Cell Physiology Overview

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Questions and Answers

What percentage of the body weight is contributed by fluids?

60% (correct)

50%

70%

80%

Which fluid compartment holds the majority of the body's fluids?

Plasma

Intracellular (correct)

Extracellular

Interstitial

What is the primary cause of hyponatremia?

Fluid loss due to diarrhea or vomiting (correct)

Fluid overload

Excess sodium intake

High potassium levels

Which of the following is typically a clinical sign of hyponatremia?

Muscle weakness Signup and view all the answers

Which electrolyte is considered the major extracellular electrolyte?

Sodium Signup and view all the answers

What percentage of extracellular fluid is composed of plasma?

5% Signup and view all the answers

Which statement is most accurate regarding extracellular fluid accumulation?

It can occur due to injury or compromised circulation. Signup and view all the answers

Which of the following is not an intracellular electrolyte?

Calcium Signup and view all the answers

Which fluid compartment consists of both interstitial and plasma fluids?

Extracellular Signup and view all the answers

Which of the following represents a common cause for sodium reabsorption issues?

Addison’s disease Signup and view all the answers

What is the primary function of the cell membrane?

To restrict movement of electrons and proteins Signup and view all the answers

What serious clinical signs are particularly associated with changes in potassium levels?

Bradycardia Signup and view all the answers

Which mechanism involves the movement of water across a membrane?

Osmosis Signup and view all the answers

What serum potassium concentration is considered hypotonic?

< 3.5 mEq/L Signup and view all the answers

What is the role of channel and carrier proteins in the cell membrane?

To facilitate movement of electrolytes and molecules Signup and view all the answers

How does passive transport differ from active transport?

Active transport requires energy while passive transport does not Signup and view all the answers

What is hypokalemia most commonly caused by?

Anorexia and excessive fluid loss Signup and view all the answers

What condition is hyperkalemia most likely associated with?

Urinary obstruction Signup and view all the answers

What is the primary purpose of the sodium-potassium pump?

To generate action potentials in nerve cells Signup and view all the answers

In the context of fluid therapy, why is it important to formulate the degree of dehydration?

To determine the appropriate fluid type and amount Signup and view all the answers

What is a common clinical sign of hyperkalemia?

Lethargy Signup and view all the answers

Which test is frequently performed to assess plasma concentration?

Specific gravity Signup and view all the answers

Which clinical sign is indicative of fluid overload?

Swelling in the extremities Signup and view all the answers

What compensatory mechanism occurs when blood supply to the kidneys is decreased?

Renin-angiotensin system activation Signup and view all the answers

What differentiates IV catheter types in veterinary settings?

Size and intended fluid administration type Signup and view all the answers

What is a disadvantage of using hypertonic fluids in veterinary medicine?

They can cause cellular dehydration Signup and view all the answers

Which electrolyte imbalance is characterized by symptoms of bradycardia and cardiac arrhythmias?

Hyperkalemia Signup and view all the answers

What can cause a drop in serum potassium levels?

Potassium being driven into the cells Signup and view all the answers

What is the primary method of fluid movement between the extracellular fluid (ECF) and intracellular fluid (ICF)?

Simple diffusion through the cell membrane Signup and view all the answers

What is a potential risk of acidosis in relation to potassium levels?

Potassium being driven out of the cells Signup and view all the answers

What is the primary mechanism for moving electrolytes against their concentration gradient?

Active transport Signup and view all the answers

Which statement accurately describes the function of the cell membrane?

It divides the body into different fluid compartments. Signup and view all the answers

Which route of fluid administration is often used for rapid rehydration?

Intravenous injection Signup and view all the answers

What is a notable disadvantage of using hypertonic fluids in therapy?

They may cause fluid overload rapidly. Signup and view all the answers

What is the primary role of the sodium-potassium pump in cell physiology?

To generate action potentials in nerve and muscle cells Signup and view all the answers

Which condition is commonly associated with fluid overload?

Pulmonary edema Signup and view all the answers

Which mechanism of fluid movement allows for the diffusion of molecules down their concentration gradient?

Facilitated diffusion Signup and view all the answers

What factor must be calculated to determine the appropriate amount of fluids a patient requires?

Degree of dehydration Signup and view all the answers

What does passive transport primarily rely on?

Concentration gradient Signup and view all the answers

Which type of intravenous catheter is typically used for short-term fluid administration?

Peripheral catheter Signup and view all the answers

Which fluid compartment makes up 15% of the body's fluid?

