Anatomy

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Anatomy PathoPhysiology of the Kidneys

• C Neph ( C ) Review

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Function

• Regulate the composition and concentration of the
  extracellular fluids surrounding the body cells.
• Function is accomplished by the production of
  urine.
• During the process of urine formation other
  functions are occurring
• Regulate volume of blood plasma
• Control the concentration of waste products in
  the blood
• Regulate concentration of the plasmas
  electrolytes.
• Contribute to the acid/base level (the pH) of the
  plasma

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Find those kidneys!

• To locate your kidneys, put your hands on your
  hips, and then slide your hands up until you can
  feel your ribs. Place your thumbs on your back
  and you have located the kidneys. You cant feel
  them, but they are there.

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Gross Anatomy

• The kidney
• Paired bean-shaped organs.
• Size of your fist
• Each kidney weighs average 0.5 of your total
  body weight (113 170g), 10 - 12 cm long, 5 -
  6cm wide, 5.5 cm thick.

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• Behind the peritoneum at the back of the
  abdominal cavity.
• Referred to as retroperitoneal
• Symmetrical to the spinal column at the level of
  the 12th Thoracic vertebra (T12) to the 3rd
  lumbar vertebra (L3).
• Right kidney is lower than the left due to the
  location of the liver.

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Anatomy of the Kidney

• Each kidney covered by a fibrous capsule.
• This is covered by a perinephric fat then by
  the perinephric (Perirenal Fascia, which also
  encloses the adrenal gland.
• Hilus

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Sagittal section
Renal Medulla

• Renal cortex is the outer zone of the kidney and
  the renal medulla is the inner zone made up of
  the renal pyramids.
• The cortex contains all the glomeruli and medulla
  contains the loops of Henle, the vasa recta, and
  final portions of the collecting ducts.

Renal Cortex
Cortex
Medulla
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Draining System

• The pelvis of the ureter divides into two or
  three major calyces
• Subdivides into two or three minor calyces.
• Each minor calyx contains a renal papilla, which
  is the apex of the medullary pyramid.

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Draining System

• Ureter passes out of the kidney behind the
  peritoneum on the psoas muscle and then enters
  the pelvis in front of the sacroiliac joint.
• Moves down the the lateral pelivc wall towards
  the ischial spine and then turns forward and
  medially to enter the bladder.

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Vessels Nerves

• Blood vessels and the ureter connect with the
  kidney at the renal hilus

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• Renal artery from the aorta and usually divides
  into three branches.
• Two pass in front of the ureter
• One goes behind
• Renal Vein
• Comprised of five or six small veins coming
  together entering the inferior vena cava.

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Glomerulus
Efferent Arterioles
Renal Artery
Interlobular Veins
Arcuate Veins
Segmental artery
Interlobar artery
Arcuate artery
Interlobular Artery
Afferent Arterioles
Glomerulus
Interlobar veins
Segmental Vein
Renal Vein
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Nerves

• Position of the lymphatic and renal sympathetic
  nerves is variable
• Lymphatic drain to the aortic lymph nodes
• Sympathetic nerves supply the renal vasculature,
  juxtaglomerular apparatus, and to a lesser extent
  rest of the nephron.
• Afferent fibers enter the spinal cord at T10,
  T11, T12.
• Afferent nerves from the ureter enter the spinal
  cord at T11, T12, L1, and L2.
• The bladder connection is at S3, S4, and S5

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Production of Urine

• Urine formed by filtration in the glomerulus it
  is then modified in the tubules by the
  reabsorption and secretion of substances.

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Microanatomy

• The Nephron
• Basic unit of the kidney
• Responsible for the actual purification and
  filtration of the blood
• About one million nephrons are in each kidney

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Types of nephrons

• Cortical nephrons located throughout the renal
  cortex and have short loops of Henle
• Juxtamedullary nephrons begin near the
  corticomedullary junction and have long loops of
  Henle, descend deep into the medulla and enable
  to concentrate urine effectively.
• Cortical nephrons vs juxtamedullary 71 ratio

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Renal Corpuscles

• Each nephron is made up of a very small filter
  called a glomerulus
• Each glomerulus is attached to a tubule

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Functional Unit of the Kidney
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Source http//people.eku.edu/ritchisong/bird_excr
etion.htm
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Osmotic Gradient
Proximal convoluted tubule
Peritubular capillary
Passive Transport
Cl-
Na
Accumulation of Na
Active Transport
stimulates
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Proximal Convoluted tubules
Peritubular
H2O
Na
Cl
Na
Cl
H2O
Cl
Na
Na
Na
Cl
Cl
Na
H2O
Cl
Na
Cl
Na
Cl
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Juxtaglomerular Apparatus

• Consist of Macular densa (specialised cells) and
  renin releasing cells. They are responsible for
  maintaining a constant blood flow though the
  glomerulus and thus a constant GFR despite
  fluctuations in arterial pressure.
• Localized feedback system

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Juxtaglomerular apparatus
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Hormone Activity

• Anitdiuretic hormone (ADH)
• Opens membrane pores in the collecting duct and
  allows water to pass
• Produced by neurons in the hypothalamus
• Secreted by the posterior lobe of the pituitary
  gland
• Stimulated when chemical receptors in the
  hypothalmus respond to an increase or decrease of
  sodium and other ions in the blood.

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Aldosterone

• In the distal convoluted tubules
• Reabsorption of sodium ions
• Reabsorption of water
• Stimulates secretion of potassium from blood into
  the fluid of the distal convoluted tubule.
• Secreted by the cortex of the adrenal gland.

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Urine

• 95 water
• 5 solids (organic wastes, ions, salts)
• Organic wastes
• Urea product of liver metabolism
• Produced during the conversion of amino acids to
  energy-supplying compounds
• Ammonia
• Uric acid (from nucleic acid breakdown)
• Creatinine (product of creatine phosphate
  utilization in the muscle cells)
• Ketones resulting breakdown of fat molecules

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• Ions
• Cations (sodium, potassium, magnesium, and
  calcium)
• Anions (chloride, sulfate, and phosphate)

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Characteristics of Human Urine

• Clarity Transparent or clear becomes cloudy on
  standing
• Specific Gravity 1.015 to 1.020
• Color Amber or straw-colored
• Amount in 24 hours About 3 pints (1500ml)
  varies according to fluid intake, amount of
  perspiration, and other factors
• pH Acidic, may be alkaline normal pH range is
  4.6 to 8.0 average, about 6.
• Odor Characteristics urine odor develops
  ammonia on standing from formation of ammonium
  compounds

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Excretory Organs

• Small Intestine
• Approximately 20 feet (6m) long
• Coiled tube contains roughly 2700 square feet
  (300m2) of surface area for absorbing nutrients
  into the bloodstream

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Excretory Organs

• Large Intestine
• Functions as a receptacle where water and
  electrolytes can be reabsorbed into the
  bloodstream and undigested material is compacted
  and stored as feces.

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Excretory Organs

• Liver
• Metabolizes the products of hemoglobin or red
  blood cells and excretes the products of
  hemoglobin breakdown as bile pigments.
• Lungs
• Excrete carbon dioxide and give off some water
• Skin
• Excretory organ it excretes perspiration during
  sweating