the urinary system 1.why do we need a urinary system? a. introduction a.regulate body composition...
Post on 29-Dec-2015
212 Views
Preview:
TRANSCRIPT
The Urinary System
1. Why do we need a urinary system?
A. Introduction
a. Regulate body composition and volume
b. Rid the body of nitrogenous wastes
c. Maintain body pH
2. Components and locations
a. 2 kidneys
b. 2 ureters
c. 1 urinary bladder
3. Other functions
cortexrenal columns
renal pyramids
ureter
calyces
The Urinary System
1. Kidneys
B. Review of structure and function
a. Cortex vs. medulla
b. Renal pyramids
c. Calyces
d. Renal pelvis
e. Renal tubule
i. Nephron
ii. Collecting duct
glomerulus
Bowman’s capsule proximal convoluted
tubule
distal convoluted
tubule
proximal straight tubule
distal straight tubule
loop of Henlecollecting duct
The Urinary System
1. Kidneys
B. Review of structure and function
f. The nephron
i. Bowman’s capsule
ii. Proximal convoluted tubule
iii. Proximal straight tubule
iv. Loop of Henle
v. Distal straight tubule
vi. Distal convoluted tubule
The Urinary System
1. Kidneys
B. Review of structure and function
g. Glomerular capsule
i. Afferent arteriole glomerulus efferent arteriole
ii. Blood-kidney barrier
The Urinary System
1. Kidneys
B. Review of structure and function
h. Filtrate formation
i. What is filtrate?
ii. How is it formed?
iii. How much is formed each day?
iv. What is tubular reabsorption?
v. What is anti-diuretic hormone (ADH) and what does it do?
The Urinary System
2. Ureters
3. Urinary bladder
4. Urethra
B. Review of structure and function
a. Internal urethral sphincter
b. External urethral sphincter
c. Micturition reflex
The Urinary System
1. Kidneys
C. Age-related changes
a. Loss of renal mass due to loss of glomeruli
i. Normal at age 40; 30% weight loss at age 80
ii. Another 30% of glomeruli abnormal at 80
b. Decreased glomerular filtration rate
i. Pre-40 normal = 125 ml/min
ii. By age 75, 50% function = ~60 ml/min)
c. Altered permeability = proteinuria
The Urinary System
C. Age-related changes
f. Decreased ability to handle body pH changes
1. Kidneys
d. Degeneration and loss of nephrons
i. Decreased ability to concentrate urine
ii. Decreased ability to clear some drugs
e. Diminished blood flow through kidneys
i. Normal at age 20 = 1,250 ml/min
ii. By age 80, 50% = ~600 ml/min
The Urinary System
2. Bladder and urethra
C. Age-related changes
a. Loss of muscle tone and elasticity
i. Bladder less able to expand and contract
ii. Normal capacity = ~600 ml; elderly = ~250 ml
iii. 100 ml urine may be retained after micturition
b. Loss of awareness of need to urinate
c. Increased frequency, especially at night
d. Loss of muscle tone in pelvic floor (stress incontinence)
The Urinary System
D. Age-related dysfunctions
1. Urinary incontinence
a. Results from:
i. Weakened sphincters
ii. Reduction in bladder volume
iii. Delayed sensation of need to go
iv. Muscle atrophy in pelvic floor (bedridden)
b. No evidence that normal aging causes incontinence, but 30% of elderly experience some level of incontinence
c. Decreased estrogen
The Urinary System
D. Age-related dysfunctions
2. Nocturia (excessive night urination)
a. 60% over 65 complain about it
b. Not a real problem except for loss of sleep
c. May be caused by drugs, loss of bladder elasticity, and inability to concentrate urine (increased urine volume)
The Urinary System
D. Age-related dysfunctions
3. Prostate gland dysfunctions
a. How is the prostate gland involved in urination?
b. Benign prostatic hyperplasia
i. Cause
ii. Symptoms
iii. Treatments
c. Prostatic carcinoma
i. Who gets it?
ii. Symptoms
iii. Treatments
The Urinary System
D. Age-related dysfunctions
4. Pyelonephritis
a. Bacterial infection
b. Most chronic cases occur in people >65
c. Kidneys swell with fluids, abscesses form, pus fills renal pelvis
d. Scar formation leads to renal insufficiency/failure
The Urinary System
D. Age-related dysfunctions
5. Renal calculi (kidneys stones)
a. Not a problem of aging, but becomes progressively more common with age
b. Causes poorly understood
c. Stones are usually passed, but in elderly they are more likely to form an obstruction
end
The Urinary System
E. Take home messages
1. Although there are a number of age-related changes, the kidneys are more than capable of maintaining homeostasis throughout lifespan
2. Some glomeruli and nephrons degenerate while others become abnormal; therefore, glomerular filtration rate decreases and ability to concentrate urine decreases
3. Ability to clear drugs can become a major issue
top related