Transcript endocrine glands - OCPS TeacherPress

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
For your hormone……

HOW DOES IT WORK? WHAT DOES IT DO?
– Suggestion conversation topics:
•
•
•
•
WHAT DOES IT CONTROL?
WHAT DOES IT TARGET?
WHAT EFFECT DOES IT HAVE?
WHAT TRIGGERS ITS RELEASE?
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

Glucocorticoids – regulate metabolism and
resistance to stress
Ex: cortisone
3.
Androgens (sex hormone)
2.
1. In puberty: stimulate axillary/pubic hair
growth/growth spurt
2. Insignificant effect in males after puberty
3. In females: libido and converted into estrogens
d. Thyroid-stimulating hormone (TSH)

Tropic hormone

Growth & activity of thyroid gland:
– 1. Thyroid hormone
 Controls rate at which glucose is “burned”
(oxidized)
 Targets every cell
– 2. Calcitonin (not influenced by TSH)
• Decreases blood calcium levels by causing
calcium to be deposited in the bones.
• Stimulus?
• Target?
What is a tropic hormone?
a.
b.
c.
d.
A synthetic (“man-made”) hormone
Hormones that affect the gonads
Hormones of the thyroid gland
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.
b.
c.
d.
Prolactin
Adrenocorticotropic hormone
Growth hormone
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

2. PARATHYROID
GLAND
POSTERIOR
OF THYROID
2. PARATHYROID GLAND

1.
Found posterior side of thyroid
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

Glucocorticoids – regulate metabolism and
resistance to stress
Ex: cortisone
3.
Androgens (sex hormone)
2.
1.
2.
3.
In puberty: stimulate axillary/pubic hair growth/growth
spurt
Insignificant effect in males after puberty
In females: libido and converted into estrogens
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

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
testes
7b) Testes
1. Testosterone
• cause growth and maturation of reproductive
system
• secondary sex characteristics; sperm
production in adult
• Hyposecretion = infertility
8. PLACENTA (Temporary organ)
1.
2.
3.
human chorionic gonadotropin (hCG) –
stimulates ovary to continue producing
estrogen and progesterone
Estrogen & progesterone (3rd month)
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

MECHANISM OF ACTION OF
LIPID-SOLUBLE HORMONES
VIDEO CLIP
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