L3 Nuts and Bolts CC Flashcards
Clinical Manifestations of endocrine diseases?
- Hormone overproduction
- Hormone underproduction
- Tumour/mass lesion which can be:
1. Non-functional → pressure effect
2. Associated over production of hormones
Histology of the anterior pituitary gland
Acidophils- secrete growth hormone, prolactin
Chromophobe- ACTH, TSH, FSH, LH
Basophils
What cells secrete ACTH?
Secreted from both chromophobes and basophils
Productive adenomas cause hyperpituitarism. What is this?
producing hormones
Pituitary adenomas
‘Pressure effect causing hypopituitarism’
What does this mean?
not producing hormones
Presentation of Pituitary Adenoma
bitemporal hemianopsia due to compression of optic chiasma
Role of Thyroxine (T4) and Triiodothyronine (T3)
stimulates metabolic rate
What is required for the synthesis of T3 and T4?
Iodine
Features of the Thyroid Gland
-Very vascular
-The endothelial cells lining the capillaries are fenestrated (i.e. have gaps between them)
→a common feature in endocrine glands
- Fenestration allows passage of hormones into the circulation
- Para-follicular cells or clear cells (C cells) are found between the follicles
- C cells secrete calcitonin which promotes reduction of calcium concentration in the blood
Grave’s disease
- Auto-antibodies stimulate TSH receptors
- Diffuse enlargement of the thyroid gland – goitre due to hyperplasia of thyroid cells
Hashimoto Thyroiditis
An autoimmune disease – immune system destroys its own thyroid tissue
-Progressive depletion of thyroid cells by inflammation replaced by fibrosis
↓T3/T4↑TSH
Hashimoto Thyroiditis
- gross appearance
- histological appearance
- The gland is irregular with a solid cut surface
- On histology there is a prominent lymphocytic infiltrate
Para-follicular Cells
-location
a.k.a.
C cells
between follicles
C cells secrete calcitonin which promotes reduction of calcium concentration in the blood
What are C cells?
origin of medullary carcinoma of the thyroid
Phaechromocytoma
Tumour/neoplasm of the adrenal medulla
originate from chromaffin cells
secrete excess catcholamines
10% malignant/10% familial/10% extra-adrenal/10% bilateral
What does ADH do?
facilitates the absorption of water in kidneys which concentrates the urine
What does oxytocin do?
Oxytocin promotes contractions of the smooth muscle in the uterus during childbirth and myoepithelial cells in the breast during breast feeding
Features of the Thyroid Gland
- 35-45g
- 2 lobes and isthmus
- Thyroid tissue is composed of follicles with variable-sized lumina
- Follicles contain colloid with eosinophilic or pink appearance
- Follicles are lined with cuboidal cells
Implications for thyroidectomy if patient has multi-nodular goite
The trachea may be compressed by the multi-nodular goitre
This can cause tracheomalacia (ie softening of the trachea) causing its collapse and obstruction of the airway
Triad of signs/symptoms in Graves Disease
- autoimmune thyrotoxicosis
- thyroid eye disease
- pre-tibial myxoedema
Histopathology of thyroid gland in Graves Disease
The colloid has a soap-bubble appearance due to hyperactivity
Histopathology of thyroid gland in Hashimotos Thyroiditis
prominent lymphocytic infiltrate/inflammation
Parathyroid Glands
Secrete parathyroid hormone (PTH)
Controls the levels of calcium in the blood
Decrease in blood calcium stimulates PTH secretion
What embryological layer is the adrenal cortex derived from?
mesoderm
In embryology, where is the adrenal medulla derived from?
neural crest
Diseases due to Adrenocortical hyperactivity
- Cushings- excess cortisol
- Conns Syndrome- excess aldosterone
- Adrenogenital syndrome- excess androgens
Diseases due to Adrenocortical insufficiency
Addisons
C cells
origin of medullary carcinoma of thyroid
Origin of adrenal cortex
mesoderm
Origin of adrenal medulla
neural crest
