Pituitary Gland Flashcards by Iseoluwa Ojo

Pituitary gland

-Anterior pituitary (_____) – derived from the epithelial tissue of the embryonic _____.

adenohypophysis

oral cavity

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During embryonic development, the roof of the ____ bulges (downwards or upwards ?) (____) to form a tiny, ___-like structure known as ___, which then fuses with the ____ portion of the pituitary gland

Failure of the above process to occur normally may lead to an abnormal pituitary structure or the formation of ___ and ____

Roof; mouth

Upwards; invaginates

bubble; Rathke’s pouch

posterior

cysts and clefts

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The anterior pituitary accounts for approximately ____% of the total mass of the gland and includes two major parts:

Pars distalis – (smaller or larger?) , ____ portion
Pars tuberalis – highly ____ sheath wrapped around the _____
A third (intermediate) region of the pituitary gland is often recognisable and this is known as the ______ and is usually present as a (thin or thick?) band of tissue that marks the point where the ____ and ____ ——

70-80

Larger; bulbous

vascular; infundibular stalk.

pars intermedia;Thin

anterior and posterior pituitaries fuse

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Hormones of the posterior pituitary

-____ and _____ are concentrated and stored in the pars _____ before being released into the blood when required.

ADH and oxytocin

nervosa

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Posterior pituitary hormones are amine hormones

T/F

Peptide

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Posterior pituitary hormones are peptide hormones and, as they are produced by _____, they are often called ______

neurons

neuropeptides.

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Antidiuretic hormone

ADH plays a vital role in regulating ___ balance and_____
Specialised ___receptors located in the hypothalamus continually monitor the _____ of the blood.
When the body loses water dehydration may occur and the _____ rises.
This is detected by the ____ osmoreceptors, which initiate the release of ADH from the _____.

fluid

blood pressure.

osmo

solute concentration

plasma solute concentration

hypothalamic

posterior pituitary

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ADH primarily acts on the ____

-This ____ the volume of urine produced, resulting in the urine being (lighter or darker?) and ____ concentrated.

kidneys

reduces

darker

more highly

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By ____ fluid reabsorption back into the blood, ADH helps normalise the ______ of the blood.

Increasing

solute concentration

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ADH is also released after a drop in blood volume or pressure.
T/F

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normalisation of blood pressure is further enhanced by ADH acting as a powerful vasodilator
T/F

Vasopressor

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ADH-induced vasoconstriction, particularly in the_____ (_____), further increases and normalises blood pressure

peripheral arterioles; small arteries

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(Increased or Reduced ?) secretion of ADH can lead to diabetes _____

Reduced

insipidus (DI).

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diabetes insipidus (DI)
-Patients with DI cannot _____ their urine, resulting in _____.
-Large volumes of urine (_-_L/ day) are usually produced
-if not treated, this can lead to ____
-two major types are recognised:
_______ and _____

concentrate

polyuria

3-20

severe dehydration.

Neurogenic; nephrogenic

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DI is (common or rare?) , affecting around 1 in _____ people

Rare

25,000

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Neurogenic or ____ DI is caused by the ____secretion of ___ by the posterior pituitary. This is most often due to ____ ,____ affecting the hypothalamus or pituitary or, more rarely,____; treated with _____

central

under

ADH

trauma

tumors

infections

desmopressin

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desmopressin is a _____of ____

synthetic analogue

ADH

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Nephrogenic DI is a rarer form, in which patients usually have ___ ADH synthesis and secretion, but their kidneys are ______ to the effects of ADH – most commonly due to _____ or ___-induced kidney damage

normal

insensitive

kidney disease

drug

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Which type of diabetes insupidus has a more complex treatment

Nephrogenic

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Oxytocin
-Oxytocin is released into the blood at high concentration towards the (start or end?) of the ____ period and initiates ___ by stimulating____ of the ______

End

gestational

parturition

contractions

Myometrium

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Myometrium is the ____ layer of the uterus

muscular

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Oxytocin secretion is regulated by a ______ feedback mechanism, whereby increased oxytocin stimulates more-powerful _____, which in turn stimulate ______

positive

myometrial contractions

the release of more oxytocin

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Oxytocin also stimulates the ‘ _____ reflex’ in lactating mothers; here the ____ muscle linings of the ____ in the breast contract, making milk available to the baby during ____.

this is regulated by ____ feedback

letdown

smooth

milk ducts

suckling

positive

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______ is often referred to as ‘the love hormone’ because it plays an important role in promoting ______
-it is also thought to facilitate _____ between partners.

