Physiology

Question 1

Age-related changes: renal tract

Answer 1

Structure:

Decreased renal mass
Glomeruli become sclerosed

Function:

Decreased GFR
Reduced in max and mim urine osmolality
Reduced sodium conservation, prone to hyponatraemia with volume depletion

Question 2

Age-related changes: lower urinary tract

Answer 2

Reduced bladder capacity and contractility
Inc detrusor hyperactivity
Dec urethral outflow resistance (women), opposite in men
Inc nocturna polyuria

Question 3

Age-related changes: adrenals

Answer 3

Basal renin decreased
Reduction in aldosterone
Inc risk hyperkalaemia
Stimulus response preserved, but magnitude decreased

Question 4

Age-related changes: liver

Answer 4

Reduced volume and weight of liver
Reduced blood flow, therefore affects drug clearance

LFTs and albumin NO SIGNIFICANT CHANGE if well

Question 5

Age-related changes: heart

Answer 5

CO at rest unchanged
Dec maximal heart rate
Some myocardial hypertrophy, inc LV wall thickness and LA size
Dec arterial compliance and valve mobility
Dec HR response to stress and respiration

Question 6

Age-related changes: lungs

Answer 6

20% reduction in size
Structural changes
Loss of elastic recoil
20%  reduction in surface area
FEV1 and FVC reduced
Residual volume increases
Inc V/Q mismatching (due to inc physiological dead space)
Blunted ventilatory response to declining pO2 and increasing pCO2
Diminished mucociliary clearance

Question 7

Age-related changes: immune system (humoral)

Answer 7

IgA and IgG increase, others decrease - concentration of immunoglobulin therefore stable
Diminished Ab response (peak and duration)
Autoantibodies more common
Monoclonal immunoglobulin inc significantly >70yo

Question 8

Age-related changes: cell-mediated immunity

Answer 8

Thymus involutes
Total T and B cells constant
Inc CD4+, dec CD8+
Impaired T cell response, diminished hypersensitivity response
Impaired proliferation response to TB, VZV, influenza

Question 9

Age-related changes: endocrine

Answer 9

Inc in insulin in response to insulin resistance
Inc autoimmune thyroiditis
Inc PTH –> inc bone resorption
Inc ADH and inc risk hyponatraemia and ANP inc in response to inc intravascular volume –> nocturia
Inc FSH/LH (male and female)
Uterine and vulval atrophy
Decreased vaginal lactobacilli secretion of peroxide –> inc UTIs
Decrease male testosterone
Reduced growth hormone