1. Excretory System
How to make pee …

3. Renal Artery
Renal Vein
Renal Cortex
Adrenal Gland
Renal Pelvis
Kidney
Renal Medulla
Ureter
Urinary Bladder
Urethra

4. Every Cell in your body produces wastes
Metabolic waste, not feces (undigested material)

5. Skin excretes water and salts in perspiration
Lungs excrete CO2 as a gas
Liver excretes bile pigments
Kidneys excrete nitrogeneous wastes in urine

6. Role of Kidneys
Important in protein breakdown (proteins are amino acid based which is nitrogen based)
Nucleotides (metabolic products) are metabolized to form uric acid
Uric acid is not very soluble - if it precipitates out of solution, you have gout

7. Urea
H2N ---C---NH2 // O

8. What do kidneys do? 2 kidneys located high up in the abdomal cavity
Purposes -
filter blood
maintain blood volume
remove waste products
recover vital substances
Maintains homeostasis in the body

9. Little bit of protection by rib cage
Covered by tough fibrous cap of connective tissue - surrounded by adipose tissue (inside fibrous tissue)

10. Ureters Ureters connect bladder to kidney - smooth muscle
Ureters and bladder made of transitional epithelium

11. Urinary bladder can stretch to accommodate up to 600 ml or more (sometimes in excess of 1000ml) (600 ml is conservative)
has folds - rugae (like folds of stomach) - running throughout is smooth muscle fibers
Urethra extends from bladder to outside the body

12. Females urethra is about 1-2” - this leads to more frequent urinary tract infections
Male urethra is about 6” - prostate in later years can enlarge (very often does) which causes an obstruction in urine flow
Histology of Kidney
Bean shaped

14. 3 regions
Cortex
Medulla which contains renal pyramids (appear striated)
Renal Pelvis (or inner space) - continuous with ureter

15. Nephron
Plasma minus the proteins pass through filtration cells, then you need to recover vital molecules - glucose, water, etc.
over 1 million nephrons
Nephron is the filtration unit of the kidney - made of cells that are specialized for active transport, diffusion, moving substances across membranes

16. Nephron Structure of nephron cup shaped structure - Bowman’s capsule
Parts of nephron beyond Bowman’s capsule
specialized tube

17. Bowman’s Capsule
Renal Arteriole
Glomerulus
Capillaries
Collecting Tubule
Loop of Henle

19. Nephron
part closest to glomerulus is the proximal convoluted tubule (closest to renal corpuscle
Loop of Henley or Henley’s Loop - descending and ascending limb with a hairpin turn
Distal convoluted tubule - farthest away from renal corpuscle
each has a role in recovery of nutrients and leads away from nephron to collecting duct and away

20. Formation of Urine Pressure Filtration
Blood from arteriole is flowing into glomerulus, due to bp, filtration
Everything from plasma that is filterable leaves through glomerulus - water, glucose, amino acids, salts, urea, uric acid and creatinine (nitrogen wastes)
blood cells, platelets and proteins are not filtered

21. Concentration of water is same as plasma
Body needs to recover water and nutrients
Selective Reabsorption

22. Almost 180 L of filtrate pass into collecting tubules per day
Almost 180 L of filtrate pass into collecting tubules per day L bottles!
Diffusion and active transport (passive and active processes)
water glucose amino acids and salts are reabsorbed. About 99% of the water is reabsorbed.

23. Region most highly specialized for selective reabsorption is the proximal convoluted tubule
Many mitochondria needed - produce atp for active transport

24. Reabsorption of water
happens in loop of Henle
Lower part of ascending limb - dealing with passive diffusion of NaCl
Regulate pH of blood by regulating particular ions
Beside filtration, keeping good stuff and getting rid of waste

25. Maintaining blood volume
ADH - Produced in Hypothalamus by neurosecratory cells, stored and secreted from posterior pituitary gland
ADH increases the permeability of the collecting duct to water so more water can be reabsorbed.

26. Increase Blood Pressure and Blood Volume
Diuresis - increases amount of water in urine
Alcohol is a diuretic - decreases production of ADH
Believed after effects of alcohol (hangover) is due to dehydration
Kidney stones - calcium salts or uric acid precipitate and form kidney stone