Histology of Endocrine Organs Flashcards
2 ways to influence physiologic functions of other organs?
Nervous system OR Endocrine system
Describe the effects of nervous system induced changes to other organs
Fast communication but short lived effects
Describe the effects of endocrine system induced changes to other organs
Slower communication but longer lived effects
Can some neurons secrete hormones?
Yes
Hormonal release controlled by monitoring levels of ions
Humoral stimuli
Hormonal release stimulated by nerve signals
Neuronal stimuli
Hormonal release caused by a hormone secreted into bloodstream by other organ
Hormonal stimuli
What cell type are endocrine glands derived from?
Epithelial
Fenestrated blood vessels?
Contain pores
List Direct targets of hypothalamic hormones
Anterior pituitary
Kidney and Uterus (via release from posterior pituitary)
Adrenal medulla (via sympathetic innervation)
What does the hypothalamus release to target Indirect organs?
Tropic hormones = releasing or release-inhibiting hormones to the anterior pituitary
Another name for the anterior pituitary
Adenohypophysis
Another name for the posterior pituitary
Neurohypophysis
Both lobes of the pituitary gland come from different sources but are made of what tissue type?
Ectoderm
Anterior pituitary comes from?
Oral ectoderm
Posterior pituitary comes from?
Neuroectoderm
What are the 3 parts of the adenohypophysis?
Pars Distalis
Pars Intermedia
Pars Tuberalis
What are the parts of the neurohypophysis?
Pars Nervosa
What is the overall cell type of the anterior pituitary?
Glandular epithelial cells
In the pars distalis, list the acidphils
Somatotrophs
Mammotrophs
What color do the acidphils stain?
Lighter pink
In the pars distalis, list the basophils
Corticotrophs
Gonadotrophs
Thyrotrophs
What color do the basophils stain?
Darker purple
There is another cell in the anterior pituitary that does not really stain a certain color, what is it called and what is it’s function?
Chromophobes - function is unknown
What can be seen in the pars nervosa, that appear bigger than the other cells?
Herring bodies
Function of herring bodies?
Expanded axonal nerve terminal that store ADH/oxytocin
What are pituicytes?
Supporting nerve fibers in the pars nervosa
Describe the hypothalamo-hypophyseal portal system
The hypothalamus releases its hormones into the primary capillary plexus, which sends them to hypophyseal portal veins at the anterior pituitary
- Anterior pituitary then releases its hormones into the secondary capillary plexus
What covers the pineal gland?
Pia mater
What does the pineal gland synthesize?
Melatonin and seratonin
How do you detect the pineal gland on a CT?
Calcium phosphate crystals that arise in childhood
Main role of pineal gland?
Circadian rhythms
What does the thyroid gland consist of?
Follicles that contain follicular cells and colloid in the center
What type of cells are follicular cells?
Simple cuboidal/simple columnar
What does colloid contain?
Thyroglobulin
What is thyroglobulin?
Storage form of T3 and T4
Only gland to store a hormone outside of the cell?
Thyroid
Thyroglobulin has to be _____ to form T3 and T4
Iodinated
Where are parafollicular C cells?
Just outside the follicles of the thyroid gland
Job of parafollicular C cells?
Secrete calcitonin in response to high blood calcium levels
Graves disease
- Antibodies that cause over-secretion of T3 and T4 by binding to the TSH receptor
- Elevated metabolism, high HR and protruding eyeballs
Hypothyroidism
- Insufficient T3 and T4 production due to follicle death
- Decreased metabolism, weight gain, lethargy, chilliness
Goiter
Thyroid gland enlargement due to iodine insufficiency
What types of cells are found in the parathyroid gland?
Chief cells and oxyphils
Function of chief cells in the parathyroid gland?
Secrete PTH
Function of oxyphils in the parathyroid gland?
Unknown
2 Parts to the Adrenal gland?
Adrenal cortex shell and inner core of Adrenal Medulla
3 zones of the Adrenal Cortex?
Zona Granulosa
Zona Fasciculata
Zona Reticularis
Influences sodium and potassium levels and releases Aldosterone
Zona Granulosa
Type of corticoid that Zona Granulosa relases
Mineralcorticoid
Influences glucose metabolism and immune system and releases Cortisol
Zona Fasciculata
Type of corticoid that Zona Fasciculata releases
Glucocorticoid
What does the Zona Reticularis release?
Androgens to influence secondary sex characteristics
What type of cell does the Adrenal Medulla consist of?
Chromaffin cells
What does the Adrenal medulla secrete?
Epinephrine and Norepinephrine
Hyposecretary disorder involving mineralcorticoids and glucocorticoids
Addison’s disease
Symptoms of Addison’s disease
Severe dehydration, loss of appetite and fatigue
Hypersecretion of glucocorticoids due to possible ACTH tumor in the anterior pituitary or adrenal cortex tumor
Cushing’s syndrome
Symptoms of Cushing’s syndrome
High glucose, swollen face, buffalo hump, weight gain and muscle weakness
Exocrine cells of the pancreas
Pancreatic acini
Endocrine cells of the pancreas
Pancreatic islets/islets of Langerhans
Pancreas alpha cells release
Glucagon
Pancreas beta cells release
Insulin
Pancreas delta cells release
Somatostatin
Pancreas F cells release
Pancreatic polypeptide