Diseases & Evaluation of the Hypothalamo-hypophyseal axis

Endocrinopathies are classified as primary, secondary, or tertiary. Primary endocrine disease inhibits the action of downstream glands/ target endocrine glands. Secondary endocrine disease is indicative of a problem with the pituitary gland. Tertiary endocrine disease is associated with dysfunction of the hypothalamus and its releasing hormones. Vasopression excess (SIADH) Causes: 1) Ectopic production by carcinoma of lungs & pancreas 2) CNS: Trauma, infections ,tumours 3) Drug induced: Chlopropamide, Nicotine, Morphine Pathophysiology: Antidiuresis Water reabsorption Concentrated Read more…

Pituitary Tumours

This is a normal anterior pituitary gland histology. Note the bluish colour of the basophils, and pinkish colour of the acidophils. This is a histology slide of the posterior pituitary. The brown-stained cells are cells that secrete Growth Hormones – Somatotropes. The cells are stained for immunochemistry evaluation. _____________________________________________________________________ Pituitary Tumours **Definition: Neoplasm located in the sella turcica. Comprises of 10-15% of all intracranial tumours. 27% pituitary glands contain incidental adenomas (very common in people). Read more…

Growth Hormones & Growth Factors

Synthesis & Structure of Growth Hormone Synthesized by somatotropes ( a subclass of anterior pituitary cells). It’s a single polypeptide hormone (191 amino acids), with 2 disulphide linkages. GH, prolactin, chorionic somatomammotropin have similar sequence homology, therefore all have growth and lactating effects. Growth Hormone Receptor All receptors are proteins. When GH binds to a cell surface receptor (receptor no.1), it will pull another cell surface receptor (receptor no. 2) and binds with it, causing Read more…

Hormones of the hypothalamo-hypopheseal axis

Hypothalamo-hypophyseal axis means the hormones that are released from the hypothalamus to the pituitary gland will stimulate the release of pituitary hormones into the blood to the target organs. Review the Pituitary Gland before you continue reading. Not mentioned in the anatomy of the pituitary gland, the hypothalamus has many types of nuclei. However, the ones that we will be touching on are the paraventricular, supraoptic and arcuate nuclues. Each of these nuclei has 2 Read more…

Hormonal Function & It’s Mode of Action

Hormones are secreted by specialized endocrine glands/tissues. Endocrine: ductless, and secreted straight into the blood Exocrine: with ducts It then acts on target organs to produce certain functions, and is important for the balance in the body (homeostasis). Many hormones are released in a pulsatile fashion (in it’s own timing, not all the time). Here are the major endocrine glands with it’s hormones: Hypothalamus TRH, CRH, GHRH, GHIH, GnRH, PIF Ant Pituitary HH, TSH, ACTH, Read more…

Pituitary Gland

The pituitary gland consists of the anterior and posterior lobe, which are controlled by the hypothalamus to secrete hormones. It is also known as the hypophysis (hypo: below, physis: hypothalamus). The hypothalamus is connected to the pituitary gland via the pituitary stalk (infundibulum). This pituitary gland is very small, roughly the size of a pea and lies in the sella turcica/putuitary fossa. This fossa (a depression in the skull) can be approached thru the nasal Read more…

Haematology FLMs

Lymph node   Section of a portion of the outer cortex of a lymph node showing the capsule, subcapsular sinuses, diffuse lymphoid tissue, and lymphatic nodules H & E stain Medium magnification _____________________________________________________________________________________________  Lymph node: sections Figure A Section of a lymph node showing the cortex and the medulla & their primary components H & E stain Low magnification Figure B (1) capsule (2) lymphoid nodule with germinative center (3) subcapsular sinus (4) intermediate sinus Read more…

Respi Lab Session (Sem 3)

Lung: Bronchiectasis Show a resected upper lobe with with widely dilated bronchi. Thickening of the bronchial walls Collapse & fibrosis of the pulmonary parenchyma _____________________________________________________________________________________________ Lung: Acute Pneumonia   Microscopic photograph _____________________________________________________________________________________________ Lung: Pulmonary Embolism Seen in the pulmonary artery to the left lung on cut section is a large pulmonary thromboembolus Such thromboemboli typically originate in the leg veins/pelvic veins of persons who are immobilized _____________________________________________________________________________________________ Squamous Cell Carcinoma of Lung   Microscopic appearance Read more…