Download Thymus Pineal Thyroid Parathyroid

Thymus,
Pineal,
Thyroid,
Parathyroids
The Thymus
• Location: upper
thorax, posterior to
sternum
• Description:
– Large in
infants/children
– Decreases in size
throughout adulthood
– Made of fibrous
connective tissue and
fat
Thymosin
• Main hormone of the
thymus
• Essential for
development of Tcells (a group of
white blood cells)
and immune
response
The Pineal Gland
• Location: brain (roof
of 3rd ventricle)
• Description:
– Small, cone-shaped
gland
– Not a lot is known
about it beyond the
secretion of
melatonin
Melatonin
• Main hormone of the
pineal
• Peak levels at nightdrowsiness
• Lowest levels around noon
• In animals, also helps
regulate mating behavior
and rhythms
Seasonal Affective Disorder
• Type of depression
• Related to changes in seasons
• May occur due to drops in
serotonin (reduced sunlight)
and affect melatonin (sleep
patterns, mood)
• Begins and ends about the
same time each year
(fall/winter)
• Saps energy, moodiness
• Treatment: light therapy,
psychotherapy, medication
Summary- be ready to answer!
Match the location of each gland.
1.
2.
3.
4.
Hypothalamus
Pituitary
Thymus
Pineal
A.
B.
C.
D.
Above pituitary
3rd ventricle
Sella turcica
Thorax
Summary- be ready to answer!
Match the function of each hormone.
1.
2.
3.
4.
5.
6.
LH
Melatonin
OXT
PRL
Thymosin
TSH
a)
b)
c)
d)
e)
Mammary gland development and lactation
Plays a major part in the immune response
Plays a role in sleep-wake cycles
Tells the thyroid to make thyroid hormones
Induces ovulation and the release of other
hormones
f) For bonding, promoting labor, and milk
ejection
Summary- be ready to answer!
Match the function of each hormone.
1.
2.
3.
4.
5.
6.
ACTH
ADH
FSH
GH
GH-IH
ICSH
a) Inhibits urine production
b) Prevents secretion of growth hormone
c) In males, stimulates androgen
production
d) Makes adrenal cortices release
hormones
e) In females, induces follicle & egg
development
f) Maintenance and repair of body tissues
Thyroid Gland
• Location: in the neck
– Base of throat, inferior to Adam’s apple
• Description:
– Two lobes joined by an isthmus
– Composed of follicles
– Regulates metabolism
– Influences mental & physical abilities
– For normal growth (along with GH)
– Requires iodine
Thyroid Hormone
• Controls the rate at
which glucose is
oxidized (“burned”)
and converted into
heat and energy
• Every cell in the body
is a target cell
Thyroid Hormone
• 2 similar, iodine-containing
hormones
– Thyroxine (T4)- major thyroid
hormone
– Triiodothyronine (T3)- most formed
at target tissues when T4 is
converted to T3
• Made and stored in follicles
• Constructed from two tyrosine
amino acids linked together plus
bound iodine (T3=3; T4=4)
Calcitonin
• Decreases blood calcium levels (deposits the
calcium in bones)
• Is the antagonist of parathyroid hormone
• Made by parafollicular cells (connective
tissues between follicles)
Abnormal Growths
• Nodule- any
abnormal growth
that forms a lump
• Goiter- enlargement
of the thyroid
– Results from iodine
deficiency
– Can also result from
overproduction of
hormones
Goiter
• CRETINISM: hyposecretion
of thyroxine in early
childhood
– Lack of physical growth
– Lack of mental development
– If caught early, hormone
replacement can prevent
mental retardation and
some other symptoms
• MYXEDEMA:
hyposecretion of
thyroxine as adult
– Physical and mental
sluggishness
– Puffiness of the face,
obesity
– Fatigue, poor muscle
tone, low body
temperature
– Treat with oral thyroxine
• HASHIMOTO’S
DISEASE:
autoimmune
hypothyroidism
– Autoimmune
thyroiditis- immune
system attacks the
thyroid
– May result in goiter
– Treat with hormone
replacement, surgery
HYPERTHYROIDISM
• Overactive thyroid
• Metabolism increases,
weight loss
• Rapid pulse, tremors,
sweating, anxiety
• Treat with thyroidblocking drugs,
radioactive iodine to kill
thyroid cells, or surgical
removal of part of the
thyroid
HYPERTHYROIDISM
• GRAVE’S DISEASE:
autoimmune
hyperthyroidism
– Symptoms of
hyperthyroidism
– Thyroid enlarges
– Eyes may bulge or
protrude anteriorly
(exophthalmos)
THYROID
CANCER
• Papillary: most
common (70-80% of
cases).
– Usually diagnosed age
30-50
– Occurs 3x more often in
women
– Least aggressive type
– May spread, but usually
not beyond the neck
THYROID CANCER
• Follicular: 10-15% of cases
– Women 3x more
– Usually diagnosed between ages 40-60
– Cancer cells may invade blood vessels and travel
– Can be more aggressive in older patients
THYROID CANCER
• Medullary: 5-10% of all
cancer cases
– Tends to run in families
– Often diagnosed ages 4050
– Males/females affected
equally
– Develops in parafollicular
cells; elevated calcitonin
levels can indicate cancer
THYROID CANCER
• Anaplastic (rare- fewer than 5% of all cases)
– Generally in older people (over the age 65)
– Females affected more often than males
– Aggressive and invasive
– Very difficult to treat
Thyroid Neck Check
• https://www.youtube.com/watch?v=kfsG7p1hSk (start at 0:29)
Parathyroid Glands
• Location: Posterior
surface of thyroid gland
(embedded)
• Description:
– Four tiny masses of
glandular tissue
– Regulate blood calcium
homeostasis
Parathyroid Hormone (PTH) or
parathormone
• Released when blood
calcium (Ca+2) levels drop
• Major target tissue: bone
– Stimulates osteoclasts to
break down bone matrix
and release Ca+2 into
blood
• Also stimulates kidneys
and intestine to absorb
more Ca+2
Parathyroid Hormone Diseases
• TETANY:
uncontrollable muscle
spasms due to
hypocalcemia (makes
neurons irritable and
overactive)
– May be fatal
Parathyroid Hormone Diseases
• Hyperparathyroidism
– If too much calcium is
removed and put in blood,
bones become fragile
– Kidneys excrete calcium;
too much can lead to kidney
stones
– If severe, bones undergo
massive destruction. Likely
to experience spontaneous
fractures.
Be ready to answer!
• Why is iodine important for proper thyroid
function?
• Some thyroid diseases are autoimmune.
What does “autoimmune” mean?
• Which hormone is hypercalcemic
(increases blood calcium levels)? Which
gland makes it?
• Which hormone is hypocalcemic
(decreases blood calcium levels)? Which
gland makes it?
• How are the thyroid and parathyroids
linked anatomically?