Higher_Order_Physiology_Flashcards
What is the principle of homeostasis?
Maintenance of stable internal conditions despite external changes.
Who coined the term ‘homeostasis’?
Walter Cannon.
How does negative feedback work in homeostasis?
It detects deviations from a set point and triggers responses to return to that point.
What is an example of a positive feedback system in the body?
Childbirth contractions (labor).
What is the main function of body fluids?
Transport of nutrients, waste removal, and maintaining cellular environment.
What percentage of body weight is total body water (TBW) in an average person?
About 60%.
What is the difference between intracellular fluid (ICF) and extracellular fluid (ECF)?
ICF is within cells, ECF is outside cells.
What are the primary components of extracellular fluid?
Sodium, chloride, and bicarbonate.
How does osmotic pressure influence fluid movement between compartments?
Water moves from areas of low solute concentration to high solute concentration across a membrane.
What is the role of capillary hydrostatic pressure?
It pushes water out of capillaries into the interstitial space.
How is intracellular fluid volume calculated?
It is 40% of total body weight.
What is the normal range of blood plasma volume in the human body?
4-5 liters.
How does albumin maintain blood volume?
By generating oncotic pressure to pull water into capillaries.
What is edema and how does it occur?
Accumulation of fluid in tissues due to imbalance in fluid movement, often from low plasma oncotic pressure.
What is the primary effect of hypertonic extracellular fluid on cells?
It causes cells to shrink as water moves out.
What is the significance of sodium in plasma osmolarity?
It regulates the osmolarity and water balance in the extracellular fluid.
Why are electrolytes crucial for homeostasis?
They regulate fluid balance, pH, and electrical conductivity in cells.
What condition occurs with low potassium levels (hypokalemia)?
Muscle weakness and cardiac arrhythmias.
What is the effect of hypervolemia during pregnancy?
Increased blood volume due to the demands of the fetus and placenta.
How does water move between intracellular and extracellular compartments?
Through osmosis driven by solute concentration gradients.
What is the function of cerebrospinal fluid?
Protects and nourishes the brain and spinal cord.
What is the clinical use of mannitol?
To reduce intracranial pressure by drawing water out of the brain via osmosis.
What happens when extracellular fluid becomes hypotonic?
Water enters cells, causing them to swell.
What is the key distinction between interstitial fluid and blood plasma?
Blood plasma contains more protein anions.
How does the body regulate blood pH?
Through buffers, respiration, and renal function.
What is the physiological role of chloride in the body?
It helps maintain osmotic pressure and acid-base balance.
What is hypovolemia and what can cause it?
Decreased blood volume, often due to dehydration or hemorrhage.
Why is capillary permeability important in fluid exchange?
It allows selective movement of substances between blood and tissues.
What are transcellular fluids?
Fluids in special compartments such as synovial and cerebrospinal fluid.
What is the effect of osmosis on the equilibrium between intracellular and extracellular fluid?
It maintains equal osmotic pressure across cell membranes.
