1. Week 15 Lecture 7.0 – The Human Renal System
Mr.ZAKARIYA AL NAAMANI Anatomy & Physiology II (NURS 190)

2. Mr.ZAKARIYA AL NAAMANI Anatomy & Physiology II (NURS 190)
Course Outcomes
On completion of the week’s activity, the students should be able to
describe the structures and functions of the organs of renal system;
describe a nephron;
describe the process of urine formation.
Mr.ZAKARIYA AL NAAMANI Anatomy & Physiology II (NURS 190)

3. Mr.ZAKARIYA AL NAAMANI Anatomy & Physiology II (NURS 190)
Kidneys’ functions
Allowing wastes & excess ions to leave the body in urine
Returning needed substances to the blood
Regulate the blood’s volume & chemical make up, so that the proper balance between water & salt & between acids & bases is maintained
Producing the enzyme : Renin, help regulate blood pressure & hormone: erthropoietin, stimulates red blood cells production in bone marrow
Mr.ZAKARIYA AL NAAMANI Anatomy & Physiology II (NURS 190)

4. Mr.ZAKARIYA AL NAAMANI Anatomy & Physiology II (NURS 190)
Kidneys
Two bean-shaped organs that are located at the back of the peritoneum (retroperitoneal) in the superior lumbar region.
Right kidney positioned slightly lower than the left due to the liver position
Mr.ZAKARIYA AL NAAMANI Anatomy & Physiology II (NURS 190)

5. Kidneys Enclose each kidney & give a glistening appearance.
surrounds each kidney a fatty mass , adipose capsule , helps hold it in the place
Mr.ZAKARIYA AL NAAMANI Anatomy & Physiology II (NURS 190)

6. Kidneys The outer region, light in color
Mr.ZAKARIYA AL NAAMANI Anatomy & Physiology II (NURS 190)

7. Mr.ZAKARIYA AL NAAMANI Anatomy & Physiology II (NURS 190)
Kidneys
Kidney Anatomy
Darker, reddish-brown area.
Medulla has :
Medullary pyramids which are separated by cortex like tissue called renal columns
Mr.ZAKARIYA AL NAAMANI Anatomy & Physiology II (NURS 190)

8. Mr.ZAKARIYA AL NAAMANI Anatomy & Physiology II (NURS 190)
Kidneys
Basinlike cavity, located in the medial to the hilus. It is continuous with the ureter
Mr.ZAKARIYA AL NAAMANI Anatomy & Physiology II (NURS 190)

9. Mr.ZAKARIYA AL NAAMANI Anatomy & Physiology II (NURS 190)
Kidneys
A cup – shaped areas, extensions of the pelvis that enclose the tips of the pyramids
Collect urine which continuously drains from the tips of the pyramids into the renal pelvis
Mr.ZAKARIYA AL NAAMANI Anatomy & Physiology II (NURS 190)

10. Mr.ZAKARIYA AL NAAMANI Anatomy & Physiology II (NURS 190)
Blood Supply
Mr.ZAKARIYA AL NAAMANI Anatomy & Physiology II (NURS 190)

11. Nephrons & Urine Formation
Structural and functional units of the kidneys are called nephrons
Responsible for forming the urine product
Mr.ZAKARIYA AL NAAMANI Anatomy & Physiology II (NURS 190)

12. Structure of the Nephron
Kidney Anatomy
Each nephron
Consists of a glomerulus and renal tubule
Subdivisions of the renal tubule
(from the glomerulus) are
Glomerular (Bowman’s) capsule
Proximal convoluted tubule (PCT)
Loop of Henle (LOH)
Distal convoluted tubule (DCT)
Collecting duct (CD)
Mr.ZAKARIYA AL NAAMANI Anatomy & Physiology II (NURS 190)

13. Structure of the Nephron
Each nephron associated with two capillary beds
Peritubular Capillaries
Specialized for absorption
Arises from efferent arteriole
Has low pressure & porous vessels
Glomerulus Capillaries:
Specialized in filtration
Fed and drain the glomerulus capsule (Afferent & Efferent)
Afferent arteriole has large diameter than efferent with a high blood pressure
Mr.ZAKARIYA AL NAAMANI Anatomy & Physiology II (NURS 190)

14. Nephrons & Urine Formation
Also called Bowman’s capsule
Specializes for filtration
Fed & Drain by arterioles
(Afferent & Efferent)
Has large diameter,
Very high blood pressure (To forces fluid and solutes out of the blood into the glomerular capsule)
Mr.ZAKARIYA AL NAAMANI Anatomy & Physiology II (NURS 190)

