Deleted Flashcards
What are the major endocrine glands?
- pituitary
- thyroid
- parathyroid
- adrenal
- endocrine pancreas
What are the common features of endocrine tissues?
- Ductless
- vascular
- Organization: blocks, plates, cord
- epithelial
- polyhedral
- numerous organelles
What are the characteristics of endocrine cells?
- specialized for secreting
- secrete into interstitial fluid and then into blood stream
- Do not require ducts
- requires proximity to blood vessels: fine vascular network
- Fenestrated endothelium to allow for easy diffusion
What are the different patterns of endocrine cells?
- epithelial
- mesenchymal
- neural
- individual cell
What do fenestrated capillaries contain?
They contain windows that offer easy passage to larger molecules
Which endocrine glands have an epithelial growth pattern?
- thyroid
- parathyroid
- anterior pituitary
- adrenal cortex
- pancreatic islets
What endocrine glands have a mesenchymal growth pattern?
- leydig cells
- ovarian stromal cells
- granulosa cells
- luteal cells
CONNECTIVE TISSUE
What is Rathke’s pouch?
Ectoderm of oropharynx
Where the adenohypophysis originates from
What are the characteristics of the anterior pituitary gland?
Develops from ORAL ECTODERM from buccal mucosa (Rathke’s pouch)
The master gland, epithelial properties
Secretes FLATPEG
Regulated by hypothalamic neurons
What are the characteristics of the posterior pituitary?
- Develops from NEURAL ectoderm
- secretory endings of axons from nerve cells whose cell bodies are located in hypothalamus
Secretes oxytocin and ADH
What are the three anatomic portions of the anterior pituitary?
- pars distalis (antrerior)
- pars intermedia
- pars tuberalis (posterior and superior)
What are the two anatomic parts of the posterior pituitary?
- Pars Nervosa (contains neurosecretory endings of axons, unmyelinated)
- Infundibulum (the stalk)
What are the 3 cell types in the Pars Distalis?
- Acidophils
- Basophils
Both of which are chromophils as well as - Chromophobes
Pink cells = acidophils
Purple cells = basophils
Chormophobes = NOT taking up any color
What cells in the pars distalis are the ACIDophils?
1. somatotropes Produce GH 2. Lactotropes Produce prolactin The PEG hormones
What cells in the pars distalis are the BASOphils?
1. Corticotropes Produce ACTH 2. Gonadotropes Produce LH/FSH 3. Thyrotropes Produce TSH The FLAT hormones
What are the functional parts of the neurohypophysis?
- median eminence
- infundibular stalk
- pars nervosa
What is in the pars nervosa?
- Unmyelinatiedpothalamus axons with cell bodies in hypothalamus
- pituicytes (supportive cells)
How do nerve endings in pars nervosa differ from normal endings?
- non-synaptic
2. secrete hormones rather than neurotransmitters
What are Herring Bodies?
Storage site for hormones secreted by the pars nervosa axons
What do Herring Bodies store? EXAM Q
ADH
Oxytocin
What are the key characteristics of the thyroid gland?
Characteristic follicles each with a large lumen surrounded by a simple cuboidal epithelium
Follicular cells store thyroglobulin in the follicles for subsequent use in production and secretion of T3 and T4
Parafollicular cells (C cells) produce calcitonin
What do parafollicular cells of the thyroid produce? EXAM Q
Calcitonin, course director question
What does follicular cells do?
Store thyroglobulin
What is thyroxine?
T3
Histological characteristics of the
parafollicular cell?
Next to follicular cells
PALE STAINING
Cytoplasm should be clear
What is the significance of fat cells in parathyroid?
Fat cells increase with age with 60-70% of the gland eventually becoming fat
What are the three types of parenchymal cells in parathyroid?
- principal (chief) cells
- Oxyphil cells (function unknown, egg cell)
- adipocytes (fat cells)
What are the histological features of the parathyroid chief cells?
Centrally located nucleus Cytoplasm contains -glycogen -lipid droplets -dense vesicles
What are the histological features of the oxyphil cells?
Look like a sunny side up egg
What is the function of chief (principal) cells in parathyroid?
Makes PTH
What does the Zona Fasiculata of the adrenal gland produce? EXAM QUESTION
Glucocorticoids
Cortisol
What are the three zones of the adrenal cortex?
- Zona Glomerulosa
-mineralocorticoids - Zona Fasciculata
-glucocorticoids, cortisol - Zona Reticularis
-gonadocorticoids
Mnemonc = GFR for zones
Salt, Stress, Sex for hormones produced
What are the characteristics of the adrenal medulla?
- composed of CHROMAFFIN cells arranged in groups or cords clustered around capillaries and venules
- modified neurons innervated by presynaptic sympathetic nerve fibers
- considered “post synaptic neurons” which lack axons
What are the two types of chromaffin cells?
- Large dense core vesicles
- secrete norepinephrine - Small less dense core vesicles
- secrete epinephrine
What is key about large dense core vesicles?
One type of chromaffin cells of adrenal medulla
Secretes NORepinephrine
What is key about small dense core vesicles?
One type of chromaffin cells of adrenal medulla
Secretes Epinephrine
What is the most common lesion seen in adrenal medulla?
Pheochromocytoma
Originates in chromaffin cells
What does cortisol do in
Adrenal medulla?
Cortisol probably inhibits
Growth of axonal processes
Of chromaffin cells
And induces conversion of norepi to epi
What is the nesting pattern?
Endocrine cells grow in a ball of cells
Vascularity is around the cells so blood vessels that surround endocrine cells make it a “nesting” pattern
