body that can remove excess fixed acids is the kidney. Fixed acids are also called metabolic acids.

Electrolyte - Na+

When the concentration of Na+ in the ECF decreases, there is an increase in the level of aldosterone, which causes facultative Na+ reabsorption.

Hypoventilation

Hypoventilation causes a drop in pH. Breathing slowly increases PCO2.

Acids

Weak acids only dissociate partially in solution.

Strong acids dissociate fully, and weak acids dissociate incompletely.

Na+

Na+ is the only cation exerting significant osmotic pressure in the ECF.

Buffer system

The most important buffer system in the intracellular fluid compartment (ICF) is the: protein buffer system.

Most of the buffering power of body fluids resides in cells, and most of this reflects the buffering activity of intracellular proteins.

Kidneys - infant

The kidneys are immature at birth; they are approximately half as proficient at concentrating urine as mature kidneys. Infant kidneys are also inefficient in ridding the body of acids.

Adipose

Adipose tissue is the least hydrated body tissue.

Body water

the following individuals would have the most body water?
An infant

Body water declines to about 45% of body mass in old age. In addition, increased body fat decreases the total body water because adipose tissue contains the least water of all body tissues.

Plasma

Plasma circulates throughout the body and links the internal and external environments.

Water loss

Water lost through expired air is referred to as:
insensible water loss.

Water intake is a catchall term for the water gained by the body, regardless of the route.

Plasma osmolality

If the plasma osmolality increases, ADH would be released.

Hypothalamic thirst center

A decline in blood volume would stimulate the hypothalamic thirst center.

diuresis

Diuresis peaks one hour after drinking water.

Edema

Edema is the accumulation of water in the interstitial space.

Incompetent venous valves increase the blood pressure in the veins and push fluid into the interstitial space, causing edema.


Edema is caused by increased movement of fluid from the plasma into the interstitial fluids.

Edema may be caused by high blood pressure, which intensifies filtration.

Electrolyte balance

Electrolyte balance in the body usually refers to the balance of salts.

Pica

Pica, or eating of clay chalk or burnt match tips, occurs when there is a deficiency of minerals such as iron from the body.

Renal acid base control

Renal acid-base control is coupled to Na+ transport.

Na + transport

Renal acid-base control is coupled to Na+ transport.

Estrogens

Estrogens are chemically similar to aldosterone and are therefore are associated with water retention.

Aldosterone

Estrogens are chemically similar to aldosterone and are therefore are associated with water retention.

Physiological acidosis

Any arterial pH between 7.0 and 7.35 is considered physiological acidosis.

K+

It is the lack of aldosterone that encourages K+ conservation.

Aldosterone

It is the lack of aldosterone that encourages K+ conservation.

Chloride balance

Chloride balance is directly tied to sodium balance.
Chloride passively follows sodium.

Sodium balance

Chloride balance is directly tied to sodium balance.
Chloride passively follows sodium.

Hyperventilation

Hyperventilation causes the pH to elevate.

Hyperventilation causes respiratory alkalosis.

Water loss - insensible

Insensible water loss occurs via water vaporizing out of the lungs in expired air and via direct diffusion through the skin.

Metabolic alkalosis

Vomiting and excessive aldosterone secretion would cause metabolic alkalosis.

Buffers

Proteins are the most abundant buffers in the body.
At least 3/4 of the body's buffering capacity is via intracellular proteins.

Alkaline reserve

The alkaline reserve refers to the available bicarbonate buffering capacity.

Water

Water represents roughly 50-60% of the body's weight.

Blood pH

A blood pH < 7.35 indicates acidosis, but it does NOT tell you the cause.
The cause could be either abnormally high CO2 levels or other metabolic factors.

Respiratory acidosis

Abnormally high levels of CO2 levels in the blood would result in respiratory acidosis.

Aldosterone

An important means of regulating Na+ and H2O balance in the body is through secretion of aldosterone.

The hormone aldosterone "has the most to say" about renal regulation of sodium ion concentrations in the ECF. Aldosterone usually promotes both sodium and water retention.

Na+ - regulation

An important means of regulating Na+ and H2O balance in the body is through secretion of aldosterone.

Water / H2O - balance

An important means of regulating Na+ and H2O balance in the body is through secretion of aldosterone.

Hydrogen Ions

Only a small amount of acidic substances enter the body via ingested foods. Most hydrogen ions originate as byproducts or end products of metabolism.

Hemoglobin

Hemoglobin is an important protein buffer that absorbs hydrogen ions released from carbonic acid as oxygen is unloaded in tissue capillaries.