15. Nephrons & Urine Formation
Functions of the nephrons:
Filtration
Reabsorption
Secretion
Regulate the volume, composition, pH of the blood, and eliminate nitrogenous metabolic wastes (urea)
Mr.ZAKARIYA AL NAAMANI Anatomy & Physiology II (NURS 190)

16. Mechanism Urine formation :
1. Filtration :
Occurs in the glomerulus due to the high pressure in the capillary
Is a nonselective, passive process through filtration membrane .
Forms filtrate which is blood plasma without proteins or large blood cells.
Filtrate consists of useful substances, wasted & excess ions,
Mr.ZAKARIYA AL NAAMANI Anatomy & Physiology II (NURS 190)

17. Mechanism Urine formation :
Nitrogenous waste include:
Urea : formed by liver, end product of protein breakdown when amino acids are used to produce energy.
Uric acid : released when nucleic acids are metabolized.
Creatinine : associated with creatine metabolism in muscle tissue
2. Reabsorption:
Occurs in proximal convoluted tubule
Is a very selective , active process which use membrane carriers
Nitrogenous waste products are poorly reabsorbed, if at all .
Some ions are reabsorbed or allow to go out in the urine, (To maintain the proper PH and electrolyte composition of the blood)
Useful substances
(water, glucose & amino acid) must be reclaimed from the filtrate to the peritubular capillaries.
Mr.ZAKARIYA AL NAAMANI Anatomy & Physiology II (NURS 190)

18. Mechanism Urine formation :
Actively reabsorbed substances include
glucose
amino acids
some ions
PCT cells are most active in reabsorption
most of the nutrients, 65% of the water and sodium ions, and the bulk of actively transported ions are reabsorbed in the PCT
Mr.ZAKARIYA AL NAAMANI Anatomy & Physiology II (NURS 190)

19. Mr.ZAKARIYA AL NAAMANI Anatomy & Physiology II (NURS 190)

20. Kidney Physiology: Mechanisms of Urine Formation
Mechanism Urine formation :
Kidney Physiology: Mechanisms of Urine Formation
Reabsorption of additional sodium ions and water occurs in the DCT and CD, and is “hormonally” controlled:
Aldosterone increases the primary reabsorption of sodium (water follows after) mostly at the DCT
Antidiuretic hormone (ADH) enhances water reabsorption by the CD, not salt
Mr.ZAKARIYA AL NAAMANI Anatomy & Physiology II (NURS 190)

21. Kidney Physiology: Mechanisms of Urine Formation
Mechanism Urine formation :
Kidney Physiology: Mechanisms of Urine Formation
3. Secretion
means of adding substances to the filtrate
(from the blood or tubule cells)
active process that is important in eliminating drugs, certain wastes, & excess ions & in maintaining the acid-base balance of the blood
Mr.ZAKARIYA AL NAAMANI Anatomy & Physiology II (NURS 190)

22. Mechanism Urine formation :
The normal yellow color is due to urochrome (pigment that results from destruction of hemoglobin)
Characteristics of Urine
95% water
Clear & pale to deep yellow
Odor: slightly aromatic
Urine Ph around 6, Acidic.
Specific gritty (1.001 to 1.035)
Substances not founds in urine include :
Glucose
Blood proteins (albumin)
Red blood cells
Hemoglobin
White blood cells (pus)
Bile
Solutes founds in urine include :
sodium & Potassium ions
urea
Uric acid
Creatinine
Ammonia
Bicarbonate ions
Mr.ZAKARIYA AL NAAMANI Anatomy & Physiology II (NURS 190)

23. Mr.ZAKARIYA AL NAAMANI Anatomy & Physiology II (NURS 190)

24. Ureters, Urinary Bladder & Urethra:
Slander tubes each cm
Are passageways that carry urine from kidneys to the bladder by peristalsis movement
Mr.ZAKARIYA AL NAAMANI Anatomy & Physiology II (NURS 190)

25. Ureters, Urinary Bladder & Urethra:
A smooth, collapsible muscular sac that stores urine temporarily
Located in the pelvis just posterior to the pubic symphysis.
Three openings are seen in the bladder :
Two ureter openings
One urthra opening
Mr.ZAKARIYA AL NAAMANI Anatomy & Physiology II (NURS 190)

26. Ureters, Urinary Bladder & Urethra:
Is a smooth triangular region of the bladder base outlined by the three openings
Infection tend to persist in this region
Mr.ZAKARIYA AL NAAMANI Anatomy & Physiology II (NURS 190)

