Urinalysis and Body Fluids Exam
1|104 Complete Q’s and A’s
Urine formation - -It is an ultrafiltrate of plasma
- Average daily urine output - -600-2000 mL
- Urine composition - -95% water
5% solute
- Urea: breakdown of protein and amino acids
- Other organic substances: Creatinine and uric acid
- Inorganic substances: chloride (major component), sodium and potassium
- Urine volume - -body state of hydration
- Oliguria - -decreased urine output
less than 400 mL adult
excessive water loss: diarrhea, vomiting, severe burns, perspiration
- Anuria - -cessation of urine flow
serious damage to the kidney
decrease blood flow to the kidney
- polyuria - -increase of urine output
greater than 2.5 L/day adult
- Diabetes mellitus (increased specific gravity)
- Diabetes insipidus (decreased specific gravity, decreased or impaired ADH
production)
- Nocturia - -increased urination during the night
- Nephrons - -functional unit of the kidney
there is about 1 to 1.5 million nephrons in each kidney
- Cortical nephrons - -85% of nephrons
cortex of kidney
removal of waster products
reabsorption of nutrients
- Juxtamedullary nephrons - -longer loop of henle
medulla of kidney
concentration of urine
, - Renal Blood Flow - -Renal artery supplies 25% of blood. It enters the
nephron through afferent arteriole -> glomerulus -> efferent arteriole
- Arterioles - -the various sizes control hydrostatic pressure in glomerulus
- Peritubular capillaries surround: - -proximal for reabsorption of essential
substances
distal convoluted tubules for final urinary composition
- Vesa recta - -adjacent to loops of Henle in juxtamedullary nephrons
major exchange of water and salts between medullary interstitium and blood
(which maintains osmotic gradient in medulla)
- Nephron and component parts - -
- Glomerulus filtrate - -Glomerulus filtrate= plasma-protein
The specific gravity is about 1.010
- Bowmans capsule - -forms the beginning of the renal tubule and contains
the glomerulus
- glomerulus - -it is a coil of 8 capillary lobes, it has a nonselective filter
(less than 70,000 MW plasma substances)
- factors that influence filtration - -cellular structure- bowmans capsule,
capillary walls
hydrostatic and oncotic pressures
feedback mechanism of renin-angiotensin-aldosterone system
- factors influencing filtration - -- bowmans capsule and capillary walls
-plasma filtrate passes through 3 cellular barriers
- capillary membrane
-contains pores (fenestrated)
- increase capillary permeability but prevent passage of large molecules &
blood cells
- basement membrane (basal lamina)
- bowmans capsule visceral epithelium
- foot processes of the podocytes
- Shield of negativity - -repels molecules from filtering the 3 barriers. it is
negatively charge and proteins like albumin are repelled.
- Diagram of glomerular filtration - -
- Glomerular pressure (factors influencing filtration) - -- Enhanced filtration
, - Hydrostatic pressure combined with small size of efferent arteriole/
glomerulus capillaries
- overcomes fluid pressure from bowmans capsule and oncotic pressure in
glomerulus capillaries
- pressure maintained at constant rate, regulated by juxtaglomerular
apparatus
- dilation of afferent arterioles
- constriction of efferent arterioles
- juxtaglomerular apparatus - -
- renin-angiotensin-aldosterone system (factors influencing filtration) - --
regulates the blood flow to and within the glomerulus
- responds to changes in plasma sodium and blood pressure
- monitored by juxtaglomerular apparatus:
- juxtaglomerular cells in afferent arteriole and macula densa of distal
convuluted tubule
- Conversion in lung alveoli - -Angiotensin I -> Angiotensin II by angiotensin-
converting enzyme (ACE)
- Angiotensin II corrects renal blood flow by: - -- dilation of afferent
arterioles
- constriction of efferent arterioles
- stimulating reabsorption of water and sodium in proximal convoluted
tubules
- triggering the release of aldosterone (sodium retaining hormone) by
adrenal cortex
- triggering the release of antidiuretic hormone (ADH) by the hypothalamus
- Renin decreases - -sodium content and blood pressure back to normal
- Tubular Reabsorption - -glomerular filtrations = 120 mL/min
mechanisms are needed to reabsorb essential substances
- Reabsorption mechanisms - -• Active transport: substance must combine
with a carrier protein in renal tubular epi.
