Transcript Urinary System

‫دانشگاه علوم پزشكي و خدمات بهداشتي درماني استان‬
‫فارس‬
‫معاونت درمان‬
‫اداره امور بيماريهاي خاص‬
‫دكتر محمدرضا مرواريدي‬
‫كارشناس اداره امور بيماريهاي خاص‬
KIDNEYS AND THE
URINARY SYSTEM
MAJOR PARTS OF THE MACHINE
food, water intake
oxygen intake
Digestive System
nutrients,
water,
salts
Based on: Starr, C., Biology:
Concepts and Applications,
Brooks/Cole
Respiratory System
elimination
of carbon
dioxide
oxygen
carbon
dioxide
Circulatory System
Urinary System
water
solutes
elimination
of food
residues
rapid transport
to and from all
living cells
elimination of
excess water
salts, wastes
EXCRETION

Separation of wastes from body fluids and
eliminating them
 respiratory
system: CO2
 integumentary system: water, salts, lactic acid,
urea
 digestive system: water, salts, CO2, lipids, bile
pigments, cholesterol
 urinary system: many metabolic wastes, toxins,
drugs, hormones, salts, H+ and water
KIDNEY FUNCTIONS
Filters blood plasma, eliminates waste, returns
useful chemicals to blood
 Regulates blood volume and pressure
 Regulates osmolarity of body fluids
 Secretes renin, activates angiotensin,
aldosterone

 controls
BP, electrolyte balance
Secretes erythropoietin, controls RBC count
 Regulates PCO and acid base balance
2
 Detoxifies free radicals and drugs
 Gluconeogenesis

KIDNEYS AS FILTERS
• Diuretic- loose water; coffee, alcohol
• Antidiuretic- retain water; ADH
• Aldosterone- sodium & water reabsorption, and
K+ excretion
• GFR= 180 liters (50 gal) of blood/day
• 178-179 liters are reabsorbed back into blood
• Excrete a protein free filtrate
Examples
of Amino
Acids
All 20 amino acids have a nitrogen group (NH2).
When broken down for energy, the nitrogen group
is converted to ammonia (NH3).
Circulatory
System
Ammonia is
converted into urea
by the liver. Urea is
then transported in
the blood to the
kidneys where the
urea is removed
from the blood.
Based on: Mader, S., Inquiry Into Life
NITROGENOUS WASTES

Urea
acids NH2 removed
forms ammonia, liver converts to urea
 proteinsamino

Uric acid
 nucleic

acid catabolism
Creatinine
 creatinine

Amonia
phosphate catabolism
N ‫ـــــ‬H 3
Urinary System
Based on: Mader, S., Inquiry Into Life, McGraw-Hill
ANATOMY OF KIDNEY

Position, weight and size
 retroperitoneal,
level of T12 to L3
 about 150-160 g each
 about size of a bar of soap (12x6x3 cm)

