ap exam 4

What are electrolytes?

Ions released through dissociation of inorganic compounds

• Can conduct electrical current in solution

What two main fluids make up the ECF? Note: there are small amounts of other fluids such as lymph

interstitial fluid of peripheral tissues and the plasma of circulating blood

What fluid makes up the ICF

cytosol

List three principal ions found in the ECF.

sodium, chloride, and bicarbonate (HCO3−).

List three principal ions found in the ICF. What negatively charged organic molecule is found in large quantities in the ICF?

potassium, magnesium, and phosphate ions (HPO42−),

large amounts of negatively charged 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?

monitor plasma volume and osmotic concentration.

Which pituitary hormone promotes water retention by the kidney?

antidiuretic hormone (ADH)

What two important effects occur when ADH release is increased?

(1) It stimulates water conservation by the kidneys, reducing urinary water losses and concentrating the urine;

(2) it stimulates the hypothalamic thirst center, promoting the intake of fluids.

Which corticosteroid hormone regulates sodium and water balance by signaling sodium reabsorption by the kidney? (Remember, water follows salt!)

aldosterone

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

aldosterone

Which two hormones are released from cardiac cell walls in response to stretching (ie: increased blood volume)

ANP and BNP

The release of natriuretic peptides reduces thirst and blocks the release of ADH and aldosterone. What is the result?

The resulting diuresis (fluid loss by the kidneys) decreases both blood pressure and plasma volume, eliminating the stretching.

Define diuresis

increased excretion of urine (fluid loss by the kidneys)

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

Metabolic generation

-Results from oxidative phosphorylation in mitochondria uring aerobic metabolism

Describe sensible and insensible perspiration.

sensible perspiration—evaporation due to the secretory activities of the sweat glands—vary with physical activity.

insensible perspiration—the evaporation of water across the epithelia of the skin and lungs.

What is edema

Swelling caused by a fluid imbalance in cells

Define fluid shift

a rapid water movement between the ECF and the ICF in response to an osmotic gradient

What is hypernatremia? What is hyponatremia?

hyponatremia: abnormally low Na+ concentration

hypernatremia: abnormally high Na+ concentration

What is the principal cation in the ECF? What is the principal cation in the ICF?

Sodium is the main cation in the ECF.

Potassium is the main cation in the ICF

Imbalances in which electrolyte causes the most common problems?

imbalance between gains and losses of Na+.

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

K+

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

sodium; potassium

What is hyperkalemia? What is hypokalemia?

hyperkalemia: elevated level of K+

hypokalemia: deficiency of K+

Severe cardiac arrhythmias and muscle spasms are caused by which disorder

hyperkalemia

Muscular weakness and paralysis are caused by which disorder?

hypokalemia

What is the normal pH range of the ECF

7.35-7.45

What blood pH is considered a state of acidosis? What blood pH is considered a state of alkalosis?

acidosis: When the pH of blood falls below 7.35

alkalosis: When the pH of blood rises above 7.45

List three mechanisms that contribute to acid-base balance

including buffer systems and compensation by the respiratory and urinary systems. renal

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

volatile

Which acid spontaneously forms from carbon dioxide and water?

Carbonic acid (H2CO3)

What molecule has the molecular formula H2CO3? What molecule has the molecular formula HCO3-?

carbonic acid

bicarbonate ion

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

carbon dioxide (pCO2)

PCO2 is (choose one: directly or indirectly) proportional to blood pH

indirectly

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

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

H+ and HCO3- are released and pH decreases

H+ and HCO3- in alveolar capillaries decrease and pH increases

What is a buffer and what is its function?

dissolved compounds that stabilize the pH of a solution by adding or removing H+. Buffers include weak acids that can donate H+, and weak bases that can absorb H+.

Which two major buffer systems buffer the ICF

phosphate buffer system and protein buffer system

Which two major buffer systems buffer the ECF?

carbonic acid-bicarbonate and protein buffer systems

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

protein buffer system

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

Carbonic Acid-Bicarbonate Buffer System

Define respiratory compensation

Respiratory compensation is a change in the respiratory rate that helps stabilize the pH of the ECF.

