Lesson 32: HYPOTHALAMUS, PITUITARY GLAND AND THYROID GLAND Flashcards
posterior pituitary gland
ADH and oxytocin, that are carried through nerve fibers to the posterior pituitary gland for storage.
Antidiuretic hormone (ADH)
If osmoreceptors sense dehydration, neurally induced ADH release follows. The hormone targets the distal convoluted tubules of nephrons, opening the pores and allowing water reabsorption from the urine to correct dehydration.
oxytocin
The other hormone of the hypothalamus that is stored in the pituitary gland is oxytocin, two main functions in females. It stimulates the uterine contractions that occur during labor and delivery, and it contracts the ducts in mammary tissue during lactation causing milk ejection from breast tissue
Growth hormone (GH)
a protein hormone produced by the anterior pituitary, stimulates body cells to increase in size and divide more rapidly
growth hormone releasing hormone (GHRH)
The hypothalamus produces growth hormone releasing hormone (GHRH) to promote GH production by the pituitary
epiphyseal discs
At birth, the cartilage has been replaced by bone except at thin disks near the top and bottom of each bone. The discs are these
hypopituitary dwarfism
This is characterized by short stature but a body that is still normally proportioned., little GH
gigantism
Before disk closure, too much GH causes gigantism- the individual grows much larger than normal. Height may exceed eight feet. But again, the body has normal proportions.
acromegaly
Now excess growth hormone, Bones grow thicker rather than longer. Soft tissue accumulates producing enlarged fingers, toes and facial features. The brow and jaw protrude and the tongue enlarges
somatomedin
Growth hormone causes the liver to release a factor called somatomedin that is also necessary to promote growth
prolactin
The anterior pituitary also produces prolactin, a hormone that stimulates mammary glands to produce milk.
prolactin inhibiting hormone (PIH)
The hypothalamus releases prolactin inhibiting hormone (PIH) to reduce prolactin release by the pituitary. PIH levels fall during pregnancy and shortly after the birth of a child, she begins producing breast milk.
thyroid gland
It consists of right and left lobes connected inferiorly by a portion of the gland called the isthmus, Hormones of the thyroid gland regulate metabolic rate and hormones of both the thyroid and parathyroid glands regulate blood calcium levels
parathyroid glands
On the posterior surface of the thyroid gland are four small glands called this,
thyroxin (T4) and triiodothyronine (T3)
The thyroid gland produces, act to increase metabolic rate
thyroid follicles
Hormones controlling metabolic rate are produced here
colloid
Follicles are composed of spheres of simple cuboidal epithelium filled with a glycoprotein substance called this
thyroglobulin
These hormones are produced in the colloid and stored on large molecules called this, to be released from the colloid as needed.
TSH (thyroid stimulating hormone)
stimulates the synthesis of thyroxin and T3 and their release into the blood from the thyroglobulin molecules.
calcitonin
is produced by cells between the follicles
iodine and the amino acid tyrosine.
The raw materials required for hormone production in the follicles
euthyroid.
Persons with normal circulating levels of thyroxin and T3 are termed this
hyperthyroidism
If levels of thyroxin and T3 are higher than normal, the condition is termed
hypothyroidism
If levels of thyroxin and T3 are lower than normal, the condition is termed
(BMR) basal metabolic rate
This is a measure of the minimum amount of oxygen consumption necessary to maintain the body in a totally rested condition. The normal adult value is about 250 ml of oxygen per minute
Thyroid disease
may be caused by a defect in the thyroid gland itself (a primary defect), or by defects in glands that control thyroid secretion (a secondary defect).
toxic goiter
An enlarged thyroid gland in the hyperthyroid patient
exophthalmus
Hyperthyroidism is often accompanied by edema formation in the back of the orbits of the eyes. The result is a characteristic bulging of the eyeballs referred to as this
Graves’s disease
The most common type of hyperthyroidism, is caused by defect in the immune system and is accompanied by exophthalmus
simple goiter
It is important to realize that hypothyroidism can also produce enlargement of the gland
cretinism
Thyroid deficiency in newborn infants causes retarded growth and mental retardation
