1. HS130: Anatomy and Physiology II
Unit 7 Seminar:
The Urinary System
Dr. Daudi K. Langat
Adjunct Professor, Kaplan University
Welcome to today’s Seminar! We will begin at the top of the hour.

2. Housekeeping issues (Unit 9 Writing Assignment)
A reminder that the Unit 9 Assignment due date is coming up soon (it is worth 100 points!)
You will continue with your voyage. Your “Fantastic Voyage!” is continuing inside a 55 year old man eating a hamburger, french fries and a root beer. You go through the following systems:
Digestive tract to review the digestion to completion
Absorption at the distal ilieum to the superior mesenteric Vein.
Urinary system, to the left kidney (trace your path from the superior mesenteric vein to the left renal artery, via the hepatic portal vein, heart and lungs
Go into the nephron and follow the urinary pathway to the outside
Wrap up your report by explaining the integration of the body systems in maintaining homeostasis. You must include at least the circulatory, digestive and urinary systems in your explanation.
References should be in APA format. Review the other PowerPoint entitled “APA Style Formatting” for more information.

3. Instructions for Unit 9 Assignment

4. APA Formatting

5. Chapter 17 The Urinary System
Seminar Topic: This week we will discuss the major components of the urinary system and the formation of urine.
Chapter 17 The Urinary System

6. KIDNEYS
Location—under back muscles, behind parietal peritoneum, just above waistline; right kidney usually a little lower than left.

7. Kidney Internal structure
Cortex —outer layer of kidney substance
Medulla—inner portion of kidney
Pyramids —triangular divisions of medulla
Papilla —narrow, innermost end of pyramid
Pelvis —expansion of upper end of ureter; lies inside kidney
Calyces —divisions of renal pelvis

8. KIDNEYS
Microscopic structure—nephrons are microscopic units of kidneys; consist of the following (Figure 17-3):
Renal corpuscle
Bowman’s capsule —the cup-shaped top
Glomerulus —network of blood capillaries surrounded by Bowman’s capsule
Renal tubule
Proximal convoluted tubule —first segment
Loop of Henle —extension of proximal tubule; consists of descending limb, loop, and ascending limb
Distal convoluted tubule —extension of ascending limb of loop of Henle
Collecting tubule —straight extension of distal tubule

10. KIDNEYS Functions Excretes toxins and nitrogenous wastes
Regulates levels of many chemicals in blood
Maintains water balance
Helps regulate blood pressure via secretion of renin

11. FORMATION OF URINE
Occurs by a series of three processes that take place in successive parts of nephron
Filtration —goes on continually in renal corpuscles; glomerular blood pressure causes water and dissolved substances to filter out of glomeruli into Bowman’s capsule; normal glomerular filtration rate 125 mL per minute
Reabsorption —movement of substances out of renal tubules into blood in peritubular capillaries; water, nutrients, and ions are reabsorbed; water is reabsorbed by osmosis from proximal tubules
Secretion —movement of substances into urine in the distal and collecting tubules from blood in peritubular capillaries; hydrogen ions, potassium ions, and certain drugs are secreted by active transport; ammonia is secreted by diffusion
Control of urine volume —mainly by posterior pituitary hormone’s ADH, which decreases it

12. Formation of urine

13. Functions of the Nephron Components
PART
FUNCTION
Renal Corpuscle
Glomerulus
Filtration of water and dissolved substances from the plasma
Receives the glomerular filtrate
Renal tubule
Proximal convoluted tubule
Reabsorption of glucose, amino acids, creatinine, lactic, citric, uric and ascorbic acids, PO42-, SO42-, Ca2+, K+, Na+ ions by active transport.
Reabsorption of proteins by pinocytosis
Reabsorption of water by osmosis
Reabsorption of chloride ions and other negatively charged ions by electrochemical attraction
Active secretion of substances such as penicillin, histamine, creatinine and hydrogen ions
Descending limb of the nephron loop
Ascending limb of nephron loop
Reabsorption of Na+, K+, Cl- ions by active transport
Distal convoluted tubule
Reabsorption of Na+ ions by active transport
Active secretion of hydrogen ions
Secretion of K+ ions both actively and by electrochemical attraction
Collecting duct

14. URETERS
Structure —narrow, long tubes with expanded upper end (renal pelvis) located inside kidney and lined with mucous membrane
Function—drain urine from renal pelvis to urinary bladder

15. URINARY BLADDER Structure (Figure 17-7) Functions
Elastic muscular organ, capable of great expansion
Lined with mucous membrane arranged in rugae, as is stomach mucosa
Functions
Storage of urine before voiding
Voiding

16. URETHRA Structure Functions
Narrow tube from urinary bladder to exterior
Lined with mucous membrane
Opening of urethra to the exterior called urinary meatus
Functions
Passage of urine from bladder to exterior of the body
Passage of male reproductive fluid (semen) from the body

17. Comparison of male and female urinary systems

18. MICTURITION
Passage of urine from body (also called urination or voiding)
Regulatory sphincters
Internal urethral sphincter (involuntary)
External urethral sphincter (voluntary)
Bladder wall permits storage of urine with little increase in pressure
Emptying reflex
Initiated by stretch reflex in bladder wall
Bladder wall contracts
Internal sphincter relaxes
External sphincter relaxes, and urination occurs

19. PROBLEMS WITH MICTURITION
Urinary retention —urine produced but not voided
Urinary suppression —no urine produced but bladder is normal
Incontinence —urine is voided involuntarily
May be caused by spinal injury or stroke
Retention of urine may cause cystitis
Cystitis —bladder infection
Overactive bladder —need for frequent urination
Called interstitial cystitis
Amounts voided are small
Extreme urgency and pain are common

20. Major Disorders of the Urinary System
Hydronephrosis
Calculi (stones)
Neurogenic bladder
Tumors
Urethritis
Infection
Cystitis
Pyelonephritis
Renal Failure

21. Course Questions, Problems & Issues: Please post in “Instructor Questions” in the class
GOODNIGHT EVERYBODY!!