Lab 12: Histophysiology of the Endocrine Glands
How many kinds of hormones does the anterior pituitary secrete?
7 major ones
In the parathyroid gland, what two cells are there? Which is more common?
Chief cells (most numerous), oxyphilic cells (larger and less numerous).
What hormones do acidophilic cells produce?
GH, prolactin
What is another name for the posterior pituitary?
Neurohypophysis
What do we call hormones that influence another endocrine gland?
Tropins or tropic hormones
Another name for the anterior pituitary is the (blank).
adenohypophysis.
Delta cells of pancreas secrete the hormone (blank).
somatostatin.
Thyroid hormones (inhibit/stimulate) oxygen consumption, cellular metabolism, and (increase/decrease) basal metabolic rate.
stimulate, increase
What hormones does the thyroid produce?
thyroid hormones thyroxine (T4) and triiodothyronine (T3)
Name the major endocrine glands and point to them on your body.
Hypothalamus, pituitary gland, pineal gland, thyroid gland, parathyroid glands, pancreas, adrenal glands, gonads.
What does the hormone oxytocin do?
In women during delivery: Target's smooth muscle in the mother's uterus to contract. In women after delivery: Targets breast's to release milk when the infant sucks. It is unsure if oxytocin has a function in non-pregnant women or males, but it is thought to possibly induce feelings of parental caretaking or sexual pleasure during and after sex.
Explain what ADH does, including its target tissues and an explanation of ADH's other name.
It decreases water lost by sweating and also causes kidneys to return more water to the blood. This decreases urine volume a ton. ADH also acts to increase blood pressure, and is therefore also called vasopressin.
Describe the anatomy of the pituitary.
It has two anatomically and functionally separate portions: Anterior pituitary (about 75% of the gland's weight) and posterior pituitary (has axon terminals of >10,000 neurons whose cell bodies are in the supraoptic and paraventricular nuclei of the hypothalamus.
What is the median eminence of the hypothalamus?
The area of the hypothalamus that meets the infundibulum.
How do the hypothalamus and the pituitary work together?
The hypothalamus secretes hormones that regulate the pituitary and the pituitary then secretes several hormones that stimulate other endocrine glands.
Describe the outer appearance of the thyroid gland, where it is located, and the outermost anatomical parts.
The thyroid is about the size of a medium-sized butterfly. It sits near the top of the trachea and has two "lobes" that point upwards on either side of the trachea. Connecting the two lobes (across the anterior side of the trachea) is the "isthmus" sometimes there is a pyramidal lobe arising from the isthmus in front of the larynx.
The hypothalamus is located below (blank) near the base of the brain. There is a stalk attached to the hypothalamus called the (blank). To this stalk, the (blank) attaches and rests in a bony, protective cavity called the (blank).
The two lobes of the thalamus, Infundibulum, pituitary gland, sella turcica
The space inside the follicles of the thyroid contains a fluid called the (blank).
colloid.
The anterior pituitary secretes several tropins. The two (blanks), FSH and LH regulate the functions of the (blank). IN addition, TSH and ACTH are also called (blank) and (blank) because they are tropic hormones that act on the thyroid and adrenal cortex. Finally, the hypothalamic hormones that act on the pituitary gland (or the hypophysis) are also called (blank) hormones because they are tropic to the pituitary gland.
gonadotropins, gonads, thyrotropin, corticotropin, hypophysiotropic
Explain, very briefly, how a hormone gives a signal.
1) Sent to the body by the blood. 2) Hormone binds receptors on specific effector organs called "target organs" or "target tissues". 3) Hormone-receptor complex causes change in cellular enzymatic activity or gene expression
What are the five principle types of anterior pituitary cells and what hormones do they secrete?
1) Somatotrophs: Human growth hormone (hGH or somatotropin). 2) Thyrotrophs: Thyroid-stimulating hormone (TSH). 3) Gonadotrophs: Follicle-stimulating hormone (FSH) AND luteinizing hormone (LH). 4) Lactotrophs: Prolactin (PRL). 5) Corticotrophs: adrenocorticotropic hormone (ACTH) AND sometimes Melanocyte-stimulating hormone (MSH)
How many kinds of hormones does the posterior pituitary secrete? Name them
2 (oxytocin and ADH/antidiuretic hormone/vasopressin)
In an islet of Langerhans, the beta cells constitute about (blank) percent of the cells in an islet, they also produce, store, and secrete the hormone (blank).
