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
Corticotropes are (acidophilic or basophilic?) cells in the anterior pituitary that produce _____ which undergoes cleavage to _____ , ____ , and ____
basophilic
pro-opiomelanocortin (POMC)
adrenocorticotropin (ACTH)
β-lipotropin (β-LPH)
melanocyte-stimulating hormone (MSH).
THE POSTERIOR PITUITARY GLAND
- Also called the _____
- is composed mainly of ___-like cells called ____.
neurohypophysis
glial; pituicytes
The pituicytes secrete hormones and act as a supporting structure in the posterior pituitary lobe
T/F
F
They don’t secrete
Just serve as supporting structure
the supraoptic and para ventricular nuclei of the hypothalamus secretes two posterior pituitary hormones:
(1) antidiuretic hormone (ADH), also called ____
(2) _____.
-The tracts pass to the neurohypophysis through the ____ (_______).
vasopressin
oxytocin
pituitary stalk ; hypophysial stalk
ADH
-acts on ____ of the kidney
-____eases water retention
collecting duct
Incr
Control of ADH
- Stimulate secretion
- ___ease osmotic pressure
- ___ease ECF vol
- pain, emotion, stress etc
Incr
Decr
Control of ADH
inhibit secretion
- ___ease osmotic press
- ___ase ECF vol
Decr
Incr
alcohol stimulates the secretion of ADH
T/F
F
Inhibits it
Diabetes insipidus:
-Damage to the pituitary gland may result in ___eased ADH and therefore the production of (small or large?) amounts of urine up to __-__ liters per day.
Decr
large
20-30
In nephrogenic Diabetes insipidus kidney _____ to ADH
Symptoms include
Poly___
poly____
fail to resond to
Uria
Dipsia
Oxytocin
Action primarily on:
*breast (relaxation or contraction ?) of ____ cells to squeeze milk out of ____
*uterus to cause ____ of _____
contraction; myoepithelial ; alveoli
contraction of smooth muscle
Oxytocin facilitates sperm transport in non-pregnant Uterus
T/F
T
Oxytocin propels sperm toward the urethra
T/F
T
Growth hormone (GH):
- Also known as ____
- produced by the somatotropes
- forms __% of the secetory cells in the ant. Pituitary
Somatotropin
50
Growth hormone is Essential and the only hormone responsible for growth.
T/F
F
not the only one responsible for it
Growth hormone Stimulates growth of bones and soft tissues
T/F
T
Growth hormone
-inhibits somatomedin secretion by the liver.
T/F
F
Stimulates
somatomedin is an hormone which acts as an ______ in the stimulation of ____ growth by ____ hormone.
Intermediate
tissue
growth
Physiologic Effects of Growth Hormone
- A critical concept in understanding growth hormone activity is that it has two distinct types of effects:
1. Direct effects are the result of growth hormone ______
2. Indirect effects are mediated primarily by a _______
binding its receptor on target cells.
insulin-like growth factor-I (IGF-I)
insulin-like growth factor-I (IGF-I) is an hormone that is secreted from the liver and other tissues in response to ____ hormone.
growth
Majority of the growth promoting effects of growth hormone is actually due to ____ acting on its target cells
IGF-I
Effects on Growth:
-The major role of growth hormone in stimulating body growth is to stimulate the ___ and other tissues to secrete ____
liver
IGF-I
IGF-I stimulates proliferation of _____cytes ( ____ cells), resulting in bone growth.
chondro; cartilage
Growth hormone does seem to have a direct effect on bone growth in stimulating differentiation of chondrocytes.
T/F
T
IGF-I also appears to be the key player in muscle growth.
T/F
T
IGF-1 also stimulates amino acid (uptake or expulsion?) and protein ____ in muscle and other tissues.
uptake
synthesis
Metabolic Effects of growth hormone:
Protein metabolism:
- In general it stimulates protein __bolism in many tissues.
- ___eased protein synthesis
- ___eased oxidation of proteins.
ana
Incr
Decr
Growth hormone has important effects on metabolism
T/F
T
Metabolic effect of growth hormone
Fat metabolism:
-Growth hormone enhances (utilization or production ?) of fat by stimulating triglyceride ____ and ____ in adipocytes.
utilization
breakdown
oxidation
Metabolic effect of growth hormone
Carbohydrate metabolism:
-Growth hormone helps to maintain blood glucose within a normal range
T/F
T
Metabolic effect of growth hormone On Carbohydrate metabolism:
It is often said to have insulin-like activity
T/F
F
Anti-insulin activity
Growth hormone suppresses the abilities of insulin to stimulate uptake of glucose in peripheral tissues and enhance glucose synthesis in the liver.
T/F
T
Regulation of Growth Hormone Secretion
Production of growth hormone is modulated by many factors including:
stress,exercise, nutrition , sleep and growth hormone itself
T/F
T
However, primary controllers of growth hormone secretion are:
- _______ hormone
- ______: a peptide hormone
- _______ (SS): a peptide produced by several tissues in the body, including the hypothalamus.
Growth hormone-releasing
Ghrelin
Somatostatin
Ghrelin a peptide hormone secreted from the _____. (stimulates or Inhibits?) secretion of growth hormone.
stomach
Stimulates
Ghrelin’s hallmark functions are its stimulatory effects on _____, fat ____ and _____ hormone release.
food intake
deposition
Growth
Ghrelin is famously known as the “_____ hormone”.
hunger
Somatostatin (stimulates or inhibits?) growth hormone release in response to GHRH and other stimulatory factors such as (high or low?) blood glucose concentration.
Inhibits
low
High blood levels of IGF-I lead to ___eased secretion of growth hormone (stimulating release of _____ from the hypothalamus).