27. Ureters, Urinary Bladder & Urethra:
The bladder wall contains three layers of smooth muscle collectively called the detrusor muscle.
Its mucosa is a special type of epithelium called transitional epithelium (A highly modified, stratified epithelium)
Bladder holds 500ml of urine, but it is capable of holding more than twice that amount
Mr.ZAKARIYA AL NAAMANI Anatomy & Physiology II (NURS 190)

28. Ureters, Urinary Bladder & Urethra:
muscular tube that helps move urine from the bladder to the body exterior
It has two sphincters
Internal urethral : involuntary sphincter that keeps the urethra closed when urine is not being passed.
External urethral: voluntarily controlled
Mr.ZAKARIYA AL NAAMANI Anatomy & Physiology II (NURS 190)

29. Ureters, Urinary Bladder & Urethra:
in females, the urethra is 3 – 4 cm long
conducts only urine
in males, it is 20 cm long
conducts both urine & semen (“urogenital system”)
Mr.ZAKARIYA AL NAAMANI Anatomy & Physiology II (NURS 190)

30. Mr.ZAKARIYA AL NAAMANI Anatomy & Physiology II (NURS 190)

31. Micturition, or Voiding Act of emptying the bladder.
When about 200ml of urine accumulate in the bladder
A person feels the urge to void, and can post pone the time of voiding because the external sphincter is voluntarily controlled
Stretching of the bladder wall activates stretch receptors
As contraction become stronger, stored urine is forced to move from internal sphincter into the upper part of the urethra
Impulses transmitted to the sacral region , and then back to the bladder via pelvic splanchnic nerves
Cause the bladder into relax contraction,
Mr.ZAKARIYA AL NAAMANI Anatomy & Physiology II (NURS 190)

32. Fluid, Electrolyte & Acid-Base balance
Kidneys are responsible to maintain our body fluid volume & electrolytes
How??
Reabsorption of water & electrolytes by the kidneys is regulated by Hormones
2. Aldosterone Hormone
1. Antidiuretic Hormone (ADH)
Mr.ZAKARIYA AL NAAMANI Anatomy & Physiology II (NURS 190)

33. Fluid, Electrolyte & Acid-Base balance
Antidiuretic Hormone (ADH):
Anti means against
Diuresis means “flow of urine from kidney”
This hormone prevents excessive water loss in the urine
ADH released from posterior pituitary gland & travels in the blood to the kidney’s collecting ducts, where it causes the duct cell to reabsorb more water
Mr.ZAKARIYA AL NAAMANI Anatomy & Physiology II (NURS 190)

34. Fluid, Electrolyte & Acid-Base balance
2. Aldosterone :
Is the major factor regulating sodium ion content of the ECF & helps regulate the concentration of the other ions (CL,K & Mg).
About 80% of sodium in the filtrate is reabsorbed in the proximal convoluted tubules
Mr.ZAKARIYA AL NAAMANI Anatomy & Physiology II (NURS 190)

35. Fluid, Electrolyte & Acid-Base balance
When aldosterone concentrations are high in the blood
Remaining sodium chloride is actively reabsorbed in the distal convoluted tubules and collecting ducts
For each sodium ion reabsorbed, a potassium ion is secreted to the filtrate, which will bring these two ions to normal balance in the blood
Also, aldosterone will increase water reabsorption by tubules cell, because as sodium reclaimed in the blood water will follow, which will increase fluid volume
Mr.ZAKARIYA AL NAAMANI Anatomy & Physiology II (NURS 190)

36. Renin Angiotensin Aldosterone Mechanism (RAA)
Mr.ZAKARIYA AL NAAMANI Anatomy & Physiology II (NURS 190)

37. Maintaining Acid-Base balance of Blood
Blood PH must be maintained between 7.35 to 7.45
Blood PH maintained by:
respiratory system control
renal mechanism
Mr.ZAKARIYA AL NAAMANI Anatomy & Physiology II (NURS 190)

38. Maintaining Acid-Base balance of Blood
Renal mechanism:
The most important means by which the kidneys maintaining acid-base balance of the blood are :
Excreting bicarbonate (HCO3).
Reabsorbing or generating new bicarbonate
Mr.ZAKARIYA AL NAAMANI Anatomy & Physiology II (NURS 190)

39. Mr.ZAKARIYA AL NAAMANI Anatomy & Physiology II (NURS 190)
References
Marieb, E.N. (2006). Essentials of human anatomy and physiology. San Francisco, Pearson.
Tortora, G. J. (2006). Principles of anatomy and physiology. (11th. Ed.). New Jersey, John Wiley and Sons, Inc.
Mr.ZAKARIYA AL NAAMANI Anatomy & Physiology II (NURS 190)