Oxytocin

mother/baby bonding

pair bonding

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oxytocin can reduce anxiety T/F

oxytocin can promote maternal behaviour T/F

The _____ pituitary produces a far greater range of hormones than the ______ pituitary.

Anterior Posterior

Hormones of the anterior pituitary -The anterior pituitary’s cells are usually classified into five major types based on the nature of their secretions. -These are listed below with their hormonal secretions: ● _____ – ____ or growth hormone (GH) ●____ – prolactin ●____ – thyroid-stimulating hormone (TSH) ●_____ – adrenocorticotropic hormone (ACTH) and ________ hormone ●______ – follicle-stimulating hormone (FSH) and luteinising hormone (LH).

Somatotrophs somatotropin Lactotrophs Thyrotrophs Corticotropths melanocytestimulating hormone (MSH) Gonadotrophs

Growth hormone - the primary function of GH is to promote ______ - Most famously, GH promotes the widening of the growth plates in the _____ of the long bones of the skeleton, which results in elongation of the major bones of the ___and ____, progressively increasing ____. - GH also enhances _____ uptake from the blood into cells, increasing the rate of ____ synthesis in tissues such as muscle; this is why it is known as an _____ hormone.

bodily growth. epiphyses arms and legs height amino acid protein; anabolic

Thyroid hormones T3 and T4 (thyroxine), which regulate metabolism, are necessary for GH to exert its effects efficiently. T/F

The anabolic effects of GH are also enhanced by the presence of other anabolic hormones such as ____.

testosterone

GH also stimulates the growth of bone but not any major internal organs T/F

F It does

Deficiency of GH during childhood may result in______; this is characterised by below-average growth and, commonly, an underdeveloped ___ of the____ and prominent _____.

pituitary dwarfism bridge of the nose forehead

Unlike achondroplastic dwarfism, pituitary dwarfism, although associated with reduced height, is characterised by _____

normal bodily proportions.

achondroplastic dwarfism is a genetic disorder | T/F

_____is available to treat children who are deficient in GH. -It is usually injected ____, __times a day, and growth rate and potential side-effects then carefully monitored

Recombinant human GH subcutaneously once

Elevated secretion of GH in childhood often leads to _____, in which rapid growth of the long bones can result in an adult height of >_____.

gigantism 2.4m

Elevated secretion of GH in adults, after their epiphyseal growth plates have fused, can lead to _____, in which the ____, ____ and some ___ features (particularly the ____) can grow abnormally large and usually out of normal proportion

acromegaly hands; feet;facial lower jawbone

Prolactin - Prolactin (___genic hormone) initiates milk secretion (lactation) in breast tissue. - By itself, prolactin has a (weak or strong ?) effect, but during pregnancy prolactin levels increase and it acts synergistically with other hormones including ____,____,and____ , to promote the enlargement and engorgement of the ____ in preparation for lactation.

lacto Weak oestrogens, progesterone and cortisol breasts

It has been hypothesised that the release of prolactin is regulated and fine-tuned by the antagonistic actions of a _____ hormone and a ______hormone, both of which are thought to be produced by the _____

prolactin releasing prolactin-inhibiting hypothalamus

Tropic hormones -Tropic hormones have a stimulating effect on ____, inducing the synthesis and secretion of the target hormone(s). _____ major tropic hormones are synthesised and secreted by the _____ pituitary

other endocrine glands Four anterior

Thyroid-stimulating hormone (thyrotrophin) - TSH stimulates the thyroid gland to secrete the ____-containing hormones T3 and T4. - These are primarily responsible for regulating metabolism, with ___ being the more potent. - Most cell types in the body have (internal or external?) receptors for T3 and T4.