75%, insulin.
Cells in the hypothalamus synthesize at least (blank) different hormones, and the pituitary gland secretes at least (blank).
9, 16
What hormones do basophilic cells produce?
ACTH, MSH, TSH, FSH, and LH
About how big is the pituitary gland?
About the size of a pea
There are three classes of anterior pituitary secreting cells that we can identify based on the color they stain. Name them.
Basophilic (cytoplasm stains blue), acidophilic (cytoplasm stains red or pink), chromophobic (cytoplasm doesn't stain).
By regulating the autonomic nervous system, the hypothalamus can regulate what five important things?
Body temperature, hunger, thirst, sex drive, defencive reactions (ex: fear,rage)
T or F: Parafolicular cells of the thyroid gland secrete T3 which works to promote deposition of calcium into the bone matrix.
False! Calcitonin, not T3
T or F: The neurohypophysis is the gland that synthesizes, stores, and releases hormones.
False! It does not synthesize hormones, it does store and release two hormones though.
The placement of the hypothalamus maximizes its ability to do what?
Integrate nervous and endocrine systems
What is the primary regulator of blood calcium level.
PTH.
Some organs have major nonendocrine functions but still contain endocrine cells. Name these tissues.
Skin, thymus, heart, stomach, small intestine, kidneys, liver, placenta (during pregnancy). See p 174 in lab manual for location
Where are the adrenal glands, how big are they, and what are their two constituent parts? How are these constituent parts different developmentally?
The adrenal glands are on top of the kidneys (1:1 kidney:gland ratio). They are about 4-6 cm long, 1-2 cm wide, and 4-6 mm thick. (so thin and not super big). The two constituent portions are the outer adrenal cortex and the inner adrenal medulla. These both have separate embryological origins.
What cells in what organ secrete PTH?
The chief cells of the parathyroid.
What hormones do chromophobic cells produce?
The function of these cells is unclear, though we know they are present in the anterior pituitary.
Name the major hormones produced by the anterior pituitary cells. Tell what each does
There are seven. 1) Human growth hormone (hGH or somatotropin): General body growth, regulates parts of metabolism. 2) Thyroid-stimulating hormones (TSH): Controls secretions and other functions of the thyroid gland. 3+4) Follicle-stimulating hormone (FSH) and Luteinizing hormone (LH): Work together to (in women) stimulate estrogen and progesterone secretion by the overies, maturation of ova, and (in men) secretion of testosterone, production of sperm in testes. 5) Prolactin (PRL): initiates milk production in mammary glands. 6) adrenocorticotropic hormone (ACTH): Stimulates adrenal cortex to secrete glucocoriticoids. 7) Melanocyte-stimulating hormone (MSH): Darkens skin when in large concentration, but has no normal function in humans.
Explain how the hypothalamic hormones (releasing and inhibiting) get to the anterior pituitary.
They go by the blood flowing from the median eminence of the hypothalamus (where the hypothalamus connects to the infundibulum) to both the infundibulum and anterior pituitary via the "superior hypophyseal arteries".
T or F: Thyroid hormones are necessary for normal growth and development.
True
T or F: Pituicytes are another kind of neuroglia.
True!
T or F: The nervous system influences many endocrine functions.
True!
T or F: The pancreas is both an endocrine and exocrine gland.
True!
T or F: PTH stands for parathormone.
True! PTH = parathyroid hormone = parathormone
In the pancreas there are exocrine clusters of cells called (blank). These produce (blanks) that flow along a duct system into the first part of the small intestine, the duodenum.
acini, digestive enzymes
The inner portion of the adrenal gland, called the (blank) is derived from (blank) tissue. It secretes (#) (type of hormone) hormones named (names of the hormones produced).
adrenal medulla, nervous, 2, catecholamine (non-steroid), epinephrine, norepinephrine.
The main moineralocorticoid is called (blank) and is vital in the regulation of (blank). The main glucocorticoid is called (blank) and (function). For example, cortisol increases blood glucose level, providing energy rich molecules for ATP production. The main sex steroids are (blank) and are normally produced in (low/high) quantity.
aldosterone, sodium resorption (by extension water resorption) in the kidneys, cortisol, it functions to affect several metabolic processes and helps one cope with physical and emotional stress, androgens, low.
