Renal structure & function anatomy and physiology .ppt

Renal

1. Structure and
Function of the
Kidneys

2. Kidney External Structure
-Renal Capsule - fibrous outer layer
-Renal Hilum - indentation that gives it bean shape
-Where renal arteries, veins, and ureters attach

3. Three Layers of Internal Anatomy
-Renal Cortex: outer layer under the
capsule where blood is actually
filtered
-Renal Medulla: middle layer that
contains renal pyramids
-Renal pyramids: collect urine once it is
made in the cortex
-Separated by renal columns which
are extensions of the cortex
-Renal Pelvis: innermost layer that
contains large urine collecting cups
-Large collecting cups are called major
calyces and are made up of smaller ones
called minor calyces

4. Blood Flow to the Kidney
-Renal artery enters the kidney and
then branches into smaller and
smaller arteries inside the kidney
-The smallest of the arteries is the
arcuate arteries that arch around
the base of the renal pyramids

5. Blood Flow Through the Kidney
-Each capillary bed can be
found in close association
with a renal nephron, which
is the filtration unit of the
kidney

6. Nephron Structure
-Renal Corpuscle Filter for blood
→
-Enters via glomerulus, which is
surrounded in a double-layered
membrane called Bowman’s Capsule
-Membrane filters out everything but
blood cells and proteins into Bowman’s
capsule
-Called glomerular filtrate

7. Nephron Structure
-Renal Tubule -> Series of tubes that
filters the glomerular filtrate so all
the bad stuff gets removed and all
the good stuff goes back to the
blood
-Proximal Tubule Loop of Henele
→ →
Distal Tubule Collecting Ducts Minor
→ →
Calyces Major calyces Renal Pelvis
→ → →
Ureter
-Surrounding capillaries allow for
reabsorption back into the
bloodstream

8. Filtration
-Glomerular Filtration: Blood filtered by glomerulus forms glomerular
filtrate containing water, salts, nutrients, and waste
-Tubular Reabsorption: Nutrients and salts are actively reabsorbed and
some water is passively reabsorbed by the peritubular capillaries
-Tubular Secretion: Substances such as urea and creatinine are actively
secreted from the peritubular capillaries into the distal tubule for
removal from the body via urine

9. Kidney Fluid Chemistry
Substance Filtered, Reabsorbed, or
Secreted
Amount in Plasma
(mg/100mL)
Amount in
Glomerular Filtrate
(mg/100mL)
Amount in Urine
(mg/100mL)
Protein Not Filtered 4000-5000 none none
Glucose Filtered and Reabsorbed 100 100 0
Sodium Filtered and Mostly
Reabsorbed
142 142 128
Potassium Filtered and Secreted 5 5 60
Urea Filtered and Secreted 26 26 1820
Creatinine Filtered and Secreted 1.1 1.1 140

10. Control of Tubular Reabsorption and Secretion
-Active and passive transport move substances across the tubular membrane to
either secrete or reabsorb them
-Hormones regulate blood pressure
-Antidiuretic hormone: causes more water to be reabsorbed to increase blood
pressure
-Aldosterone: increase reabsorption of sodium and secretion of potassium to
increase blood pressure
-Atrial natriuretic peptide (ANP): protein secreted by the atria of the heart that
decreases sodium reabsorption and increases urination to decrease blood
pressure

11. Urinary Bladder
-Once the glomerular filtrate
leaves the collecting ducts is it
called urine
-
→
Renal Pelvis Ureters
→ →
Urinary Bladder
-As urine accumulates the
bladder stretches due to the
transitional epithelial lining
and the rugae within it

12. Urination
-When the bladder is full it
sends a signal up the spinal
cord to the pons, which sends
signals down the spinal cord
to cause the contraction of
the muscular walls of the
bladder which causes it to
empty through the urethra