Chapter 16: Renal System Flashcards Preview

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Flashcards in Chapter 16: Renal System Deck (20):

Body Fluid

Fluid in body – 60% of body weight
Intracellular fluid (ICF) – 40% of body weight,
Extracellular fluid (ECF) – 20% of body weight,
Interstitial fluid (IF) – 15% of body weight,
Blood plasma (BP)– 5% of body weight,

If your weight is 70 Kg, your fluid is:
ICF = 70 Kg X 0.40 = 28 Liters,
ECF = 70 Kg X 0.20 = 14 Liters,
IF = 70 Kg X 0.15 = 10.5 Liters,
BP = 70 Kg X 0.05 = 3.5 Liters.

Fluid in BP – determines blood pressure!


Renal Cortex Range

~ 300 mOsm
Isotonic to blood


Renal Medulla Ranges

~300 - 1400 mOsm
hypertonic to blood


Renal Corpuscle

Blood plasma is filtered through the glomerulus-capsule membrane, the fluid that moves into the Bowman’s space is called filtrate.


Processes in Blood Filtration and Urine Formation

First step in blood processing, occurs in the renal corpuscles:
Water and solutes filter into bowman’s capsule, through glomerular-capsular membrane.


Glomerular Hydrostatic Pressure (GHP)

+ 60 mmHg. Forcing filtration. Increased GHP increases filtration/fluid in urine.


Glomerular Oncotic Pressure (GOP)

- 32 mmHG. Against filtration. Increased GOP decreases filtration/less fluid in urine. Albumin changes


Bowman's Hydrostatic Pressure (BHP)

-18 mmHg. Against filtration. Increased BHP decreases filtration/less fluid in urine.


Reabsorption at Proximal Convoluted Tubule

First part of renal tubule nearest to Bowman’s capsule,
Follows a winding, convoluted course,
Reabsorption: movement of molecules OUT of the tubule and INTO blood. Water, electrolytes and glucose are reabsorbed through secondary active transport dependent on Na+ gradient set-up by Na+/K+-ATPase pump.


Reabsorption in Loop of Henle

Water conservation process: Counter-current mechanism filtrate concentration
Separates reabsorption of water and solutes.

Descending loop
Permeable to water

Ascending loop
Permeable to NaCl, but NOT water,
Last segment hypotonic (100 mOsm/L) to ECF


Reabsorption by Distal tubule and Collecting Duct

DT and CD Function in water conservation, solute and pH balance
A small amount of solute reabsorption



functions in Na+ reabsorption


Antidiuretic hormone (ADH)

functions in water reabsorption


Natriuretic peptides

function in decreasing Na+ reabsorption


Intercalated cells

Function in pH balance – in acidosis secrete H+ in alkalosis conserve H+.


Tubular Secretion in Distal tubule

Distal Tubule: MOST secretion by mass
Primarily K+, H+

Proximal tubule – small amount
Cellular transporters – transport blood hormones, metabolites, medications, toxins, etc


Compensation for Hypertension

Atrial natriuretric hormone (ANH) - secreted by specialized cardiac atrial and ventricular muscle fibers

Promotes ↑[Na+] in urine ↑H2O in urine ↑urine volume ↑H2O loss, (opposes Aldosterone).
Secreted in response to ↑blood pressure or ↑blood volume.


Compensation for Hypotension

ADH secreted by hypothalamus influences water reabsorption:
↑H2O reabsorption ↓urine volume preventing water loss.

Aldosterone: activated by the RAAS (renin-angiotensin-aldosterone system) mechanism
↑Na+ reabsorption in distal tubule ↑[Na+] in blood ↑ H2O reabsorption into blood.


RAAS (Renin, Angiotensin, Aldosterone)

For hypotension. Renin (kidney) + Angiotensin-converting enzyme (ACE) (Liver) = Angiotensin 1 (Lungs) --> Angiotensin 2 --> Aldosterone --> Salt + Water Retention/Vasoconstriction


Ethanol decreases ADH, what does that do to urine volume?

Increases Urine volume (it's a diuretic)