Mr. Hartsell, a 70-year-old man, had his thymus gland removed as a treatment for an autoimmune disease he has. Predict the effect of his thymectomy on T cell production
What will be an ideal response?
We would not expect to see a decline in immune function in a 70-year-old man due to the enormous number of immunocompetent T cells produced during infancy and childhood. The thymus is very active in infants and children and reaches its maximum size in individuals about 12-14 years old. After this point, it begins to atrophy and the thymic tissue is gradually replaced with fat. As the thymus atrophies, its production of mature T cells decreases as well. Indeed, by age 65, the rate of T cell production falls to about 2% of the rate at which an infant produces T cells. So, although new mature T cell production would cease, it is already very low at his age and so would likely have little overall effect.
You might also like to view...
Steroid hormones act through the second-messenger system
Indicate whether the statement is true or false
Overall, PTH (parathyroid hormone) _____ blood phosphate levels
A. increases B. decreases C. elevates D. enhances E. has no effect on
The phase of a muscle twitch during which the muscle fiber fires an action potential is the
A. latent phase. B. subthreshold phase. C. pre-stimulation phase. D. contraction phase.
Epinephrine (EP), norepinephrine (NE), cortisol, and aldosterone are all produced in the
a. pituitary gland. b. adrenal glands. c. thyroid gland. d. pancreas. e. hypothalamus.