Physiology Total Body Water Quiz

Physiology

• Physiology is the study of the normal functions of a living organism.

Total Body Water

• In adult males, 60% of body weight is water.
• Total body water decreases with age, obesity and in females.
• Water is distributed into intracellular fluid (ICF) and extracellular fluid (ECF).
• ICF comprises 2/3 of the body's water and is located inside the cells.
• ECF compromises 1/3 of the body's water and surrounds the cells.
• ECF is further divided into interstitial fluid (ISF) and plasma.
• ISF constitutes 3/4 of the ECF and surrounds cells outside the vascular system.
• Plasma makes up 1/4 of the ECF and is the liquid component of blood.

Composition of Body Fluids

• The composition of intracellular fluid (ICF) differs greatly from extracellular fluid (ECF).
• ECF has high concentrations of sodium (Na+) and chloride (Cl-) ions, with low concentrations of potassium (K+) ions and proteins.
• ICF has high concentrations of potassium (K+) ions and proteins with low concentrations of sodium (Na+) and chloride (Cl-) ions.

Water Balance

• Sources of water gain include drinking, water in food, and metabolic water production.
• Sources of water loss include urine, insensible water loss through the skin and respiratory tract, and feces.
• Water balance is achieved when water gain equals water loss.
• Dehydration occurs if water loss exceeds water gain.
• Overhydration, or water loading, occurs if water gain exceeds water loss.

Homeostasis

• Homeostasis refers to the maintenance of constant internal conditions in the body.
• The internal environment is the extracellular fluid (ECF) which surrounds the cells.
• Homeostasis is essential for maintaining normal cell function.
• Factors that must be homeostastically maintained include pH, blood volume, blood pressure, and core body temperature.

Body Systems and Homeostasis

• Circulatory System: Continuous circulation of blood throughout the body.
• Respiratory System: Oxygen uptake and carbon dioxide release during blood passage through the lungs.
• Musculoskeletal System: Enables movement for obtaining resources and protection.
• Nervous System: Regulates movement by sending impulses to muscles.
• Endocrine System: Regulates cellular functions through hormones.
• Digestive System: Nutrient absorption into the bloodstream via the gastrointestinal tract.
• Kidneys and Urinary System: Waste and excess water removal from the blood during filtration in the kidneys.
• Immune System: Defense against foreign invaders.
• Skin: Protective outer barrier.
• Reproductive System: Continuation of the species.
• The nervous and endocrine systems are the primary regulatory systems maintaining homeostasis.