Shape
 Bean
shape
 lateral surface - convex; medial - concave
Anatomy of the
Kidney
Based on: Mader, S., Inquiry Into Life, McGraw-Hill
LOBE OF KIDNEY
BLOOD SUPPLY DIAGRAM
RENAL CORPUSCLE
Glomerular filtrate collects in capsular
space, flows into renal tubule
FILTRATION MEMBRANE DIAGRAM
FILTRATION PRESSURE
URINE FORMATION PREVIEW
Nephron
Based on: Mader, S., Inquiry Into Life, McGraw-Hill
REGULATION OF WATER BALANCE
Brain monitors water content of blood
If low water content, pituitary releases ADH
ADH travels in blood to nephron
ADH causes more water to move from urine
back into blood
Nephron
Based on: Mader, S., Inquiry Into Life, McGraw-Hill
EFFECTS OF GFR ABNORMALITIES
•
•
•
GFR, urine output rises  dehydration,
electrolyte depletion
GFR  wastes reabsorbed (azotemia possible)
GFR controlled by adjusting glomerular blood
pressure
–
–
–
hormonal mechanism: renin and angiotensin
autoregulation
sympathetic control
HORMONAL CONTROL
OF KIDNEY FUNCTION
high plasma
solute
concentration
low blood volume
heart receptors
hypothalamus
HORMONAL CONTROL
OF KIDNEY FUNCTION
hypothalamus
posterior pituitary
antidiuretic hormone
collecting ducts
HORMONAL
CONTROL OF
KIDNEY
FUNCTION
HORMONAL CONTROL
OF KIDNEY FUNCTION
reduced blood pressure and
glomerular filtrate
juxtaglomerular apparatus
renin
HORMONAL CONTROL
OF KIDNEY FUNCTION
angiotensinogen
angiotensin I
angiotensin II
renin
HORMONAL CONTROL
OF KIDNEY FUNCTION
angiotensin II
adrenal cortex
aldosterone
convoluted tubules
HORMONAL
CONTROL OF
KIDNEY
FUNCTION
HORMONAL CONTROL OF GFR
-efferent arterioles
JUXTAGLOMERULAR APPARATUS
- vasomotion
- monitor salinity
RENAL AUTOREGULATION OF GFR
 BP  constrict afferent
arteriole, dilate efferent
  BP  dilate afferent
arteriole, constrict efferent
 Stable for BP range of 80 to
170 mmHg (systolic)
 Cannot compensate for
extreme BP

NEGATIVE FEEDBACK CONTROL OF GFR
SYMPATHETIC CONTROL OF GFR
Strenuous exercise or acute conditions
(circulatory shock) stimulate afferent arterioles
to constrict
  GFR and urine production, redirecting blood
flow to heart, brain and skeletal muscles

URINE VOLUME
Normal volume - 1 to 2 L/day
 Polyuria > 2L/day
 Oliguria < 500 mL/day
 Anuria - 0 to 100 mL

• Contents of urine
Water
Salts
Glucose
Urea
Daily filtration
180 liter
700 gm
170 gm
50 gm
Actual excretion
1.5 liter
15 gm
0
30 gm
• Urine
– Daily output 1200 to 1500 ml
– 95 % water, 5 % salts & organic matter
– Urea, uric acid, salts of potassium, magnesium and
calcium
Urinalysis
Why do doctors ask for a urine sample?
characteristics:
• smell- ammonia-like
• pH- 4.5-8, ave 6.0
• specific gravity– more than 1.0; ~1.001-1.003
• color- affected by what we eat: salty foods,
vitamins
Abnormal Constitutes of Urine
Glucose- when present in urine condition called
glycosuria (nonpathological) [glucose not
normally found in urine]
Indicative of:
• Excessive carbohydrate intake
• Stress
• Diabetes mellitus
Abnormal Constitutes of Urine
Albumin-abnormal in urine; it’s a very large
molecule, too large to pass through glomerular
membrane > abnormal increase in permeability of
membrane
Albuminuria- nonpathological conditions- excessive
exertion, pregnancy, overabundant protein intake-leads to physiologic albuminuria
Pathological condition- kidney trauma due to blows,
heavy metals, bacterial toxin
Abnormal Constitutes of Urine
Ketone bodies- normal in urine but in small amts
Ketonuria- find during starvation, using fat stores
Ketonuria is couples w/a finding of glycosuria-- which is
usually diagnosed as diabetes mellitus
RBC-hematuria
HemoglobinHemoglobinuria- due to fragmentation or hemolysis of
RBC; conditions: hemolytic anemia, transfusion reaction,
burns or renal disease
Abnormal Constitutes of Urine
Bile pigmentsBilirubinuria (bile pigment in urine)- liver pathology such as hepatitis
or cirrhosis
WBCPyuria- urinary tract infection; indicates inflammation of urinary tract
Casts- hardened cell fragments, cylindrical, flushed out of urinary
tract
WBC casts- pyelonephritus
RBC casts- glomerulonephritus
Fatty casts- renal damage