Interstitial Signup and view all the answers

What percentage of the body's fluids is stored in the intracellular compartment?

40% Signup and view all the answers

Which anion is primarily found in extracellular fluid?

Chloride Signup and view all the answers

What is the clinical consequence of significant sodium loss?

Cerebral edema Signup and view all the answers

Which condition is not commonly associated with hyponatremia?

Volume overload Signup and view all the answers

Which electrolyte is predominantly located within cells?

Potassium Signup and view all the answers

What can excessive extracellular fluid accumulation in the body lead to?

Edema Signup and view all the answers

Which of the following represents a major intracellular electrolyte?

Potassium Signup and view all the answers

Which condition can lead to hyponatremia due to fluid loss?

Addison's disease Signup and view all the answers

Which of the following best describes the plasma fluid compartment's percentage in body fluids?

5% Signup and view all the answers

What is the most common cause of hypokalemia?

Anorexia Signup and view all the answers

Which clinical signs are most closely associated with hyperkalemia?

Bradycardia and arrhythmias Signup and view all the answers

What serum potassium concentration indicates hypokalemia?

3.5 mEq/L Signup and view all the answers

Which condition may lead to hyperkalemia due to cellular release of potassium?

Acidosis Signup and view all the answers

What is the most common cause of hyperkalemia in animals?

Urinary obstruction Signup and view all the answers

When serum potassium levels drop due to cellular uptake, what happens to total body potassium?

It's lost in excess Signup and view all the answers

Which hormone is primarily involved in potassium regulation through kidney function?

Aldosterone Signup and view all the answers

What might be a clinical sign of severe potassium depletion?

Muscle weakness Signup and view all the answers

Under what condition is hyperkalemia most likely to become life-threatening?

Along with renal failure Signup and view all the answers

What can cause a significant drop in serum potassium levels in animals?

Excessive fluid loss from diarrhea Signup and view all the answers

Study Notes

Cell Physiology

Cell membrane: A semi-permeable membrane, restricting movement of large molecules like electrolytes and proteins.
Channel proteins and carrier proteins: Within the cell membrane, they are responsible for moving electrolytes and proteins.
Fluid Compartments: The body is comprised of 60% fluid, divided into intracellular (40%) and extracellular (20%).
- Extracellular fluid: Further divided into interstitial fluid (15%) and Plasma (5%).
Movement of fluids: Water moves freely between the intracellular and extracellular fluid, requiring no specific channels.
Sodium Potassium Pump: Essential for transmission of electrical messages. It is crucial for heart contractions, nerve stimulation, and muscle movement.

Electrolytes

Major Electrolytes:
- Sodium (Na+): Major extracellular electrolyte.
- Potassium (K+): Major intracellular electrolyte.
Other Electrolytes: Chloride (Cl-), Phosphorus (H2PO4-), Magnesium (Mg++), Calcium (Ca++), and Bicarbonate (HCO3-).

Hyponatremia

Most common electrolyte disturbance due to fluid loss.
- Most common causes: Diarrhea and Vomiting.
- Other causes: Diuretics, Renal disease, and Addison’s disease.
- Dramatic losses can cause cerebral edema and neurological signs.
Clinical Signs: Lethargy and muscle weakness.

Potassium

The main intracellular electrolyte.
Changes in potassium levels are serious due to their clinical signs.
Clinical Signs of Hypokalemia: Bradycardia, cardiac arrhythmias, and lethargy.
Causes of Hypokalemia:
- Anorexia
- Excessive fluid loss (GI/diarrhea or Urinary)

Hypokalemia

Serum Potassium levels: Levels begin to drop when potassium is driven into the cells. Serum potassium concentration decreases only after significant total body potassium loss (below 3.5 mEq/L).
Clinical Signs: Muscle weakness, and in severe cases, hypoventilation and hypotension.

Hyperkalemia

Causes: Urinary obstruction, trauma to the renal system, anuria or oliguria, and Addison’s disease.
Life-threatening: Potassium is normally excreted by the kidneys.
Acidosis: Potassium is driven out of the cells.
Clinical Signs: Bradycardia, arrhythmia, and lethargy.

Hypernatremia

Cause: Excessive sodium intake or insufficient water intake.
Clinical Signs:
- Mild: Thirst, lethargy, and restlessness.
- Severe: Seizures, coma, and death.
Treatment: Fluid therapy with hypotonic solutions and correction of underlying cause.

