Week 2

Question 1

What is the immunological theory

Answer 1

Aging is controlled by the immune system
Aging is a mild, prolonged, auto-immune disorder
Inflammation can lead to cell death

Question 1

Explain how the prevalence of Chronic Disease Increases with age

Answer 1

after our 40s-50s, chronic disease risk increases because of a decrease in our immune system

Question 2

What are major events in the immune system that happen as we age? (NON-Specific/general response to pathogen)

Answer 2

• skin cells deteriorate (therefore weakened barriers, easier for pathogens to enter)
• phagocyte dysfunction (protein concentration decreases, fewer overall)

Question 3

What are major evens in the immune system that happens as we age? (Specific to certain pathogens)

Answer 3

• bone marrow decreases; b-cell production decreases
• thymus mass decreases; t-cells decrease

Question 4

What are b-cells? Do they divide through life?

Answer 4

B-cells are made in the bone marrow and attack pathogens outside the cells.
They do divide throughout life

Question 5

What are t-cells? Do they divide throughout life?

Answer 5

T-cells are made in the thymus
They attack infected cells inside muscle cells
They do divide throughout life

Question 6

What are phagocytes? Do they divide throughout life?

Answer 6

Phagocytes are the first line of defence if a pathogen gets passed the skin barrier

It does NOT divide throughout life

Question 7

How can we prevent the decline in the immune system?

Answer 7

Exercise and nutrition
Reduce inflammation
Anti-inflammatories

Question 8

Explain the flowchart of aging and the immune system

Answer 8

decreased barrier, phagocyte function, b-cells and t-cells - decreased immune system functioning - results in increased inflammation (low levels, starts negative cycle of immune system functioning)

ROS increase - contributes to elevated inflammation

Question 9

What are other contributing factors in promoting chronic inflammation?

Answer 9

age-related frailty
cancer
cvd
ocular disease
autoimmune disease
pulmonary disease
neurodegenerative disease
periodontitis
metabolic syndrome

Question 10

Describe the difference between programmed longevity theory and the immunological theory of aging

Answer 10

Programmed Longevity = biological clock, telomeres shorten and cells die

Immunological Theory = cells die as a result of inflammation

Question 11

What is not subject to hayflicks limit, but is susceptible to the biological clock?

Answer 11

b cells
phagocytes
skin barrier

Question 12

What is the endocrine theory?

Answer 12

Changes in endocrine control of homeostasis results in age-related changes in physiology

Question 13

What is the hypothalamus?

Answer 13

Connects the NS system with the endocrine system through the pituitary gland

It stimulates or inhibits functions to maintain homeostasis

Question 14

What happens to the hypothalamus as we age?

Answer 14

The number of cells in the hypothalamus decreases and therefore decreases hormone production

Also an increase in calcification (results in non-functional tissue), more calcium means organs are less able to function

Question 15

The endocrine is responsible for maintaining homeostasis in……

Answer 15

metabolism
growth and development
sexual function and reproduction
heart rate
blood pressure
appetite
sleeping and waking cycles
body temp

Question 16

The endocrine is responsible for maintaining homeostasis in……

Answer 16

metabolism
growth and development
sexual function and reproduction
heart rate
blood pressure
appetite
sleeping and waking cycles
body temp

Question 17

How could you test the importance of hypothalamus cell numbers on aging?

Answer 17

most ideal: tracking the same individual over time and looking at the changes in their hormone levels

most direct way: increasing/decreasing the number of cells and evaluating the effects

Question 18

What happens when we increase hypothalamus cells vs when we decrease hypothalamus cells in mice

Answer 18

increase cells: we have enough already, increasing does not give benefits in performance

decreasing cells: substantial declines in mice, has an affect on physical, cognitive and social contexts

Question 19

What is the similarity between the endocrine and immunological theories of aging?

Answer 19

• all lead to a reduction in cells
• all involve damage to cells that result in a loss of functioning
• endo not functioning; things being our of homeostasis , increased inflammation, immune system declines

Question 20

Describe the relationship between the programmed longevity theory, immunological theory and the endocrine theory of aging

Answer 20

– all lead to a reduction in cells
- all involve damage to cells that result in a loss of functioning
- endo not functioning; things being our of homeostasis, increased inflammation, immune system declines
- biological clocks involved in all 3; reduction in hypo cells not subject to hayflicks limit

Question 21

What is the wear and tear theory?

Answer 21

• progressive damage to cells and tissue due to use over time
• vital parts “wear out”
• e.g., free radical theory (damage to tissue due to disuse over time)

Question 22

What are free radicals?

Answer 22

• atoms with an uneven number of electrons
• the unpaired electron makes them unstable (looking for something to bind to)
• easily reacts with healthy atoms

Question 23

What are reactive oxygen species?

Answer 23

Free radicals that contain oxygen

Question 24

How and why do we get ROS?

Answer 24

• produced through metabolism
• ETC in mitochondria (leaks electrons - combines with oxygen to produce free radicals/ROS)

Question 25

What are the functions of ROS?

Answer 25

Cell Signalling
- cell differentiation, autophagy (consumed/killed) immune system (takes care of something that needs to be removed)
- highly regulated; we have ways to get rid of excess (through anti-oxidants)

Question 26

What is oxidative stress?

Answer 26

Oxidative stress is when we have too much ROS and not enough anti-oxidants to neutralize them.

This leads to damage to DNA cells and cell death

Question 27

What are some other causes of ROS?

Answer 27

• UV rays
• Air pollution
• Chronic Inflammation
• Metabolism
• Radiation
• Obesity
• Smoking

Question 28

How can we reduce ROS?

Answer 28

diet and exercise (increases antioxidants, decreases ROS)
caloric restriction - reduces metabolic rate

Question 29

There is a reduction in muscle mass with advanced age. How would this reduction be explained by each of the
1. programmed longevity theory
2. Immunological theory
3. Endocrine Theory
4. Wear and Tear

Answer 29

1. Telomeres shorten with each cell division, resulting in cell death (hayflicks), muscle cells die after a certain age
2. As we use muscles they produce waste, which causes chronic inflammation - leads to cell death because of a weakened immune system. Also a reduction in phagocytes, b cells and t cells
3. Hypothalamus is responsible for homeostasis in growth and development, shrinking of the hypothalamus results in fewer hormones being produced, and fewer growth hormone directly affects muscle growth
4. ROS increases as we age - oxidative stress - elevated ROS in cells disrupts function by damaging DNA and results in cell death - loss of muscle mass