Pituitary Gland Hormones Adenohypophysis & Neurohypophysis

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: