The Endocrine System
Name: ANSWERS
VIDEO: THE ENDOCRINE SYSTEM
1.
What do the glands of the endocrine system produce?
Hormones (chemical messengers)
2.
What structures are NOT present in endocrine glands?
No secretion ducts (like the sweat glands in your skin have)
3.
How do hormones reach their target cells?
Bloodstream
4.
Complete the following table, by identifying hormones mentioned in the video.
EXAMPLE OF
HORMONE
5.
ENDOCRINE GLAND
THAT SECRETES
HORMONE
ONE EFFECT OF
HORMONE
testosterone
testes
Sex drive; aggression
Growth hormone
pituitary
Makes you grow
thyroxine
thyroid
metabolism
insulin
pancreas
Reduces blood sugar
Why is the pituitary gland often referred to as the ‘master gland’?
Secretes hormones that control other glands.
6.
What role does the pituitary gland play in regulating growth?
Secretes growth hormone.
7.
What is one process that the thyroid gland controls
Metabolism.
8.
(A)
Describe how blood glucose levels are maintained by the endocrine system.
Increased blood glucose triggers the release of insulin from the pancreas. This causes
the extra glucose to be stored in the liver as glycogen.
(B)
Which gland and hormone/s are responsible?
Pancreas/insulin (when too much glucose)/glucagon (not enough glucose)
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9.
What is homeostasis?
The maintenance of a constant internal environment (pH, body temperature etc)
10.
Identify some examples of stimuli that might result in the release of adrenalin.
Giant scary swing, skydiving, almost getting hit by car etc.
11.
Describe some changes to the body that occur as a result of the release of adrenalin.
Increased reaction time, increased heart rate, shallow breathing, sugar dumped from
liver, appetite suppressed
12.
(A)
Which glands play a major role in our sexual development?
Testes, ovaries
(B)
Describe their role.
Secrete hormones to produce sexual characteristics.
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Endocrine vs nervous Systems
Complete the table with the main differences between the endocrine and the nervous systems
in the human body.
CHARACTERISTIC
NERVOUS
ENDOCRINE
Method of
transmission
Speed of travel
Electrical impulses through
networks of nerve cells
As hormones (chemical
messengers) through the
bloodstream
fast
slow
fast
Varies (could be slow as in
growth hormone or could be
faster like adrenalin)
Not long
A long time
Whole body (not necessarily
all at once)
Whole body (though some
glands are specific eg. In
reproductive system)
Speed of response
Duration of response
Area of response
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THE ENDOCRINE SYSTEM- Slow Control
The nervous system works with the endocrine
system to control and coordinate the body’s
processes.
There are eight (8) endocrine glands in the
human body.
The endocrine system is a system that consists of
ductless glands.
The glands of the endocrine system use
hormones (chemical messengers) to
communicate. The hormones are
directly into the blood stream and
information to specific regions (target
body.
released
carry
cells) of the
The pituitary gland, found at the base
of the brain controls the endocrine glands, which in turn control the
release of hormones. It is called the master gland because its
secretions determine the secretion of hormones by other endocrine
glands.
1.
Define the terms ‘hormone’ and ‘endocrine gland’.
Hormone: chemical messengers released from glands
Endocrine gland: gland within the endocrine system that secretes hormones
2.
Describe how hormones travel throughout the body.
Through the bloodstream
3.
Explain why adrenaline is referred to as the ‘fight or flight’ hormone.
It is released by the adrenal glands when the brain detects a dangerous situation. The response to danger is “fight
or flight” and adrenalin helps these processes.
4.
Compare the role of glucagon and insulin in the regulation of blood sugar levels.
Insulin reduces blood sugar and glucagon increases blood sugar. Both are released by the pancreas.
4
5.
Construct a three-column table with the headings ‘Name of endocrine gland’, ‘Name of hormone’ and
‘Action of hormone’. Include all of the endocrine glands labelled in the diagram.
Name of endocrine gland
Pituitary
Name of hormone
Growth hormone
Action of hormone
Makes you grow
Pancreas
Thyroid stimulating hormone
Insulin
Makes thyroid produce hormones
Reduces blood sugar (extra sugar
stored in liver as glycogen)
glucagon
6.
Thyroid
Ovaries
thyroxin
Oestrogen
Testes
Adrenals
Hypothalamus
progesterone
Testosterone
adrenalin
Dopamine
pineal
somatostatin
melatonin
Increases blood sugar (by telling
liver to break glycogen down into
glucose)
Regulates metabolism
Involved in reproduction
processes/female sex
characteristics
Male sex characteristics
Increase heart rate/blood pressure
Neurotransmitter involved in
sleep, mood, memory, behaviour
Inhibits release of insulin and
glucagon
Regulates circadian rhythm
Define the term ‘negative feedback’ and provide an example.
Negative feedback loops are how homeostasis is maintained. An example is body temperature. If we get too
cold we will start shivering to warm up. If we get too hot we will start sweating to cool.
7.
Explain why the pituitary gland is sometimes referred to as the master gland.
Because it secretes hormones that control the other glands in the endocrine system.
8.
The thyroid gland releases a hormone that increases metabolic rate. Suggest what the symptoms of an
underactive thyroid gland might involve.
Put on weight, get fatigued.
9.
Long periods of continued stress can increase the chance of heart disease. Use your knowledge of
adrenalin and its effect on the body to account for this.
Adrenalin increases heart rate and blood pressure. If this happens for too long it stresses the heart and causes
disease.
10. Explain how the control of body temperature can be described as a negative feedback reaction.
See question 6
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ACTIVITY: HUNTING FOR HORMONES
1.
Use secondary resources (internet or books) to draw lines connecting each hormone
with the organ which produces it and with one of its effects on the body. The first one
is done for you.