• Electrochemical energy required to complete transport back to blood
stream
• Proximal convoluted tubule-glucose, amino acids, and salts
• Ascending loop of Henle-chloride
• Distal convoluted tubule-sodium
• Maximum reabsorption capacity (Tm)
• Abnormal high concentration of substance
• Exceeds renal threshold,
1|104 Complete Q’s and A’s
Urine formation - -It is an ultrafiltrate of plasma
- Average daily urine output - -600-2000 mL
- Urine composition - -95% water
5% solute
- Urea: breakdown of protein and amino acids
- Other organic substances: Creatinine and uric acid
- Inorganic substances: chloride (major component), sodium and potassium
- Urine volume - -body state of hydration
- Oliguria - -decreased urine output
less than 400 mL adult
excessive water loss: diarrhea, vomiting, severe burns, perspiration
- Anuria - -cessation of urine flow
serious damage to the kidney
decrease blood flow to the kidney
- polyuria - -increase of urine output
greater than 2.5 L/day adult
- Diabetes mellitus (increased specific gravity)
- Diabetes insipidus (decreased specific gravity, decreased or impaired ADH
production)
- Nocturia - -increased urination during the night
- Nephrons - -functional unit of the kidney
there is about 1 to 1.5 million nephrons in each kidney
- Cortical nephrons - -85% of nephrons
cortex of kidney
removal of waster products
reabsorption of nutrients
- Juxtamedullary nephrons - -longer loop of henle
medulla of kidney
concentration of urine
, - Renal Blood Flow - -Renal artery supplies 25% of blood. It enters the
nephron through afferent arteriole -> glomerulus -> efferent arteriole
- Arterioles - -the various sizes control hydrostatic pressure in glomerulus
- Peritubular capillaries surround: - -proximal for reabsorption of essential
substances
distal convoluted tubules for final urinary composition
- Vesa recta - -adjacent to loops of Henle in juxtamedullary nephrons
major exchange of water and salts between medullary interstitium and blood
(which maintains osmotic gradient in medulla)
- Nephron and component parts - -
- Glomerulus filtrate - -Glomerulus filtrate= plasma-protein
The specific gravity is about 1.010
- Bowmans capsule - -forms the beginning of the renal tubule and contains
the glomerulus
- glomerulus - -it is a coil of 8 capillary lobes, it has a nonselective filter
(less than 70,000 MW plasma substances)
- factors that influence filtration - -cellular structure- bowmans capsule,
capillary walls
hydrostatic and oncotic pressures
feedback mechanism of renin-angiotensin-aldosterone system
- factors influencing filtration - -- bowmans capsule and capillary walls
-plasma filtrate passes through 3 cellular barriers
- capillary membrane
-contains pores (fenestrated)
- increase capillary permeability but prevent passage of large molecules &
blood cells
- basement membrane (basal lamina)
- bowmans capsule visceral epithelium
- foot processes of the podocytes
- Shield of negativity - -repels molecules from filtering the 3 barriers. it is
negatively charge and proteins like albumin are repelled.
- Diagram of glomerular filtration - -
- Glomerular pressure (factors influencing filtration) - -- Enhanced filtration
, - Hydrostatic pressure combined with small size of efferent arteriole/
glomerulus capillaries
- overcomes fluid pressure from bowmans capsule and oncotic pressure in
glomerulus capillaries
- pressure maintained at constant rate, regulated by juxtaglomerular
apparatus
- dilation of afferent arterioles
- constriction of efferent arterioles
- juxtaglomerular apparatus - -
- renin-angiotensin-aldosterone system (factors influencing filtration) - --
regulates the blood flow to and within the glomerulus
- responds to changes in plasma sodium and blood pressure
- monitored by juxtaglomerular apparatus:
- juxtaglomerular cells in afferent arteriole and macula densa of distal
convuluted tubule
- Conversion in lung alveoli - -Angiotensin I -> Angiotensin II by angiotensin-
converting enzyme (ACE)
- Angiotensin II corrects renal blood flow by: - -- dilation of afferent
arterioles
- constriction of efferent arterioles
- stimulating reabsorption of water and sodium in proximal convoluted
tubules
- triggering the release of aldosterone (sodium retaining hormone) by
adrenal cortex
- triggering the release of antidiuretic hormone (ADH) by the hypothalamus
- Renin decreases - -sodium content and blood pressure back to normal
- Tubular Reabsorption - -glomerular filtrations = 120 mL/min
mechanisms are needed to reabsorb essential substances
- Reabsorption mechanisms - -• Active transport: substance must combine
with a carrier protein in renal tubular epi.
• Electrochemical energy required to complete transport back to blood
stream
• Proximal convoluted tubule-glucose, amino acids, and salts
• Ascending loop of Henle-chloride
• Distal convoluted tubule-sodium
• Maximum reabsorption capacity (Tm)
• Abnormal high concentration of substance
• Exceeds renal threshold,
