Body Fluids and Their Compartments

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Questions and Answers

What is the primary role of cerebrospinal fluid (CSF)?

Hydraulic shock absorber (correct)

Support neuronal regeneration

Store glucose for metabolic processes

Transport oxygen to the brain

Which statement accurately describes the composition of amniotic fluid?

Has a pH range of 7.2 to 7.6

Contains high concentrations of glucose

Is produced solely by the fetus

Is clear with some fetal cells and lipids (correct)

What is the consequence of a blockade in the flow of aqueous humor?

Cataract formation

Reduced eye lubrication

Improved vision

Increased intraocular pressure leading to glaucoma (correct)

What is the typical range of daily insensible perspiration?

800-1200 ml Signup and view all the answers

What component of tears protects the eye from infections?

Lysozyme Signup and view all the answers

What is the function of synovial fluid in joints?

To lubricate joints and provide cushion Signup and view all the answers

What is the primary function of urine?

Eliminate liquid waste and maintain chemical balance Signup and view all the answers

What is the main role of pericardial fluid?

Reduce friction between pericardial membranes Signup and view all the answers

Which electrolyte is found in sweat at varying levels?

Chloride Signup and view all the answers

What is the typical pH range of peritoneal fluid?

7.46 - 8.10 Signup and view all the answers

What percentage of total body water is comprised by intracellular fluid (ICF)?

55% Signup and view all the answers

Which of the following is considered the most abundant cation in extracellular fluid (ECF)?

Sodium Signup and view all the answers

What is the primary role of sodium (Na+) in the body?

Muscle contraction and impulse transmission Signup and view all the answers

Which fluid is primarily responsible for transporting lymphocytes in the body?

Lymph Signup and view all the answers

What is the primary anion found in intracellular fluid (ICF)?

Proteins and phosphates Signup and view all the answers

What function does bicarbonate (HCO3-) primarily serve in the body?

Balancing levels of anions in fluids Signup and view all the answers

Which of the following is NOT a component of extracellular fluid (ECF)?

Cytosol Signup and view all the answers

What is the composition of lymph primarily made up of?

96% water and 4% solids Signup and view all the answers

Which component of milk provides a structural unit for growing infants?

Milk sugar (lactose) Signup and view all the answers

What is the function of chloride (Cl-) in extracellular fluid?

Balances levels of anions in fluids Signup and view all the answers

Which of the following correctly describes the composition of body fluids?

Both organic and inorganic substances are present. Signup and view all the answers

How does magnesium (Mg2+) primarily function in the body?

As a cofactor for enzymes Signup and view all the answers

What is the function of potassium (K+) in intracellular fluid?

Establishes resting membrane potential Signup and view all the answers

In which type of body fluid would you most likely find triacylglycerols?

Lymph Signup and view all the answers

Study Notes

Body Fluids

Total body fluid is roughly 70% of body weight.
Divided into two compartments: intracellular fluid (ICF) and extracellular fluid (ECF).
ICF is inside cells and comprises 55% of total body water.
ECF is outside cells and comprises 45% of total body water.

Body Fluid Compartments

ECF contains interstitial fluid, present between cells, making up 80% of ECF.
ECF also contains plasma, present in blood, making up 20% of ECF.
Other ECF components include lymph, synovial fluid, vitreous body, aqueous humor, endolymph, cerebrospinal fluid, perilymph, pleural, pericardial, and peritoneal fluids.

Barriers

The plasma membrane separates ICF from interstitial fluid.
The blood vessel wall separates interstitial fluid from plasma.

Composition of Body Fluids

Body fluids contain organic substances, including glucose, amino acids, fatty acids, hormones, and enzymes.
Body fluids also contain inorganic substances such as sodium, potassium, calcium, magnesium, chloride, phosphate, and sulfate.

ECF vs ICF

The most abundant cation in ECF is sodium (Na+), responsible for muscle contraction, impulse transmission, and fluid and electrolyte balance.
The most abundant cation in ICF is potassium (K+), important for resting membrane potential, action potentials, and maintaining intracellular volume.
The most abundant anion in ECF is chloride (Cl-), regulating osmotic pressure and forming HCl in gastric acid.
The most abundant anions in ICF are proteins and phosphates (HPO42-), involved in pH regulation.
Sodium-potassium pumps maintain high K+ inside cells and high Na+ outside cells.

Sodium (Na+)

The most abundant ion in ECF, accounting for 90% of extracellular cations.
Plays a crucial role in fluid and electrolyte balance, contributing half of ECF osmolarity.

Chloride (Cl-)

The most prevalent anion in ECF.
Moves easily between ECF and ICF due to Cl- leakage channels and transporters.
Helps balance anion levels in different fluids.

