Exam 1: Cellular Metabolism/Adaptation, Genetics, Fluid
Homeostasis, Acid-Bases UPDATED ACTUAL Questions and
CORRECT Answers
Sodium Homeostasis Primarily regulated by the RAAS, ADH, and ANP. Proper sodium balance maintains
fluid volume, blood pressure, and overall osmotic balance.
; Mechanisms: hormones released to regular blood pressure/volume/osmolarity
(concentration):
1. Renin-Angiotensin-Aldosterone System (RASS)
2. Antidiuretic Hormone (ADH)
3. Atrial Natriuretic Peptide (ANP)
Renin-Angiotensin-Aldosterone System (RAAS) Definition:
A hormone system that regulates blood pressure and fluid balance. Upon
activation (due to low blood pressure/volume), renin converts angiotensinogen to
angiotensin I, which is then converted to angiotensin II, leading to aldosterone
release and increased sodium and water absorption.
1. Renin release:
Low blood pressure or low blood volume triggers the release of renin from the
juxtaglomerular cells in the kidneys.
2. Angiotensin II formation:
Renin converts angiotensinogen (from the liver) into angiotensin I, which is then
converted to angiotensin II by the angiotensin-converting enzyme (ACE) in the
lungs.
3. Aldosterone Secretion:
Angiotensin II stimulates the adrenal cortex to release aldosterone.
4. Sodium reabsorption:
Aldosterone increases sodium reabsorption and water retention, thereby raising
blood volume and pressure.
Antidiuretic Hormone (ADH) Definition: A hormone produced by the hypothalamus and released by the
posterior pituitary gland. It promotes water reabsorption in the kidneys' collecting
ducts, concentrating urine and increasing blood volume.
Mechanisms:
1. Release in response to high osmolarity/low blood volume:
High plasma osmolarity (concentration) triggers the release of ADH from the
posterior pituitary gland.
2. Water reabsorption:
ADH increases the permeability of the collecting ducts in the kidneys to water,
promoting water reabsorption and dilution of sodium concentration in the blood.
,Atrial Natriuretic Peptide (ANP) Release in response to high blood volume:
Stretch receptors in the atria of the heart sense increased blood volume and
release ANP.
Inhibition of RAAS:
ANP inhibits renin, aldosterone, and ADH, promoting the excretion of sodium and
water, thus lowering blood volume and pressure.
Potassium Homeostasis Mainly controlled by aldosterone, insulin, acid-base balance, and kidney function.
Aldosterone Potassium excretion:
Aldosterone promotes the excretion of potassium by the distal convoluted tubule
and collecting ducts in exchange for sodium reabsorption. This is critical for
regulating serum potassium levels.
; aldosterone increases sodium reabsorption and water retention, which raises
blood volume and pressure.
--> risk for hypernatremia: hypokalemia
Insulin Cellular update:
Insulin facilitates the uptake of potassium into cells, particularly muscle cells, by
activating the sodium-potassium ATPase pump. This helps lower extracellular
potassium concentration.
>Hyperkalemia --> give insulin to lower serum potassium level.
Acid-Base Balance Acidosis:
In acidosis, hydrogen ions (H+) enter cells in exchange for K+ ions (to maintain
electrical neutrality), leading to hyperkalemia (K+ out of cell and into
blood/serum).
Alkalosis:
In alkalosis, H+ move out of cell, K+ moving into cells, and risk for hypokalemia.
Kidney function Filtration and reabsorption:
The kidneys filter K+ in the glomerulus.
K+:
K+ is secreted in exchange for Na+ under the influence of aldosterone. This means
aldosterone leads to K+ excretion.
, Regulation of Na+ and K+ Feedback mechanisms:
The body uses negative feedback mechanisms where deviations from normal
levels trigger responses to restore balance.
Hormonal control:
Hormones like aldosterone, ADH, and ANP play critical roles in regulating sodium
and potassium levels.
Dietary intake:
Adequate dietary intake of sodium and potassium is crucial for maintaining their
balance. The kidneys adjust excretion rates to match intake levels.
Osmolality Definition:
Measurement of solute concentration per kilogram of solvent. It reflects the
number of osmotically active particles in a solution and affects the distribution of
water between compartments.
Osmosis Definition: The movement of water across a semipermeable membrane from an
area of lower solute concentration to an area of higher solute concentration.
Driven by osmolarity, primarily influenced by electrolytes like sodium and
potassium. This process aims to equalize solute concentrations on both sides of
the membrane.
Osmotic Pressure Definition: The force exerted by solutes in a solution that causes the movement of
water across a semipermeable membrane. It is a critical factor in maintaining fluid
balance between compartments.
Principles:
1. The force that drives water movement across cell membranes due to differences
in solute concentration.
2. Water moves from areas of low solute concentration (hypotonic) to areas of
high solute concentration (hypertonic) until equilibrium is reached.
