Transcript Pituitary Gland Hormones

Pituitary Gland Hormones
Adenohypophysis
&
Neurohypophysis
Growth Hormone (GH)
Gland Source: Adenohypophysis
Target: all cells, epiphyseal plate, skeletal mms
Action: 1. Inc. cell growth, mitosis, protein syn.
2. stim. epiphyseal plate & repair &maintence of
skeletal mms
3. encourages cells to use fats for fuel
(glyconeogenesis=create new glucose)
Stimulus for release: hypothalamus release of GRH
(Growth Releasing Hormone)
Inhibit: GIH from hypothalamus
Problems:
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Pituitary Dwarfism: dec. GH in children
 Pituitary Gigantism: Inc. GH in children
 Acromegaly: Inc. GH in adulthood
Thyroid Stimulation Hormone
(TSH)
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Gland Source: adenohypophysis
Target: Thyroid Gland
Action: stimulates the thyroid to make and
release thyroxine (T4) and triiodothyronine (T3)
Stimulus for Release: TRH from hypothalamus
when thyroid hormone levels in the bl. are low
Inhibit: Neg. feedback, when hypothalamus
detects an inc. or normal levels of thyroid
hormone in the bl., it will stop sending TRH
Adrenocorticotropic Hormone
(ACTH)
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Gland Source: Adenhypophysis
Target: Adrenal Cortex (outer layer of gland)
Action: stim. release of corticosteroid
hormones (Cortisol is the main one) to help the
body resist stress
Stimulus for release: CRH (corticotropic
releasing hormone) from hypothalamus
Inhibit: Neg. feedback, an inc. of Cortisol in bl.
causes hypothal. to decr. or stop CRH
Follicle Stimulating Hormone
(FSH)
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Gland Source: adenohypophysis
Target: Follicleegg maturation in the follicle in the ovary;
sperm production in the seminiferous tubules of the testes (700
ft)
Action: prim. fn. is to stimulate gamete formation. Can also
help w/ release of estrogen and testosterone from the gonads.
Stimulus for release: beg. of puberty and all thru reprod. yrs.,
the hypothalamus will release GNrH (Gonadotropin Releasing
Hormone)
Inhibit: Neg. feedback, when levels of estrogen/testosterone
rise, the hypothal. Decreases release of GnRH
Luteinizing Hormone (LH)
Interstitial Cell Stimulating Hormone
(ICSH)
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Gland Source: Adenohypophysis
Target: ovaries and testes
Action: stim. ovulation, ovulation process causes release
of progesterone; testosterone prod. in the testes (in males
it is known as ICSH, interstitial cell stimulating hormone).
The interstitial cells that make testosterone are between
the seminiferous tubules.
Stimulus for release: GnRH from hypothalamus
Inhibit: Neg. feedback, hypothalamus dec. release of
GnRH as levels of progesterone and testosterone inc.
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FSH and LH/ICSH are known
as Gonadotropins. They work
together to stimulate the
ovaries and testes. They are
NOT made until puberty.
Prolactin (PRL)
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Gland Source: Adenohypophysis
Target: prim. target is the mammary glands (breasts)
Action: stim. Mammary glands to produce milk in
females; in males, it enhances the effects of ICSH (LH)
Stimulus for release: PRF from hypothalamus, also
when already breastfeeding, the infant sucking on the
nipple will cause her to make more milk
Inhibit: PRIF (Prolactin release inhibiting factor) from
hypothalamus.
Oxytocin (OT)
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Gland Source: Neurohypophysis
Target: uterine wall and breast area around the nipple to
eject milk. (there is no known normal function for OT in
males)
Action: causes STRONG uterine contractions during birth
Stimulus for release: Positive Feedback, stretch receptors in
the vagina and touch receptors around the nipple for milk
ejection (lactation)
Inhibit: no more stretching of vaginal wall, so hypothal. Will
stop releasing OT to the uterus. It will continue to the breast
Pitocin: synthetic OT to induce labor
Antidiuretic Hormone (ADH)
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Gland Source: Neurohypophysis
Target: kidneys
Action: instructs kidneys to reabsorb water & place it
back into the blood, instead of this water being apart of
the urine and going to the bladder. This hormone rehydrates us.
Stimulus for release: dehydration (humoral control)
Inhibit: hydrated. Alcohol is an inhibitor….the
“hangover” is a result of alcohol dehydration. Caffeine
also inhibit ADH.
