Body fluids, electrolyte balance and the basics of kidney function Flashcards
Describe how total body water is distributed between intracellular, extracellular and vascular compartments Describe the factors influencing disposition of fluid in the body Describe the distribution of ions across a physiological membrane List the basic physiological functions/roles of the kidney
What are the 2 types of body fluids?
Intra and extra cellular fluid
What is intracellular fluid? (3)
Represents all fluid inside of cells
Provides stable medium for normal cell functioning
2/3 of total body fluids
What is extracellular fluid? (4)
Represents all fluids outside of cells
Plasma, interstitial fluid
Transcellular fluid
1/3 of total body fluids
What is homeostasis?
Mechanisms which control the internal environment to keep conditions in the body relatively constant
What is the ratio of fluids in the body?
Intra cellular - 40% (out of 60%)
Extracellular: interstitial 15%, plasma 5%
What is the difference between plasma and interstitial fluid?
Higher concentration of proteins present in plasma
What is responsible for the osmotic gradient across capillary walls and what else does it do?
Plasma proteins
Counteracts hydrostatic pressure of capillary blood
What are the 2 forces that influence the exchange of water between body parts?
Hydrostatic pressure
Colloid osmotic pressure
What is colloid osmotic pressure?
The hydrostatic pressure which is applied to the compartment containing solute, to prevent net entry of water
What is hydrostatic pressure equal to?
The fluid pressure of the solution
What is osmolality and what is its units?
Concentration per unit weight of water
mosmoles/kg H2O
What pump maintains a concentration gradient within a cell?
Active Na+/K+ transport pump
What does the osmolality of extracellular fluid depend on?
What does the osmolality of intracellular fluid depend on?
Extracellular: Na+ content
Intracellular: K+ content
What are the 2 ions in extracellular fluid and what do they do?
Na+: key role in fluid and electrolyte balance
Cl-: regulates osmotic pressure ans renard réabsorption of Na+
What are the 2 main ions in intracellular ions and what do they do?
K+ (lots): mairitaing intracellular volume and regulates pH
Anions
What is the composition of ions in extracellular and intracellular environments? (3x2)
: :Extracellular Intracellular
Na+: 142mmol/L 12mmol/L
Cl-: 103mmol/L 4mmol/L
K+: 4mmol/L 150mmol/L
What 2 factors are regulated to maintain extracellular fluid balance?
Volume
Osmolality
Why must extracellular volume be regulated? (2)
Maintain blood pressure
Maintain Salt balance
Why must extracellular osmolality be regulated? (2)
Prevent shrinking/swelling of cells
Maintain water balance
How does the kidney play a part in regulating fluid balance in the body? (2)
Maintains salt and water balance
Where are the kidneys located?
Lumbar region
What are the physiological roles of the kidney? (7)
Removal of wastes, toxic substances and drugs
Production of urine
Determination of salt balance
Determination of fluid content
Production of hormones involved in BP regulation
Production of RBCs
Long term BP control
What is the kidney surrounded by?
Tough protective fibrous renal capsule
What passes through the notch in the kidney? (5)
Renal artery Renal vein Nerves Pelvis Ureter
What is the renal cortex? (3)
Outer region of the kidney
Initial steps of urine formation are located there
Contains renal tubules
What is the renal medulla? (2)
Inner region of the kidney
Made of striated traingles - renal pyramids
What is the blood supply situation? (2)
Single renal artery from abdominal aorta
Single renal vein draining into inferior vena cava
How much cardiac output does the kidney receive?
20%
What is the blood flow ratio of cortex:medulla?
cortex 90:10 medulla