Think "water follows salt" - water moves from low solute to high solute to balance
concentrations.
Homeostasis, Acid-Bases UPDATED ACTUAL Questions and
CORRECT Answers
Sodium Homeostasis Primarily regulated by the RAAS, ADH, and ANP. Proper sodium balance maintains
fluid volume, blood pressure, and overall osmotic balance.
; Mechanisms: hormones released to regular blood pressure/volume/osmolarity
(concentration):
1. Renin-Angiotensin-Aldosterone System (RASS)
2. Antidiuretic Hormone (ADH)
3. Atrial Natriuretic Peptide (ANP)
Renin-Angiotensin-Aldosterone System (RAAS) Definition:
A hormone system that regulates blood pressure and fluid balance. Upon
activation (due to low blood pressure/volume), renin converts angiotensinogen to
angiotensin I, which is then converted to angiotensin II, leading to aldosterone
release and increased sodium and water absorption.
1. Renin release:
Low blood pressure or low blood volume triggers the release of renin from the
juxtaglomerular cells in the kidneys.
2. Angiotensin II formation:
Renin converts angiotensinogen (from the liver) into angiotensin I, which is then
converted to angiotensin II by the angiotensin-converting enzyme (ACE) in the
lungs.
3. Aldosterone Secretion:
Angiotensin II stimulates the adrenal cortex to release aldosterone.
4. Sodium reabsorption:
Aldosterone increases sodium reabsorption and water retention, thereby raising
blood volume and pressure.
Antidiuretic Hormone (ADH) Definition: A hormone produced by the hypothalamus and released by the
posterior pituitary gland. It promotes water reabsorption in the kidneys' collecting
ducts, concentrating urine and increasing blood volume.
Mechanisms:
1. Release in response to high osmolarity/low blood volume:
High plasma osmolarity (concentration) triggers the release of ADH from the
posterior pituitary gland.
2. Water reabsorption:
ADH increases the permeability of the collecting ducts in the kidneys to water,
promoting water reabsorption and dilution of sodium concentration in the blood.
,Atrial Natriuretic Peptide (ANP) Release in response to high blood volume:
Stretch receptors in the atria of the heart sense increased blood volume and
release ANP.
Inhibition of RAAS:
ANP inhibits renin, aldosterone, and ADH, promoting the excretion of sodium and
water, thus lowering blood volume and pressure.
Potassium Homeostasis Mainly controlled by aldosterone, insulin, acid-base balance, and kidney function.
Aldosterone Potassium excretion:
Aldosterone promotes the excretion of potassium by the distal convoluted tubule
and collecting ducts in exchange for sodium reabsorption. This is critical for
regulating serum potassium levels.
; aldosterone increases sodium reabsorption and water retention, which raises
blood volume and pressure.
--> risk for hypernatremia: hypokalemia
Insulin Cellular update:
Insulin facilitates the uptake of potassium into cells, particularly muscle cells, by
activating the sodium-potassium ATPase pump. This helps lower extracellular
potassium concentration.
>Hyperkalemia --> give insulin to lower serum potassium level.
Acid-Base Balance Acidosis:
In acidosis, hydrogen ions (H+) enter cells in exchange for K+ ions (to maintain
electrical neutrality), leading to hyperkalemia (K+ out of cell and into
blood/serum).
Alkalosis:
In alkalosis, H+ move out of cell, K+ moving into cells, and risk for hypokalemia.
Kidney function Filtration and reabsorption:
The kidneys filter K+ in the glomerulus.
K+:
K+ is secreted in exchange for Na+ under the influence of aldosterone. This means
aldosterone leads to K+ excretion.
, Regulation of Na+ and K+ Feedback mechanisms:
The body uses negative feedback mechanisms where deviations from normal
levels trigger responses to restore balance.
Hormonal control:
Hormones like aldosterone, ADH, and ANP play critical roles in regulating sodium
and potassium levels.
Dietary intake:
Adequate dietary intake of sodium and potassium is crucial for maintaining their
balance. The kidneys adjust excretion rates to match intake levels.
Osmolality Definition:
Measurement of solute concentration per kilogram of solvent. It reflects the
number of osmotically active particles in a solution and affects the distribution of
water between compartments.
Osmosis Definition: The movement of water across a semipermeable membrane from an
area of lower solute concentration to an area of higher solute concentration.
Driven by osmolarity, primarily influenced by electrolytes like sodium and
potassium. This process aims to equalize solute concentrations on both sides of
the membrane.
Osmotic Pressure Definition: The force exerted by solutes in a solution that causes the movement of
water across a semipermeable membrane. It is a critical factor in maintaining fluid
balance between compartments.
Principles:
1. The force that drives water movement across cell membranes due to differences
in solute concentration.
2. Water moves from areas of low solute concentration (hypotonic) to areas of
high solute concentration (hypertonic) until equilibrium is reached.
Think "water follows salt" - water moves from low solute to high solute to balance
concentrations.
