Lab 8: The Endocrine System & Blood
rev 3/11
The Endocrine system is a system of glands which
release hormones directly into the bloodstream so
they can be carried to their target organs or cells
– Hormones are chemical “messengers” carried
by the blood to be transported throughout the
body
– They communicate with target cells—cells
which have hormone receptors
• Target cells are specific for each hormone; if a cell
does not have an appropriate hormone receptor,
the cell will be unresponsive to the hormone
– Target cells can be compared to a radio transmitter; we tune
the radio and pick up the signals of specific stations
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Lab 8-The Endocrine System
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Defining features of hormones
1. Come from endocrine glands
2. Circulate in the bloodstream
3. Act only upon specific cells in the body
• Endocrine glands release hormones directly into
the bloodstream; they do not need ducts to help
with secretion
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Lab 8-The Endocrine System
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Hormones fall into two categories
• Non-Steroid or Peptide hormones
– Built from amino acids and closely resemble
neurotransmitters
• Steroid hormones
– Are structurally related to cholesterol and are
lipid (fat) soluable
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Lab 8-The Endocrine System -Blood
Ways that a gland is stimulated to release hormones:
1. Humoral Control Mechanism
– The cells of a gland are sensitive to changes in
circulating levels of chemicals which it regulates
2. The gland may be stimulated directly by the
nervous system
– ANS stimulates epinephrine
3. The gland may be controlled by hormones of
other glands
– Pituitary hormone stimulates the ovaries
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Lab 8-The Endocrine System
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MAJOR ENDOCRINE GLANDS
(find these glands on the model, NOT on your pig)
• Hypothalamus
– Controls pituitary function and release of
hormones
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Lab 8-The Endocrine System
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• Pituitary Gland
– Is connected to the hypothalamus by a narrow
strip of tissue (called the infidibulum)
– Is located right behind the center of the eyes
– Often called the master gland because it
secretes 8 different hormones and regulates
many of the other endocrine glands
– HOWEVER, the hypothalamus actually
controls the function of the pituitary gland
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Lab 8-The Endocrine System
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– The pituitary gland also releases Tropic
Hormones, hormones which control other
endocrine glands
• ACTH-Adrenocorticotropic Hormone
– Stimulates the adrenal cortex to release
glucocorticosteroids (steroid hormones
involved in stress related conditions and the
metabolism of glucose)
– TSH-Thyroid Stimulating Hormone
• Stimulates the gland to produce thyroxine
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Lab 8-The Endocrine System
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Thyroid Gland
– Located just below (or inferior to) the larynx at
the front and side of the trachea
– Produces thyroxine and calcitonin
– Thyroxine contains iodine and helps regulate
the rate of cellular metabolism
– Calcitonin helps the body to store calcium in
the bones. This works to lower blood calcium
levels.
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Lab 8-The Endocrine System
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Parathyroid Gland
– Located in the back of the thyroid gland
– Produces PTH Hormone (Parathyroid
Hormone) which
1. Removes calcium and phosphate from
bone
2. Increases absorption of calcium by the
digestive tract
3. Increases production of vitamin D
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Lab 8-The Endocrine System
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Adrenal Glands
• Located just above the kidneys
• Each gland has an outer layer, the adrenal
cortex and an inner core, the adrenal
medulla
– You do not need to know the different tissue layers of the adrenal
glands
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• Adrenal Cortex produces
– Aldosterone, a mineralocorticoid (mineral
regulating hormone primarily sodium and
potassium)
– Glucocorticoids including cortisone, cortisol and
corticosterone
– Androgens which have a role in the development
of male and female secondary sexual
characteristics
• Adrenal Medulla
• Produces epinephrine (commonly known as
adrenalin) and norepinephrine,
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Lab 8-The Endocrine System
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Pancreas
– Has groups of hormone producing cells called
the Islets of Langerhans
• Pancreas Hormones
–
–
Insulin allows other cells to absorb glucose
from the blood and store it as glycogen
Glucagon stimulates the liver to break down
glycogen into glucose so the body can use it
for energy
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Lab 8-The Endocrine System
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Gonads
– The testes, in males, are located in the
scrotum and produce testosterone
– The ovaries, in females, are located in the
pelvic cavity and produce estrogen and
progesterone
Thymus Gland
– Located near the heart
– Plays a major role in the body’s immune
system
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Lab 8-The Endocrine System
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Pineal Gland or Pineal Body
– Located in the brain
– Secretes melatonin which is believed to
synchronize the day-night cycles of our body
The Kidneys
– can also function as an endocrine gland
– Produce
• Renin which can increase blood pressure
• and Erythropoietin which stimulates RBC
production
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REMINDER, Endocrine Glands:
1. You will be given a fetal pig today but we will
begin to dissect it next week. There is too much
we must do in today’s lab.
