overview of endocrinology Flashcards
describe the major endocrine organs and their secretions
- HYPOTHALAMUS - Releasing & inhibiting hormones
PITUITARY GLAND - - Anterior lobe - trophic hormones
- Posterior lobe – oxytocin & vasopressin (ADH)
- THYROID GLAND - Thyroxine, tri-iodothyronine
ADRENAL GLAND - - Cortex: Cortisol, aldosterone
- Medulla: Adrenaline/noradrenaline
- GONADS - Oestrogens, androgens, progesterones
- PANCREAS - Insulin, glucagon
- PARATHYROID GLAND - Parathyroid hormone
what are the signaling mechanisms in the endocrine systems ?
- There are different ways that cells communicate via hormones
- Endocrine such as renin released by the kidney
- Paracrine an example clotting factors
Autocrine: cytokines such IL-1, also can be seen in cancers - Intracrine: steroid hormones-Androgen that act through nuclear receptors.
what are the general functions of hormones ?
Reproduction, growth and development
* Sex Steroids, thyroid hormones, prolactin, growth hormone
Maintenance of internal environment
* Aldosterone, parathyroid hormone, vitamin D
Energy production, utilization and storage
* Insulin, glucagon, thyroid hormones, cortisol, growth hormone
describe the chemical classifications of hormones ?
describe the chemical nature of hormones and their transport
what are the hormones secreted by the anterior and posterior lobes of the pituitary gland ?
Parvocellular neurones
* Neurosecretory cells release hormones to capillaries of median eminence (supplied by superior hypophysial artery); conveyed by portal veins to anterior pituitary where they regulate endocrine secretion
Magnocellular neurones
* Project to posterior pituitary and release to capillaries supplied by inferior hypophysial artery
describe how Glands are controlled by the hypothalmic-pituitary axis
describe Hypothalamic control of anterior pituitary secretions
what is acromegaly ?
- Excess growth hormone
- Most commonly due to pituitary adenoma: increase in GH-secreting somatotrophs
- Less commonly secondary: tumour elsewhere secretes GHRH
what is hypothyroidism ?
- Thyroid hormone imbalance
- Hypothyroidism because of:
- Decrease in thyroid hormone production
and/or - Impaired action of thyroid hormones on target tissues
describe the control of cortisol
what is Androgen insensitivity syndrome?
- The inability to respond to androgens, typically due to androgen receptor syndrome dysfunction
- This unresponsiveness can impair or prevent the development of male genitalia
What two major hormones are released from the posterior pituitary gland?
What is the difference between paracrine and autocrine signalling?
In the classification of hormones, what is the difference between peptide and steroid hormones? Can you name some examples?
