Download Unit One – Concept Two - Calgary Christian School

Unit One – Concept Two
Endocrine System and Homeostasis
http://www.youtube.com/watch?v=W
VrlHH14q3o
Crash course
A. Intro. to the Endocrine
System

The endocrine system is designed to
maintain control of various organs and
tissues. Unlike the nervous system that
allows the body to make quick
adjustments to stimuli, the endocrine
system maintains this control over a
longer duration
1. Definition of endo/exocrine
endocrine: non-ducted: goes into
extracellular fluid (ECF), secretion ends up in
the blood stream where it is picked up by
capillaries
 exocrine: ducted – materials end up outside
(saliva, sweat, mammary glands)
http://www.youtube.com/watch?v=VBwCBdd0ru8&
playnext=1&list=PLEEE5A627695E1E4A

2. Definition of hormone




Hormones are chemicals that have targets
(needed only in trace amounts)
Hormones are regulators, speeding up or
slowing down certain body processes
When hormones encounter their target cells
they bind to receptor proteins on the target
cell membrane
The two main classes of hormones are
lipid-based (steroid) and protein-based
2. Definition of hormone
http://www.youtube.com/watch?v=AhVRNbc
aTIA

Steroid hormones are
made of cholesterol
and are not soluble in
water


they combine with
receptor molecules in
the cytoplasm of cells
the hormone receptor
complex moves into
the nucleus and
attaches to DNA

Examples of lipid based hormones



Testosterone
Estrogen
Cortisol
2. Definition of hormone

protein and protein
related hormones
contain chains of amino
acids



combine with receptors
on the cell membrane
the hormone receptor
complex activates the
production of adenylyl
catalase which causes
the cell to convert ATP
into cyclic AMP
cyclic AMP functions as a
messenger that
activates enzymes in
the cytoplasm to perform
their normal functions

Examples of protein based hormones




Epinephrine
Human growth hormone
Thyroxine
Insulin
B. Principle Endocrine Glands
and Their Hormones
1. Hypothalamus/Pituitary Complex
http://www.abcbodybuilding.com/exercisestress2.php
a. terms





anterior lobe – in the front, produces its own
hormones
posterior lobe – in back, hormones stored here
neurosecretion – nerve cells secreting hormones in
the posterior lobe – happens in adrenal gland
pituitary portal system (pg. 445) – releasing
factors in the hypothalamus control releasing factors
in the anterior lobe
Tropic hormone – a hormone that targets other
endocrine glands (many of the hormones of the
hypothalamus/pituitary are trophic)
b. Hormones

Hypothalamus


Hormones released from the posterior
pituitary were manufactured in the
hypothalamus
Other hypothalamus hormones:
Releasing hormones – stimulate the release
of hormones from the pituitary
 Somatostatin – a regulating hormone that
inhibits the release of growth hormone
 Dopamine – a regulating hormone that
inhibits the release of prolactin

b. Hormones

Anterior Lobe:

human growth hormone (HGH or Somatotropin) – promotes
growth in bones and muscles

Disorders:




Gigantism (person becomes extremely tall, but body proportions are
normal)
Acromegaly (leads to the growth of some bones such as the eyebrow
ridge, lower jaw, nose, hands and feet)
ACTH (Corticotropin adrenal steroid) – targets adrenal cortex,
stimulates the release of hormones involved in stress response
(cortisol and aldosterone)
TSH (Thyroid Stimulating Hormone) – targets the thyroid,
stimulates the release of thyroxin which regulates cellular
metabolism (stimulated by thyroid releasing factor from nerve
cells)

Gigantism
www.gigantism.com
http://www.youtub
e.com/watch?v=u
TrRM9C6K20&fe
ature=related

Acromegaly
The Science of Gigantism on the
National Geographic Channel


http://vimeo.com/629
85496
(25 min)



National
Geographic Science of Dwarfism
(45 min)
http://www.youtube.c
om/watch?v=jXyfXfq
Vmis or
http://search.mywebs
earch.com/mywebsea
rch/video.jhtml?searc
hfor=the+science+of+
Growth Hormone Use

http://www.youtube.
com/watch?v=Xhw8
GLIVKPY
b. Hormones

Anterior Lobe:

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
Prolactin (PRL) – targets mammary glands,
stimulates milk production (inhibited by an
inhibitory hormone produced in the
hypothalamus - dopamine )
Follicle Stimulating Hormone (FSH) – targets
ovaries and testes, stimulates follicle
development in female ovaries and stimulates
the development of sperm cells in testes
Luteinizing hormone (LH) – targets ovaries
and testes, in females, LH stimulates ovulation
and formation of the corpus luteum
(progesterone production). In males, LH
stimulates the production of the male sex
hormone testosterone (called ICSH)
b. Hormones

Posterior Lobe:


antidiruetic hormone (ADH) –
increases water reabsorption into the
blood resulting in decreased urine
production, regulates water in the body
oxytocin – causes the muscles of the
uterus walls to contract and makes
birth easier, involved in the discharge of
afterbirth, stimulates the release of
milk
2. Thyroid Gland

Located at the base of the neck in front of the
trachea
http://www.yourdictionary.com/ahd/t/t0200300.html
a. Hormones
http://www.youtube.com/watch?v=Vae5CcaP
N_8

Thyroid Gland:


