Physiology of Stress

Stress: Dynamic state within the body resulting from the interaction of the body with the stressor. Stressors: Stimuli that impose strain on body homeostasis. Types of stressors: Physiological pregnancy adolescence mating ageing Physical orthostasis (upright standing position) exertion trauma infection Metabolic hypoxia hypoglycemia acidosis External/ Environmental loud noise air polution bright light threats Mental/Psychological anger…

Adrenal Steroid Hormones

Basic Anatomy of the Adrenal Glands   The adrenal glands consists of 2 regions: 1) Adrenal Cortex Outer region Encapsulates the medullary region Secretes: Steroid hormones (corticosteroids, mainly C19, C21) 2) Adrenal Medulla Inner region Composed of: modified sympathetic ganglion cells (nervous) Secrets: Epinenephine & norepinephrine (catecholamines) Adrenal Cortex It contains cells with large amounts…

PBL: Nephrogenic Diabetes Insipidus

Keywords: 28 y/o female marketing executive thirsty often urinate frequently ongoing: 3 months drinks 8-16 glasses of water & several cans of juice in 2-3 hours consumes caffeine-free drinks & non-alcoholic drinks only tried limiting fluid intake – no improvement otherwise healthy, no past medical history Sodium high Osmolality high Water deprivation test – urine…

Adverse Drug Effects & Drug Interactions

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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…

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…

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…

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…

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…

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…