Exercise 28
Endocrine System
Glucometer
Portland Community College
BI 232
The endocrine system
• Diverse collection of organs and tissues that
contain endocrine glands.
• Glands secrete chemicals called hormones
into blood capillaries
• Hormones are transported to target cells at a
distant location
• Hormone binds to a specific receptor and
the cell responds to message.
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Endocrine and Exocrine
• Exocrine glands
secrete substances into
ducts, which transport
the secretions internal
cavities of organs or to
surface of the skin.
3
Effects of Hormones
• Areas receptive to
hormones are called
target cells and may be
tissues or organs.
• Can have many effects
such as growth,
development, metabolism,
etc.
• Many organs produce
hormones such as heart,
stomach and kidneys.
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Pineal Gland
• Secretes:
• Melatonin
• Involved in circadian
rhythms
• Day  melatonin,
Night  melatonin
• Produces sleepiness
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Hypothalamus and Pituitary
Gland (Hypophysis)
• Hypothalamus produces a
number of releasing hormones
and inhibiting hormones.
• Stored in posterior pituitary
(neurohypophysis)
•
•
ADH (antidiuretic hormone)
• Reduces urine output by increasing
water reabsorption in the kidney
• Plays small role in blood pressure
regulation
• Also called vasopressin
Oxytocin
• Causes uterine contractions in
labor
• Causes milk let down in lactating
mothers
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Anterior lobe
(Adenohypophysis)
•
•
•
ACTH (adrenocorticotropic
hormone)
• Regulates the activity of the
cortex of the adrenal gland
TSH (thyroid stimulating hormone)
• Stimulates production and
release of thyroid hormone
GH (growth hormone)
• Stimulates growth of bones,
cartilage, muscle
• Timing and amount released
determines body size
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Endocrine Organs in Head
•
•
•
PRL (prolactin)
• Stimulates breast development
• Promotes and maintains
lactation after childbirth
FSH (follicle stimulating hormone)
• Causes formation of ovarian
follicles and stimulates them to
produce estrogen
• Stimulates sperm development
in men
LH (luteinizing hormone)
• Initiates ovulation, maintains
corpus luteum
• Regulates testosterone
production in males
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Pituitary
Histology
Intermediate lobe
(part of the
anterior lobe)
produces
melanocyte
stimulating
hormone
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Thyroid Gland
• Secretes:
• Thyroid Hormone
• Regulates metabolic rate of
the entire body
• Important in development
of the nervous system
•
•
Calcitonin
• Decreases bone reabsorption,
lowering serum calcium levels
PTH (parathyroid hormone)
• Increases serum calcium
• Decreases serum phosphorus
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Thyroid Histology
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Thyroid Histology
• Follicular cells
produce the
colloid (contains
precursors to
thyroid hormone)
• Parafollicular
cells secrete
calcitonin
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Parathyroid
Histology
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Thymus
• Active in young
individuals and plays a
part in
immunocompetency.
• Produces thymosin
which causes
maturation of T cells.
• T cells start out in
bone marrow and
migrate to thymus
The T cells migrate to
lymph nodes and spleen
to carry out their
functions.
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Hormones secreted by heart
• Heart: If blood volume is
elevated above normal, cardiac
muscle cells in the heart was
secrete natriuretic peptides.
• Act on the kidneys to promote
the loss of sodium ions and
water.
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Pancreas
•
Secretes:
•
Insulin (alpha cells)
• Released in response to high blood
sugar
• Increases cellular absorption of
glucose
• Increases rate of lipogenesis and
formation of glycogen in the liver
Glucagon (beta cells)
• Released in response to low blood
sugar
• Elevates blood glucose levels by
promoting the breakdown of
glycogen.
Somatostatin (delta cells)
inhibit both Insulin and glucagon
and may increase efficiency in
digestion.
•
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Pancreas
•Acinar cells secrete
digestive enzymes
(exocrine)
•Islet cells secrete
insulin (beta cells) and
glucagon (alpha cells)
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Adrenal Glands
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Adrenal Glands
•
•
•
Secrete:
Glucocorticoids (Cortisone)
• Released in response to stress
• Increases formation of glucose
from protein and fat
breakdown
• Decreases inflammation
Aldosterone
• Increases blood volume by
causing kidneys to retain
sodium (where sodium goes
water goes too) in exchange
for potassium
• Increased blood volume will
increase blood pressure
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Adrenal Glands
• Androgens
• Are male sex hormones that
are produced in small
quantities and converted to
estrogens (female sex
hormones) when they enter
the blood
• Epinephrine & Norepinephrine
• Fight or flight response
• Increase heart rate, increase
skeletal muscle blood flow,
decrease skin blood flow
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Adrenal
Histology
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Adrenal Cortex
Zona
Reticularis:
Androgens
Zona Fasiculata:
Glucocorticoids
(Cortisone)
Zona
Glomerulosa:
Aldosterone
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Hormones from the Kidneys
• Erythropoietin
• Stimulates RBC
production
• Calcitriol
• Stimulates calcium and
phosphate absorption
• Stimulates calcium
release from bone
• Inhibits PTH secretion
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Gonads
• Ovaries in females
produce estrogens
• Testes in males produce
testosterone
• Both are stimulated by
FSH from anterior
pituitary
• Influenced by LH which
increases the level of
hormone produced
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Testis
• Produce testosterone
responsible for secondary
sex characteristics such as
facial hair and expansion
of larynx.
• Inhibin involved in
negative feedback
providing regulation of
testosterone production
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Testes
• seminiferous tubules
where the sperm are
produced
• The interstitial areas
contain interstitial
(Leydig) cells where
the testosterone is
produced.
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Ovary
• Produce oocytes
(eggs) and have an
endocrine function by
producing estrogen
and progesterone
• Responsible for
secondary sex
characteristics in
women.
•
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Endocrine physiology
experiment
• LH stimulates the final maturation of the oocyte
and causes ovulation.
• About 24-36 hours prior to ovulation there is a
spike.
• Are there any students in the middle of your
ovarian cycle like to volunteer to test for the
presence of LH?
• If a woman has significant amounts of LH then the
test strip produces a color (usually blue)
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Glucometer Exercise
• We need 4 volunteers to
let us test their blood
glucose levels at 30
minute intervals.
• Measure glucose level
• Drink soda or juice
• After 30 min test again
• 1 hour after drinking test
again
• If levels haven’t gone
down after test again after
2 hours
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Diabetes
•
•
•
•
Type 1: Insulin Dependent Diabetes
AKA: juvenile diabetes
Caused by a lack of insulin
Autoimmune disorder
• Immune system destroys beta cells in the pancreas
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Diabetes
• Type 2: Non-Insulin Dependent
• Caused by an insensitivity of cells to
insulin.
• Diabetes mellitus marked by hyperglycemia
•  urine production (polyuria)
•  thirst (polydipsia)
•  eating (polyphagia)
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Diagnosing Diabetes Mellitus
• Normal blood glucose levels: 70-100 mg/dl
• Diabetes mellitus:
• A fasting glucose level above 140 mg/dl on two
separate occasions, or
• A blood sugar over 200 mg/dl 2 hours after oral
glucose tolerance test with 75gm of glucose
• Impaired Glucose Tolerance (Pre-Diabetes)
• A fasting glucose level between 100-126 mg/dl on two
separate occasions, or
• A blood sugar between 140-200 mg/dl 2 hours after
oral glucose tolerance test with 75gm of glucose
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The End
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