Anatomy Final

• Kidneys


  The pair of organs that regulate fluid balance and filter waste from the blood
• Ureters


  Connect the kidneys to a storage container
• Urinary bladder


  Muscular storage container which can change shape to accommodate fluid
• Urethra


  Allows fluid collected in the urinary bladder to be released from the body
• Functions of Urinary System

  1. Fluid filtration

  2. Regulates blood volume

  3. Maintains salt/water balance

  4. Maintains acid/base balance

  5. Gluconeogenesis

  6. Produces renin and erythropoietin hormones

  7. Activation of Vitamin D
• Fluid Filtration


  The kidney's filter plasma (liquid part of the blood)
• Regulates blood volume


  Increase in fluid being filtered in the kidneys, blood volume decreases (amount of fluid in circulation is lower)
• Maintains salt/water balance


  -Water follows Na+

  -If you move ions, you move fluid
• Gluconeogenesis


  Production of new glucose

  -Occurs in the liver
• Renin regulation


  Regulates BP

  1. Produces aldosterone

  2. Resorption of Na+

  3. water follows

  4.Blood pressure increases
• Erythropoietin regulation


  Regulates RBC

  -Low oxygen levels, more erythropoietin
• Activation of vitamin D

  1. Skin exposed to sun

  2. Inactive vitamin D production

  3. kidneys activate vitamin D

  4. Ca2+ absorption can occur
• Renal capsule


  Most outer portion, external covering of the kidney
• Renal cortex


  superficial region of kidney, under the capsule
• Renal medulla


  Region deep to the cortex
• renal pelvis


  Flattened region in the middle
• Renal sinus


  A structure within the pelvis which can hold filtrate
• Renal pyramids


  triangular structures made up of collecting tubules (the stripes in the pyramid)
• Renal columns


  Inward extensions of the cortex separating the renal pyramids
• Minor calces


  Merge to form major calyces
• Renal hilus


  Indentation where the ureter attaches
• retroperitoneal


  Kidneys are located behind the peritoneum

  (NOT a part of it)
• Supportive layers of the Kidney

  Renal capsule

  Adipose capsule

  Renal fascia
• Adipose capsule


  1. Acts as a cushion to prevent damage

  2. Insulates the kidney-prevents heat loss to environment
• Renal fascia


  anchors the kidneys to the rear abdominal wall
• Nephron


  structural and functional unit of the kidney
• Components of the Nephron

  Glomerulus

  Renal tubule

  Collecting ducts

  Renal Corpuscles
• Glomerulus


  Specialized true capillary bed of the kidney

  -Located between two arterioles

  -Contain leaky capillaries
• Renal tubule


  -glomerular (Bowman's) capsule

  -proximal convoluted tubule

  -loop of Henle

  -distal convoluted tubule
• Glomerular (Bowman's) capsule


  Completely surrounds the glomerulus
• Proximal convoluted tubule (PCT)


  First tube that leaves the glomerulus
• Loop of Henle


  Loop after the proximal convoluted tubule

  -Ascending and Descending
• Distal convoluted tubule (DCT)

  -Located after the loop of henle

  -Connects to a collecting duct
• Collecting ducts


  -Several nephrons can connect to a single collecting duct

  -Ultimately connect to a ureter, which carries urine to the bladder
• Renal Corpuscle


  consists of Bowman's capsule and glomerulus
• Types of Nephrons


  cortical and juxtamedullary
• Cortical nephron


  -85% of all nephrons

  -Mostly in the cortex, small part of loop of henle in medulla

  -Less concentrated urine
• juxtamedullary nephrons


  -15% of all nephrons

  -More tubule into medulla

  -More concentrated urine
• Most concentrated urine


  The deeper the loop of henle goes into the medulla, the more concentrated the urine will be

  (deeper the nephron goes into the medulla, the more resorption of water back into the blood stream)
• Change of blood flow mechanism

  Change of blood flow is used to make more concentrated urine

  1. Constrict vessels going into cortical nephrons

  2. Dilate vessels going to juxtamedullary nephrons

  (When we need to reabsorb more water, we send more blood through the JM nephrons because it is deeper in the medulla and JM makes more concentrated urine)