As tissue cells release CO2, carbonic acid forms in RBCs and dissociates into bicarbonate ions and hydrogen ions. As oxygen is unloaded to tissue cells, the negatively charged Hb attracts the free hydrogen ions, keeping them from causing a major pH change.

Water balance

When water intake equals water output, water balance is achieved.

Equilibrium is achieved when there is no net change.

K+ conservation

It is the lack of aldosterone that encourages K+ conservation.

Water

See page 996.

Water in the body occupies two main fluid compartments. Most fluid is in the intracellular fluid (ICF) compartment. ICF is fluid found inside of cells. The rest of our body water is in the extracellular fluid (ECF) compartment. The ECF consists of plasma and interstitial fluid (IF), the fluid in the spaces between tissue cells.

Electrolytes

See page 996.

Electrolytes are inorganic substances that dissociate into ions in water. Examples of electrolytes include salts [for example, sodium chloride (NaCl) and magnesium chloride (MgCl2)] and ions [for example, potassium (K+)].

Nonelectrolytes

Nonelectrolytes have bonds (usually covalent bonds) that prevent them from dissociating in water. Most nonelectrolytes are organic molecules. For example, glucose, lipids, urea, creatinine, and cholesterol are nonelectrolytes.

Na+ - sodium

See page 997.

The most abundant cation (or positively charged ion) in the extracellular fluid (ECF) is sodium (Na+). The most abundant anion (or negatively charged ion) in the ECF is chloride (Cl-).

The most abundant cation in the intracellular fluid (ICF) is potassium (K+). The most abundant anion in the ICF is hydrogen phosphate (HPO4-).

CI- chloride

The most abundant anion (or negatively charged ion) in the ECF is chloride (Cl-).

K+

The most abundant cation in the intracellular fluid (ICF) is potassium (K+).

HPO4- hydrogen phosphate

The most abundant anion in the ICF is hydrogen phosphate (HPO4-).

Extracellular fluid

The most abundant cation (or positively charged ion) in the extracellular fluid (ECF) is sodium (Na+).

The most abundant anion (or negatively charged ion) in the ECF is chloride (Cl-).

Intracellular fluid

The most abundant cation in the intracellular fluid (ICF) is potassium (K+). The most abundant anion in the ICF is hydrogen phosphate (HPO4-).

Water loss

See pages 998-999.

Water output occurs by several routes. Water that vaporizes out of the lungs in expired air or diffuses directly through the skin is called insensible water loss. Some water is also lost in perspiration and feces. The rest, about 60% of the total water output, is excreted by the kidneys in urine.

ADH

ADH acts on the ____________ to ___________ water excretion.
kidneys; decrease

See pages 999-1000.

Antidiuretic hormone (ADH) acts on the kidneys to decrease water excretion. When ADH levels are high, most or all of the filtered water is reabsorbed and a small amount of concentrated urine is excreted. When ADH levels are low, less water is reabsorbed and dilute urine is excreted.

Kidneys - decrease water excretion

Antidiuretic hormone (ADH) acts on the kidneys to decrease water excretion. When ADH levels are high, most or all of the filtered water is reabsorbed and a small amount of concentrated urine is excreted. When ADH levels are low, less water is reabsorbed and dilute urine is excreted.

Hypotonic hydration

See page 1001.

Hypotonic hydration causes hyponatremia (low concentration of Na+ in the extracellular fluid), leading to cell swelling.
,br>Edema (tissue swelling) is an atypical accumulation of fluid in the interstitial space, leading to tissue (not cell) swelling. Edema can be caused by any event that increases fluid loss from the blood to the tissues, or that prevents effective return of fluid from the interstitial space to the bloodstream.

Na+ - low concentration

Hypotonic hydration causes hyponatremia (low concentration of Na+ in the extracellular fluid), leading to cell swelling.

Na+ - excretion; reabsorption

See pages 1004-1006.

Reabsorption of sodium does not exhibit a transport maximum. In healthy individuals, nearly all sodium in the renal filtrate is reabsorbed in the proximal convoluted tubules of the kidneys.

Atrial natriuretic peptide (ANP) and progesterone increase Na+ excretion. Aldosterone is the key regulator of sodium reabsorption in the kidney. It encourages Na+ reabsorption. Estrogens, like aldosterone, also encourage Na+ reabsorption.

Ca++ - low levels

See page 1008.

Parathyroid hormone (PTH) is released in response to low Ca2+ levels. PTH causes the release of Ca2+ from the bones, increases absorption of Ca2+ by the small intestine, and increases calcium reabsorption in the proximal convoluted tubule of the kidneys.

