Function of Kidneys & ICF and ECF

What are the 2 functions of the kidney?

It acts as an

• Excretory organ and

• Regulatory organ

Kidney as an regulatory organ:

• What does it maintain?

• How does it achieve this?

Maintains:

• Water balance

• Electrolyte balance

• Acid-base balance (in extracellular fluid)

Achieves this through: Formation of urine

What are the 2 systems involved in feedback loops to maintain the homeostasis of renal function?

• Nervous system

• Endocrine system

How does nervous and endocrine system maintain homeostasis?

Nervous system:

• By sensing system deviations

• Sending nerve impulses to organs

Endocrine system:

• Uses release and action of hormones

Bodily Fluids

• Composed of

• 2 main compartments

  • Location

Composed of: Water and electrolytes

2 main compartments:

• Intracellular fluid (ICF)

  • Location: Inside the cell

• Extracellular fluid (ECF)

  • Location: Outside the cell

Interstitial Fluid

• AKA

• Subcategory of

• Location

  • Examples

• Major ions

• Loss of plasma

• Too much plasma

AKA: Plasma or transcellular fluid

Subcategory of: Extracellular fluid

Location: Between cells but not in blood vessels

• Examples: Usually within epithelial-lined spaces

  • Synovial fluid, CSF, bladder urine

Major ions: Sodium, chlorine, carbonate

Loss of plasma: Causes drop in blood pressure

Too much plasma: Causes high blood pressure

Extracellular Fluid (ECF)

• Appears mostly as

• What is the primary mechanism in regulation of ECF

  • How

  • Mechanism

Appears mostly as:

• Interstitial (tissue) fluid

• Intravascular fluid (within blood vessels)

What is the primary mechanism in regulation of ECF: Thirst center in hypothalamus

• What: It stimulates or inhibits the desire to drink

• How:

  • Release of vasopressin

  • Effects RAA system

  • Release of ANP (atrial natriuretic peptide) hormone

Intracellular Fluid (ICF)

• Function

Function:

• Stabilising agent

• Maintain cell shape

• Transport of nutrients

Terminology

• Function of ADH (vasopressin)

• Function of RAA system

• Edema

• Polydipsia

• Polyuria

• Diuresis

Function of ADH (vasopressin): Tells kidneys how much water to conserve

Function of RAA system: Controls fluid volume

Edema: Excess accumulation of fluid in interstitial (tissue) spaces

Polydipsia: Excessive fluid intake

Polyuria: Production of large volumes of diluted urine

Diuresis: Increased or excessive production of urine