Principles of endocrine control Flashcards
What is autocrine signaling?
a single cell that secretes a chemical message to another cell and acts on the same type of cell
e.g. cytokines
What is paracrine signaling?
chemical secreted by one type of cell and acts on another type of cell
e.g. prostaglandins
What is endocrine signaling?
hormone secreted from one type of cell and travels in the blood and acts on a different tissue/organ
What are the main differences between peptides and steroids?
peptides - produced by normal protein synthesis, travel in the blood in solution, bind to cells surface receptors and fast acting
steroids - produced by modification of cholesterol molecules by enzymes, travel in blood bound to plasma proteins, bind to intracellular receptors and slow acting
What are G-protein coupled receptors?
cyclic AMP, calcium/phosphoinositides and cyclic GMP
What is the role of the endocrine system?
metabolism, water and electrolyte balance stress response growth and development reproduction red cell production coordination of circulation and control
What is the role of the posterior pituitary gland?
- extension of hyothalamus
- regulates water balance, uterine contractions and ejection of milk
- releases ADH and oxytocin
What does the anterior pituitary do?
- vascular link between hypothalamus and the body
- controls other endocrine glands
What is the role of the hypothalamus?
- interface between outside events and inside the body
- release TRH, GnRH, PRH and CRH
What happens in hypothyroidism?
- iodine deficenciency
- reduced production of T3 and T4
What happens in hyperthyroidism?
- over production of T3 and T4
- Grave’s disease is an autoimmune disease which produces antibodies that mimic the effects of TSH
What is the role of the thyroid?
- control of metabolic rate
- needed for normal growth and development
What is the role of the parathyroids?
- calcium metabolism
- mobilises bone store
- reduces urine loss
- increases gut reabsorption
- releases parathyroid hormone
What do the kidneys do?
release renin if circulating volume/BP is low
release erythropoietin when hypoxic
What does the adrenal cortex do?
metabolic response to stress
releases cortisol, aldosterone and DHEA