The hypothalamus controls the (blank) nervous system.
autonomic
OT and ADH are synthesized in the (blank). Explain how these then enter the blood stream.
cell bodies of neurosecretory cells. Hormones synthesized, carried (in secretory vesicles) down the axon towards the axon terminals located in the posterior pituitary. Now that they are there, AP's can later travel down the axon, cause the secretory vesicles filled with either OT or ADH to fuse to the membrane, diffuse out of the posterior pituitary, and finally enter into nearby capillaries.
What do we call the study of the structure and function of ductless glands?
endocrinology
During embryological development, surface (blank) cells absorb substances from the surrounding medium. The cells can modify these substances and secrete them as different products. AS the embryo continues to grow, these (blank) cells invaginate and form (blank).
epithelial, secretory, glands
During embryological development, if a gland retains an opening to a surface epithelium, its products are secreted through this duct. Such a gland is called a/an (blank) gland. If a gland loses its opening to the surface, its products are secreted and absorbed directly into the surrounding (blanks). Such a gland is called a/an (blank) gland.
exocrine, blood capillaries, endocrine
The hypothalamus and pituitary play important roles in virtually all aspects of what four basic processes?
growth, development, metabolism, and homeostasis
What do we call a secretory product of a ductless gland?
hormone
From the primary plexus, blood drains into the (blank) that pass down the outside of the (blank). In the (anterior/posterior) pituitary, the veins form a (blank) of capillaries. This direct route permits hypothalamic hormones to act quickly on the (anterior/posterior) pituitary cells before the hormones are diluted or destroyed in the systematic circulation. Hormones secreted by (anterior/posterior) pituitary cells pass into the (blank) and then into the anterior (blank) for distribution to target tissues throughout the body.
hypophyseal portal veins, infundibulum, anterior, secondary plexus, anterior, anterior, secondary plexus, hypophseal veins
Another name for the pituitary?
hypophysis
What is the main link between the nervous and endocrine systems?
hypothalamus
The superior hypophyseal arteries are branches of the (blank) and (blank) arteries. The superior hypophyseal arteries channel blood into the (blank), a capillary network at the base of the hypothalamus. Hypothalamic hormones (releasing and inhibiting) are secreted by the hypothalamic (blank) near the (blank) and then diffuse into the capillaries of the (blank).
internal carotid, posterior communicating, primary plexus, neurons, median eminence of the hypothalamus, primary plexus.
Name four things that provide input to the hypothalamus.
limbic system, cerebral cortex, thalamus, and reticular activating system (RAS). (also internal organs, visual system)
The cells of the anterior pituitary gland are mainly (blank) while the posterior pituitary gland is mainly (blank). Also, the anterior has much (more/less) mass than the posterior pituitary.
mainly epithelial cells, mainly nerve axons.
The adrenal cortex is derived from (blank) and is made of (blank) tissue. It secretes (#) types of (neurotransmitter/fatty acid/steroid/cholesterol/gasseous) hormones named (multiple blanks).
mesoderm, epithelial, 3, steroid, mineralo-corticoids, glucocorticoids, sex steroids.
What are the two main ways by which the body responds to changes in its external and internal environment?
nervous system, endocrine system
The F cells of the pancreas secrete the hormone (blank).
pancreatic peptide
The axon terminals in the posterior pituitary are associated with specialized neuroglia called (blank).
pituicytes
The posterior pituitary consists of cells called (blank). There are also (blank) from secretory (neurons/glands) of the hypothalamus, and these (neurons/glands) are called (blank). The cell bodies of these cells are in the (blank) and (blank) nuclei of the hypothalamus. Their axons form the (blank) tract. This tract extends from the hypothalamus to the (anterior/posterior) pituitary and terminates near (blank) in the (anterior/posterior) pituitary. Different neurosecretory cells produce two hormones: (blank) and (blank).
pituicytes, axon terminals, neurons, neurons, neurosecretory cells, paraventricular, supraoptic, hypothalamohypophyseal tract, posterior, blood capillaries, posterior, oxytocin/OT, ADH/antidiuretic hormone/vasopressin
The hypothalamus releases (blank) hormones to stimulate the (anterior/posterior) pituitary to release hormones. The hypothalamus also releases (blank) hormones to suppress the release of hormones from the (anterior/posterior) pituitary.
releasing, anterior, inhibiting, anterior
T or F: While the nervous system produces fast effects, those of the endocrine system are generally slower.
true
