Cholesterol is a precursor for the synthesis of
progesterone, aldosterone, and estradiol (&testosterone)
Which hormone is currently thought to decrease plasma calcium levels in pregnant women and children?
calcitonin
PTH promotes the formation of which hormone?
calcitriol
What would NOT be a way that parathyroid hormone (PTH) could alter plasma calcium levels?
increase osteoblasts on bone
(PTH would NOT increase osteoblasts. Osteoblasts store calcium on bone, thus lowering plasma calcium levels.)
Which hormone works directly in the intestine to increase plasma calcium levels?
calcitriol
(Yes, parathyroid hormone (PTH) activates Vitamin D into calcitriol in the kidney. Calcitriol then increases absorption of calcium in the intestine.)
Parathyroid hormone
-raises the level of calcium ion in the blood.
-increases the rate of calcium absorption.
-stimulates osteoclast activity.
-decreases the rate of calcium excretion.
The pituitary hormone that triggers the release of thyroid hormone from the thyroid gland is
TSH (Thyroid Stimulating Hormone)
Mature, less active bone cells are termed
osteocytes
Somatostatin is another name for
growth hormone-inhibiting hormone
The most important metabolic effect of ________ is protection against ________, crucial to surviving significant stress
cortisol, hypoglycemia
Vitamin D (calcitriol)
s formed by sunlight and bound to plasma protein for transport
What is the strongest negative feedback signal inhibiting corticotropin-releasing hormone release?
cortisol
T/F
All of the hormones secreted by the adrenal gland play a major role in growth and metabolism
FALSE
Cortisol secretion shows a ________ pattern of secretion, normally peaking in the ________.
Circadian, morning
Which of the following is not one of the factors that affect normal body growth?
activity level
T/F
The Thyroid hormones T3 and T4 are lipophilic so they do not require transporters to cross cell membranes.
FALSE
How is the hypothalamic control of growth hormone (GH) release different from the control of TSH and ACTH?
The hypothalamus releases both stimulatory and inhibitory tropic hormones for GH, whereas it only releases stimulatory hormones for TSH and ACTH.
The parathyroid glands produce a hormone that
increase the level of calcium ions in the blood
In bone, the calcium phosphate forms crystals of
hydroxyapatite
Calcium reabsorption at the kidneys is promoted by the hormone
calcitriol
Thyroid hormones are structural derivatives of the amino acid
tyrosine
The common precursor for all steroid hormones is ________.
cholesterol
The pituitary hormone that controls hormone synthesis and release from the thyroid gland is
TSH
What is a specialized region of the circulation where a blood vessel connects to sets of capillaries called
portal system
The inner portion of the adrenal gland is called the adrenal
medulla
The hormones of the anterior pituitary are controlled by trophic hormones from the
hypothalamus
The ________ of a hormone is an indicator of how long a hormone is active in the body.
half-life
lipophobic molecule that interacts with receptors on cell surface
peptide
Typically, when steroid hormones bind to their receptors,
gene transcription may increase or decrease
Exercise causes a general stimulation of the hypothalamus resulting in the release of most hypothalamic neurohormones. What would the general effect of this stimulation be?
an increase in metabolism, energy availability, and blood volume
Chemical signals released into the blood by neurons are called
neurohormones
The pituitary hormone that stimulates milk production by the mammary glands is
prolactin
What determines whether or not a particular cell will respond to a particular hormone?
the target cell must have a receptor that specifically binds to that hormone
If the release of thyroid hormone (TH) was regulated by a long-loop negative feedback system, where would the target cells be located to which TH would bind to inhibit the pathway?
hypothalamus
The adrenal cortex produces a steroid hormone called ________ that controls Na+ and K+ homeostasis and another steroid hormone called ________ that controls blood glucose levels.
aldosterone, cortisol
Neurohormones are classified as such because _______.
They are produced by neurons
T/F
Peptide hormones in the bloodstream are always bound to carrier proteins.
False
Most amine hormones are derived from which source?
Tyrosine
The sex hormones from the anterior pituitary that regulate the male and female reproductive organs are collectively called
gonadotropins
________ is a decrease in the number of receptors of target cells in order to dampen the effects of excess hormone.
Down-regulation
After a hormone has exerted its effects, it typically
is inactivated or removed from the blood
The study of hormones is known as the field of
endocrinology
Which embryonic structure gives rise to the seminal vesicles and vas deferens during fetal differentiation into a male?
Wolffian duct
________ is a hormone secreted by both the Sertoli cells of the testes and the granulosa cells of the ovaries.
Anti-M�llerian hormone
The average length of the menstrual cycle is
28 days
Periodic pulsatile secretion of GnRH appears to be important in
preventing down-regulation of GnRH receptors
If the ovaries were removed from an otherwise healthy 20-year-old female, which of the following would you expect to see?
-cessation of menstruation
-increased blood levels of GnRH
-increased blood levels of FSH
-increased blood levels of LH
In males, what is the target of FSH and what effect does it have?
Sertoli cells, release of paracrine factors to stimulate spermatogenesis
The structure(s) in testes that produces testosterone is/are the ________.
leydig cells (anatomically called the interstitial cells)
In the late follicular phase of the ovarian cycle, LH is ________ FSH.
greater than
The structure that transports the ovum to the uterus is the
fallopian tube
Sperm production occurs in the
seminiferous tubules
Which enzyme converts androgens to estrogens and where is it found?
aromatase, found in the ovaries and the testes
What is unique about GnRH secretion patterns from the hypothalamus?
It is secreted in a pulsatile manner
During the luteal phase of the ovarian cycle, progesterone is ________ estrogen.
greater than
progesterone, early in pregnancy, secreted by
corpus luteum
The male gamete is called a
sperm
testosterone secreted by
leydig cells
Menstruation is triggered by a drop in the level(s) of
estrogen and progesterone
What causes the LH surge that occurs during the late follicular phase?
Progesterone and high estrogen output stimulate GnRH release from the hypothalamus.
Female secondary sexual characteristics (libido, pubic and axillary hair, fat distribution pattern, and breast development) are controlled by ________.
estrogen and adrenal androgen