Respiratory compensation takes place whenever body pH strays outside normal limits. Such compensation works because respiratory activity has a direct effect on the carbonic acid-bicarbonate buffer system

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

pH increases

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

pH decreases

Define renal compensation

a change in the rates of H+ and HCO3− secretion or reabsorption by the kidneys in response to changes in plasma pH.

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

increase in pH

decrease in pH

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

result from a mismatch between CO2 generation in peripheral tissues and CO2 excretion by the lungs. When a respiratory acid-base disorder is present, the CO2 level of the ECF is abnormal.

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

volatile acids and bicarbonate ions. are caused by the generation of metabolic acids or fixed acids or by conditions affecting the concentration of HCO3− in the ECF.

Define hypercapnia

an excess of carbon dioxide in the blood

Which acid/base imbalance is caused by hypoventilation?

high blood pCO2

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

emphysema, congestive heart failure, and pneumonia

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

the kidneys respond by increasing the rate of H+ secretion into tubular fluid. This response slows the rate of pH change.

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

hypocapnia

Define hypocapnia

PCO2 is lower than normal in blood

-due to hyperventilation

Which acid/base imbalance is caused by hyperventilation

reduced pCO2 levels in blood

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

This condition generally corrects itself, because the reduction in PCO2 halts the stimulation of the chemoreceptors, so the urge to breathe fades until the CO2 level has returned to normal.

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

High production of fixed or metabolic acids

- H+ overload buffer system

Lactic acidosis• After strenuous exercise or hypoxia- Ketoacidosis• In starvation and diabetes mellitus (decrease in blood pH)

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

an impaired ability to excrete H+ by the kidneys

How does the body compensate for a state of metabolic acidosis

decreased pCO2, increase in bicarbonate ions and decrease in hydrogen ions

Which acid/base imbalance is caused by alkaline tide

due to the influx into the ECF of large numbers of bicarbonate ions associated with the secretion of H+ and Cl−by the gastric mucosa. The alkaline tide temporarily increases the HCO3− concentration in the ECF during meals.; metabolic alkaliosis

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

involves a decrease in the breathing rate, coupled with an increased loss of HCO3−in urine.

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

A decrease in the glomerular filtration rate and in the number of functional nephrons reduces the body's ability to regulate pH through renal compensation.

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

A reduction in ADH and aldosterone sensitivity makes older people less able than younger people to conserve body water when losses exceed gains.

List the organs of the urinary system and briefly state their function.

kidneys: produce urine

ureters: transport urine toward the urinary bladder

urinary bladder: temporarily stores urine prior to urination

urethra: conducts urine to exterior;

in males, it also transports semen

Urination is the elimination of urine from the body. What is the medical term for urination?

micturition

Define excretion and elimination.

excretion: the removal of metabolic waste products from body fluids

elimination: the discharge of these wastes out of the body

Where are the kidneys positioned in the body?

Located on either side of vertebral column

What endocrine gland sits on top of each kidney?

adrenal glands

What condition can occur is the kidney's suspensory fibers break or become detached?

floating kidney

What is the name of the prominent medial indentation in the kidney that is the entry point for the renal artery and renal nerves and the point of exit for the renal vein and the ureter?

hilum

Inside the renal capsule, the kidney has an outer and inner region. What are they called? Which region contains renal pyramids

renal cortex (outer region)

renal medulla (inner region)-contains renal pyramids

Which vessels deliver blood directly to capillaries supplying individual nephrons?

afferent arteriole

What are the functional units of the kidneys called?

nephrons

What are two names given to the cup-shaped chamber that is part of the renal corpuscle?

glomerular capsule

bowman's capsule

Part of the renal corpuscle is the glomerulus. What is the glomerulus?

knot of capillaries that projects into the proximal end of the nephron; the site of filtration, the first step in the production of urine

Which arteriole carries blood out of the glomerulus?

efferent arteriole

What type of capillaries are glomerular capillaries?

