Physiology

Question 1

How does kidney function change with age?

Answer 1

Declines

- elderly people have a reduced GFR

Question 2

Describe the effect of ageing on blood pressure

Answer 2

Blood pressure increases due to reduced efficiency of baroreceptors

Question 3

Describe the effect of ageing on a person’s homeostatic reserve

Answer 3

Reduced homeostatic reserve

Poor temperature regulation - higher risk of hypothermia

Question 4

Describe the effect of ageing on cardiac function

Answer 4

Heart rate decreases slightly (and less capacity to increase with exertion i.e. lower max heart rate)
Decreased stroke volume
Decreased cardiac output

Question 5

Describe the effect of ageing on respiratory function

Answer 5

Decreased vital capacity
Decreased lung compliance
Increased residual volume

Question 6

Describe the effect of ageing on the GI tract

Answer 6

Decreased gut motility with subsequent increased transit time, with a subsequent predisposition to constipation

Question 7

Describe the effects of ageing of body composition

Answer 7

Decreased muscle mass
Increased adipose tissue
Decreased body water content
Increased blood brain barrier permeability

Question 8

Describe the pharmacokinetic changes that occur with old age

Answer 8

Absorption - slower GI absorption (but total absorption remains unchanged, just takes longer)
Distribution changes depend on drug properties, due to changes in body composition (e.g. whether the drug is fat-soluble or water-soluble)
- decreased albumin means decreased protein binding, therefore some drugs will be poorly distributed in the elderly
Metabolism - decreases due to decreased liver function
Excretion - slower clearance due to decreased renal function