Histology of Endocrine Organs Flashcards
What are the three things that control Hormonal release
Humoral stimuli: release controlled by monitoring levels of ions and nutrients in blood and body fluids
Neuronal Stimuli: release stimulated by nerve signals
Hormonal stimuli: Release caused by a hormone secreted into the bloodstream by another endocrine organ or gland
What are the direct targets of the Hypothalamic hormones
anterior pituitary gland
kidney and uterus (via the releasing of ADH and oxytocin in the posterior pituitary)
Adrenal medulla (via sympathetic innervation)
What are the indirect targets of the hypothalamic hormones
via the tropic (inhibiting and releasing) hormones
done through the anterior pituitary gland
influences: Thyroid gland Adrenal cortex mammary gland Gonads Bone and other organs
What are the 5 microscopic apperacnes of the Pituitary
Pars Distalis Pars Nervosa Pars Tuberalis Pars Intermedia Cyst intermedia
WHat are the 5 major cell types of the anterior pituitary
Somatotropic cells Thyrotropic cells Corticotropic cells Gonadotropic cells Mammotropic cells
What is the function of: Somatotropic cells
Secrete growth hormone
What is the function of: Thyrotropic cells
Secrete thyroid stimulating hormone that regulates thyroid gland secretion
What is the function of: Cortcotropic cells
Secrete adrenocorticoidtropic hormone (ACTH) and Melanocyte stimulating hormone (MSH)
ACTH stimulates the adrenal cortex to secrete stress related hormones and mediate metabolism
MSH stimulates melanocytes to produce melanin
What is the function of: Gonadotropic cells
Secrete follicle-stimulating hormone and lutenizing hormone to act on the gonads
What is the function of: Mammotropic cells
Secrete prolactin that stimulates milk production
what are herring bodies
Found in the Pars Nervosa
expanded axonal nerve terminals storing ADH and Oxytocin
How many capillary beds are in the anterior pituitary
2
the hypothalamus releases hormones into the primary capillary plexus which acts on the anterior pituitary
then the anterior pituitary releases its hormones into the secondary plexus that targets specific glands in the body
What does the antidiuretic hormone and oxytocin do
Antidiuretic Hormone: Targets the kidney and regulates sodium and water retention
Oxytocin: Targets uterine smooth muscle and stimulates lactation and induces birth, may also be involved in sexual arousal and pair and social bonding
What does the colloid contain in the thyroid
COntains thyroglobulin, a storage form of the thyroid hormones T3 and T4
only gland to store hormone outside of the cell
What does Parafollicular C cells do
Lie just outside of the follicles
secrete calcitonin when blood levels of calcium are high
lowers circulating calcium by:
stimulating Calcium secretion by kidneys
decreases the calcium releasing activity of osteoclasts
increases osteogenesis by osteoblasts
Graves Disease
abnormal stimulating TSH receptors causing oversecretion of T3 and T4
elevated metabolism, sweating, rapid heart rate, weight loss, eyeballs protrude
more common in females
Hypothyroidism
insuffcient T3 and T4 production and often an autoimmune disease causing follicle cell death
symptoms: low metabolic rate, weight gain, lethargy, chilliness, edema, mental sluggish ness
treated with synthetic T3/T4
Goiters
Thyroid Enlargement
due to iodine deficiency
follicle cells keep producing thyroglobulin but cannont iodinate it to make TH
Purpose of the Parathyroid gland
small oval glands found on posterior surface of the thyroid gland
releases parathyroid hormone
regulates calcium and phosphate levels
what are the two cells in the Parathyroid gland and what are their function
Chief (principle cells): release Parathyroid hormone
Oxyphil cells: Function unknown
How does Parathyroid hormone physiologically affect calcium
Stimulates osteoclast resorb of bone and release its calcium stores
increases calcium retention by the kidneys
stimulates kidney to convert an inactive form of Vitamin D to calcitriol (active form)
Calcitriol increases calcium absorption by the intestines
What are the 4 layers of the adrenal cortex
Capsule
Zona glomerulosa
Zona fasciculata
Zona reticularis
What is produced in the Zona glomerulosa
Mineral corticoids produce aldosterone
-used in response to low blood pressure or blood volume and it influences potassium and sodium
controlled by renin and angiotensin system
what is produced in the Zona fasciculata
glucocorticoids
under the control of ACTH
influence glcose metabolism and immune system
produce cortisol
deals with stress and mediates glucose metabolism and serves as a negative feedback system for the immune system
the zona reticularis also releases some cortisol
What is the function of: Zona reticularis
influence secondary sex characteristics by releasing androgens
WHat is found in the adrenal medulla and what does it release
inner core of the adrenal gland
contains chromaffin cells that produce epinephrine and norepinephrine
Addisons disease
hyposecretory disorder usually in both glucocorticoids and mineralocorticoids
blood glucose and sodium levels drop there is severe dehydration and low blood pressure along with fatigue and loss of appetite
autoimmune disease die to inherited metabolic disease
Cushings syndrome
due to hypersecretion of glucocorticoids because of either an ACTH secreting pituitary tumor or a tumor in the adrenal cortex
high glucose levels
protein loss in muscles
muscle weakness
and lethargy
swollen face, buffalo hump, weight gain, sweating, depression of immune system
in the pancreas what are the two types of structures
pancreatic acini: containe exocrine cells
pancreatic islets or islets of langerhans: containe endocrine cells
What are the 4 types of Endocrine cells and what do they release for what purpose
ALpha cells: secrete glucagon
Beta cells: secrete insulin
Delta cells: secrete somatostatin which slows the release of insulin and glucagon helping controll the rate of nutrient entry into the bloodstream
Fcells: secrete pancreatic polypeptide that inhibit the release of somatostatin
Blood supply to the pancrease
Insuloacinar portal system for the islet of langerhans
acinar vascular system for the pancreatic acini