Fenestrated capillaries

-Endothelium contains large-diameter pores

In which part of the nephron does filtration take place?

renal corpuscle

in healthy individuals, filtration produces an essentially protein-free solution, known as __________

filtrate

What is glomerulonephritis?

an inflammation of the glomeruli that impairs filtration in the kidneys.

Glomerulonephritis is often an immune complex disorder. It may develop after an infection involving which genus of bacteria?

Streptococcus

What occurs during reabsorption? What occurs during secretion?

When a substance is reabsorbed, it is "reclaimed," eventually reentering the blood.

When a substance is secreted, it enters the tubular fluid from the blood.

Reabsorption is the movement of water and solutes from the tubular lumen to the peritubular interstitium, while secretion is the movement of water and solutes from the peritubular interstitium to the tubular lumen

What is the primary function of the proximal convoluted tubule (PCT)?

Primary function is reabsorption of ions

What is the primary function of the distal convoluted tubule (DCT)?

Primary function is to reabsorb water and selected ions•

-Actively secretes undesirable substances

The juxtaglomerular complex contains a structure called the macula densa. The cells of the macula densa act like what two type of receptors

chemoreceptors or baroreceptors.

Juxtaglomerular cells in the juxtaglomerular complex are modified smooth muscle cells in the wall of the afferent arteriole. These cells function as baroreceptors. What do they monitor?

monitor blood pressure in the afferent arteriole

Juxtaglomerular cells in the juxtaglomerular complex secrete which hormone?

renin

What is the function of intercalated cells of the collecting duct?

these cells regulate the acid-base balance in the blood

there are two types of nephrons in the kidney called cortical nephrons and juxtaglomerular nephrons.

What region of the kidney is most of the renal tubule found in cortical nephrons?

What region of the kidney is most of the renal tubule found in juxtaglomerular nephrons?

superficial cortex

in renal pyramids of the renal medulla

Long, straight capillaries that parallel the juxtamedullary nephron loop are called the ________

vasa recta

What is the primary function of the descending limb of the nephron loop?

reabsorption of water from tubular fluid

List three important wastes produced during metabolism

urea, creatinine, uric acid

List the three distinct processes that form urine in the kidney

filtration, reabsorption, secretion

What two transport mechanisms are used during the reabsorption of substances and water in the renal tubule

simple diffusion or carrier proteins

osmosis used for water

Just to reiterate: _____________ is the transport of solutes from the peritubular fluid, across the tubular epithelium, and into the tubular fluid

secretion

Which four nutrients are not detected or are detected in very small amounts (<0.2 mg/dL) in urine from a healthy adult

glucose, lipids, amino acids, proteins

What is the physical reason why glomerular hydrostatic pressure (GHP) is greater than hydrostatic pressure in typical systemic capillaries

the glomerular capillaries flows into an efferent glomerular arteriole, whose luminal diameter is smaller than that of the afferent glomerular arteriole. For this reason, the efferent arteriole offers considerable resistance.

-high pressure helps with efficent filtration

What would happen if the glomerular hydrostatic pressure (GHP) and the hydrostatic pressure in typical systemic capillaries were equal? [Hint: What would not be able to happen in the renal corpuscle]?

Not be able to push water and solutes out of the bloodstream and into filtrate.

What causes capsular hydrostatic pressure?

The CsHP results from the resistance to flow along the nephron and the conducting system. (Before additional filtrate can enter the capsule, some of the filtrate already present must be forced into the PCT.)

Define net hydrostatic pressure (NHP).

the difference between the glomerular hydrostatic pressure, which tends to push water and solutes out of the bloodstream, and the capsular hydrostatic pressure, which tends to push water and solutes into the bloodstream.

What organic molecule is responsible for blood colloid osmotic pressure (pressure due to materials in a solution) (BCOP)?

suspended proteins