2. You are responsible for locating the pituitary,
hypothalamus, and pineal glands on the human
brain model.
3. Locate on the human model the endocrine glands
listed in the diagram on page 98 of the lab manual
(the thyroid, thymus, pancreas, adrenal glands,
ovaries, and testes). Use Table 11.1 to learn about
the endocrine glands, its hormones and the
function of these hormones.
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Blood
• Blood is actually a liquid body tissue and is
classified as a connective tissue because its cells
protect the body
• it communicates with all cells of the body
– capillaries are one cell thick and connect the
arterial circulation to the venous circulation
– because the capillaries are small and thin,
molecules move freely across their walls
– this allows for waste products to be exchanged
for nutrients
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Lab 8-The Endocrine System
Blood
• Fluid portion of blood
– called plasma
– plasma contains several different kinds of
proteins called “formed elements”
• Formed Elements of the Blood
– Red blood cells, white blood cells and platelets
are collectively called “formed elements”
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• Red Blood Cells (RBC) or erythrocytes
– contain hemoglobin, a protein which carries
oxygen and carbon dioxide
– RBC live for approximately 4 months.
– As they mature, they expel their nucleus so they
can carry more hemoglobin.
– They also assume a biconcave shape. This
shape makes them more flexible and allows
more of them to fit into blood vessels to
increase the surface area available for gas (O2
and CO2) exchange.
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Lab 8-The Endocrine System
Blood
• Hemoglobin Molecule
• Hemoglobin is an oxygen binding protein which
consists of 4 polypeptide chains coiled around a
“heme group”
• The “heme group” has an iron atom in its center.
This combines easily with oxygen at the lungs
AND lets go of the oxygen when reaching body
tissues.
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Lab 8-The Endocrine System
Blood
Hematocrit
• is a measure of the oxygen carrying capacity of
blood
• is obtained by spinning down blood and
measuring the amount of formed elements
• RBCs make up nearly 99% of formed elements
• Normal hematocrit
– men: 42-52%
women: 37-47%
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Lab 8-The Endocrine System
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Anemia
– refers to a deficiency in oxygen carrying
capacity of the blood
Types of Anemia
• Pernicious Anemia
– body is unable to absorb vitamin B12 from the
digestive tract
– the body uses B12 to produce normal RBC
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Lab 8-The Endocrine System
Blood
• Sickle cell Anemia
– is an inherited disorder in which the RBC
become sickle or crescent shaped when the
oxygen concentration of the blood is low. This
shape doesn’t travel easily through blood
vessels because the cells clump, get stuck in the
vessels and cause a great deal of pain.
– Sickle shaped cells can’t carry a normal amount
of oxygen.
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Lab 8-The Endocrine System
Blood
• Iron deficiency anemia occurs when there is
insufficient iron ingested.
Polycythemia is a term used to describe an
abnormally high RBC count
– this increases the thickness of blood and slows
down the flow of blood.
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REMINDER: BLOOD-RBC
• Do not do the hematocrit or blood typing activity.
