18.12 PINEAL GLAND AND THYMUS

Question 1

Where is the pineal gland located?

Answer 1

it is a small endocrine gland that is attached to the roof of the third ventricle of the brain at the midline, it is part of the epithalamus and positioned between the 2 superior colliculi and covered by a capsule formed by the pia mater

Question 2

the pineal gland consists of masses of neuroglia and secretory cells called?

Answer 2

pinealocytes

Question 3

what does the pineal gland secrete?

Answer 3

melatonin

Question 4

Melatonin is what type of hormone and what is it derived from?

Answer 4

an amine hormone
Derived from serotonin

Question 5

Melatonin contributes to what in the body?

Answer 5

the biological clock (which is controlled by the suprachiasmatic nucleus of the hypothalamus)

Question 6

in response to visual input from eyes, the suprachiasmatic nucleus stimulates sympathetic postganglionic neutrons of the superior cervicle region which in turn stimulate?

Answer 6

the pinealocytes of the pineal gland to secrete melatonin in a rhythmic pattern (high levels at night, low levels in the day)

Question 7

melatonin may provide some protection against damaging oxygen free radicals because it is also a ?

Answer 7

potent antioxidant

Question 8

where is the thymus located?

Answer 8

behind the sternum between the lungs

Question 9

What is the role of the thymus

Answer 9

immunity

Question 10

what are the hormones produced by the thymus? (4)

Answer 10

thymus-thymosin
thymic humoral factor (THF)
thymic factor (TF)
thymopoietin

Question 11

What do these hormones produced by the thymus promote?

Answer 11

promotion of maturation of T cells (a type of WBC that destroys microbes and foreign substances) and may retard the aging process