Bicarbonate (HCO3-)

The second most prevalent extracellular anion.
Its concentration increases in blood passing through systemic capillaries due to carbon dioxide uptake.
The chloride shift helps maintain anion balance in ECF and ICF.

Potassium (K+)

The most abundant cation in ICF.
Establishes resting membrane potential in neurons and muscle fibers.
Maintains normal ICF fluid volume.
Regulates pH of body fluids by exchanging with H+.

Magnesium (Mg2+)

Found primarily in ICF (45%) or ECF (1%).
The second most common intracellular cation.
Acts as a cofactor for certain enzymes and the sodium-potassium pump.
Essential for synaptic transmission, neuromuscular activity, and myocardial function.

Specialized Fluids of the Body

Lymph: Clear, colorless fluid composed of 96% water and 4% solids. Solids include proteins (albumin, globulin, fibrinogen, prothrombin, clotting factors, antibodies, enzymes), lipids (chylomicrons, lipoproteins), carbohydrates (glucose), non-protein nitrogen (urea and creatinine), and electrolytes (sodium, calcium, potassium, chloride, bicarbonates).
Milk: Secreted by mammary glands, providing a complete natural food. Composition: 83-87% water, 13-17% solids (lactose, triacylglycerols, palmitic acid, myristic acid, stearic acid, lauric acid, butyric acid, oleic acid, caesin, lactalbumin, enzymes, immunoglobulins, Ca, Mg, P, Na, K, Cl, fat-soluble and water-soluble vitamins except vitamin C).
Cerebrospinal Fluid (CSF): Clear, colorless liquid formed within brain cavities and surrounding the spinal cord. Volume is 120-150ml, replaced three times daily.
Amniotic Fluid (AF): Liquid produced by membranes and the fetus. Volume increases with gestational age; contains fetal cells and lipid.
Aqueous Humor: Fluid filling the anterior chamber of the eye, secreted by the ciliary body. Blockage leads to glaucoma due to increased intraocular pressure.
Sweat: Secretion of sweat glands, regulating body temperature. Controlled by the autonomic nervous system and influenced by adrenal cortical steroids.
Tears: Produced by lacrimal glands, initially isotonic but becomes hypertonic due to evaporation.
Synovial Fluid: Clear, colorless fluid with a pH of 7.40-8.16, composed of hyaluronan, lubricin, proteinase, collagenases, and prostaglandins.
Urine: pH 6.0–7.5, composed of water (95%), urea (2%), creatinine (0.1%), uric acid (0.03%), chloride, sodium, potassium, sulfate, ammonium, phosphate, and other ions and molecules.
Pericardial Fluid: pH 7.35 to 7.55, clear, straw-colored fluid with nucleated cells, mesothelial cells, leucocytes, lymphocytes, protein, albumin, LDH.
Peritoneal Fluid: pH range 7.46 - 8.10, clear to pale yellow fluid, less than 50 mL with 3.0 g/mL of protein. Found in the peritoneal cavity, a space between the abdominal wall and internal organs.

Functions of Body Fluids

Lymph: Returns protein from tissue spaces to blood, redistributes fluids, removes bacteria, toxins, and foreign bodies, maintains tissue integrity, helps with intestinal fat absorption, and transports lymphocytes.
Milk: Provides galactose for infant growth, metabolized to lactic acid in the intestine to eliminate harmful bacteria, a source of protein, minerals, and vitamins.
CSF: Acts as a hydraulic shock absorber, regulates intracranial pressure, influences hunger and eating behaviors.
AF: Protects the fetus physically, serves as a medium for chemical exchange.
Aqueous Humor: Fills the anterior chamber of the eye, provides nutrients to the cornea and lens, helps maintain eye pressure.
Sweat: Regulates body temperature through cooling and evaporation.
Tears: Protect the eye from infectious agents, lubricate the cornea, improve optical properties, protect from injury.
Synovial Fluid: Lubricates joints, cushions bone ends, provides nutrients.
Urine: Eliminates liquid waste (urea), balances chemicals (potassium, sodium) and water.
Pericardial Fluid: Reduces friction between pericardial membranes during heartbeats, fixes the heart in the chest cavity, prevents heart overstretching and overfilling.
Peritoneal Fluid: Supports abdominal organs, facilitates passage of nerves, blood vessels, and lymphatics, lubricates peritoneal cavity organs.

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Description

Explore the crucial roles of body fluids in human physiology. This quiz covers the composition, distribution, and significance of intracellular and extracellular fluids, along with their individual components. Test your knowledge on how these fluids interact and maintain homeostasis within the body.