Chapter 12
 Urinary System - Notes
Return to Chapter Index

Return to Main Index

 1. Name the seven main functions of the urinary system and explain how each function is important.

     1. eliminate toxins and wastes - from metabolism and intakes to avoid cell injury (e.g., dietary, medications, urea, creatinine, uroglobin) to avoid cell injury
     2. osmotic pressure - for cell size and internal concentrations
     3. individuals minerals - for individual cell functions
     4. regulate pH - for molecular shapes and functioning
     5. regulate blood pressure - for proper circulation without heart or vessel problems
     6. activate vitamin D - for calcium absorption (e.g., for bones, cell functions)
     7. regulate O2 - to maintain O2 for energy

 2. Name and briefly describe the three functions of nephrons and explain the importance of modifying these functions.

     1. filtration - moving much water and small dissolved molecules from the blood through the glomerulus into the tubule
          reabsorption - moving most water and useful dissolved molecules from the tubule back into the blood
          secretion - moving more waste molecules from the blood into the fluid in the tubule
     2. adaptability needed to compensate for changes in intake or loss by other means (e.g., diet, perspiration, medications, G.I. tract disturbances {vomiting, diarrhea})

 3. Describe the overall age changes in kidney structure and functioning and explain the effects and consequences of these changes on urinary system functioning.

     - age changes
          - structure = decr. size, decr. and altered small vessels, decr. # and altered structure of glomeruli, decr. # and altered nephrons
          - functions = gradual and variable rates of decr. osmotic and BP control, decr. removal of meds., decr. vitamin D activation (especially after age 65)
               - from gradual and variable rates of decr. blood flow including decr. GFR, decr. adaptability of blood flow, decr. renin production
     - effects = decr. reserve capacity of all functions except O2 regulation -> incr. need to avoid extreme conditions to avoid excursions out of homeostasis (e.g., temperatures, diet, exercise, meds)
     - consequences = kidneys do OK unless pushed to their limits since the limits of functioning (i.e., reserve capacity) shrink
          - but incr. risk of more frequent, more severe, and longer lasting excursions from homeostasis
          - therefore = incr. need for conscious regulation and avoiding extremes that could overpower kidney adaptive capacity

 4. Explain why the incidence and severity of excursions beyond the kidneys' capabilities increase with age.

     1. incr. age change in other systems  (e.g., decr. thirst sensations)
     2. incr. diseases (e.g., diabetes, G.I. tract, disabilities)
     3. incr. use of meds (e.g., diuretics)

5. Name four specific factors that increase demands on kidney functioning.

     - incr. salt intake, incr. salt substitute intake, decr. water intake, incr. perspiration, diarrhea, incr. diuretics, respiratory problems (varying pH), decr. thirst sensitivity, incr. meds. , I.V.s, diabetes mellitus

     - see supplementary table Body Water, Sodium, Potassium, and Acid Abnormalities & Effects from Deviations

6. Name four specific effects when the kidneys are not able to maintain homeostasis.

     - urea toxicity, acidosis, edema, incr.BP, arrhythmias,   CNS functioning, bone demineralization, muscle spasms, muscle weakness, anorexia, poor vit. D absorption, anemia, incr. risk of systemic infection, kidney stones, medication toxicity from build-up, cell swelling (e.g., increased intracranial pressure in brain)
     - see supplementary table Body Water, Sodium, Potassium, and Acid Abnormalities & Effects from Deviations

 7. Name three strategies that help balance kidney functioning with body needs.

     1. regulate fluid and mineral intake
     2. regulate medications that affect kidney functioning
     3. prevent and treat abnormal and disease conditions that adversely affect kidney functioning (e.g., atherosclerosis, diabetes, diarrhea)

 8. Describe the functions and age changes in the ureters.

     - functions = pass urine to the bladder
     - age changes = none of importance

 9. Describe the functioning of the urinary bladder and describe age changes in the bladder and the effects from these age changes.

     - functioning = store urine and signal need to void
     - age changes
          1. decr. capacity and decr. elasticity
               effects = incr. frequency of voiding, decr. emptying -> incr. risk of infection
          2. decr. sensitivity
               effects = incr. risk of urinary incontinence

10. Describe the functioning of the urethra and describe age changes in the urethra and the effects from these age changes.

     - functions = controls passage of urine out of the body
     - age changes = thinner + weaker sphincter
     - effect = incr. risk of urinary incontinence

11. Indicate that urinary incontinence is an abnormal condition.

12. Explain why the incidence and severity of urinary incontinence increases with age.

     - incr. incidence and severity of contributing factors
     - see supplementary table on Urinary Incontinence

13. List and describe five types of urinary incontinence.

     - overflow incontinence - from excess urine retention
     - urge incontinence - from bladder spasms
     - stress incontinence - from weak muscles and sudden pressure
     - functional incontinence - from nervous system malfunction
     - mixed incontinence - from a combination of the other types

14. Name four specific factors that increase the incidence of urinary incontinence.

     - dementia, strokes, disability, neuroactive meds., diuretics, diabetes mellitus, decr. bladder sensitivity, decr. sphincter strength, decr. estrogen, bladder spasms, lifting, coughing, laughing, alcohol, caffeine, UTI, BPH, perineal surgery
     - see supplementary table on Urinary Incontinence

15. Describe biological and non-biological consequences from urinary incontinence.

     - skin problems (inflammation, infection), social, psychological, economic, institutionalization

16. Describe the general strategy for treating urinary incontinence.

     1. identify cause(s)
     2. develop individualized treatments to avoid causes and minimize consequences from urinary incontinence (See page 264 for examples.)
    - see supplementary table on Urinary Incontinence

Return to Top of Page

Return to Chapter Index

Return to Main Index
 
© Copyright 1999 - Augustine G. DiGiovanna - All rights reserved.
This material MAY be reproduced or distributed in any form or by any means, or stored in any data base or retrieval system ONLY under one of the following two conditions: (1) If no individual, group, organization, institution, company, corporation or other entity is charged for its use and only for use by instructors and students in courses where students are required to purchase the book HUMAN AGING: BIOLOGICAL PERSPECTIVES by Augustine G. DiGiovanna, The McGraw-Hill Companies, New York, 1994 or 2000; (2) If prior written permission is obtained from Augustine G. DiGiovanna.