Endocrine Glands Part 2 Flashcards
Small, oval endocrine glands associated with thyroid
parathyroid gland
parathyroid is usually two pairs in mammals (2),
present on
superior & inferior
posterior surface of thyroid gland
Parathyroid Gland is embryologically derived from
third and fourth branchial (pharyngeal) pouches
Parathyroid Gland
secretes (1)
PTH (parathyroid hormone, parathormone)
PTH regulates
serum Ca and P
PTH is — to calcitonin
antagonistic
Have reciprocal effects—parathyroid hormone
slowly — serum Ca; calcitonin rapidly — serum Ca
increases
decreases
Parathyroid hormone increases serum Ca 3 ways—
- increases osteoclast activity (inhibits osteoblasts)
- increases renal tubular absorption of Ca in kidneys (& inhibits resorption of phosphate)
- increases Ca absorption from gut via Vit D
• Parathyroid hormone secretion stimulated by
decrease in blood Ca
Damage/removal parathyroid results in
hypoparathyroidism
Hyperparathyroidism—
excess PTH production
Hyperparathyroidism—excess PTH production results in (2)
bony erosion & lysis
2 types of secretory cells:
chief (principal) cells
oxyphil cells
most abundant
chief cells
chief cells secrete
PTH
chief cells stain
clear to light pink, with dark nuclei & moderate amount of cytoplasm
Oxyphil cells are —, less numerous
larger
oxyphil cells stain
dark pink with more cytoplasm
oxyphil cells occur in —
clusters
oxyphil cells contain large numbers of —, but no —
mitochondria
secretory vesicles
function of oxyphil cells
unknown
— — of parathyroid gland common in older individuals
Fatty infiltration
Adrenal Gland=
suprarenal gland
Adrenal Gland is located
superior to kidneys
Adrenal Glands are covered by
thin CT capsule
Adrenal Gland: In mammals, — endocrine gland with — different
embryological origins
single
two
Adrenal Gland: In lower vertebrates, (2) are two separate
glands
medulla & cortex
Adrenal cortex is — embryological origin, similar to —
mesodermal
gonads
Adrenal cortex is regulated by
ACTH secreted by anterior pituitary
Steroid hormones structurally related to — precursor
cholesterol
3 functional classes of adrenal hormones :
mineralocorticoids
glucocorticoids
sex hormones
Mineralocorticoids—(e.g., aldosterone) control (2) balance
electrolyte & fluid balance
Mineralocorticoids regulates Na and K levels via
Na pumps, especially in renal tubules
mineralocorticoids regulate BP via
JGA
Glucocorticoids—(e.g., cortisol)
Stimulate (2)
gluconeogenesis & glycogenolysis
gluconeogenesis & glycogenolysis both — blood glucose
increase
Glucocorticoids increase metabolism and breakdown of (3)
proteins
carbs
lipids
Sex hormones—(e.g., androgens) very — amount; supplement — production
small
gonadal
Cortex has three layers (from superficial to deep):
zona glomerulosa
zona fasciculata
zona reticularis
Zona glomerulosa—
~15% of cortex: thin, dark-staining band
zona glomerulosa secretes
mineralocorticoids, e.g., aldosterone
Zona fasciculata—
~80% of cortex; broad, light-staining band
Zona fasciculata contains cells called
spongioctes
Zona fasciculata secretes (2)
glucocorticoids eg. cortisol
small amounts of androgens
Stress promotes secretion of cortisol, which — immune response
decreases
Zona reticularis—
~5% of cortex; thin, dark-staining band
Zona reticularis secretes small quantities of (2)
androgens and glucorticoids
Hypoadrenocorticism is also known as
Addison’s disease
Addison’s disease
Failure of adrenal cortex to produce hormone
mineralo- & glucocorticoids
Addisons disease is usually due to
atrophy of gland (often caused by autoimmune disease)
decrease in aldosterone results in (4)
decrease in ECF volume,
hyponatremia,
hyperkalemia,
mild acidosis
mild acidosis results in (2)
shock, death
aka Addisonian crisis
decrease in cortisol results in decrease in
blood glucose