Download The Endocrine System

Chapter 13
The Endocrine
System
What is the Endocrine System?
• The endocrine system releases chemical
hormones into the blood
• This system is slower in producing its effect
than the nervous system, however, the effect
lasts longer
• It helps to maintain homeostasis by monitoring
changes in organs or tissues of the body.
What are hormones?
• Hormones are chemicals that circulate
through the blood and affect every organ and
tissue in the body.
How do hormones work?
• Hormones only affect organs and tissues if
they have the correct receptor sites.
• The receptor will bind with the hormone
(like a lock-and-key)
• An organ that contains receptors for a
particular hormone is called a target organ.
What are the types of glands?
(i) Endocrine glands - are ductless glands that
secrete hormones directly into the
bloodstream. (See diagram – next page)
(ii) Exocrine glands - release their secretions
through ducts or tubes (Exits the body).
Examples: sweat glands, salivary glands, tear
glands, mammary glands
Steroid Hormones
• Steroid hormones are fat-soluble which means
they are able to pass through the cell
membrane of the target cell easily.
• Once inside the cell, they bond to a protein
receptor molecule in the membrane in the
cytoplasm. (hormone-receptor complex)
• The hormone receptor complex enters the
nucleus and activates a specific gene on the
cells DNA molecule.
• Examples:
– cortisol
– Progesterone
Video:
http://highered.mcgrawhill.com/olcweb/cgi/pluginpop.cgi?it=swf::535::535::/sites/dl/free/0072437316/12
0109/bio46.swf::Mechanism%20of%20Steroid%20Hormone%20Action
Turn to Page 2 in Booklet
Explain how steroid hormones cause changes
in target cells, using a diagram
(Include: solubility in cell membrane, locations
of receptors and the end result)
Draw Figure 13.5 A on page 425
Non-Steroid Hormones
• Non-steroid hormones are secreted from
glands into the blood stream.
• These hormones are NOT fat-soluble and
CANNOT pass through the cell membrane.
Instead they work from outside the cell.
• Non-steroid hormones are called first
messengers. They bind to receptors on the
surface of the cell and activate an enzyme.
• This enzyme triggers the production of the
second messenger (cyclic-AMP).
• C-AMP causes a chain reaction to occur inside
the cell. This is referred to as a biological
amplifying system because a small amount of
a hormone has a great effect.
• Examples:
– adrenaline
– luteinizing hormone (LH)
– follicle stimulating hormone (FSH)
Draw Figure 13.5 B on page 425
Turn to Page 3 in Booklet
• Explain how non-steroid hormones cause
changes in target cells, using a diagram
(Include: solubility in cell membrane, locations
of receptors and the end result)
Anabolic Steroid
Video: Steroids and their side effects
• http://www.youtube.com/watch?v=Ctmg2OeF0Q
4&safe=active
Video: Steroid debate in baseball
http://www.youtube.com/watch?v=PRwClA0NExo&
safe=active
Video: Lance Armstrong
http://www.youtube.com/watch?v=Q0WuZA3PZUE
&safe=active
Public Exam Practice Question
The abuse of steroid hormones, such as
testosterone, by athletes can lead to problems
with homeostasis. Explain how this abuse can
have a negative impact on the body. (2%)
How do stimulants interfere with the
Endocrine System?
• Caffeine has stimulating properties, such as
causing the heart muscle to contract
• Caffeine is also considered to be a diuretic
(increases urine production) and as a result,
leads to more calcium excretion.
Is caffeine making us crazy? - video
• http://www.youtube.com/watch?v=xngUYihthE&list=PLayDotgyoEYODnhGOQcDiM5i4B5kqnaeh&index=4
&safety_mode=true&safe=active&persist_safety_mode=1
Turn to page 4 in Booklet
Basic functions of the endocrine glands:
Pituitary gland:
• The master gland
• It has two parts:
1. Anterior Pituitary
2. Posterior Pituitary
• The pea-sized pituitary
gland is beneath the
hypothalamus
Hormones found in the Anterior Pituitary
1. Somatotropin (Human Growth Hormone) –
growth of bones and muscles
2. TSH (Thyroid Stimulating Hormone) –
stimulates the thyroid to release hormones
3. ACTH – stimulates the adrenal glands
4. FSH (Follicle Stimulating Hormone) – stimulates
the ovaries/testes to make eggs/sperm
5. LH (Luteinizing Hormone) – stimulates the
ovaries/testes to release eggs/sperm
Hormones found in the Anterior Pituitary
1. Oxytocin – stimulates uterine contractions
during labour
2. ADH (anti-direutic hormone) – leave out
Pineal Gland
Melatonin – controls our sleep/wake cycle
Thyroid Gland
• Thyroxine – controls
metabolism
• Calcitonine – absorbs
calcium into our
bones
Parathyroid Gland
PTH (Parathyroid Hormone) – releases
calcium from the bones
Thymus Gland
Thymosine – stimulates the immune system
Adrenal Medulla
• Adrenaline – fight or flight response
Adrenal Cortex
• Cortisol – prepares the body for long term
stress
Pancreas
Insulin – increases the uptake of glucose into
cells (during and immediately after a meal)
Glucagon – triggers the cellular release of
glucose (when glucose levels are low)
Ovaries
• Hormones - Estrogen, progesterone
Influences secondary sex characteristics and
menstrual cycle
Testes
Hormones – Testosterone and inhibin
• Influences secondary sex characteristics.
Who wants to be a millionaire?
• http://freenursetutor.com/menuparentendocrine-system/millionaire-gameendocrine-system.html
• SAVE THIS GAME TILL THE END, AS REVIEW