Decr
somatostatin
Growth hormone also feeds back to inhibit GHRH secretion
T/F
T
DISORDERS OF GH
-Growth hormone disorders can reflect lesions in either the _____, the ____ or in ____ cells.
hypothalamus
pituitary
target
Clinically, deficiency in growth hormone or defects in its binding to receptor are seen as growth ____ or ______.
retardation
dwarfism
The manifestation of growth hormone deficiency doesn’t depend on the age of onset of the disorder.
T/F
F
It does
Panhypopituitarism
-This means decreased secretion of ______ hormones.
all the anterior pituitary
Panhypopituitarism
It may be ____ or it may occur suddenly or slowly at any time during the life of the individual, most often resulting from a ______ that destroys the pituitary gland.
congenital
pituitary tumor
Panhypopituitarism during childhood ( _____)
-Most instances of it results from generalized deficiency of _____ secretion.
Dwarfism
Anterior pituitary
Dwarfism
In general, all the physical parts of the body develop in inappropriate proportion to one another
T/F
F
It’s appropriate
Dwarfism
the rate of development is greatly ___eased
Decr
The panhypopituitary dwarf does not pass through puberty
T/F
T
The panhypopituitary dwarf never secretes sufficient quantities of gonadotropic hormones to develop adult sexual functions.
T/F
T
In ____ of such dwarfs, there is the deficiency of growth hormone alone; these persons do mature sexually and occasionally reproduce.
one third
In the LeviLorain dwarf, the rate of growth hormone secretion is ___ or ____, but there is a hereditary inability to form ______
normal or high
somatomedin C
Panhypopituitarism in the Adult.
In adulthood frequently due to:
-tumors which may compress the pituitary gland until the functioning ______ cells are totally or almost totally destroyed.
-OR, thrombosis of the _____ blood vessels.
anterior pituitary
pituitary
thrombosis of the pituitary blood vessels can occur when a new mother develops _____ after the birth of her baby.
circulatory shock
Effects of panhypopituitarism in adults in general are
-(hyper or hypothyroidism?)
-(depressed or elevated?) production of glucocorticoids by the adrenal gland
-(suppressed or elevated?) secretion of the gonadotropic hormones
hypothyroidism
depressed
suppressed
Except for the abnormal sexual functions, the patient suffering from panhypopituitarism in adults can usually be treated satisfactorily by administration of adrenocortical and thyroid hormones.
T/F
T
Gigantism
-Is the result of excessive growth hormone secretion that begins in ______ or ______
young children or adolescents.
Gigantism is a very (common or rare?) disorder, usually resulting from a tumor of _____ cells.
Rare
somatotropes
In gigantism, All body tissues grow rapidly, excluding the bones.
T/F
F
Including the bones
Gigantism
Because the condition occurs before adolescence before the ____ of the (short or long?) bones have become fused with the ____, height increases so that the person becomes a giant as tall as ____
epiphyses
long
shafts
8 feet
The giant in gigantism ordinarily has ___glycemia, and the beta cells of the islets of Langerhans in the pancreas are prone to ____ because they become _____
Hyper
degenerate
overactive
Consequently, in about ___ per cent of giants, full-blown diabetes mellitus finally develops.
10
In most giants,________ eventually develops if they remain untreated, because the gigantism is usually caused by a tumor of the ____ that grows until the gland itself is destroyed.
panhypopituitarism
pituitary gland
In giants,
This eventual general deficiency of pituitary hormones usually causes death in early adulthood.
T/F
T
once gigantism is diagnosed, further effects can often be blocked by ______ from the pituitary gland or by _____ of the gland.
microsurgical removal of the tumor
irradiation
Acromegaly
- Results from excessive secretion of growth hormone in _____ (adolescence) (before or after?) the epiphyses of the long bones have fused with the shafts, and the person (can or cannot?) grow taller, but the soft tissues (can or can’t ?) continue to grow and the bones can grow in (length or thickness?) .
- Usually the result of (benign or malignant?) pituitary tumors
adults
After
cannot
can
thickness
Benign
Clinical signs of acromegaly include:
- overgrowth of _____
- Enlargement especially marked in the bones of the ____ and ____ and in the (membranous or cartilagenous?) bones
extremities
hands and feet
membranous
Acromegaly affects alot of places including the
___,__ on the ____; ____, ____ ridges, ____, and portions of the ______ (because their growth does not cease at ______ ).
cranium
bones; forehead
nose
supraorbital
lower jawbone
vertebrae
adolescence
In acromegaly,
Consequently, the lower jaw protrudes forward, fingers become extremely (thinned or thickened?) so that the hands develop a size almost ___ normal.
- In addition to these effects, changes in the vertebrae ordinarily cause a _____, which is known clinically as _____.
- many soft tissue organs, such as the ___, ____, and especially the ______, become greatly enlarged.
thickened
twice
hunched back
kyphosis
tongue; liver; kidneys
In people who have lost their ability to secrete growth hormone, the aging process (accelerates or decelerates?)
accelerates
For instance, a person at age 50 who has been without growth hormone for many years will probably have the appearance of a person aged 65
T/F
T
Possible Role of Decreased Growth Hormone Secretion in Causing Aging
The aging seems to result mainly from deceased ___ deposition in most tissues of the body and in its place increased deposition of ___.
-The physical and physiologic effects are increased ___ of the skin, (diminished or elevated?) rates of function of some of the organs, and (diminished or elevated?) muscle mass and strength.
protein
fat
wrinkling ; diminished ; diminished
As one ages, the average plasma concentration of growth hormone in an otherwise normal person ___eases with age.
-Thus, it is highly possible that some of the aging effects in normal older life result from _____ growth hormone secretion.
decr
diminished