Thyroxine (T4) – hormone secreted by the
thyroid gland, which regulates the rate of body
metabolism, by the oxidation of sugars and
other nutrients. An increase in thyroxin
increases metabolism, thus decreasing body
weight
Calcitonin – hormone secreted in the thyroid
gland which lowers calcium and phosphate
levels of blood by inhibiting bone breakdown
and accelerating Ca2+ absorption into bones
b. Thyroid disorders
http://www.youtube.com/watch?v=sVa0L1Rka4
Y

goiter – enlargement of the thyroid gland, occurs
when inadequate amounts of iodine are not
obtained in the diet

hypothyroidism – inactivity of the thyroid resulting
in a decrease in thyroxine secretion

hyperthyroidism – over activity of the thyroid
resulting in an increase in thyroxine secretion

thyroid cancer – cancer of the thyroid
Goiter
Cretinism – thyroid
doesn’t develop properly
people are shorter and
stockier (hypothyroidism)
http://fashionablechaos.com/2005_04_01_archive.html
http://www.netterimaghttp://cretinism.net/Video-ofCretinism.html
es.com/image/endocrinology%5Cmetabolism.htm
Grave’s disease – overactive
thyroid often results in swelling of
muscles around the eyes
http://www.5min.com/Video/Understanding-Graves-Disease326721644
http://hubnet.buffalo.edu/ophthalmology/site/Home/Eye_Disorders/Double_Vision/double_vision.html
c. Parathyroid Glands

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The parathyroid
glands produce
parathyroid hormone
Blood Ca2+ levels are
raised by increasing
the absorption from the
GI tract and from the
release of Ca2+ from
the bones
http://www.endocrineweb.com/surthyroid.html
3. Adrenal Glands
http://www.yourdictionary.com/ahd/a/a0097500.html

Stress response
http://www.youtube.com/watch?v=Igm
aJC-Km5U&feature=related
Science of Stress response
http://video.nationalgeographic.com/video/
science/health-human-body-sci/humanbody/science-stress-sci/
a. Hormones

Adrenal Cortex (outer portion):

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cortisol – associated with blood glucose levels.
An increase in cortisol increases amino acid
levels in the blood to relieve stress, amino acids
are converted to glucose in the liver, thus
raising blood sugar levels
aldosterone – increase sodium retention and
water reabsorption in kidneys and helps
maintain body fluid levels
small amounts of sex hormones
a. Hormones

Adrenal Medulla (inner portion):

epinephrine (adrenaline) – initiates the fight or flight
response

norepinephrine (nor-adrenaline) – initiates the fight or
flight response

in stress – hormones released increase blood sugar levels
thus increasing energy levels, also increasing heart rate,
blood pressure, metabolic rate, urine production, blood
glucose
4. Pancreas Islet Cells
http://www.youtube.com/watch?v=ae_jC4FDOUc
Insulin, Glucose and you
a. Hormones

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Insulin – produced in the beta cells of the
Islets of Langerhans, it is released when
blood sugars are high, it increases glucose
utilization by make cells more permeable to
glucose
Glucagon – causes an increase in blood
sugar levels, it is released when blood
sugar levels are too low, promotes glycogen
to convert to glucose which is absorbed into
the blood
Somatotropin (hGH)
Blood Glucose Regulation

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Glucagon – raises blood glucose
Insulin – lowers blood glucose
Adrenaline – raises blood glucose
Thyroxine – decreases blood glucose
levels by increasing metabolism (more
glucose used due to increased cellular
respiration)
Blood Glucose Disorders

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Hypoglycemia – low blood sugar caused by an
increase in insulin and a decrease in glucagon
production
Hyperglycemia (diabetes mellitus)– high blood
sugar caused by decreased insulin production
Juvenile Diabetes (Type 1) – onset before age 20,
usually caused by degeneration of beta cells
Mature Onset diabetes (Type 2) – insulin is
produced but the body cannot use it, is regulated by
diet
http://www.youtube.com/watch?v=OXAe3eOjqCk
Type 2 Diabetes
Other Glands and Hormones

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Pineal Gland – secretes melatonin
(regulates sleep)
Thymus – produces T-cells (immunity)
http://en.wikipedia.org/wiki/Pineal_gland
http://en.wikipedia.org/wiki/Thymus
Feedback Diagrams
C. Feedback Diagrams
http://www.phys.unsw.edu.au/biosnippets/
http://health.howstuffworks.com/human-body/systems/endocrine/adam200092.htm
http://www.youtube.com/watch?v=H4Xi1R_pJKU&feature=related
1. Testosterone and LH
(494)
2. Cortisol (453)
3. Insulin and Glucagon (457)
4. TSH and Thyroxin
(448)
http://www.youtube.co
m/watch?v=zf_n2
mmp3vM
Thyroid Hormone 2 -
5. Parathyroid Hormone and
calcium (449)
D. Control of Hormone Release
http://www.phys.unsw.edu.au/biosnippets/
homeostasis animation
http://health.howstuffworks.com/humanbody/systems/endocrine/adam-200092.htm

negative feedback
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negative feedback based on need for
hormone
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eg. Insulin responds to increasing blood glucose
nervous system
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Hormone A causes a release of hormone B,
which inhibits hormone A
Epinephrine from adrenal medulla
antagonistic hormones

eg. Insulin vs. glucagon