ORGAN
HORMONE
FUNCTION
Posterior pituitary
Insulin
Decreases immune response
Pancreas
Cortisone
Decreases blood glucose level
Adrenal cortex
Oxytocin
Stimulates uterine contractions
Anterior pituitary
Thyroxine
Stimulates production of
digestive enzyme
Corpus luteum
Adrenaline
Stimulates milk and secretion
Thyroid
Prolactin
Adrenal medulla
Progesterone
Speeds up growth and
metabolism
Develop female sexual
characteristics
Stomach
Gastrin
Maintenance of pregnancy
Parathyroid
Oestrogen
Increases heart rate
Testes
Parathormone
Ovary
Androgens
Develop male sexual
characteristics
Stimulates calcium release
2.
Label the diagram below using the
following words.
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DIABETES & OTHER NON- INFECTIOUS DISEASES
Alcoholism
exercise
Arthritis
life-style
changes
colour
Depression
liver Obesity
pathogen
Skin
Diabetes diseases
smoking
A non-infectious disease is one that is not caused by a pathogen. There are seven
categories of non-infectious __diseases.
Some non-infectious diseases are also referred to as ‘lifestyle’ diseases. These are
diseases which are caused by decisions people make in the way they live their lives (eg
sclerosis of the liver caused by drinking excessive alcohol, lung cancer by_smoking, obesity
which may be due to poor diet or lack of __exercise. These diseases can often be avoided by
_changes_ in lifestyle.
TYPE OF NON
DESCRIPTION
EXAMPLE
INFECTIOUS DISEASE
Nutritional
Overeating, under eating, or not
eating a balanced diet
__obesity_, heart disease,
malnutrition, scurvy and anaemia
Ageing
The gradual breakdown of body
tissues and conditions
___arthritis_, osteoporosis, heart
disease and nerve disorders
Cancer
Multiplication of body cells at an
abnormal rate
___skin cancer
Inherited
Mental
Environmental disorders
Chemical (metabolic)
Diseases that are passed on from
generation to generation
Disorders with a variety of causes,
such as chemical deficiencies in the
body, stress and trauma
Diseases resulting from exposure to
dangerous poisons, asbestos, fire,
motor accidents and drugs such as
alcohol
Chemical deficiencies in the body
Haemophilia and _colour_
blindness
_depression__, schizophrenia and
anxiety
__alcoholism
__diabetes
Diabetes is an example of chemical disease. It prevents the proper control of the amount of glucose
circulating in the bloodstream. Glucose, a type of sugar, provides the energy necessary for the body to
work. A special chemical
messenger called insulin
ensures that the amount of
glucose in the bloodstream
can be quickly regulated.
Some diabetics are unable
to produce enough insulin.
Most, however produce
enough but their bodies are
unable to use it properly.
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RESEARCH ACTIVITY: DIABETES
Your Task: (optional activity)
You are to prepare a pamphlet, brochure or a fact
sheet to inform others about diabetes. You will
need to consider what information you will
include to inform people about the effects of
diabetes and its prevention. Use the following
website to help you:
www.diabetesaustralia.com.au
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WORKSHEET: DIABETES
1.
The graph below shows the amount of glucose in blood over a 24 – hour period.
(A)
What do you think caused the peaks in the graph?
An increase in the level of glucose in the blood stream.
(B)
(i)
At what times during the 24 hours did the amount of insulin being
released
from the pancreas increase?
6.30am, 12.30pm and 6.30pm
(ii)
Suggest what caused this increase.
Meals were eaten just before this time and digestion has started.
(iii)
What was the effect of the increase in insulin in the blood?
An increase in insulin decreases the amount of glucose in the blood.
(C)
Suggest why the level of blood glucose decreases slightly during sleep.
Whilst sleeping, no eating occurs so glucose levels do not increase but they
decrease slightly as the body is still using energy.
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2.
Read the following text.
After a meal, the level of glucose in the bloodstream increases. This stimulates certain cells (the islets of
Langerhans) in the pancreas to secrete insulin, which causes fat tissue to convert glucose to fat, and both the
liver and muscles of the skeleton to produce glycogen from glucose. Some skeletal muscles can also remove
glucose itself. All these events reduce the level of glucose in the bloodstream.
a) The information can be
summarised in diagrammatic form.
Complete the diagram by inserting
the following words or phrases into
the appropriate place.
Muscles of the
skeleton
(E)
Fat tissue
(C)
Increased blood
glucose level
(A)
Secretion of insulin
(B)
Liver
(D)
b) A different process occurs after a long period without food, such as fasting. This is shown
in the diagram on the right.
Use this diagram to write a series of cause and effect statements. Record your statements in
the table below. The first ONE has been done for you.
CAUSE
EFFECT
Person fasts for many hours
Blood glucose level drops
Adrenal medulla detects low blood
glucose
Adrenal medulla secretes
adrenalin
Pancreas detects low blood
glucose level
Pancreas secretes glucagon
Fat tissue is broken down for
energy and glucose
Increases blood sugar level
Skeletal muscle breaks down
glycogen to glucose
Increases blood sugar level
Liver breaks down glucagon to
glycogen to glucose
Increases blood sugar level
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3.
The graph below shows the regulation of glucose concentration in the bloodstream. The
hormone insulin acts to reduce the concentration of glucose in the blood; the hormone
glucagon acts to increase the glucose level. Through the combined action of these two
hormones, the blood glucose level is controlled within strict limits.
Match the letters in the graph with the following labels.
I
effect of insulin on concentration of blood glucose
II
digestion and absorption of food nutrients alters the
…C
glucose concentration in the blood
…A
III
effect of glucagon on concentration of blood glucose
…E
IV
signal for the secretion of insulin
…B
V
signal for the secretion of glucagon
…D
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