Homeostasis and Body Fluid Composition

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Questions and Answers

What is the term used to describe the abnormal collection of fluid within a cell?

Ascites

Hydropic degeneration (correct)

Pitting oedema

Interstitial fluid accumulation

Which type of oedema is characterized by the formation of pitting when pressure is applied?

Lymphatic oedema

Hydrothorax

Non-pitting oedema

Pitting oedema (correct)

What distinguishes transudate from exudate in oedema fluid?

Exudate is more common in cardiac and renal diseases compared to transudate.

Exudate is often associated with inflammation and has a higher protein content. (correct)

Transudate is typically found in inflammatory conditions.

Transudate has a higher protein content than exudate.

Which type of oedema is termed generalised or systemic in distribution?

Anasarca Signup and view all the answers

What is the term for fluid accumulation in the peritoneal cavity?

Ascites Signup and view all the answers

What can be a consequence of a sudden loss of 33% of blood volume?

Death Signup and view all the answers

Chronic blood loss typically leads to which condition?

Iron deficiency anemia Signup and view all the answers

What is the primary purpose of homeostasis in the body?

To maintain the normal morphology and function of cells and tissues Signup and view all the answers

Which compartment contains about 33% of the body weight in a normal adult?

Intracellular fluid compartment Signup and view all the answers

Which is a characteristic of true (or secondary) shock?

Hypoperfusion of cells and tissues Signup and view all the answers

Initial (or primary) shock is often caused by which of the following?

Neurogenic vasodilatation Signup and view all the answers

In which compartment is sodium the predominant cation?

Extracellular fluid compartment Signup and view all the answers

Which type of shock occurs due to a failure of the heart to pump effectively?

Cardiogenic shock Signup and view all the answers

What defines oedema in the context of body fluids?

Abnormal and excessive accumulation of free fluid Signup and view all the answers

What is a potential result of uncompensated circulatory shock?

Impaired cellular metabolism Signup and view all the answers

Which of the following statements about water distribution in the body is correct?

Total body water comprises 50-70% of body weight in normal adult males. Signup and view all the answers

Which of the following is NOT typically associated with primary shock?

Severe hemorrhage Signup and view all the answers

What are the main cations found in the intracellular fluid compartment?

Potassium and magnesium Signup and view all the answers

What is the primary role of living membranes in maintaining homeostasis?

To control the barrier function between compartments Signup and view all the answers

All of the following factors can lead to hypovolemic shock EXCEPT:

Infection leading to anaphylaxis Signup and view all the answers

What is the average total body water percentage in an adult female?

50% Signup and view all the answers

What is the primary feature that distinguishes cardiogenic shock from other types of shock?

Normal blood volume with sudden fall in cardiac output Signup and view all the answers

Which of the following conditions is NOT associated with cardiogenic shock?

Pulmonary embolism Signup and view all the answers

What type of shock is primarily induced by severe bacterial infections or septicaemia?

Septic (toxaemic) shock Signup and view all the answers

In neurogenic shock, which mechanism leads to the condition?

Interruption of the sympathetic vasomotor supply Signup and view all the answers

Which mechanism does NOT contribute to reduced effective circulating blood volume in shock?

Compensatory mechanisms Signup and view all the answers

What critical role do inflammatory mediators and toxins play in shock?

They induce cellular injury leading to organ dysfunction Signup and view all the answers

Which type of shock may result from adrenal insufficiency due to severe stress events?

Hypoadrenal shock Signup and view all the answers

Traumatic shock is characterized primarily by which of the following?

Inadequate plasma volume due to interstitial loss Signup and view all the answers

What is a complication that arises from progressive decompensated shock?

Pulmonary hypoperfusion Signup and view all the answers

Which metabolic change occurs as a result of impaired tissue perfusion during decompensated shock?

Switch to anaerobic glycolysis Signup and view all the answers

Which vital sign is typically depressed during decompensated shock?

Low blood pressure Signup and view all the answers

What is the clinical term for shock that exhibits no recovery despite therapy?

Irreversible shock Signup and view all the answers

Which complication is most likely to occur due to hypoxic cell injury in shock?

