Download The Endocrine System.

Chemical Control of the Animal Body:
The Endocrine System
pineal gland
hypothalamus
pituitary gland
thyroid gland
thymus
adrenal glands
(one at
each kidney)
pancreas
gonads
testis
ovary
II. Hormones—chemical signals
of change

A. Classes of animal hormones
•
•
•
1. Peptide hormones
2. Amino acid derivatives
3. Steroid hormones
(a)
(extracellular
fluid)
hormone:
(1st messenger)
(plasma membrane)
1
(cytoplasm)
activates
(nuclear membrane)
2
cAMPsynthesizing
enzyme
active
enzyme
product
hormone
receptor
protein
4
(2nd messenger)
3
activates
enzyme
inactive
reactant
(nucleus)
(b)
steroid hormone
(plasma membrane)
1
(extracellular
fluid)
(nuclear
membrane)
hormone-receptor
complex
2
DNA
3
(cytoplasm)
ribosome
5
RNA
polymerase
hormone
receptor
protein
4
gene
mRNA
protein
synthesized
(nucleus)
II. Hormones—chemical signals
of change

B. Function of animal hormones
•
•
•
1. Binding to surface receptors
2. Binding to intracellular receptors
3. Negative feedback as a regulatory mechanism
for hormone synthesis and release
Endocrine cells
release hormone.
Hormone is distributed
throughout the body.
capillary
Hormone enters
bloodstream.
receptor on
target cell
hormonereceptor
complex
SKELETAL MUSCLE TISSUE
binding occurs,
hormonal effects appear
NEURAL TISSUE
no binding, no
hormone effects
The mammalian endocrine system
Major endocrine glands
Hypothalamus–
pituitary complex
•
Anterior pituitary
hormones
•
Posterior pituitary
hormones
neurosecretory cells
in hypothalamus
HYPOTHALAMUS
hormone
artery
direction of
blood flow
Oxytocin or ADH is
secreted into the blood
by neurosecretory cells.
PITUITARY
(anterior lobe)
PITUITARY
(posterior lobe)
capillary
bed
capillary
bed
Hormone is secreted
into the blood by
pituitary cells.
endocrine
cells
vein
artery
Hypothalamus
sends impulses
to posterior
pituitary.
hypothalamus
hunger
posterior
pituitary
Oxytocin is
released and
carried in blood
to the breast.
Muscles contract and
squeeze out milk.
Nerve impulses
are sent to
Hypothalamus.
Suckling stimulates
nerves in breast.
milk
gland
muscle
duct
cells milk-producing
cells
nipple
The mammalian endocrine system
Thyroid and parathyroid
glands
a. Thyroxine and
metabolism
b. Hyperthyroidism and
Graves' disease
(a)
larynx
thyroid gland
esophagus
trachea
(b)
The mammalian endocrine system
3. Pancreas as an endocrine
gland
a. Regulation of blood
glucose levels by insulin
and glucagon
b. Insulin insensitivity and
diabetes mellitus
eating
insulin-producing
cells
pancreas
glucagon-producing
cells
glucagon
glucose
glycogen
liver
insulin
The mammalian endocrine system
4. Sex organs and
steroid hormones
a. Puberty and
secondary sex
characteristics
b. Gamete production
The mammalian endocrine system
Adrenal glands
a. Adrenal medulla
1) Produces adrenaline and noradrenaline
a) Released in response to stress or emergency situations
b. Adrenal cortex
1) Produces glucocorticoids
a) Steroid hormones that help regulate glucose metabolism
b) Glucocorticoids and sports medicine
2) Produces aldosterone
a)
Steroid hormone that regulates the sodium content of the blood by
affecting the kidneys and sweat glands
3) Testosterone synthesis and the bearded lady
adrenal medulla
(epinephrine,
norepinephrine)
adrenal
gland
adrenal cortex
(glucocorticoids,
testosterone,
aldosterone)
kidney
The mammalian endocrine system
Kidneys
a.
Erythropoietin
1) Response to low oxygen content in the blood
2) Stimulates the production of RBC in the bone marrow
b. Renin
1) Response to low blood pressure
2) Activates the production of angiotensin, which
constricts arterioles