Cell Physiology

The cell membrane is a semi-permeable membrane that restricts the movement of electrons and proteins
Channel proteins and carrier proteins within the membrane are responsible for electron transport
The cell membrane divides the body into different compartments
Electrolytes and molecules flow through these compartments through either passive or active transport
Passive transport moves molecules down the concentration gradient (high to low), examples include diffusion and osmosis
Active transport moves electrolytes or proteins against the concentration gradient, an example is the Sodium Potassium Pump

Fluid Movement in the Body

Water moves freely between the extracellular fluid (ECF) and intracellular fluid (ICF) without requiring channels, carriers, or other proteins
The pumping of sodium against its concentration gradient is used for transmitting electrical signals within nerve cells
The sodium-potassium pump generates action potentials responsible for heart contraction, nerve stimulation, and overall movement of muscles and limbs
Even small changes in sodium and potassium concentrations can cause changes to bodily function, large shifts will manifest into clinical symptoms

Fluid Compartments

Approximately 60% of the body weight is composed of fluids
Intracellular fluid is approximately 40% of body weight
Extracellular fluid accounts for approximately 20% of body weight, with 15% being interstitial fluid and approximately 5% being plasma
Sodium reabsorption from the distal convoluted tubule (DCT) influences fluid compartments

Electrolytes

Major electrolytes:
- Sodium (Na+) - extracellular
- Potassium (K+) - intracellular
Other electrolytes:
- Chloride (Cl-) - major extracellular anion
- Phosphorus (H2PO4-)
- Magnesium (Mg++)
- Calcium (Ca++)
- Bicarbonate (HCO3-)

Hyponatremia

The most common electrolyte disturbance due to fluid loss
Volume loss, often due to diarrhea or vomiting
Other causes include diuretics, renal disease, and Addison’s disease
More dramatic losses can lead to cerebral edema and neurological signs
Clinical signs include lethargy and muscle weakness

Potassium

The main intracellular electrolyte
Changes in potassium levels are particularly serious due to the clinical signs that can be seen, including bradycardia, cardiac arrhythmias, and lethargy

Potassium Levels

Serum levels begin to drop when potassium (K+) is driven into the cells
Serum potassium will decrease only after a considerable loss of total body K+ loss
Serum potassium concentration < 3.5 mEq/L signifies a significant loss
Clinical signs do not appear until depletion is severe, including muscle weakness, hypoventilation, and hypotension (seen in very severe losses)

Abnormal Serum Concentrations of Potassium (K+)

Frequently occur in animals with fluid disturbances
Hypokalemia:
- Most commonly seen
- Requires supplementation
- Causes: anorexia, excessive fluid loss (GI/diarrhea or urinary)
Hyperkalemia:
- Less commonly encountered
- Causes: urinary obstruction, trauma to the renal system (ureter, bladder, etc.), anuric or oliguric states, Addison’s disease
- Life-threatening, as potassium (K+) is normally excreted by the kidneys
- Acidosis can drive potassium (K+) out of the cells, increasing serum levels

Hyperkalemia

Clinical signs include bradycardia, arrhythmia, and lethargy
Can be life-threatening, as potassium (K+) is normally excreted by the kidneys
Acidosis can drive potassium (K+) out of the cells, increasing serum levels

Questions Answered

Which of the following is not a major fluid compartment?
- Pericardial
The body is comprised of 60% fluid. What are the percentages of the two major compartments?
- 40% intracellular, 20% extracellular
What is the major extracellular electrolyte?
- Sodium
Which of the following best represents the major intracellular electrolytes?
- Phosphate, Magnesium, Potassium
Some extracellular fluids can collect in various parts of the body secondary to infection, injury, or compromised circulation?
- True
Which of the following is the largest fluid compartment of the body?
- Intracellular
What part of the brain detects an increase in plasma concentration?
- Hypothalamus
What test is routinely performed that indicates plasma concentration?
- Specific gravity
When the blood supply to the kidneys is decreased, what homeostatic mechanism is used to compensate for it?
- Renin-angiotensin system
Which electrolyte would exhibit the following clinical signs: bradycardia, cardiac arrhythmia, and lethargy?
- Hyperkalemia

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Description

This quiz covers the fundamental concepts of cell physiology, including the functions of the cell membrane, the roles of channel and carrier proteins, and the distribution of fluids in the body. Additionally, it explores the importance of electrolytes such as sodium and potassium and their roles in various physiological processes. Test your knowledge on these critical topics!