Acute renal failure Signup and view all the answers

Study Notes

### Homeostasis

The internal environment or milieu interieur refers to the state of the body where interstitial fluid and plasma maintain normal cell and tissue functions.
Homeostasis is the mechanism maintaining the constancy of the internal environment.
Membranes like vascular endothelium and cell walls play a crucial role in fluid, electrolyte, nutrient, and metabolite exchange.

Body Fluid Composition

Water is the primary component, comprising 50-70% of body weight in males and 50% in females.
Total body water is divided into intracellular fluid (33% body weight, mainly in muscles) and extracellular fluid (27% body weight).
Intracellular fluid has high potassium and magnesium, and low sodium and chloride.
Extracellular fluid has high sodium and chloride, and low potassium and magnesium.

### Oedema

Oedema is excessive fluid accumulation in interstitial spaces and serous cavities.
Intracellular oedema is fluid accumulation within cells, also known as hydropic degeneration.
Ascites refers to fluid in the peritoneal cavity, hydrothorax/pleural effusion in the pleural cavity, and hydropericardium/pericardial effusion in the pericardial cavity.
Pitting oedema occurs in subcutaneous tissues, where pressure creates a depression.
Non-pitting or solid oedema occurs in conditions like myxoedema and lipedema.
Localised oedema affects a specific organ or limb, while generalised oedema (anasarca or dropsy) is systemic.
Oedema fluid can be transudate (in cardiac and renal diseases) or exudate (in inflammatory oedema).

### Blood Loss

Losing up to 20% of blood volume has minimal clinical effects due to compensatory mechanisms.
Sudden loss of 33% of blood volume can be fatal, while loss of 50% over 24 hours may not be fatal.
Chronic blood loss causes iron deficiency anaemia while acute haemorrhage leads to hypovolaemic shock.

### Shock

Shock is a life-threatening syndrome of cardiovascular collapse with reduced effective circulating blood volume and inadequate cell and tissue perfusion.
Primary shock is a transient, usually benign vasovagal attack caused by reduced venous return to the heart due to neurogenic vasodilatation.
Anaphylactic shock is caused by type 1 immunologic reaction and is not due to circulatory derangement.
“True” shock is a circulatory imbalance between oxygen supply and demand.

Shock Etiology

Hypovolemic Shock: Caused by reduced circulating blood volume due to haemorrhage or plasma loss.
Cardiogenic Shock: Caused by acute heart disease leading to reduced cardiac output, not blood volume reduction.
- Deficient emptying (Myocardial infarction, cardiomyopathies, heart rupture)
- Deficient filling (Cardiac tamponade)
- Outflow obstruction (Pulmonary embolism, tension pneumothorax)
Septic Shock: Caused by severe bacterial infections or septicaemia, more commonly from Gram-negative bacteria (endotoxic shock) than Gram-positive bacteria (exotoxic shock).
Other types:
- Traumatic Shock: Caused by trauma, initially hypovolaemic, but continues with plasma loss into injured tissue.
- Neurogenic Shock: Caused by interruption of sympathetic vasomotor supply.
- Hypoadrenal Shock: Caused by adrenal insufficiency, preventing normal stress response.

### Shock Pathogenesis

Reduced Effective Circulating Blood Volume: Loss of blood volume or reduced cardiac output.
Reduced Oxygen Supply: Hypoperfusion causes cellular anoxia.
Inflammatory Mediators and Toxins: Released from shock-induced cellular injury.

Shock Complications

Pulmonary Hypoperfusion: Worsened perfusion leading to tachypnoea and ARDS.
Tissue Ischaemia: Anaerobic glycolysis causes lactic acidosis, lowering tissue pH and leading to vasodilatation.
Decompensated Shock: Progressive deterioration despite compensatory mechanisms and treatment.

### Decompensated Shock

Clinical Features: Low blood pressure, subnormal temperature, weak & irregular pulse, shallow & sighing respiration, pale face, sunken eyes, weakness, cold & clammy skin.
Life-threatening Complications:
- Acute Respiratory Distress Syndrome (ARDS)
- Disseminated Intravascular Coagulation (DIC)
- Acute Renal Failure (ARF)
- Multiple Organ Dysfunction Syndrome (MODS)
- Stupor, coma, and death.

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Description

This quiz covers the concepts of homeostasis, fluid composition, and oedema in the human body. Explore how the internal environment is maintained and the significance of body fluids in cellular functions. Test your knowledge on the various compositions and the impact of fluid accumulation disorders.