Endocrine System Flashcards
Glands
Are structures that secrete substances - 2 types of
Exocrine gland
Release products (sperm , eggs) into tubes or ducts eg salivary glands
Endocrine gland
Ductless glands that produce hormones and release them into the bloodstream
-have a lot of capillaries around them as their hormones are transported in the blood
Hormone
A chemical messenger produced by and endocrine gland carried in the bloodstream
-most made of protein
Pituitary gland
Location - beneath the brain
Hormone- growth hormone (GH)
Function- bone elongation (growth)
Hypothalamus
Location- base of the brain above the pituitary
Hormone- anti- diuretic hormone (ADH) - stored in pituitary + secreted
-function- makes the walls of the distal tube and collecting duct more permeable so more water can be absorbed
Pineal
Location - brain , near the hypothalamus
Hormone- melatonin
Function - controls body rhythms eg sleeping patterns
Thyroid
Location - in the neck
Hormone - thyroxine
Function - controls rate of metabolism
Thyroxine deficiency
Reduced metabolic rates
-symptoms - tiredness ,weight gain , causes thyroid to swell
-treatment - take thyroxine tablets to prevent myxoedema
Thyroxine excess
Increased metabolism rate (called Graves’ disease )
Symptoms - bulging eyes ,loss of weight
Treatment - some of the thyroid can be removed or killed using radioactive iodine
Control of thyroxine levels - feedback mechanism
-pituitary gland produces thyroid stimulating hormone
-this stimulates thyroid gland to produce thyroxine
-iodine from diet is needed
-when level of thyroxine increases the pituitary gland stops producing thyroid stimulating hormone
-when the level of one hormone affects the production of another hormone this is called negative feedback
Feedback
When the level of a hormone in the bloodstream controls the production of another
Parathyroid
(There are four of these)
Location - in the neck attached to the thyroid gland
Hormone - parathormone
Function - controls the release of calcium from bones
Thymus
Location - top of chest
Hormone - thymosine
Function - matures white blood cells
Adrenal
Location - on top of each lkidney
Hormone - adrenaline
Function - causes emergency responses “fight or flight “
Pancreas
Both an exocrine and endocrine gland
Exocrine
Produces enzymes (amylase)
Endocrine
Islets of langerhans
Location- panvreas (in abdomen below stomach)
Hormone- insulin
Function- causes body cells to absorb glucose from bloodstream
Regulates blood sugar levels
Insulin deficiency
Diabetes
Symptoms - tiredness loss of weight
Control- insulin injections 1-4 times daily
Use of hormone supplements
Insulin for diabetes
Contraception
Fertility treatments
Comparing nervous system and endocrine system
Nervous system
- fast acting
-electrical
-short lived effect
-localised (one area )
Comparing nervous system and endocrine system
Endocrine system
-slow acting
-chemical
-long lasting effect
-effects can be widespread