This is no longer performed due to Hepatitis C,
not AIDS
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White Blood Cells or Leukocytes
Originate in the red bone marrow
• Types of WBC (page 109 of lab manual)
– Neutrophils-most common WBCapproximately 65% of WBC are neutrophils
• see in acute infections; are the first WBC to
combat infection
• main function is phagocytosis
– Lymphocytes-second most common WBC,
about 20%
• involved in immune response
• manufactures antibodies and eliminates
anything foreign to the body
Lab
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Lab 8-The Endocrine System
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– Monocytes-about 8%
• active in phagocytosis
• elevated in chronic infections
– Eosinophils-less than 5% of WBCs
• see in parasitic infections
– Basophils-are rare, less than 1% of WBCs
• initiate the inflammatory response
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Neutrophil
Eosinophil
Lymphocyte
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Basophil
Monocyte
34
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Figure 4-3: Types of white blood cells
Recognizing leukocytes/WBC-helpful hints
• Neutrophils: have smaller paramecium shaped nuclei
which are multi-lobed; cytoplasmic granules not prominent
• Eosinophils: have a really red (paramecium shaped)
nucleus; looks like a strawberry or bug eyes
• Basophils: have lots of large cytoplasmic granules
• Lymphocytes: nucleus is generally spherical; pale blue
cytoplasm
• Monocytes: its nucleus is U or kidney shaped; can see
cytoplasm around the nucleus
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REMINDER
1. Use the chart on page 109 of the manual and the
color charts around the room to help you
identify the different types of white blood cells.
2. Activity on page 110 of manual
-Do the drawings; they will help you recognize the
differences between the WBC
3. Page 111-complete chart to help you further
understand value of WBC
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Lab 8-The Endocrine System
Blood
Platelets
• are small cell fragments (not complete cells)
which play an essential role in the process
of blood clotting
• platelets are stable as they circulate, but
when they encounter a “rough surface” they
form a temporary plug and initiate the
clotting mechanism
• the body also requires vitamin K for normal
blood clotting
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Clotting process
• damage to a blood vessel triggers a vasospasm or
constriction of the damaged blood vessel
• platelets in the area swell, become sticky, adhere to the
damaged area and produce a plug which will become the
clot
• platelets also release chemicals to help in clot formation
Chemicals released:
• prothrombin activator converts prothrombin (a plasma
protein) into thrombin
• thrombin converts the fibrinogen molecules, to fibrin
which traps blood cells, forms a clot and seals the hole
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• Blood Typing
– Each of us has one of 4 types of blood--A, B, AB, O-along with some specific glycoproteins or antigens
• Our cells have surface proteins that the immune system
can recognize as “self” or “non-self”. The immune
system will recognize foreign cells as non-self .
• An antigen is a non-self cell protein that causes the
immune system to defend itself.
• The immune system builds antibodies-an opposing
protein which can kill the non-self cells.
– and causes them to stick together so it can be destroyed.
So, the transfused blood clumps or clots within our blood
vessels.
– This can be fatal
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• Another antigen found in blood is the Rh antigen-if you have it, your blood is classified as Rh
positive. If you do not have this, your blood is
classified as Rh negative.
Blood Typing Tests
– Based on the interaction between antigens and
antibodies
– performed with anti-sera which contain high
concentrations of anti-A and anti-B antibodies
• blood samples are mixed with each anti-sera
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– if clumping (similar to clotting) occurs with
anti-A sera, you have type A blood
anti-B sera, you have type B blood
– if clumping occurs with both anti-A and anti-B,
you have type AB blood
– if no clumping occurs with either anti-A and
anti-B sera, you have type O blood
• so, the antibodies you have in your body are the
opposite of your blood type
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Anti Anti
A
B
Anti
Rh
Agglutination Reactions
Blood Type?
