Senescence

Question 1

Primary vs secondary aging

Answer 1

Primary - changes occuring with age, unrelated to disease or environmental influences.

Secondary - changes cuased by interaction of primary aging with environmental influences or disease processes.

Question 2

What is antagonistic pleiotropy

Answer 2

A gene that exerts a small pre-reproductive benefit and a large post-reproductive cost will still be selected for.

Question 3

What are 3 processes that cause aging?

Answer 3

1. Oxidatve stress damage (reactive oxygen species cause damage to DNA, mitochondria)
2. Inadequate repair of damage (telomeres shorten)
3. Cell number dysregulation

Question 4

What is the Hayflick limit?

Answer 4

Limitation to cell division. Lifespan = Hayflick limit.

Question 5

Apoptosis vs senescence

Answer 5

Cells that die after reaching Hayflick limit = apoptosis

Cells that sit there sleeping = senescence

Question 6

What is cell senescence

Answer 6

Cell senscence in response to damage/replication.

It functions to arrest growth of old/damaged cells. Anti-cancer mechanism

Question 7

Endocrine function sees a mosty moderate decline in aging, except for which two things?

Answer 7

1. Growth hormones - significant decline in GH and IGF-1 due to reduction in pulsatility of hypothalamus stimulating GHRH release
2. Sex hormones - significant decline in adrenal steroids and gonad function.

Question 8

Describe the decline in function of gonads in aging women and men

Answer 8

Women - menopause: Abrupt cessation

Men - andropause: Progressive cessation - decreased hypothalamic stimuli results in atrophy of Leydig/Sertoli cells.