1.Aging of the Urinary Tract:KidneyLower Urinary Tract
2.
3.Nephron & Renal Circulation
4. Table 19-1
Major Functions of the Kidney
Water and electrolyte regulation
Metabolic products excretion
Hydrogen ion excretion and maintenance of blood pH
Endocrine functions:
Renin-angiotensin secretion (blood pressure)
Vitamin D activation (Ca++ metabolism)
Erythropoietin secretion (hematopoiesis)
5.Renal Glomerulus
Glomerulus: Tufts of capillaries between afferent and efferent renal arterioles. Filtration is through a fenestrated endothelium separated from the basal membrane by podocytes. Filtrate is the same as plasma but without proteins.
6.Renal Tubules divided into:
Proximal Tubule, mostly reabsorption of water & solutes
Loop of Henle, mostly reabsorption of water & salt
Distal Tubule, mostly water & salt (under influence of aldosterone) reabsorption and acidification of urine
Collecting Duct, water reabsorption under the influence of ADH (antidiuretic hormone from posterior pituitary)
7.Distal and Collecting Tubules function is regulated by ADH (antidiuretic hormone)
secreted by neuroendocrine hypothalamus
stored and released from the posterior pituitary
Juxtaglomerular Apparatus:
located between affarent artery and distal tubule
secretes the enzyme renin
renin acts on the liver protein angiotensinogen to form angiotensin I, and angiotensin is transformed into angiotensin II in the lungs
angiotensin II is a very potent hypertensive substance; it also stimulates the release of aldosterone from the adrenal cortex
8.Hypothalamus, Posterior Hypophysis, and their Hormones
Hypothalamus
9.Figure 19-2
10.Table 19-2
Common Renal Problems in the Elderly
Renal Failure
Impaired drug excretion
Urinary tract infections
Hypertension
Miscellaneous disorders:
Tuberculosis
Nephritis
Diabetes, etc.
12.Table 19-4
Selected Causes of Acute Renal Failure
PRE-RENAL:
Loss of body fluids
Inadequate fluid intake
Surgical shock or myocardial infarction
RENAL:
Drug toxicity
Immune reactions
Infectious diseases
Thrombosis
POST-RENAL:
Urinary tract obstruction
13.Table 19-6
Drugs and the Aging Kidneys
Questions:
Is the drug excreted primarily by the kidney?
How competent are the kidneys?
What are the side-effects?
What are the consequences of drug toxicity when the kidney is impaired?
Etiopathology of Renal Drug Toxicity:
High renal blood flow
Increased drug concentration and accumulation in kidney
Increased hepatic enzyme inhibition in the elderly
Increased autoimmune disorders in the elderly
14.Functions of the bladder
Filling with urine from the kidneys
Micturition: emptying of bladder by muscle contraction and
opening of sphincters.
Principle muscle: Detrusor muscle
Sphincters: Internal (involuntary; smooth muscle) and external (voluntary to some degree; skeletal muscle)
15.
16.Figure 19-5
17.Figure 19-6
18.
Motivation to be continent
Table 19-7
Physiologic Requirements for Continence
Adequate cognitive function
Adequate mobility and dexterity
Normal lower urinary tract function
19.
Storage:
Table 19-7
Physiologic Requirements for Continence
No involuntary bladder contractions
Appropriate bladder sensation
Closed bladder outlet
Low pressure accommodation of urine
20.
Emptying:
Table 19-7
Physiologic Requirements for Continence
Normal bladder contraction
Lack of anatomic obstruction
Coordinated sphincter relaxation & bladder contraction
Absence of environmental/iatrogenic barriers
21.Table 19-8
Age-Related Changes Contributing to Incontinence
In Females
Estrogen deficiency
Weak pelvic floor and bladder outlet
Decreased urethral muscle tone
Atrophic vaginitis
In Males
Increased prostatic size
Impaired urinary flow
Urinary retention
Detrusor muscle instability
22.Weakness of pelvic muscles
Inability to avoid voiding when bladder full
overdistended, non-contractile blood
cognitive, emotional problems