URINARY extra credit

What do the kidneys filter?

- The kidneys filter many liters of fluid from the blood, sending toxins, metabolic wastes, excess water, and excess ions out of the body in urine while returning needed substances back to the blood

2. What are three main wastes products produced?

- Three main wastes products:

1) Urea

2) Uric acid

3) Creatine

3. Where are the kidneys in the body?

• The kidneys lie “retroperitoneal” (behind the parietal peritoneum) in the superior lumbar region of the posterior abdominal wall.

4. What is the renal hilus?

Renal hilus: a vertical cleft located on the medial surface where renal blood vessels, ureters, lymphatics and nerves enter and leave the kidney.

5. What is the difference between the cortex and the medulla?

• 1) Cortex: The superficial cortex region is light in color and has a granular appearance.

• 2) Medulla: Deep to the cortex is the darker renal medulla, which consists of cone-shaped masses called medullary pyramids or renal pyramids

6. What separates the adjacent pyramids in the kidney?

-The renal columns...inward extensions of the renal cortex...separate adjacent pyramids

7. What is the flow of urine in order out of the body?

Renal papillae → Minor calyx → Major calyx → Renal pelvis →Ureter → Bladder→ Urethra → Outside of body

8. Describe the uriniferous tubules. What are 3 interacting mechanisms inside of tubules?

• Uriniferous tubules are the main structural and functional unit of the kidney.

• Filtrations, absorption and secretion

9. What is the chief function of the nephron?

Its chief function is to regulate the concentration of water and soluble substances like sodium salts by filtering the blood, reabsorbing what is needed and excreting the rest as urine.

10. What is the purpose of the renal corpuscle?

-The first part of the nephron, occurs strictly in the cortex.

11. Describe the glomerular endothelium.

-The glomerular endothelium is fenestrated allowing large quantities of fluid and small molecules to pass from the capillary blood into the hollow interior of the glomerular capsule...the capsular space.

12. Describe the glomerulus.

• The minute convoluted capillary network in between the afferent arteriole and the efferent arteriole.

13. What does the glomerular capsule contain? What are the inner and outer layers like?

-It contains the glomerulus (capillary network).

-The inner layer is very porous to extract and absorb plasma from the glomerulus.

-The outer layer is impermeable to contain the plasma that has been extracted.

14. Where is the proximal tubule confined to?

• Confined entirely to the renal cortex

15. What is the function of the Loop of Henle?

• Function of this structure is to reabsorb water and ions from urine

16. What is the function of the distal convoluted tubule?

-function more in secretion than reabsorption

17. What does the collecting duct system do?

• The collecting duct system receives urine from several nephrons and runs straight through the cortex into the deep medulla.

- Concentrates urine /adh hormone

18. Are there more cortical or juxtamedullary nephrons?

-More cortical nephrons: 85% located in the cortex

-Juxtamedullary nephrons: 15%

19. How are the afferent and efferent arteriole different?

-Afferent arterioles are a group of blood vessels that supply the nephrons in many excretory systems.

-Larger in diameter

• Efferent arteriole: The arteriole that carries the concentrated blood (more cells,less plasma) away from the glomerulus and to the peritubular capillaries.

-Smaller in diameter

20. What is the function of the peritubular capillaries?

• Function: reabsorb some of the nutrients and plasma that were

extracted in the Bowman's capsule.

21. What do the ureters do?

-propel urine from the kidneys to the urinary bladder.

22. What does the urinary bladder do?

-smooth, collapsible, muscular sac that temporarily stores urine (up to 1000 ml = 1 liter)

23. Which urethral sphincter is voluntary?

b) External urethral sphincter: voluntary sphincter surrounding the urethra as it passes through the urogenital diaphragm 

c) Levator ani muscle: voluntary urethral sphincter

24. How are the male and female urethra different?

a) Females: the urethra is just 1.5 inches long and is bound to the anterior wall of the vagina by C.T.

b) Males: the urethra is about 8 inches and three named regions