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HORMONES &
THE ENDOCRINE
SYSTEM
Ashley Gutierrez, Divya Khullar
Ms. Said
AP Biology, per.6,7
CONCEPT 45.1 THE ENDOCRINE SYSTEM AND THE
NERVOUS SYSTEM ACT INDIVIDUALLY AND TOGETHER
IN REGULATING AN ANIMALS PHYSIOLOGY
 The endocrine system of an animal
is the sum of all its hormone-secreting
cells and tissues.
 Endocrine glands are ductless and
secrete hormones directly into body
fluids
 Hormones are chemical signals that
cause a response in target cells
REVIEW OF HORMONES
 Hormones can be polypeptides, amines, or steriods and can be water –soluble
or lipid-soluble.
 Peptide/protein hormones and most hormones derived from amino acids bind
to receptors embedded in the plasma membrane. Steriod hormones and thyroid
hormones enter target cells and bind to specific protein receptors in the cytosol
and the nucleus.
 Hormones in the body can affect one tissue, a few tissues or most of tissues in
the body, or they may affect other endocrine glands
4.1 CONTINUED
 Positive and negative feedback regulates most endocrine
secretion.
CONCEPT 4.2 HORMONES AND OTHER CHEMICAL
SIGNALS BIND TO TARGET CELL RECEPTORS,
I N I T I A T I N G PA T H WAY S T H A T C U L M I N A T E I N
SPECIFIC CELL RESPONSES
 Two mechanisms of hormone action:
• Cell-surface receptors bind the hormone, and signal transduction
pathway is triggered. A signal transduction pathway consists of a
series of molecular events that initiate a response to the signal
• Example: The binding of epinephrine to liver cells causes a
cascade that leads to the conversation of glycogen to glucose
• Intracellular receptors are bound by hormones that are lipidsoluble. The receptor then acts as a transcription factor, causing a
change in gene expresion.
• Example: Testerone and estrogen enter the nuclei of target cells,
bind the DNA, and stimulate transcription of certain genes.
Cell surface receptors
Intracellular receptors
INSULIN AND GLUCOGEN: CONTROL OF BLOOD
GLUCOSE
 Insulin (from beta cells of the pancreas) reduces blood
glucose levels by promoting cellular uptake of glucose, glycogen
formation in the liver, protein synthesis, and fat storage
 Glucagon (from the alpha cells of the pancreas) increases
blood glucose levels by stimulating conversion of glycogen to
glucose in the liver and breakdown of fat and protein to
glucose.
 Diabetes mellitus, which is marked by elevated blood
glucose levels, results from inadequate production of insulin
(type 1) or loss of responsiveness to target cells to insulin(type
2)
C O N C E P T 4 5 . 3 T H E H Y P O T H A L A M U S A N D P I T U I TA RY
INTERGRATE MANY FUNCTIONS OF THE
VERTEBRATE ENDOCRINE SYSTEM
 The hyothalamus receives
information from the nerves
throughout the body and from
other parts of the brain and
then initiates endocrine signals
in response.
CONTINUE OF 45.3:POSTERIOR
P I T U I TA RY
 The posterior pituitary is an
extension of the hypothalamus that
stores and secretes two hormones:
• 1. Oxytocin causes contraction of
the uterine muscles in childbirth and
ejection of milk and nursing
• 2.Antidiuretic hormone (ADH)
makes the collecting tubules of the
kidney more permeable to water,
increasing water retention
CONTINUE OF 45.3:ANTERIOR
P I T U I TA RY
 The anterior pituitary consist of endocrine cells that synthesize and
secrete several hormones. Some of these are tropic hormones, which
means they stimulate the activity of other endocrine tissues (FSH, LH,
TSH, and ACTH).
• Follicle-stimulating hormone(FSH) stimulates development of the
ovarian follicles in females and promotes spermatogenisis in males by acting
on the cells in the seminiferous cells
• Luteinizing hormone triggers ovulation in females and stimulates the
production of testosterone by the interstitial cells of the testes
COORDINATION OF ENDOCRINE AND
N E RVO U S S Y S T E M S I N I N V E RT E B R AT E S
 Diverse hormones regulate different aspects
of homeostasis in vetebrates
 In insects, molting and development are
controlled by prothoracicotropic hormone
(PTTH), a tropic nuerohormone; ecdysone,
whose relesase is triggered by PTTH; and
juvenile hormone
COORDINATION OF ENDOCRINE AND
N E RVO U S I N V E RT E B R AT E S
 The hypothalamus, on the underside of the brain,
contains sets of neurosecretory cells. Some produce
direct-acting hormones that are stored in and released
from the posterior pituitary.
 Other hypothalamic cells produce hormones that are
transported by portal blood vessels to the anterior
pituitary. These hormones either promote or inhabit the
release of hormones from the anterior pituitary
C O N C E P T 4 5 . 4 N O N P I T U I TA RY H O R M O N E S H E L P
REGULATE METABOLISM, HOMEOSTASIS,
D E V E L O P M E N T , A N D B E H AV I O R
 The maintenance of blood
calcium level is one example of
how homeostasis is maintained by
negative feedback. Remember, in
negative feedback, more gets you
less.
A REVIEW OF THE
ENDOCRINE SYSTEM
Endocrine System
 http://www.youtube.com/watch?v=iDy_p9912ao
&feature=related
QUIZ
1. 1. All of the following are endocrine glands EXCEPT:
A. adrenal glands B. sebaceous glands C. pineal glands D. pituitary glands
2. Hormones that enter target cells and bind to receptors in the nucleus are called A. steroid
hormones B. water soluble hormones. C. peptide hormones. D. second messengers.
3. The hormones regulating blood calcium levels are A. insulin and glucagon. B. glycogen
and parathyroid hormone. C.parathyroid hormone and calcitonin. D.estrogen and
progesterone.
4. All of the following are hormones of the anterior pituitary EXCEPT A.
human growth hormone (GH). B. follicle-stimulating hormone (FSH). C.
parathyroid hormone(PTH). D. thyroid-stimulating hormone (TSH).
5. Antidiuretic hormone and oxytocin are stored and released by the A.
posterior pituitary gland. B. anterior pituitary gland. C.thyroid gland. D.
adrenal gland.