Overview of Endocrine Histology

Question 1

• What happens to the cells of the parathyroid gland?

Answer 1

Chief cells (parathyroid hormone) become oxyphil cells (non-secretory)

Question 2

• What carrier proteins transport T3 and T4 in the blood stream?

Answer 2

Thyroxine binding globulin – T4, albumin – T3

Question 3

• What are the three types of exocrine glands?

Answer 3

Merocrine, apocrine & holocrine

Question 4

• Describe how the three types of exocrine glands secrete their contents

Answer 4

Merocrine – membrane bound vesicles fuse with apical cell membrane; extrusion of secretion by exocytosis
Apocrine – secretion released within fragments of apical cell cytoplasm/membrane envelope
Holocrine – intracellular secretion released during the process of apoptosis

Question 5

• What are the three main types of hormones?

Answer 5

Peptides e.g. insulin (water soluble), steroids e.g. aldosterone (lipid soluble), tyrosine derivatives e.g. catecholamines (epinephrine) & iodothyronines (thyroxine)

Question 6

• What diseases may lead to Hyperfunction and Hypofunction?

Answer 6

Hyperfunction – hyperplasia primary, hyperplasia secondary, neoplasia
Hypofunction – feedback effect, intrinsic disease

Question 7

• Where is a craniopharyngeal duct cyst located?

Answer 7

Rathke’s pouch

Question 8

• What is the most common form of hyperadrenocorticism in dogs?

Answer 8

Pituitary dependent

Question 9

• What is a phaeochromocytoma?

Answer 9

A tumour of the medulla of the adrenal glands

Question 10

• What would pituitary adenoma cause?

Answer 10

Neurogenic diabetes insipidus

Question 11

• What is goitre?

Answer 11

Thyroid gland enlargement

Question 12

• What does secondary hyperparathyroidism result from?

Answer 12

Hypocalcaemia