iodine T3 Internal

Thyroid hormones are also vital for growth and development, and play key roles in the normal functioning of the cardiovascular, respiratory, skeletal and central nervous systems. T/F

The release of TSH is regulated by____ hormone, which is produced by the _____ .

thyrotropin-releasing hypothalamus

The fine tuning of T3 and T4 release is regulated by _____ feedback, through the sequential secretions of the _____,___ pituitary and ____ gland -This hormonal cascade is referred to as the _______ axis

negative hypothalamus anterior thyroid hypothalamic-pituitary-thyroid (HPT)

``` Adrenocorticotrophic hormone (adrenocorticotropin) -ACTH primarily regulates the production and secretion of cortisol from the_____ ```

adrenal cortex

Cortisol is a ___-term stress hormone and a steroidal hormone synthesised from _____. -It is referred to as a ___corticoid because it is produced by the _____ and influences the concentration of ____ in the blood

long cholesterol gluco; adrenal cortex; glucose

Cortisol plays a key role in regulating ____ and, during periods of food deprivation, stimulates the breakdown of ___ and ___ to generate glucose for use as fuel in glucose-dependent tissues, such as the___

metabolism protein and fat brain

Cortisol influences the sleep/wake cycle | T/F

Cortisol influences mood and behavior | T/F

Cortisol has weak anti-inflammatory/immunosupressant properties T/F

F It’s potent

ACTH also helps to regulate the release of other steroid hormones produced by the adrenal cortex, including ____ and the group of testosterone-like hormones known as _____ -The complex interplay between the hypo-thalamus, anterior pituitary and the adrenal cortex is referred to as the ____ axis

aldosterone androgens HPT

ACTH is part of the melanocortin group of hormones T/F

Melanocyte-stimulating hormone - MSH is synthesised by the ______ region of the pituitary gland. - - this region is generally considered part of the____ pituitary. - MSH exists in a range of structurally similar forms known as _______

pars intermedia anterior melanocortins

The pars intermedia ___ with age and, in adults, may only be present as a ____ or, in some cases, is ______ at all.

atrophies vestigial remnant not recognisable

melanocortins are all large peptides T/F

F Small

MSH stimulates the ______-producing cells (melanocytes) in the ____ to release the ____ pigment known as _____, which is largely responsible for ____

Pigment epidermis dark Melanin skin colour.

All races are have similar numbers of melanocytes in their epidermis T/F

it is the relative ___ of these melanocytes and the____ they synthesise and release that ultimately determines skin colour.

activity amount of melanin

Melanocytes can synthesise ____ when exposed to the ____ light in sunlight -This is essential to protect the ____ cells of the _____ from the harmful effects of ___, known to cause ___ damage that can lead to mutations and, potentially,____

MSH ultraviolet (UV) actively dividing; epidermis ; UV DNA skin cancers.

Melanin is average at absorbing UV wavelengths of light and, as it accumulates in the epidermis the skin, darkens and develops a protective suntan. T/F

F It’s excellent at it

During pregnancy, levels of MSH tend to ____, which, together with changes to the sex hormones, ____ and ____, often leads to _______ around the ______, _____ ,____ and _____. This is known as ____ or ‘_____’

increase oestrogen and progesterone hyper-pigmentation; eye sockets cheekbones lips and forehead melasma; the mask of pregnancy

Melasma usually doesn’t fade m after childbirth | T/F

F They usually gradually fade

ACTH is another hormone that can influence skin pigmentation through the (direct or indirect?) stimulation of melanocytes.

Direct

In certain forms of Cushing’s syndrome, excess ____ often causes regions of dark, hyperpigmented skin

ACTH

The ___ gland is often referred to as the master gland but, in fact, it plays more of a ‘_____’ role; many of its actions are directed by the ______.

pituitary middle-management hypothalamus

Gonadotropins - The main gonadrotrophins are ___and ___ - the release of both is regulated by ______ hormone, which is produced by the ____

FSH and LH gonadotropin-releasing hypothalamus

In females, each ____, ___ initiates the development of ____ in the ovaries.

month FSH immature follicles