Not
Agglutinated
Agglutinated
blood-cardiovascular
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REMINDER
1. You need to know the background information but will not
perform the activity for hematocrit and blood type (page
108).
2. Look at the wall charts, table charts, and your lab manual
to see erythrocytes and recognize the different
leukocytes. Note that RBC do NOT have a nucleus.
3. Your group will get a fetal pig today but we will not have
time to begin the dissection. We will start this next
week. One fetal pig will be shared by 3-4 people. Make
sure that each of you participates in the dissection.
4. When we dissect, tie long hair back so it doesn’t mix
with the pig insides when you bend down to look at the
pig.
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REMINDER, page 2 of 2:
5. If you don’t remember your microscope skills go
back to Chapter 1 for a review if needed.
--Remember to have the microscope light on low.
Blood cells are small so can be hard to see.
6. Most of the cells you will see are RBC (pale
pink/orange with no nucleus).
7. When you see a cell with a nucleus, you have
found some kind of WBC.
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Blood Types Determine Blood Compatibility
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Figure 7.12
Blood Typing
Blood Type
Reaction
Anti-A Serum Anti-B Serum
Antibody
Type
Type A
Agglutination
No
Agglutination
Anti-B
antibody
Type B
No
Agglutination
Agglutination
Anti-A
antibody
Type AB
Agglutination Agglutination No antibodies
against major
blood groups
Type O
Anti-A & Anti-B
No
No
antibodies
Agglutination Agglutination
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Lab 8-The Endocrine System
Blood
– Anemia
causes vary; can be due to low iron levels, blood loss, poor protein
absorption, improper RBC formation
•
Polycythemia However, if you live in high altitudes, this condition develops
because of the reduced oxygen capacity in the air. It is the body’s attempt to
compensate.
•
Dots in basophils are cytoplasmic granules. Cytoplasmic granules contain
proteins and enzymes to assist in phagocytosis
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The Endocrine System
•
•
•
•
Test--34 questions, last 10 practical
had sheep brain with pin in it
eye, ear model
model answers: myelin sheath, gray matter, pons, cerebellum, corpus
callosum, occipital lobe, tag closest to language center of the brain,
pons, arbor vitae, choroid coat, either balance (semicircular canal) or
sound vibrations to nervous impulses (cochlea)
• for identification of models, had 2 dots and each version of test had
different question
• FEMALE PIG HAS LARGER GENITAL PAPILLAE
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Notes for Carol
– Adrenal Cortex produces
• Aldosterone, a mineralocorticoid (mineral regulating hormone)
which is primarily responsible for regulating the amounts of sodium
and potassium in the body
• Glucocorticoids including cortisone, cortisol and corticosterone
– These increase glucose production and
– Have anti-inflammatory properties
– Suppress the immune system
• Androgens which have a role in the development of male and female
secondary sexual characteristics
– Adrenal Medulla
• Produces epinephrine and norepinephrine, commonly known as
adrenalin, which Dilate the coronary arteries, Increase blood pressure,
Increase heart rate, Dilate the bronchi of the lungs
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Lab 8-The Endocrine System
Blood
Epineph and norepin are also neurotransmitters. The distinction between a
neurotransmitter and a hormone is how it functions, not its structure. When
epi and nor are released into the blood stream and act on target cells they are
functioning as hormones
• when these have been removed from plasma the
remaining liquid is called serum
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Goes with slide 14
• Aldosterone: primary responsibility is to
regulate Na & K levels
• Glucocorticoids:
– Increase glucose production
– Has anti-inflammatory properties
– Suppress immune response
• Adrenalin: dilates coronary arteries, bronchi
– Increases BP, heart rate
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Lab 8-The Endocrine System
Blood
• Blood Typing
– Each of us has one of 4 types of blood--A, B,
AB, O-- along with some specific glycoproteins
or antigens
– If we receive blood that is different from ours,
the body recognizes this as foreign and causes
the transfused blood to stick together so it can
be destroyed
– This can be fatal
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