Thyroid & Parathyroid Glands Flashcards
Eosiniphilic staining of colloid. Identify the structures marked.
Red Circle: follicular lumen
green square: high cuboidal or columnar cells
pink circle: colloid resorption droplets
C cells are also known as _____. They secrete _____.
- parafollicular cells; these are pale cells that are present in clusters.
- Calcitonin
(they do not have direct contact with the Lumen of the follicle)
What is the effect of calcitonin (released from parafollicular cells) on osteoclast cells?
It causes them to revert into an inactive state; reducing bone resorption decreases serum calcium levels
Parafollicular cells AKA C cells
Name and describe the histologic findings of this disease.
Graves disease
Follicular cells are high columnar hyperplastic cells that are scalloped along the periphery
(increased colloid uptake into cells)
Name the disease and the two symptoms visible in the photo.
- Hyperthyroidism
- Exophthalmos & Goiter
Where is the thyroid gland located
Anterior portion of the neck, immediately inferior to the larynx
Secretions of the thyroid gland are stored _____ instead of _____.
- Extracellularly
- Intracellularly
Define follicular cells (aka principle cells).
- Low cuboidal cells when inactive; high cuboidal or columnar when active
- Epithelial secretory cells of the thyroid
The main functions of thyroid hormones are to:
- Increase protein synthesis and carbohydrate metabolism
- Body growth and nervous system development
- Find nuclear receptors and stimulate RNA transcription
Mv = Microvilli
red box = follicular cell
What does the red arrow indicate? The blue arrow?
- Red arrow indicates synthesis of thyroid hormone.
- Blue arrow indicates resorption
Location of parathyroid glands
Embedded in thyroid capsule.
(for small lobes: two superior and two inferior)
What is the effect of parathyroid hormone on osteoblasts?
Stimulates osteoclasts factor secretion/activation → bone resorption
(parathyroid glands to the right)
Chief cells also known as _____ are the main cell of the ______.
- principal cells
- parathyroid glands (to the right in micrograph)
oxyphil cells
Describe oxyphil cells
- Larger, but fewer than chief cells
- Pyknotic nucleus
- inactive or necrotic chief cells
Circle: follicle
square: parathyroid gland
arrow: blood vessel w/RBC
yellow: oxyphil
blue: principal
What are the changes associated with parathyroid glands as we age?
Turn into adipose tissue and make up 50 to 60% of the land in the elderly
