renal regulation

• infants are... percent water

  75
• adult males are... percent

  60
• adult female are... percent

  50

  • high fat content, less skeletal muscle
  • fat tissue is least hydrated
• water declines... in old age

  45
• water is a universal solvent
• solutes are dissolved in water
• electrolyte concentrations are expressed in milliequivalents per liter (mEq/L)


  this is the equation

  
• extracellular fluids contents:

  higher protein, lower Cl- content of plasma

  Major cation: Na+

  Major anion: Cl–
• intracellular fluid contents:

  contains more proteins than plasma

  Low Na+ and Cl–

  Major cation: K+

  Major anion: HPO42–
• electrolytes are the most abundant solutes in the body fluid
• Bulk of dissolved solutes consists of

  proteins, phospholipids, cholesterol, and triglycerides

  90% in plasma

  60% in IF

  97% in ICF
• a rise in osmolarity

  stimulates thirst

  causes ADH release
• decrease osmolarity

  not thirsty anymore

  ADH inhibition
• osmolality is maintained at

  280–300 mOsm
• pee and urine

  A) metabolism

  B) foods

  C) beverages

  D) feces

  E) sweat

  F) insensible

  G) urine

  
• Electrolytes have a greater osmotic power at equal concentrations
• Exchanges between plasma and interstitial fluid compartments take place across the...

  capillary walls
• The fluid flow from the capillary into interstitial flow is driven by...

  hydrostatic pressure
• The fluid flow from interstitial fluid into capillary is driven by

  osmotic pressure
• Lymphatics pick up remaining fluid and return it to blood
• Exchanges between the interstitial and intracellular fluid compartment occur across

  tissue cells
• What serves as the link between the body's external and internal environments?

  plasma
• osmolalities of all body fluids are nearly always equal
• Osmotic and hydrostatic pressures regulate continuous exchange and mixing of fluids
• ↑ ECF osmolality → water leaves cell
• ↓ ECF osmolality → water enters cell
• Ions move selectively into or out of cell
• • Nutrients, wastes, gases have unidirectional flow
• If osmolality of extracellular fluid is increased the fluid flow out of the cell will happen.
• Water intake must equal water output: ~2500 ml/day
• A dry mouth excites the thirst center, located in the hypothalamus.
• A decrease in the volume or increase in the osmolality of plasma,as well as an increase in baroreceptors input and rising blood levels of angiotensin II, stimulate the osmoreceptors of the thirst center.
• Electrolyte balance usually refers to the balance of salt, which enter the body in foods and leave the body in three ways: perspiration, urine, and feces.
• Regulating the electrolyte balance of the body is one of the most important functions of the kidneys.
• The most important and most abundant cation in the ECF is Na+.
• It is the only cation in the ECF that exerts significant osmotic pressure
• Blood volume and Blood pressure ↓

  diameter of arterioles ↓ and this stimulates granular cells
• Blood volume and Blood pressure ↓

  distal portion of ascending limb: ↑ filtrate osmolarity and this stimulates macula densa which then stimulates granular cells
• Granular cells secrete Renin → angiotensin II →aldosterone from adrenal cortex
• The juxtaglomerular complex is made up of the granular and macula densa cells