Endocrine histology Flashcards
Exocrine gland means
it secretes onto a surface, directly or through a duct
Endocrine gland means
it secretes internally and is ductless
What are the two types of hormones?
Circulating
Local
What are the two subgroups of local hormones and what do they mean?
Paracrine- acts on other cells
Autocrine- acts on itself
The hypothalamus is the ______ control center.
Autonomic
The hypothalamus is connected to the _____ via the infindibulum
pituitary gland
The pituitary gland is also known as the what?
the hypophysis
What are the two parts of the pituitary gland?
Anterior and posterior pituitary
What are the three parts of the anterior pituitary?
Pars distalis
Pars intermedia
Pars tuberalis
What are the two parts of the posterior pituitary gland?
Pars nervosa
Infindibulum
The anterior lobe of the hypophysis develops from where?
The roof of the mouth
The release of hormones from the anterior pituitary is stimulated by _____ ______ and suppressed by ______ _____. from the ______.
releasing hormones
inhibiting hormones
Hypothalamus
The regulating hormones from the hypothalamus reach the anterior lobe of the pituitary via what?
Hypothalamo-hypophyseal portal system
What are the two groups of secretaory cells in pars distalis? What is the main difference?
Chromophils
Chromophobes
This is based on staining affinity- color loving or color hating
What are the two different types of chromophils?
Basophils- affinity for basic dyes
Acidophils- affinity for acidic dyes
What are the three types of basophils?
Gonadotropic cells
Corticotropic cells
Thyrotropic cells
What are the two types of acidophils?
Somatotropic cells
Mammotropic cells
What percent of pars distalis are chromophobes?
50%
T/F the posterior pituitary doesn’t synthesize hormones?
Truthhhe.
What does the posterior pituitary do?
It stores and releases hormones
What are the two hormones of the posterior pituitary?
Oxytocin Antidiuretic hormone (ADH)
Where are the hormones of the posterior pituitary synthesized?
The (neurosecretory neurons of the) hypothalamus
What are Herring bodies?
They are dilated portions of the axon that store hormones
What is the pineal gland?
It regulates sleep and wake cycles (circadian rhythm)
What is the major hormone produced by the pineal gland?
Melatonin
What are the two types of cells in the pineal glands?
Pinealocytes (95%)
Interstitial (glial) cells (5%)
The pineal gland looks like what?
Brain sand
What are the two parts of the adrenal glands?
Medulla
Cortex
The cortex of the adrenal glands is made up of what?
Steroid secreting cells
The medulla of the adrenal glands contain what type of cells?
The catecholamine secreting cells
The adrenal medulla produces three ______ hormones.
Catecholamine
Which zone of the adrenal cortex secretes glucocoriticoids (mainly cortisol)?
The Zona fasciculata
From outside to inside, what are the layers/zones of the adrenal gland?
Zona glomerulosa
Zona fasciculata
Zona reticularis
Adrenal medulla
T/F the adrenal medulla is a modified sympathetic ganglion of the autonomic nervous system?
True
Does the adrenal medulla develop from the same embryonic tissue as the other sympathetic ganglia of the body?
Yep
What are the cells called in the adrenal medulla that cluster around blood vessels and release hormones?
Chromaffin cells
What is the endocrine portion of the pancreas called?
The islets of Langerhans
T/F the pancreas has both exocrine and endocrine functions.
True
What are the three types of cells of the islets of Langerhans?
Beta/B cells
Alpha/A cells
Delta/D cells
What do B cells do?
B cells synthesize and secrete insulin
What do alpha cells do?
A cells synthesize and secrete glucagon
What do D cells do?
D cells synthesize and secrete somatostatin
What type of cell is most commonly found in the pancreas?
Beta cells
What does insulin do?
It signals the cells for the uptake of sugar into the cell and to make glycogen
What does glucagon do?
It signals for the breakdown of glycogen and glucose gets released into the blood?
What does somatostatin do?
It inhibits insulin and glucagon secretion- think statin-stationary- no secretion
What are the two thyroid hormones?
T4- thyroxin
T3- Tri-iodothyronine
T3 and T4 are important for what?
Growth, basal metabolic rate
Parafollicular cells are responsible for the production of and are found where?
Calcitonin (CT)
Thyroid gland
What does calcitonin do?
It decreases the level of calcium in the blood by inhibiting osteoclast activity and encouraging bone deposition
How is calcitonin regulated?
Negative feedback- high levels of blood calcium stimulate the secretion of calcitonin while low levels of Ca inhibit the secretion of CT
What are the two parathyroid cell types?
Chief cells- produce parathyroid hormone
Oxyphil cells- no idea what it does
Which cells produce PTH?
The chief cells of the parathyroid gland
What does PTH do?
It increases blood calcium by stimulating osteoclast activity and allowing the kidneys to leave more calcium in the blood
How is PTH regulated?
Negative feedback