Endocrinology2 Flashcards
PITUITARY GLAND
- The pituitary gland, also known as the ______
- is sometimes called the “ _____ “ gland of the endocrine system
- it controls the functions of the other endocrine glands.
- It is a _____ organ no larger than a ____
hypophysis
master
roundish; pea
Pituitary gland
is located at the (base or apex?) of the brain (immediately beneath the _______ ).
-It sits in the _____
Base
hypothalamus
sella turcica
Physiologically the pituitary gland is divided into 2 distinct portion:the anterior pituitary or ___ and the posterior pituitary or ___
-Inbetween these two is a small relatively (vascular or avascular?) zone known as the pars intermedia or intermediate lobe ( ____ in human)
adenohypophysis
neurohypohysis
avascular
rudimentary
Pars intermedia or intermediate lobe produces ______ hormone
The posterior pituitary produces :_____ and ______
Melanocyte stimulating
ADH (antidiuretic hormone)
Oxytocin
Thyroid-stimulating hormone (TSH):
- Also known as _____
- is a _____ produced by the thyrotropes
- forms __% of the secetory cells in the ant. Pituitary
thyrotropin
glycoprotein
5
Actions of TSH
- It ___eases the secretion of T3 (triiodothyronine) and T4 (thyroxine) from the thyroid follicular cells by ___easing all the known secretory activities of the thyroid glandular cells.
- ___eased proteolysis of the thyroglobulin that has already been stored in the follicles
- ___eased activity of the iodide pump
- ____eased iodination of tyrosine
- ___eased size and secretory activity of the thyroid cells.
- ___eased number of thyroid cells.
Incr
Incr
Incr
Incr
Incr
Incr
Incr
Regulation of TSH
-Anterior pituitary secretion of TSH is controlled by a hypothalamic hormone,______ or ______, which is secreted by nerve endings in the hypothalamus.
thyrotropin-releasing hormone (TRH)
TSH-RH
TRH has not been obtained in pure form.
T/F
F
It has
TRH directly affects the anterior pituitary gland cells to increase their output of ____.
TSH
One of the best-known stimuli increasing the rate of TRH secretion by the hypothalamus and therefore TSH secretion by the anterior pituitary gland, is exposure of an animal to ____
cold
Various emotional reactions can also affect the output of TRH and TSH and therefore indirectly affect the secretion of thyroid hormones.
T/F
T
Excitement and anxiety conditions that greatly stimulate the sympathetic nervous system cause an acute ___ease in secretion of TSH.
decr
Adrenocorticotropic hormone (ACTH):
- Also called _____ or _______
- is a (small or large?) polypeptide produced by the corticotropes
- forms ___% of the secetory cells in the ant. Pituitary
corticotropin or adrenocorticotropin
Large
10
Actions of ACTH
-ACTH stimulates ____ secretion and also enhances the production of ____.
Cortisol
adrenal androgens
How ACTH enhances the production of adrenal androgens
- It stimulate ____ and ____ of zona ____ and ____ of the adrenal cortex.
- Thus activating these adrenocortical Cells to produce steroids by increasing ______
secretion and growth
fasciculata and reticularis
cyclic adenosine monophospate (cAMP).
Regulations of ACTH
-ACTH Secretion Is Controlled by _____ from the Hypothalamus.
Corticotropin-Releasing Factor
The anterior pituitary gland can secrete no quantity of ACTH in the absence of CRF.
T/F
F
It can secrete, only minute quantities tho
Any type of physical or mental stress can lead within _____ to greatly _____ secretion of ACTH.
minutes
enhanced
Pain stimuli caused by any type of physical stress or tissue damage can also stimulate release of ACTH
T/F
T
Mental stress cause a decrease in ACTH secretion.
T/F
F
Increase
Mental stress’ effect on ACTH is believed to result from ___eased activity in the ____ system.
Incr
Limbic
Gonadotropins
- They are ______ produced by the gonadotrophs
- forms __% of the secetory cells in the ant. Pituitary
glycoproteins
20
Most gonadotrophs secrete only LH or FSH, and never secrete both hormones
T/F
F
The mostly secrete just one but some secrete both
Physiologic Effects of Gonadotropin
-Physiologic effects of the gonadotrophins are known only in the ___ and ____. Together, they regulate many aspects of gonadal function in both males and females
Ovaries and testes
Luteinizing Hormone
-In both sexes, LH stimulates secretion of sex steroids from the gonads.
T/F
T
In the testes, LH binds to receptors on _____ cells, stimulating synthesis and secretion of _______.
Leydig
testosterone
In females, it stimulates _____ and _____ of _______
ovulation and luteinization
ovarian follicles
Follicle-Stimulating Hormone
-As its name implies, FSH stimulates the _____ of _______.
maturation
ovarian follicles
In male FSH is also critical for _____ production ( ______ ).
sperm
spermatogenesis
FSH supports the function of _____ cells, which in turn support many aspects of sperm cell maturation
Sertoli
Control of Gonadotropin Secretion
-The principle regulator of LH and FSH secretion is _____ , also known as _____ hormone).
gonadotropin-releasing hormone
LH-releasing
Numerous hormones influence GnRH secretion.
-The gonads secrete at least two additional hormones - ____and____ - which selectively inhibit and activate FSH secretion from the pituitary.
inhibin and activin
Hypogonadism:
- Failure of gonadal function.
- This condition is typically manifested in males as failure in ____ of ____ of ______ .
production
normal numbers
sperm
Hypogonadism:
In females, hypogonadism typically manifests as ______ of ______
cessation of reproductive cycles
Elevated blood levels of gonadotropins usually reflect lack of steroid _____ feedback.
negative
Removal of the gonads from either males or females leads to depression in LH and FSH levels
T/F
F
Causes persistent elevation
Excessive secretion of FSH and/or LH is most commonly the result of _____ tumors.
pituitary
General biologic effect of elevated levels of gonadotropins
per se have no biological effect
Prolactin
-Produced by the lactotropes which forms ____% of the secetory cells in the ant. Pituitary
10-30
Actions of prolactin
-Causes milk _____ from the breast after ___ and _____ priming.
secretion
estrogen and progesterone
Prolactin Promotes development of female breast
T/F
T
Prolactin (stimulates or Inhibit?) actions of gonadotrophins thus preventing _____ in ______ ovary.
Inhibit
ovulation
lactating
Control of Prolactin Secretion
- _____ inhibited by the hypothalamus Hypothalamic inhibitory factors ( ____ )
Tonically
PIH
PRF intermittently increase secretion of prolactin
T/F
T
Disorders of prolactin
hypoprolactinemia:
- chromophobe adenoma due to _____ or damage to _____.
tumor
portal system
chromophobe adenoma May cause galactorrhea
T/F
T
intermediate pituitary lobe:
^ ________ hormone - control skin _______
^make up __% of the cells
melanocyte-stimulating ; pigmentation
10
β-Lipotropin
- is a ___- amino acid polypeptide that is the carboxy-terminal fragment of POMC.
- It was initially reported to stimulate _____
90
melanocytes