Lecture AP Biology Chapter 45 Hormones and the endocrine system

Ch. 40 Warm-Up
1. What type of behavior in animals might be
triggered by cold temperatures?
2. What type of behaviors might be triggered in
hot temperatures?
3. List 2 examples of negative feedback. List 2
examples of positive feedback.
4. What is the main type of chemical messenger
in the endocrine system? The nervous
system?


Ch. 45 Warm-Up
1. Compare peptide hormones to steroids.
2. Explain how insulin and glucagon work to
regulate blood sugar levels.
3. Which glands and hormones respond when
your body is under stress?


Chapter 45

Hormones and the Endocrine System

A hormone called ecdysteroid regulates the timing of metamorphosis in this anise swallowtail butterfly.


You must know:
• Two ways hormones affect target organs.
• The secretion, target, action, and regulation of
at least 3 hormones.

• An illustration of both positive and negative
feedback in the regulation of homeostasis by
hormones.


Types of
Intercellular
Signaling


• Endocrine System = Hormone-secreting cells +
Tissues
• Endocrine glands: ductless, secrete hormones
directly into body fluids
• Hormones: chemical signals that cause a
response in target cells (receptor proteins for
specific hormones)
– Affects 1 tissue, a few, or most tissues in body
– Or affect other endocrine glands (tropic
hormones)
• Regulation by Positive & Negative Feedback


Pheromones

Hormones

Local
Regulators

Chemical signal
from 1 individual
to another
individual

Chemical signal
from endocrine
gland through
blood to target
cell

Chemical signal
from one cell to
an adjacent cell

Eg. ant trail; sex
phermones

Eg. cytokines,
Eg. peptide,
growth factors,
steroid hormones
nitric oxide (NO)



Discovery Video: Endocrine System


Types of Hormones

Peptide

Steroid

• Water-soluble
• Bind to receptors on
plasma membrane &
triggers signal transduction
pathway
• Affects protein activity
already present in cell
• Rapid response
• Short-lived
• Eg. oxytocin, insulin,
epinephrine

• Lipid-soluble
• Enters cell & binds to
intracellular receptors
• Causes change in gene
expression (protein
synthesis)
• Slower response
• Longer life
• Eg. androgens
(testosterone), estrogen,
progesterone, cortisol

Epinephrine:
Epinephrine one hormone  many effects

1.Liver cells break
2.Blood vessels to
down glycogen and
skeletal muscles
release glucose
dilate

3.Blood vessels
to intestines
constrict


Master Glands
Hypothalamus

Pituitary Gland


Master Glands
Hypothalamus

• Receives info from nerves and brain
• Initiates endocrine signals
Posterior pituitary gland:
•Oxytocin: contract uterine muscles, eject milk
in nursing

Pituitary Gland

•Antidiuretic Hormone (ADH): promote H2O
retention by kidneys
Anterior pituitary gland:
•Follicle-stimulating hormone (FSH):
development of ovarian follicles (eggs); promote
sperm production
•Luteinizing hormone (LH): trigger ovulation;
stimulate testosterone production in testes


Hypothalamus regulation of Posterior Pituitary gland


Hypothalamus regulation of Anterior Pituitary gland




 Negative feedback systems:
• Thyroid hormones
• Blood Ca2+ levels
• Blood glucose levels
 Positive feedback system:
• Oxytocin (birthing process; release of
milk/suckling)


BIOFLIX: HOMEOSTASIS – BLOOD SUGAR

Control of Blood Glucose
High blood
glucose
Liver breaks down
glycogen and releases
glucose into blood

Insulin released from
pancreas
Body cells take up glucose

Glucagon released
from pancreas

Liver stores glucose as
glycogen
Blood glucose
drops


Diabetes Mellitus
• Type I diabetes (10%):deficiency of insulin
– Insulin-dependent
– Autoimmune disorder  beta cells of pancreas
destroyed

• Type II diabetes (90%): failure of target cells to
respond to insulin

– Non-insulin dependent
– Insulin produced  cells don’t respond (defect in
insulin receptor or response pathway)
– Risk factors: obesity, lack of exercise


Thyroid Gland

Hypothalamus

Graves’ Disease:
• Autoimmune disorder
• Antibodies bind to TSH
receptor
• Hyperthyroidism
• High temp, sweating,
weight loss, high BP

TRH

Anterior
pituitary

TSH

Thyroid

T3

T4

Stress and the Adrenal Gland


Anabolic-Androgenic Steroid (AAS) Use
• Legally prescribed to treat hormone deficiency, loss of
muscle mass (cancer, AIDS)
• Used to enhance performance and improve physical
appearance