As each follicle enlarges, it secretes the female sex hormone ____, before maturing into a____

oestrogen Graafian follicle

A Graafian follicle is a ____-filled, pressurised sac containing a ______, primed and ready to ___.

fluid mature ovum (egg) rupture

Ovulation is triggered by ____, which initiates ___ of the follicle and ______; this explosive event propels the ovum into its adjacent _____

LH rupturing Ovarian wall fallopian tube.

Following ovulation, the remnants of the Graafian follicle collapse to form a structure known as the ____ ( ____ body). -This produces the second major female sex hormone, _____, which maintains the integrity of the ______ of the uterus to allow for the _____

corpus luteum yellow progesterone endometrial lining implantation of a fertilised ovum

FSH and LH also play crucial roles in male reproductive physiology. T/F

FSH is essential in stimulating ____ -FSH also stimulates the activity of ____ cells (‘___’ cells) in the ___; these provide nutrition to the developing spermatozoa, allowing maturation into viable gametes that are capable of fertilisation.

spermatogenesis Sertoli; nurse testes

LH stimulates the _____ cells (____ cells) of the testes to synthesise and release the male sex hormone _____

interstitial Leydig testosterone

Testosterone , is a mild anabolic steroid T/F

F Super powerful

Testosterone is largely responsible for the male sex drive T/F

The ACTH family is derived from a single precursor, ______.

pro-opiomelanocortin (POMC)

The ACTH family includes ACTH, ___ and ___ ——, ____, and ______.

γ- and β-lipotropin β-endorphin melanocyte-stimulating hormone (MSH)

_____ is the only hormone in the ACTH family with well-established physiologic actions in humans.

ACTH

MSH is involved in ____ in lower vertebrates

pigmentation

MSH has no activity in humans T/F

F has some activity in humans.

β-Endorphin is an endogenous opiate | T/F

Skin pigmentation is a symptom of addison’s Disease T/F With reason

T These MSH-containing fragments can cause skin pigmentation in humans if their blood levels are increased. For example, in Addison disease (primary adrenal insufficiency), POMC and ACTH levels are increased by negative feedback. Because POMC and ACTH contain MSH activity, skin pigmentation is a symptom of this disorder.

Growth hormone is not secreted throughout life. T/F

F | It is

Human growth hormone is functionally similar to prolactin T/F

F structurally

HPL has ___ % homology with growth hormone Prolactin has ___ % homology with growth hormone

80 75

Growth hormone is secreted in a pulsatile pattern T/F

bursts of growth hormone secretion occurs approximately every _____. The largest secretory burst occurs within 1 hour of ______ (during stages ___ and ____).

2 hours falling asleep III and IV

# Fill with inhibit or stimulate growth hormone ``` Low glucose concentration Growth hormone High free fatty acid concentration Fasting or starvation Somatostatin Hormones of puberty Exercise Stress Obesity Senescence Somatomedins β-Adrenergic agonists Pregnancy ```

``` Stimulates Inhibits Inhibits Stimulates Inhibits Stimulates Stimulates Stimulates Stimulates Inhibits Inhibits Inhibits Inhibits Inhibits ```

Somatostatin is also secreted by the hypothalamus T/F

Somatomedins, which are _____ of the growth hormone action on target tissue

byproducts

somatomedins aka ______ in the liver. The most important of the somatomedins is _____ or _____

IGFs somatomedin C or IGF-1.

Growth hormone ___eases glucose uptake and utilization by target tissues such as muscle and adipose tissue.

decr

Growth hormone also ___eases lipolysis in adipose tissue.

Incr

growth hormone causes a decrease in blood insulin levels. | T/F

F Increase

In Laron dwarfism, growth hormone levels are (elevated or depressed?) and treatment with growth hormone is (effective or ineffective?) In these individuals, ______ are defective; thus growth hormone cannot cause production of _____ in _____

Elevated ineffective growth hormone receptors IGFs in target tissues.

Prolactin inhibits ovulation | T/F

prolactin excess can be treated by administration of ______ , a dopamine _____.

bromocriptine agonist

Conditions with excess secretion of growth hormone are treated with ______ (e.g., ________)

somatostatin analogues octreotide

Pituitary Gland Flashcards

(100 cards)