Parathyroid hormone PTH

See page 1008.

Parathyroid hormone (PTH) is released in response to low Ca2+ levels. PTH causes the release of Ca2+ from the bones, increases absorption of Ca2+ by the small intestine, and increases calcium reabsorption in the proximal convoluted tubule of the kidneys.

Acids

See page 1009.

Small amounts of acids enter the body via ingested foods. However, most H+ ions originate as metabolic by-products or end products. For example, the breakdown of phosphorus-containing proteins, the anaerobic breakdown of glucose, fat metabolism, and the loading and transport of CO2 in the blood all serve as sources of hydrogen ions in the body.

K+ secretion

See page 1006.

The single most important factor that influences K+ secretion is the concentration of K+ in blood plasma.

Blood Plasma - pH

See pages 1009-1010.

The bicarbonate buffer system is the primary buffer system for the ECF. Recall that blood plasma is considered a part of the ECF.

The phosphate buffer system does not have a role in regulating ECF pH, but it is a very effective buffer system in urine and the intracellular fluid (ICF).

The protein buffer system is an abundant and powerful means of regulating pH inside cells, and has a limited role in buffering the blood plasma.

Physiological regulators of blood pH include the respiratory and renal systems. The rate and depth of respiration are affected by changes in CO2 levels.

Buffer systems

See pages 1009-1010.

The bicarbonate buffer system is the primary buffer system for the ECF. Recall that blood plasma is considered a part of the ECF.

The phosphate buffer system does not have a role in regulating ECF pH, but it is a very effective buffer system in urine and the intracellular fluid (ICF).

The protein buffer system is an abundant and powerful means of regulating pH inside cells, and has a limited role in buffering the blood plasma.

Physiological regulators of blood pH include the respiratory and renal systems. The rate and depth of respiration are affected by changes in CO2 levels.

Hyperventilation

Hyperventilation can lead to: respiratory alkalosis.

See pages 1010-1011.

Decreased CO2 levels will increase blood pH. If one hyperventilates, the levels of CO2 drop to below normal levels and can cause respiratory alkalosis.

Increased CO2 will lower blood pH. In response to high CO2 levels, the rate of and depth of breathing will increase in an effort to vent off excess CO2. If one is unable to breathe, CO2 levels increase, leading to respiratory acidosis.

CO2 - decreased

Decreased CO2 levels will increase blood pH. If one hyperventilates, the levels of CO2 drop to below normal levels and can cause respiratory alkalosis.

CO2 - increased

Increased CO2 will lower blood pH. In response to high CO2 levels, the rate of and depth of breathing will increase in an effort to vent off excess CO2. If one is unable to breathe, CO2 levels increase, leading to respiratory acidosis.

Kidneys - HCO3- balance

One way the kidneys maintain HCO3- balance is by: generating new HCO3-.

See pages 1011-1012.

The most important renal mechanism for regulating acid-base balance of the blood involves controlling blood bicarbonate (HCO3-) levels. This is achieved by conserving or generating HCO3- and excreting HCO3-.

Blood balance - renal mechanism

See pages 1011-1012.

The most important renal mechanism for regulating acid-base balance of the blood involves controlling blood bicarbonate (HCO3-) levels. This is achieved by conserving or generating HCO3- and excreting HCO3-.

Respiratory acidosis

Someone who is suffocating would develop:

respiratory acidosis.

See page 1014.

The most common cause of acid-base imbalance is respiratory acidosis, a result of elevated blood levels of CO2 due to shallow breathing, suffocation, or lung diseases that impede O2 and CO2 exchange.

Acid base imbalance

See page 1014.

The most common cause of acid-base imbalance is respiratory acidosis, a result of elevated blood levels of CO2 due to shallow breathing, suffocation, or lung diseases that impede O2 and CO2 exchange.

Kidneys - infants

increased risk for dehydration?
Their inefficient kidneys.

See page 1015.

At birth, the kidneys are inefficient; these infant kidneys do not concentrate urine or conserve water efficiently, putting infants at risk for dehydration. Vomiting, diarrhea, and a high rate of insensible water loss also increase the risk for dehydration.

Dehydration - infants

Their inefficient kidneys.

See page 1015.

At birth, the kidneys are inefficient; these infant kidneys do not concentrate urine or conserve water efficiently, putting infants at risk for dehydration. Vomiting, diarrhea, and a high rate of insensible water loss also increase the risk for dehydration.

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