Disorders of the Thyroid Gland:
• Goiter: results from an
enlarged portion of the
thyroid gland
• May result from either
hypothyroidism or
hyperthyroidism
Parathyroid Gland
Para means beside or
alone or on top!
• Four small glands embedded in the back of
the thyroid gland
• Secretes one hormone: PTH (parathyroid
hormone) or (parathormone) when calcium
levels in the blood are below normal
Parathyroid Gland
• Increases calcium by:
• Increasing the # of bone-destroying cells,
therefore releasing the calcium from storage in
the bones
• Increasing calcium re-absorption in the kidneys
• Increasing the uptake in the digestive tract.
• Works antagonistic to calcitonin
Disorders - Parathyroid
• Tetany: not enough parathyroid hormone, low blood calcium –
neurons depolarize without a stimulus, resulting in twitches,
spasms and convulsions
• Osteitis fibrosa cystica: too much parathyroid hormone, high blood
calcium – softening and demineralization of bones, calcium
deposits in kidneys and other organs
Do Section 13.2 Review page 450 # 1-7
The Adrenal Glands:
• 2 Adrenal Glands: one above each kidney
• Each of the glands contains: adrenal medulla
and adrenal cortex
Adrenal Medulla:
• Actually part of the Sympathetic Nervous
System (part of ANS)
• Hormones are epinephrine (Adrenaline)
• Part of the short term stress response
Adrenal Medulla:
• Epinephrine released as a
response to stress– Glucose is released (glycogen is
broken down)
– Heart Rate increases
– Breathing rate Increases
– Iris dilates and pupil gets larger
– Increased CNS alertness
– Increased blood Pressure (to
ensure blood is getting to the vital
organs)
– Other activities are inhibited
(bladder, stomach)
So what is an EpiPen used for?
Alpha receptors are found on the walls of
blood vessels. When adrenaline stimulates
these receptors this causes the blood vessels
to narrow, which stops the blood pressure
from falling too low. It also redirects blood to
vital organs like the heart and brain.
Beta receptors are found in the heart and
lungs. When adrenaline stimulates these
receptors this relaxes and opens the airways,
making breathing easier. It also stimulates the
heart, making it beat faster and stronger
Adrenal Cortex:
• Part of the long term
stress response
• Secretes three types of
steroid hormones:
• Aldosterone
(mineralocorticoids)
• Cortisol
(Glucocorticoids)
• Sex Hormones (in small
amounts)
(Gonadocorticoids)
Aldosterone:
• Causes blood to absorb Na+ from distal tubule and
expel/secrete K+
• Causes reabsorption of water into blood by working on
the distal tubule (Remember that water follows solute!!)
• Secretion is not only stimulated by the anterior
pituitary’s release of ACTH but also by a rise in the K+ in
the blood
Cortisol:
• Helps to resist and recover from stress
Affects glucose levels by:
• Stimulates protein degradation so amino acids are available
for glucose production
• the liver converts Amino Acids into carbohydrates when
stores are depleted
• Breaks down lipids into free fatty acids, which other tissues
can use for metabolism so that glucose can be saved for the
brain
• Inhibiting glucose uptake and use by certain tissues so it can
be spared for the brain
Cortisol:
• Polarised light micrograph of cortisol, or hydro- cortisone,
the chief steroid hormone secreted by the adrenal cortex.
Cortisol plays a role in both normal carbohydrate
metabolism and in the body's response to physical &
emotional stress.
Sex Hormones:
• Small secondary sex characteristics