Pituitary Gland Hormones Adenohypophysis & Neurohypophysis
Dec 23, 2015
Pituitary Gland Hormones
Adenohypophysis&
Neurohypophysis
Growth Hormone (GH)Gland Source: AdenohypophysisTarget: all cells, epiphyseal plate, skeletal mmsAction: 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: Pituitary Dwarfism: dec. GH in children Pituitary Gigantism: Inc. GH in children Acromegaly: Inc. GH in adulthood
Thyroid Stimulation Hormone (TSH)
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)
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) Gland Source: adenohypophysis Target: Follicleegg 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) 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.
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)
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) 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)
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 re-hydrates 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)
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 Located on the ant. Trachea
one of the largest endocrine glands has a large bl. Supply composed of circles of cuboidal cells: Follicles
Cells making up the follicles are follical cells and respond to TSH by making thyroglobin (the backbone for T3 and T4)
the cavity in the middle of the follicle: Central Cavity
Contains iodine atoms The large dome shaped cells found in between the
follicles are Parafollicular cells (make Calcitonin)
Triiodothyronine (T3)Thyroxine (T4)
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 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 Found on the posterior side of the thyroid
gland Usually 4, but there can be more
Parathyroid Hormone (PTH)
Gland Source: Parathyroid glands Target:
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++
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 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
Cortex (3 outside layers) Makes up 85% of the gland Produces 3 specific types of hormones
Medulla (inside part) Releases Epinephrine and Norepinephrine
Adrenal Cortex Outer Layer: Zona Glomerulus
Releases mineral corticoids: Aldosterone is the main hormone
Middle Layer: Zona Fasciculata Releases Glucocorticoids: Cortisol is the main hormone
here Hint: Gluco = glucose; glucose releases stress
Inner Layer: Zona Reticularis Releases gonadocorticoids: Androgens are the
hormones from this area
Aldosterone 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 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. 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 anti-inflammatory and anti-histamine
Stimulus for Release: Stress Inhibit: neg. feedback (no CRH from Hypothal
because stress is low
Androgens 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
80% Epinephrine (Adrenaline) & 20% Norepinephrine (Noradrenaline)
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 hypothalsympath 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)
Pancreas 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’ 3 types of cells
5% Delta cells: Release somatostatin to inhibit the other 2 types of cells
25% Alpha Cells: release Glucagon 70% Beta Cells: release Insulin
Glucagon Gland Source: Pancreas (alpha cells) Target: liver and adipose tissues Action: instructs the liver to change glycogen
glucose 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 Gland Source: Pancreas (Beta cells) Target: all body cells Action: resp. of glucose to ATP, excess
glucoseglycogen,
Stimulus for Release: Inhibit:
Gonads: Ovaries & Testes
Ovaries: 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 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 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
Testes 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…. A testicle is made of approx. 700 ft. of seminiferous
tubules; these tubules carry out spermatogenesis In between the seminiferous tubules are interstitial
cells. Responsible for making testosterone
Testosterone 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 Main hormone release is Melatonin.
Primary function is sleep-wake cycle. Highest during darkness….causes sleepiness
Thymus Gland School for WBCs
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 Possibly why elderly have lower immunity
Other Organ Some organs produce specific hormones
to communicate within the body. Kidneys Heart Skin GI tract Placenta
All use hormones to aid in their function or to communicate & coordinate w/ other systems in the body
Gland Source: Target Action Stimulus for Release: Inhibit:
Gland Source: Target Action Stimulus for Release: Inhibit: