1. Urinary System

2. Vocabulary Calyc-: small Cort-: covering Detrus-: to force away
Glom-: little ball
Mict-: to pass urine
Nephr-: kidney
Papill-: nipple
Trigon: triangle
De-: separation from
Extra-: outside
Im-: not
Intra-: within
Neutr-: neither

4. Kidneys
Kidneys: reddish-brown, bean-shaped organ located posterior to the top of the abdominal cavity
Renal Sinus: a hollow chamber on the surface of the kidney
Renal Pelvis: a funnel-shaped structure that leads to the ureters

5. Kidney Functions
Maintain homeostasis by regulating the composition and pH of extracellular fluid
Removing waste from blood and forming urine
Secrete erythropoietin hormone
Activation of vitamin D
Maintain blood volume and blood pressure

6. Urine Formation Urine: the product of the 3 processes below
Glomerular filtration: glomerular capillaries filter plasma
Happens through osmosis
Produces 180 liters every 24 hours
Tubular reabsorption: moves substances back into the blood stream
Tubular secretions: moves substances from the blood to the kidneys

7. Filtration Rate Glomerular Filtration Rate GFR: affected by
Blood flow
Diameter of capillaries
Hydrostatic pressure
Kidney stone obstruction
Increases when body fluids are abundant and decreases when the body needs to conserve fluids

8. Urine Composition 95% water 5% 0.6-2.5 liters/day
Amino acids
Urea
Uric acid
Electrolytes
liters/day
Factors that affect urine production:
Physical condition
Emotional condition
Temperature
Fluid intake
humidity

9. Ureters
25 cm long tube that starts at the renal pelvis and joins the urinary bladder
Propel the urine to the bladder

10. Bladder A hollow, muscular organ that stores urine
Internal urethral sphincter: prevents the bladder from emptying
Detrusor muscle: the muscular wall of the bladder that functions during urination
Holds 600 mL (2.5 cups) before stimulating pain receptors

11. Micturition (urination)
The process of expelling urine from the bladder
Micturition reflex center: in the spinal cord
Responsible for the urge to urinate

12. Urethra The tube that transfers urine from the bladder to the outside
Longer in men than in females

13. Maintaining Homeostasis
Water and electrolytes are the 2 most important substances in the body
1) lost water and electrolytes must be replaced
2) excess water and electrolytes must be excreted
Electrolytes: molecules which release ions (charged particles) in water

14. Fluid Compartments Females: 52% water Males: 63% water
Intracellular compartment: includes all the water and electrolytes in all cells
Extracellular compartment: all the fluid outside of cells
Tissue spaces (interstitial fluid)
Blood vessels (plasma)
Lymphatic vessels (lymph)
Transcellular Fluid
Cerebro spinal fluid in the nervous system
Aqueous and vitreous humor in the eyes
Synovial fluid in the joints
Serous fluid in the body cavities
Secretions of the glands

15. Water Balance Intake equals output Intake: Output: 60% from beverages
30% from food
10% byproduct of cellular metabolism
Regulated by the thirst center in the hypothalamus
Output:
60% urine
6% feces
6% sweat
28% evaporation
Regulated by urine production

16. Electrolyte Balance Intake: food, water, byproducts of metabolism
Regulated by hunger and thirst (hypothalamus)
Output: sweating, feces, urine
Regulated by kidneys and aldosterone secreted by the adrenal gland

17. Acid-Base Balance Acids: release hydrogen ions H⁺
Bases: release ions that combine with hydrogen OH⁻
Hydrogen Ion (ACID) Sources
1) aerobic cellular respiration Produces CO₂ (carbonic acid)
2) anaerobic respiration produces lactic acid
3) incomplete oxidation of fatty acids Produces ketone bodies
4) oxidation of amino acids containing sulfur Produces sulfuric acid
5) Breakdown of proteins and nucleic acids Produces phosphoric acid

18. Regulation of Acid/Base Balance
Respiratory system: rate and depth of breathing will increase to get rid of excess carbon dioxide (carbonic acid)
Kidneys: nephrons excrete hydrogen ions into urine when there is excess acid

19. Elevated acid levels
Respiratory Acidosis: increased CO₂ levels (carbonic acid)
Causes:
Injury to respiratory center of the brain
Obstruction of airways
Disease that decreases gas exchange
Ex: pneumonia, emphysema
Shallow breathing
Symptoms: drowsiness, disorientation, stupor, labored breathing, cyanosis

20. Elevated acid levels
Metabolic acidosis: Either accumulation of acids or loss of bases
Causes:
Kidney disease
Prolonged vomiting
Prolonged diarrhea
Diabetes- fatty acids produce ketone bodies
Symptoms: drowsiness, disorientation, stupor, labored breathing, cyanosis

21. Elevated base levels
Respiratory Alkalosis: Excessive loss of CO₂ and carbonic acid
Causes:
Hyperventilation
Anxiety
Fever
Poisoning
High altitudes
Symptoms-
Light-headedness
Agitation
Dizziness
Tingling

22. Elevated base levels Metabolic Alkalosis: Rise in the pH of blood
Causes-
Prolonged vomiting
Diuretic drugs
Too much antacids
Symptoms-
Decreased breathing