hormonal communication Flashcards
differentiate between endocrine gland and exocrine glands.
endocrine - release chemical messages directly into the blood stream to bring around a change at the target cell.
exocrine - secrete hormones and enzymes directly into organs or surface of the body.
describe the pituitary gland.
the ‘master’ gland. located below the hypothalamus. it can release a range of hormones to activate other glands.
there are 8 different endocrine glands you need to know. name them and their function as well as the hormones they secrete .
pituitary gland - GROWTH hormone (growing bones and muscles), ANTI-DIURECTIC reabsorption of water into the kidneys and GONADOTROPHIN development of the ovaries and testes.
pineal gland - MELATONIN daily cycles and reproduction development.
thyroid gland - THYROXINE rate of glucose use in respiration, promotes growth.
Thymus - THYMOSIN production and maturing of WBC
Pancreas - INSULIN which converts excess glucose into glycogen (in liver) and glucagon into glucose (in the liver).
Adrenal gland - ADRENALINE - increases hrt rate, breathing rate and blood sugar levels.
Ovaries - OESTROGEN ovulation PROGESTERONE preps uterus lining for receiving an embryo
Testis - TESTOSTERONE sperm production
what are the two forms of hormones. describe each one and how they enter the cell.
Steroid - lipid soluble, water insoluble, neutral, non polar, hydrophobic. they can pass straight through the plasma membrane by simple diffusion. they require a receptor carrier protein to carry them through the hydrophilic cytoplasm. they pass through the nuclear pores as a hormone receptor complex. they bind with DNA activating transcription - TRANSCRIPTION FACTORS.
non steroid hormones - mostly proteins, glycoproteins, glycolipids. hyrdophilic (charged parts or are polar). Cannot pass through the cell surface membrane so they do not cross the phospholipid bilayer of the target cell. they bind to the receptors on the plasma membrane causing a cascade of reactions inside the cell and proteins are transcribed
name the 2 parts of the adrenal gland.
adrenal cortex - outer region, hormones vital to life ie cortisol and aldosterone
adrenal medulla - inner region, non essential hormones, adrenaline reacts to stress.
what are the three main types of hormones released by the adrenal cortex?
Glucocorticoids. ie cortisol and corticosterone. regulate metabolism, blood pressure and cardiovascular functioning in response to stress. release is controlled by the hypothalamus.
mineralocorticoids ie aldosterone. control blood pressure maintaining water potential, mediated by the kidneys.
Androgens. ie small amounts of male and female sex. released after puberty and during menopause.
the hormones of the adrenal medulla are …
Adrenaline
nor adrenaline works with adrenaline in response to stress, producing effects such as increased heart rate, widening pupils and air passage ways, narrowing of blood vessels.
where is the adrenal gland in the body?
top of the kidney’s
where is the pancreas in the body?
upper abdomen behind the stomach
what is the pancreas’ role as a exocrine gland
produce digestive enzymes (amylases break down starch, proteases ie trypsin, lipase break down fatty acids and glycerol) and alkaline fluid called pancreatic juice release them via a duct which leads to pancreatic duct into the duodenum (top part of the small intestine)
what is the role of the pancreas as an endocrine gland
produce hormones insulin and glucagon and release them into the blood to regulate blood glucose concentration.
what is the islets of langerhans
tissue responsible for producing insulin and glucagon and secretion into the bloodstream. they contain two different cell types ie alpha cells - produce and secrete glucagon (bigger cells and more numerous) and beta cells - produce and secrete insulin.
why is it important to control blood glucose level
if it gets too low then cellular respiration will not take place. if it get too high then it can effect the water potential of the cell meaning water moves into the blood having huge ramifications.
what is the desired constant level of glucose in the blood
4-8mmoles/cm3
what causes glucose concentration to change
eating, stress, illness and exercise
