MYTH 6 - Lecture 20 - How does fitness change with age

Question 1

What is the centre of mass and base of support

Answer 1

COM - balance point of an object
BOS - area in contact with the support surface
As long as you maintain the centre of mass in the base of support then you are balanced

Question 2

What is postural control

Answer 2

the regulation of the body’s position in space

Question 3

What is proprioception

Answer 3

awareness of where the body’s parts are in relation to the environment and other parts of out body - the 4 information pathways are [vision; vestibular information, proprioception; receptors in the skin]

Question 4

What are semi-circular canals

Answer 4

Senses head rotations in all 3 dimensions (angular acceleration)

Question 5

What is an otolith organ

Answer 5

Senses head movement in a straight line (left/right, forward/backward and up/down) –> linear acceleration

Question 6

for proprioception, what does the muscle spindle do and what does the golgi tendon organ do

Answer 6

Spindle - helps detect changes in muscle fibre length

Organ - detects changes in muscle tension

Question 7

What is sarcopenia

Answer 7

loss of skeletal muscle mass due to loss of muscle fibres due to increasing age. This reduces muscle cross-sectional area

• loss of muscle contractility
• loss of neuronal innervation

Question 8

In a healthy young person 30% body weight is muscle and 20% is adipose tissue (fat), what are these percentages for a 75+ year old?

Answer 8

15% is muscle and 40% is adipose tissue

Question 9

List the age related changes - Summary

Answer 9

Check refill for answers - need to understand - pg 5 slide 2

Question 10

what are the 3 theories of aging

Answer 10

Free Radical
- Mitochondria create free-radicals by leaking electron transport intermediates. These free-radicals cumulatively damage DNA (esp, mitochondrial DNA), proteins and lipids. Dietary antioxidants decrease accumulation of oxidative damage but do not increase the lifespan in mice. Caloric restriction DOES decrease oxidative damage AND increase life span in numerous animal models

Damage theory
- Cumulative cell damage caused by environmental micro-insults [Physical: heat, UV, ionisation, radiation; Chemical: toxins, free radicals; Infectious: mutagenic viruses; Mechanical: trauma to vessels and joints]

Gene regulation
- Ageing due to changes in gene expression, especially insulin like growth factors (ILGF) pathway. Genetic component to longevity is clear