Chapter 15 The Urinary System

1. Chapter 15The Urinary System

2. 1. Elimination of waste • Nitrogenous wastes • Toxins • Drugs Functions of the Urinary System 2. Regulates homeostasis • Water balance • Electrolytes • Acid-base balance in the blood • Blood pressure • RBC blood cell production • Activation of vit. D

3. Importance of Water in Human Body • Water helps to remove the dangerous toxins that our body takes in from the air, the food and the chemicals we use on our skin and hair. • Water also provides cushion for our body joints. • Water carries oxygen and nutrients into all our cells. • Water also helps to regulate our body temperature.

4. Our body has integrative body systems. When we say “integrative”, this means that our body systems are interconnected to each other to maintain homeostasis.

5. What is human homeostasis? Word origin: from the Greek:homeo,meaning unchanging + stasis, meaning standing. • Human homeostasis refers to the body's ability to physiologically regulate its inner environment to ensure its stability, in response to fluctuations in the outside environment. • it is the state of balance in our body.

6. What will happen if you do not have the ability to maintain homeostasis in our body? Homeostatic imbalancewill lead to diseases or even death.

7. The Urinary System Maintaining Chemical Homeostasis

8. Organs of the Urinary system • Kidneys • Ureters • Urinary bladder • Urethra

9. Right lower than left • Attached to ureters, renal blood vessels, & nerves at renal hilus • Atop kidney is adrenal gland Location of the Kidneys

11. Renal cortex – outer region • Renal medulla – inside the cortex • Renal pelvis – inner collecting tube Regions of the Kidney

12. Blood Flow in the Kidneys

13. Structural and functional units of the kidneys • Forms urine • Main structures a. Glomerulus b. Renal tubule Nephrons

14. nephron renal artery renal vein Kidney Anatomy

15. Nephrons • Excess salts, water, wastes remain in the tubule and become urine • Urine enters collecting ducts (tubes) in the medulla • Collecting tubes empty into the renal pelvis (first section of the ureter) • All the blood in the body passes through the kidneys about 20 times every hour.

16. Actual Filtration occurs here • Excess salts, water, nitrogenous wastes • Water and solutes smaller than proteins are forced through capillary walls • Blood cells too big to filter • Becomes urine Glomerulus

17. Collecting tube • Reabsorption • Things that are useful to the body are brought back into circulation.  • water, glucose, amino acids, and sodium. • NOT: Nitrogenous waste products - Urea - Uric acid • -Creatinine • -Excess water Renal Tubule

18. Yellow due to pigment urochrome (from break-down of hemoglobin) & solutes • Sterile • Slightly aromatic • Normal pH of ~ 6 • Specific gravity of 1.001 to 1.035 Characteristics of Urine

19. The urine leaves the kidneys through the ureters,a muscular tubes 25 to 30 cm long that moves urine from the kidney to the urinary bladder. Ureters

20. Smooth, collapsible, muscular sac • Temporarily stores urine • Trigone – 3 openings - Two from ureters - One to urethrea Urinary Bladder

21. Thin-walled tube • Carries urine from bladder by peristalsis • Release controlled by 2 sphincters • Internal urethral sphincter (involuntary) • External urethral sphincter (voluntary) Urethra

22. Length - Females – 3–4 cm (1 inch) - Males – 20 cm (8 inches) • Location - Females – along wall of the vagina - Males – through the prostate and penis Urethra Gender Differences • Function - Females – only urine - Males –urine and sperm

23. Both sphincters must open • internal relaxes after bladder stretches • Activation - impulse to spinal cord and back via pelvic splanchnic nerves • external voluntarily relaxes Micturition (Voiding)