Lesson 4 - Endocrine Pt 2 Flashcards
(203 cards)
gigantism
hypersecretion of GH during childhood (before growth plates are depleted)
acromegaly
hypersecretion of GH during adulthood (after growth plates closed)
what happens with acromegaly?
thickening of the bones and soft tissues, especially hands, feet, and face
pituitary dwarfism
hyposecretion of GH during childhood
- rare because GH is now plentiful, made by genetically engineered bacteria
pineal gland
where is it located?
attached to the roof of the third ventricle beneath the posterior end of the corpus callosum
what happens to the pineal gland after age 7?
involution (shrinking)
pinealocytes synthesize _____ at night and fluctuates seasonally
melatonin
where are melatonin receptors in the body?
widespread
what are some functions of melatonin receptors? (4)
- circadian rhythm
- promotes sleep
- has antioxidant/anticancer properties
- slow maturation of sperm and egg cells
what has lack of melatonin been linked to?
premature puberty in humans
the thymus plays a role in three different systems:
endocrine, lymphoid, and immune
how many lobes does the thymus have?
two
where is the thymus located?
the mediastinum superior to the heart
what happens to the thymus after puberty?
involution
involution
shrinking
functions of the thymus (2)
- site of maturation of T cells
- secretes hormones that stimulate development of other lymphoid organs
what hormones does the thymus release? (3)
thymopoietin, thymosin, and thymulin
thyroid gland
what is special about this gland?
it is the largest gland that is purely endocrine
where is the thyroid gland located?
adjacent to the trachea, immediately below the larynx
structure of the thyroid gland (2)
- two lobes connected by a narrow bridge (isthmus)
- composed of sacs called thyroid follicles
isthmus
the narrow bridge connecting the two lobes of the thyroid
thyroid follicles
contain protein-rich colloid surrounded by simple cuboidal epithelium of follicular cells
what do follicular cells of the thyroid secrete?
thyroid hormone (TH)
T4 is also called
tetraiodothyronine because it has four iodine atoms