the endocrine system. what is an endocrine gland? endocrine: secretes substance into blood exocrine:...
TRANSCRIPT
The endocrine system
What is an endocrine gland?
Endocrine: secretes substance into blood
Exocrine: secretes substance into a duct (ex: sweat)
ENDOCRINE GLANDS
1. PITUITARY GLAND
a. Growth Hormone (GH)
Hypersecretion = gigantism (children) or acromegaly (adults)
b. Prolactin (PRL) Stimulates milk production after
childbirth
c. Adrenocorticotropic hormone (ACTH)• Tropic hormone• Stimulates cortex of
adrenal gland
Hormones of adrenal cortex(corticosteroids)1. Mineral corticoids – regulate mineral content
of blood, like sodium and potassium
2. Glucocorticoids – regulate metabolism and resistance to stress
Ex: cortisone
3. Androgens (sex hormone)1. In puberty: stimulate axillary/pubic hair
growth/growth spurt 2. Insignificant effect in males after puberty3. In females: libido and converted into estrogens
d. Thyroid-stimulating hormone (TSH) Tropic hormone Growth & activity of thyroid gland:
– 1. Calcitonin (not influenced by TSH)• Decreases blood calcium levels by causing
calcium to be deposited in the bones.• Stimulus?• Target?
– 2. Thyroid hormone Controls rate at which glucose is “burned”
(oxidized) Targets every cell
What is a tropic hormone?
a. A synthetic (“man-made”) hormone
b. Hormones that affect the gonads
c. Hormones of the thyroid gland
d. A hormone that triggers another endocrine gland to secrete its hormones
e. Gonadotropic hormones - tropic hormones
a. function: regulate activity of gonads
b. types:
1. Follicle-stimulating hormone (FSH): egg/sperm development
2. Luteinizing hormone (LH): sex hormone synthesis; ovulation
f. Oxytocin- causes contractions for birth
g. Antidiuretic hormone (ADH) Diuresis = urine production causes kidneys to reabsorb
water from the forming urine stimulus? caffeine inhibits ADH
secretion
Which of the following is NOT a hormone secreted by the pituitary gland?a. Prolactin
b. Adrenocorticotropic hormone
c. Growth hormone
d. Calcitonin
What does sterility mean?
What effect would LH and FSH have on this?
summary
Pituitary gland – considered the “master” gland
We covered 7 hormones it produces Extra credit assignment: write a story
about a character that does not have a pituitary gland. Due: by the 11th (Monday)
POSTERIOR OF THYROID
2. PARATHYROID GLAND
2. PARATHYROID GLAND
Found posterior side of thyroid
1. Parathyroid hormone (PTH)• Regulator of calcium homeostasis in blood.• Responds to LOW levels of Ca2+
• targets the skeleton• Hyposecretion: muscles uncontrollably spasm
fatal• Hypersecretion: massive bone destruction
3. ADRENAL GLANDS
ADRENAL GLANDS: SUPERIOR TO KIDNEYS
Hormones of adrenal cortex(corticosteroids)1. Mineral corticoids – regulate mineral content of
blood, like sodium and potassium Ex: aldosterones
2. Glucocorticoids – regulate metabolism and resistance to stress
Ex: cortisone
3. Androgens (sex hormone)1. In puberty: stimulate axillary/pubic hair growth/growth
spurt 2. Insignificant effect in males after puberty3. In females: libido and converted into estrogens
SKIP
Problems with adrenal cortex Hyposecretion Addison’s disease, fatal without
treatment– Weight loss – Muscle weakness – Fatigue that gets worse over time – Low blood pressure – Patchy or dark skin
Hypersecretion of glucocorticoids Cushing’s syndrome, fatal without treatment
– Weight gain, particularly around your midsection and upper back
– Fatigue – Rounding of your face (moon face) – Fatty pad or hump between your shoulders (buffalo
hump) – Pink or purple stretch marks (striae) on the skin – High blood pressure, diabetes, bone loss
SKIP
Adrenal cortex – see pituitary notes
•adrenal medulla
a. Epinephrine
b. Norepinephrine
Augments fight-or-flight
4. PANCREAS
a. Insulin – • Responds to rising blood glucose levels• Hyposecretion high blood glucose levels ….
Diabetes mellitus (classic symptoms: polyuria (frequent urination), polydipsia (increased thirst) and polyphagia (increased hunger)
– Type I – failure to make insulin– Type 2 – insulin resistance– Gestational – during pregnancy
b. Glucagon• responds to low blood glucose levels.• target: liver
5. PINEAL GLAND
a. Melatonin- regulates day-night cycles
Taken on a strict schedule, melatonin can help reduce jet lag. (But was that West Coast or London time?)
Copyright 1997 Smithsonian Magazine All rights reserved.
6. THYMUS
Produces thymosin – regulates maturation of some white blood cells; important for immune system
7. GONADS
7A) OVARIES
1. Estrogens – • stimulate secondary sex characteristics in
females• brings about menstrual cycle
2. Progesterone- • brings about menstrual cycle. • quiets muscles of uterus during pregnancy
Hyposecretion of either: infertility
7b) Testes
1. Testosterone• cause growth and maturation of reproductive
system• secondary sex characteristics; sperm
production in adult • Hyposecretion = infertility
testes
8. PLACENTA (Temporary organ)
1. human chorionic gonadotropin (hCG) – stimulates ovary to continue producing estrogen and progesterone
2. Estrogen & progesterone (3rd month)
3. Relaxin – relaxes pelvis
Aging and the endocrine glands
Late middle age: efficiency of ovaries begins to decline menopause
GH declines = muscles atrophy Mildly hypothyroid Less able to resist stress/infection (due to
thymus, glucocorticoids of adrenal and melatonin from pineal)
Some decline in insulin production diabetes
(not responsible for this slide)
How hormones work
2 categories of hormones– Soluble in lipids
• Most attached to transport protein in blood• Ex: Thyroid hormone, sex hormones
– Soluble in water• Travel by themselves in blood• Ex: epinephrine/norepinephrine, ADH, oxytocin,
GH, insulin
Lipid-soluble hormones: stimulate synthesis of new proteins
Diffuse through lipid bilayer (cell membrane)
Binds to receptors in cytoplasm or nucleus
Triggers gene on/off synthesis of new protein that alters the cell’s activity
VIDEO CLIP
MECHANISM OF ACTION OF LIPID-SOLUBLE HORMONES
Water-soluble hormones: modify existing proteins
Binds to receptor on cell membrane Activates G protein (membrane protein) that
eventually causes ATP to convert to cyclic AMP (the second messenger).
Cyclic AMP activates one/more protein kinases (enzyme that adds a phosphate group – phosphorylates – to other cellular proteins).
Phosphorylated proteins cause physiological response
Enzyme phosphodiesterase inactivates AMP
Water-soluble hormone action
Water-soluble hormone action