Melanocyte Stimulating
Hormone (MSH)
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Gland Source: Adenohypophysis
Target: melanocytes
Action: stim. prod. of melanin, levels are too low in
humans to have significant effects
Stimulus for Release: MRF (MSH-releasing Factor)
from hypothalmus. It is thought to be caused by
sunlight on the photosensitive receptors in the skin and
eyes
Inhibit: inc. levels of dopamine
Thyroid Gland
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Located on the ant. Trachea
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one of the largest endocrine glands
has a large bl. Supply
composed of circles of cuboidal cells: Follicles
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the cavity in the middle of the follicle: Central Cavity
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Cells making up the follicles are follical cells and respond to
TSH by making thyroglobin (the backbone for T3 and T4)
Contains iodine atoms
The large dome shaped cells found in between the
follicles are Parafollicular cells (make Calcitonin)
Triiodothyronine (T3)
Thyroxine (T4)
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Gland Source: Thyroid Gland
Target: All body cells
Action: accelerates the rate of cellular metabolism
(mitochondrial breakdown of carbohydrates, rate of
protein syn, and lipid breakdown) in every cell
Stimulus for Release: Low levels of T3 & T4 in the
blood trigger hypothal. To release TRH
Inhibit: Neg. feedback (normal levels T3 & T4)
Calcitonin
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Gland Source: Thyroid gland (parafollicular cells)
Target: osteoblasts and intestines
Action: stim. osteoblasts to pull Ca++ from the bl. and
deposits into bone and causes a dec. in Ca++
absorption in the intestines…Lowers bl. Ca++ levels!
Stimulus for Release: high bl. Ca++ levels (humoral)
Inhibit: Neg. feedback (normal-low bl. Ca++ levels)
Parathyroid Glands
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Found on the posterior side of the thyroid gland
 Usually 4, but there can be more
Parathyroid Hormone (PTH)
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Gland Source: Parathyroid glands
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1. osteoclasts: stim. to breakdown bony matrix and place Ca++
into the bl.
 2. instruct kidneys to retain Ca++ and not allow it to be excreted
 3. stim. the skin to produce more Vit. D to stim. Intestine to absorb
Ca++
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Action: Raise bl. Ca++ levels
 Stimulus for Release: low bl. Ca++ stim. prod. and release
of PTH
 Inhibit: Norm. Ca++ levels (9-11mg/100ml of bl.) or high
Ca++ (Neg. Feedback)
Adrenal Glands
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Paired glands, size of almonds; sits on top of a
kidney and has the shape of a Hershey’s kiss!
 Surrounded & protected by a fatty capsule
 2 Main Areas
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Cortex (3 outside layers)
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Makes up 85% of the gland
Produces 3 specific types of hormones
Medulla (inside part)
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Releases Epinephrine and Norepinephrine
Adrenal Cortex
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Outer Layer: Zona Glomerulus
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Releases mineral corticoids: Aldosterone is the main hormone
Middle Layer: Zona Fasciculata
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Releases Glucocorticoids: Cortisol is the main hormone here
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Hint: Gluco = glucose; glucose releases stress
Inner Layer: Zona Reticularis
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Releases gonadocorticoids: Androgens are the hormones from
this area
Aldosterone
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Gland Source: Adrenal Cortex (Zona Glomerulus)
Target: Kidney
Action: instructs the reabsorption of Na++ (which
causes H2O to be reabsorbed) which inc. blood
pressure
Stimulus for Release: ACTH at times of stress, Low
Na; renin-angiotensin System triggered by kidney,
Inhibit: high Na++ and Low K+, ANF released by the
heart when BP goes up. ANF inhibits renin and
aldosterone
Cortisol
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Gland Source: Zona Fasciculata
Target: adipose tissue and liver
Action: gouconeogenesis: causes glucose to be
formed from breakdown of fats and protein during times
of long term stress.
