Ch 45 pt 3 Flashcards
Describe the Thyroid hormone regulation pathway
1) hypothalamus secretes thyrotropin releasing hormone (TRH)
2) Causing the anterior pituitary to secrete thyroid-stimulating hormone (TSH)
3) TSH stimulates the release of thyroid hormone by the thyroid gland
Which hormone is the only iodine containing molecule synthesized in the body
Thyroid hormone
What causes low levels of the thyroid hormone?
lack of iodine
What does low levels of thyroid hormone lead to? (2)
1) lack of negative feedback for pituitary gland
2) thyroid enlargement and goiter
Describe hormonal regulation of growth
1) hypothalamus releases growth hormone regulating hormone (GHRH)
2) Anterior pituitary responds to GHRH and secretes Growth hormone
3) liver responds to GH and releases insulin-like growth factors (IGFs)
Growth Hormone (GH) has both _______and _______
Has tropic and nontropic effects
Tropic effect
Stimulates other endocrine glands
An excess of GH causes what?
Gigantism
What are Pituitary giants caused by?
1) Excessive GH during childhood
2) acromegaly if high levels continue in adulthood
What is Acromegaly caused by?
caused by tumors in pituitary
What is Short stature caused by? and how can it get treated?
Results from insufficient GH during childhood
Gets treated with GH injections before puberty
What gets released when Ca levels fall below a set point
Parathyroid hormone (PTH) by the parathyroid glands
What gets released when Ca levels rise above a set point
calcitonin by c-cell (parafollicular cell) of thyroid
What are the functions of PTH?
(3ways)
Increases level of blood Ca by:
1) Stimulates osteoclasts to release Ca from the bone
2) stimulates reabsorption of Ca in the kidneys
3) indirectly stimulates by promoting vitamin D production
What are the functions of Calcitonin?
(2ways)
Reduces levels of Ca by:
1) Stimulates osteoblasts to deposit Ca in bones
2) stimulates the secretion of Ca in the kidneys
Where are the Adrenal glands located?
Located above kidneys
Adrenal glands two glands
Adrenal medulla (inner)
Adrenal Cortex (outer)
Epinephrine and norepinephrine are considered what type of compounds
Catecholamines
Cause fight or flight response
How does Epinephrine trigger the release of glucose and fatty acids into blood?
Epinephrine binds to beta receptors on liver cells and activates protein kinase A
What causes direction of blood toward heart, brain, and skeletal muscles?
epinephrine binding to beta receptors on smooth muscle cells around blood vessels causing dilation
What causes direction of blood away from skin, digestive system, and kidneys?
norepinephrine binding to alpha receptors on smooth muscle cells around blood vessels causing constriction
Arenal cortex becomes active when? (3)
Stressful conditions:
1) Low blood sugar
2) decreased blood volume/pressure
3) Shock
Corticosteroids (2 types)
Two types
1) Glucocorticoids
2) Mineral corticoids
What do Glucocorticoids influence? (2)
1) glucose metabolism
2) immune system
Ex. Cortisol - synthesis of glucose from non carbs and suppresses the immune system
Mineralocorticoids
Affect salt and water balance
Ex. Aldosterone
Where are sex hormones mainly produced? (3)
Gonads, testes, and ovaries
What are the different sex hormones?
Androgens, estrogen, and progesterone
Found in both sexes but different proporitons
What do the testes synthesize?
androgens (mainly testosterone)
What is androgen responsible for?
secondary male sex characteristics
Testosterone male secondary sex characteristics
1) Penis
2) Scrotum
3) Hair
4) Aggression
5) Musculature
What is Estrogen responsible for?
Most important estradiol
Responsible for maintenance of the female reproductive system
Estrogen female secondary sex characteristics (6)
1) lack of body hair and thicker hair on head
2) Rounded hips
3) Slower generation of muscle mass
4) decreased upper body strength
5) Breasts, nurse children, menstrual cycle
6) Higher body fat
What is Progesterone responsible for?
Preparing and maintaining the uterus
What controls the synthesis of sex hormones
1) Gonadotropin
2) Follicle stimulating hormone
3) Luteinizing hormone
Found in anterior pituitary
What controls gonadotropin secretion
Gonadotropin-releasing hormone from the hypothalamus
Synthetic estrogen
diethylstilbestrol (DES)
Daughter of women treated with DES Have higher chance of reproductive abnormalities
What is an endocrine disruptor?
A molecule that interrupts normal function of a hormone pathway
Pineal Gland
Located in brain secretes melatonin
Melatonin
Relates to biological rhythms with reproduction and with daily activity levels
Suprachiasmatic nucleus (SCN)
Group of neurons in hypothalamus that control the release of melatonin
What is Melanocyte-stimulating hormone (MSH)?
Collective name for a group of peptide hormones produced by the skin, pituitary gland and hypothalamus
MSH role in amphibians, fish, reptiles
regulates skin color by controlling pigment distribution in melanocytes
MSH role in mammals
Roles in hunger and metabolism in addition to coloration
