Flashcards in Histology of the endocrine system Deck (22)
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T4
Thyroxine
Thyroid hormone, requires iodine for synthesis
2
T3
Triiodothyronine
Thyroid hormone
- Requires iodine for synthesis
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Iodine deficiency
Iodine is required for the synthesis of T3 and T4.
- Can be found in see salt.
Lack of iodine causes goitre, the enlargement of the thyroid.
- Allows more absorption of iodine.
4
Acidophils
Cells of the anterior pituitary that stain with acidic dyes.
- Appears pink
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Basophils
Cells of the anterior pituitary stained with basic dye.
- Appears blue/purple
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Chromophobes
Cells of the anterior pituitary that has no staining features.
- Appears greyish
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Immunohistochemistry and anterior pituitary
Method of identifying what cell secretes specific hormones.
Antibodies are created to bind to specific hormones.
- Causing them to bind to cells secreting those hormones.
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Cellular structure of endocrine glands
Contains cuboidal epithelial cells supported by myoepithelium
- Myoepithelium contains smooth muscle that contracts to secrete hormones.
Contains a lumen which hormones are secreted into.
- Except the pituitary and parathyroid gland.
9
Pituitary adenomas
- Description
- Manifestion
Benign neoplasm, mainly of the anterior pituitary cells.
Accounts for 10% of intracranial neoplasm.
If non-functional
- Causes pressure effects---> hypopituitarism
Function
- Secretes hormones---> Hyperpituitarism
Space occupying
- Headaches
- Vomiting
- Diplopia + visual defects
- Nausea
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Thyroid gland histology
Composed of follicles
- C cells in-between
Abundant fenestrated endothelial cells in blood vessels.
- Allows the secretion of hormones into the blood.
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C cells
Para-follicular cells of the thyroid.
- Secrete calcitonin into the blood.
Calcitonin decreases calcium levels in the blood.
12
Multi-nodular goitre
- Description
- Effects
- Treatments
Hyperplasia and hypertrophy of the thyroid cells.
- Presents as euthyroid.
Can compress airway.
Treated via removal in thyroidectomy.
- Removal can cause tracheomalacia as it weakens the airway
- Can cause airway to collapse---> cardiac arrest.
- Removal involves special care for CN X.
13
Grave's disease
- Presentation
- Pathology
Hyperthyroidism
- Can present with diffuse enlargement of the thyroid---> Goitre.
Other manifestations
- Infiltrative ophthalmology---> proptosis
- Infiltrative dermopathy---> pre-tibial myxoedema.
Pathology
- Increased vascularity
- Soap bubble colloid due to hyperactivity.
14
Hashimoto's thyroiditis
- Cause
- Biochemical presentation
- Patholgy
Autoimmune condition that destroys thyroid cells and leads to fibrosis
Causes of hypothyroidism when iodine is readily available.
Will show increased TSH levels.
- Decreased T4/T3 levels.
Pathology
- Lymphocytic infiltrate.
- Thyroid atrophy.
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Follicular adenoma
Type of benign thyroid neoplasm.
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Papillary thyroid cancer
- Description
- Metastasis
Carcinoma of the thyroid
- Accounts for most of the carcinomas
- 75-85%
Has a high risk of lymphatic metastasis.
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Follicular thyroid cancer
- Description
- Metastasis
Carcinoma of the thyroid
- Accounts for 10-20% of thyroid carcinomas
High risk of metastasis to
- Bone
- Lung
- Liver
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Medullar thyroid cancer
- Description
- Origin
Carcinoma of the thyroid.
- C cell origin
- Accounts for 5% of thyroid carcinomas
- Associated with MEN syndrome (20%)
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Anaplastic thyroid cancer
Carcinoma of the thyroid
- Mainly found in elderly patients
- <5% of all thyroid carcinomas.
20
MEN 2
- Cancers associated
Multiple endocrine neoplasia type 2
Associated with
- Phaochromocytoma [adrenal medulla]
- Medullary carcinoma of the thyroid
- Pituitary adenoma
21
Parathyroid adenoma
Benign neoplasm of the parathyroid
Affects one gland
Causes hypercalcemia
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