Download Thyroid Gland

• Two lobes on each side of larynx that contain tens of
thousands of _____________.
• Each has a sphere of ____________ glandular cells
surrounding colloid, which is thyroid hormone
precursor
• Thyroid hormones:
T3 and T4 (triiodothyronine and thyroxine)
• Produced when TSH from ant pituitary reaches
thyroid gland
• T4 produced in greater abundance than T3 but is
mostly converted to T3
• ______ more potent and considered the main
thyroid hormone.
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Thyroid
Gland
Effects of Thyroid Hormones
• Protein Metabolism:
• Encourages anabolism if diet is adequate in energy sources.
• If energy sources are inadequate, protein catabolism can occur.
• Lipid Metabolism:
• Encourages their catabolism.
• Carbohydrates:
• Hyperglycemic effect.
• Helps to maintain homeostasis of the blood glucose level by
helping to prevent it from dropping too low.
• _______________________ effect
• Allows an animal to generate heat/maintain a constant body temp
by increasing their metabolism.
• Production of thyroid hormone increases with exposure to cold
temperatures.
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• Produced by C cells (parafollicular cells)
located between thyroid follicles
• Maintains homeostasis of blood
_______________ levels
Thyroid Gland
cont’d…
Calcitonin
• Calcium is necessary for muscle
contraction, blood clotting, milk
secretion, and formation/maintenance
of skeleton. Calcium levels must be kept
within normal range.
(the other Thyroid hormone)
• Prevents _______________ by decreasing
blood calcium levels if they get too high.
• Encourages excess calcium to be
deposited into the bones.
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• Small nodules in, on, or near the thyroid
glands
• Produce Parathyroid Hormone (PTH aka
parathormone)
• Helps maintain blood Calcium levels by
producing the _____________effect of
calcitonin
• Prevents _________________ by increasing
blood calcium if gets too low.
• Causes kidneys to retain calcium and
intestines to absorb calcium from food.
• Can take calcium out of storage from the
bones.
Parathyroid
Glands
• Carefully monitor lactating animals for milk
fever (lg) or eclampsia (sm) as PTH can
become overwhelmed
inderived
these
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Located near cranial ends of ____________
• Consist of a capsule, cortex, and medulla
CORTEX produces (as directed by ACTH release):
_______________________ hormones (cortisol)
-Can increase blood glucose levels via
gluconeogenesis
-Decreases inflammation, decreases immune
response, increases body’s resistance to
stress
______________________ hormones (aldosterone)
-Increases Na reabsorption and K/H excretion
in the kidneys.
_______hormones (androgens and estrogens)
-small amount with minimal effects
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Adrenal
Cortex
Adrenal MEDULLA produces the hormones
______________ and ________________.
• Resembles ________________ tissue.
Hormone-secreting cells are modified
neurons that are able to secrete
hormones into the bloodstream.
• Controlled by sympathetic portion of
nervous system (fight or flight)
• Increases HR and CO, increases BP, dilates
air passageways in lungs, and decreases
GI function
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Adrenal
Medulla
• Located near _______________ and has both
exocrine and endocrine functions
• islets of Langerhans: groups of cells
scattered throughout the pancreas
• Alpha cells - produce ______________
• increases blood glucose levels by promoting
gluconeogenesis and glycogenolysis in the liver
• Beta cells - produce _______________
• Causes glucose, amino acids, and fatty acids to
be absorbed into body cells. Lowers blood
glucose levels. Deficiency of insulin is known
as Diabetes Mellitus.
Pancreas
• Delta cells - produce _______________
• Inhibits release of Insulin, Glucagon, and
Growth Hormone, and decreases GI activity
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Gonads: Testes
• Interstitial cells: clumps of endocrine cells that surround
the seminiferous tubules
• Produce _____________________ when stimulated by
Luteinizing Hormone from the anterior pituitary.
• LH is also known as “interstitial cell stimulating
hormone” (ICSH) in the male
• Testosterone is responsible for development of male
secondary sex characteristics and accessory sex glands,
muscular build, libido, and plays a role in
spermatogenesis
• Spermatogenesis occurs in the seminiferous tubules and
begins when ______ from the anterior pituitary reaches the
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testicles.
• Produce ______ (eggs) and the hormones
_________________ and __________________
• Controlled by FSH and LH (from anterior pituitary)
Gonads:
Ovaries
• FSH stimulates ovarian follicles to develop. As
follicle and ovum grow, increasing amounts of
estrogen are released from the follicular cells.
• Increased estrogen causes anterior pituitary to
____________production of FSH and
____________ production of LH
• When follicle is fully mature, LH level peaks and
ovulation occurs (most species)
• A Corpus Luteum is formed after ovulation and it
produces progesterone, which is needed to
maintain a pregnancy. If conception does not
occur, the CL will not be maintained an the animal
will once again prepare an ovum for ovulation.
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Produce ___________________ stimulates red bone marrow to
increase production of RBCs
Kidneys
•Stimulated by hypoxia, loss of
RBCs, increased aerobic exercise
•As RBC production increases, more
oxygen is delivered to kidneys,
which slows production of
erythropoietin
•Lack of production often results in
anemia
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Stomach and Small Intestines
• STOMACH: ________ is produced by G-cells in the pyloric antrum
• Causes HCl secretion, which will allow more pepsinogen to be activated
• SMALL INTESTINES: ______________ and __________ are
produced by duodenum
• Both cause the stomach motility to decrease and inhibit gastric secretions
• ____________ stimulates the pancreas to secrete bicarbonate into the
duodenum to neutralize the acidity of chyme
• ____________ stimulates the gallbladder to contract, allowing bile to aid in
the digestion of fats. Also stimulates pancreas to secrete protease and lipase
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• Surrounds developing fetus during
pregnancy
• Acts as interface with maternal
circulation
• Produces hormones to support and
maintain pregnancy
• Small amounts of ___________ and
_________________ are produced.
Placenta
• Chorionic gonadotropin is also
produced (horses, humans have
significant amounts)
• Basis for pregnancy tests in these species
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• Located in the cranial
____________________
• Very important during early development,
will __________ as animal approaches
adulthood.
• Important in immune system development
• Produces:
• Thymosin
• Thymopoietin
• Transform cells of the thymus into tlymphocytes (_________) which help to
attack foreign invaders in the body.
Thymus
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Pineal Body
• Influences body’s biological clock
• Produces ________________________ – hormone-like
substance that affects moods and wake-sleep cycles
• Also plays a role in timing of seasonal estrous cycles in
some species
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