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During a daily cycle, Cortisol is higher in the am; handling
stress in the am seems easier than later in the day
High levels of Cortisol can be used at act as an antiinflammatory and anti-histamine
Stimulus for Release: Stress
Inhibit: neg. feedback (no CRH from Hypothal because
stress is low
Androgens
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Gland Source: Zona Reicularis
 Target: high levels occur mostly in the fetus and in early
puberty, after this time, the gonads take over
 Action: inc. cell metab., RBC prod in infants, provide
some female hormones during menopause. In males,
more or less effect amts of body hair upon onset of
puberty
 Stimulus for Release: ACTH
 Inhibit: Neg. feedback
Epinephrine/Norepinephrine
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80% Epinephrine (Adrenaline) & 20% Norepinephrine
(Noradrenaline)
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Gland Source: Adrenal Medulla
Target: Heart, bl. Vessels, resp. system, liver, skel. mms
Action: inc. BP, bl. Sugar, heart rate, bl. fl. to brain, heart and
skeletal mms (vasodialation); Vasoconstriction to the skin and GI
(gut); Bronchi dialation to inc. air exchange
Stimulus for Release: signals from brain to hypothalsympath NS
to activate adrenal medulla
Inhibit: neural stim. Ends and the liver and kidneys quickly remove
these hormones from the body. (short term effect on the body)
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Pancreas
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Shaped like a leaf, texture of cottage cheese
Can’t live without it
First job exocrine gland: provide digestive enzymes
Within the pancreas is a patch of cells that provide two
very important hormones that balance glucose levels
Islets of Langerhans’
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3 types of cells
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5% Delta cells: Release somatostatin to inhibit the other 2 types of cells
 25% Alpha Cells: release Glucagon
 70% Beta Cells: release Insulin
Glucagon
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Gland Source: Pancreas (alpha cells)
Target: liver and adipose tissues
Action: instructs the liver to change glycogen
glucose
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Glucagon causes glucose to be formed formthe breakdown of
fats and protein to inc. BS into the normal range.
Stimulus for Release: low BS (humoral)
Inhibit: high BS
Insulin
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Gland Source: Pancreas (Beta cells)
Target: all body cells
Action: resp. of glucose to ATP, excess
glucoseglycogen,
Stimulus for Release:
Inhibit:
Gonads: Ovaries & Testes
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Ovaries:
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Small, paired organs located in the lower abdomen of
females.
 Before birth, they carry out oogenesis and will contain
approx. 1,000,000 immature eggs (ovules) per ovary!!!!
 During puberty, the ovary will mature 1 ovum / month
(usually) and release it into the fallopian tube (ovulation)
 To control control this cycle of maturing the egg; the
lining of the uterus, & secondary sex characteristics, the
ovaries produce 2 hormones: Estrogen and
Progesterone.
Estrogen
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Gland Source: ovaries
 Target: most body cells and the female’s reproductive
organs
 Action: Development of secondary sex characteristics
(female), supports the egg (oocyte) maturation, and
works with progesterone for breast development & the
menstrual cycle
 Stimulus for Release: FSH & LH
 Inhibit: Neg. Feedback
Progesterone
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Gland Source: ovaries (corpus luteum)
Target: uterus & breast (mammary glands)
Action: prepares the lining (endometrium) of the uterus
for a fertilized egg & causes swelling in the breasts
(PRL works here w/ progesterone)
Stimulus for Release: LH
Inhibit: Neg. Feedback
Gonads: Ovaries & Testes
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Testes
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The testes are the male’s equivalent to the female’s ovaries,
but these organs require a lower body temp. to function
properly.
The main jobs of the testes are to produce sperm and
testosterone
The formation of sperm begins during puberty & can continue
for the rest of the man’s life.
 Spermatogenesis occurs at a very rapid pace & is very
sensitive to temperature.
 Scrotal sac is an external sac below the pubis…keeps temp
2 degrees below body temp
Testes cont’d….
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A testicle is made of approx. 700 ft. of seminiferous tubules;
these tubules carry out spermatogenesis
 In between the seminiferous tubules are interstitial cells.
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Responsible for making testosterone
Testosterone
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Gland Source: Testes….interstitial cells
Target: most body cells and seminiferous tubules
Action: stim. the production of sperm, sec. sex
characteristics, promotes protein syn. In skeletal mms
(repair and maintenance of mms)
Stimulus for Release: ICSH
Inhibit: neg. feedback
Pineal Gland
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Main hormone release is Melatonin.
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Primary function is sleep-wake cycle.
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Highest during darkness….causes sleepiness
Thymus Gland
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School for WBCs
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Lymphocytes mature and them leave to enter the bl.
Stream to protect us from anything that is not “self”
Begins to atrophy around the age of 50
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Possibly why elderly have lower immunity
Other Organ
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Some organs produce specific hormones to
communicate within the body.
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Kidneys
 Heart
 Skin
 GI tract
 Placenta
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All use hormones to aid in their function or to
communicate & coordinate w/ other systems in
the body
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Gland Source:
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Gland Source:
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 Stimulus for Release:
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