endocrine system Flashcards
what is the endocrine system used for
to coordinate body responses
what is a gland
a structure that secretes substances
what are the two types of glands
endocrine and exocrine
what are exocrine glands
these glands release their product into ducts or tubes
what are endocrine glands
are ductless glands and produce hormones that are released into the bloodstream
why do endocrine glands have a rich supply of capillaries
they secrete hormones into the blood through capillaries
what biomolecule makes up hormones
proteins
what is a hormone
it is a chemical messenger produced by an endocrine gland and carried by the bloodstream to another part of the body and where it has a specific purpose
what is a steroid
a form of lipid
what other biomolecle can hormones be made of
lipids in the form of steroids
name 4 main endocrine glands
pituitary, hypothalmus, pineal, thyroid
write a short note on the pituitary gland
often called master gland… produces a rane of hormones that regulate other endocrine glands. produces FSH, LH and GH.
what does GH (growth hormone) do
causes body cells to absorb amino acids and form proteins which causes growth and elongation of bones
write short note on the hypothalamus
this gland link the nervous and endcrine systems. it secretes a hormone that controls the pituitary gland in reponse to messanges from the brain. it produces the hormone anti-diuretic hormone (ADH) which is stores in the pituitary and released when needed.
what does ADH do
it causes water to be reabsorbed in the kidneys- osmoregulation
write a short note on the pineal
is a tiny gland located in the brain. it produces many hormones such as melatonin which is produced mainly when we sleep
what is the function of melatonin
the funtion is not fully known but it is involved in ovulation, sleep and activity patterns
write a short note on the thyroid gland
a H shaped gland located on the trachea. produces thyroxine which is made from a combination of the amino acid tyrosine and iodine. thyroxine controls the rate of all the body’s reactions (metabolism)
what are the symptoms associated with thyoxine deficiency
symptoms- low metabolic rates and slowed mental + physical development = disease called cretinism in children. in adults reduced metabolic rate = tiredness, lack of energy, weight gains collectively known as myxoedema. thyroid gland can also swell- called goitre
what are corrective measures that can be taken to treat thyroxine deficiency
new borns get the heel test, thyroxine can be administered to prevent cretinism. in adults thyroxine tablets or iodine can be taken to prevent myxoedema
what are the symptoms of thyroxine excess
increased metabolic rate, bulgine eyes, hunger, loss of weight, anxiety. known as grave’s disease
what corrective measures can be taken to treat thyroxine excess
surgically removing part of the thyroid or by killing part of the gland usin radioactive iodine
what happens when there is a normal concentration of thyroxine
inhibits the pituitary from releasing TSH (thyroid stimulating hormone) meaning no further thyroxine is made
what happens when there is a low concentration of thyroxine
pituitary produces TSH (thyroid stimulating hormone) causing more thyroxine to be made until concentration returns to normal
explain goitre
enlargement of the thyroid gland which indicates underproduction of thyroxine, usually caused by lack of iodine in the diet. TSH combines with iodine in the thyroid to produce thyroxine.if this cannot happen due to iodine shortage then TSH is stored in the thyroid causing it to swell. can be treated by increasing iodine intake
what are parathyroids
4 glands embedded in the thhyroid gland. they make parathormone which stimulates the release of calcium from bones into blood plasma
what is the thymus gland
has two lobes located behind the breastbone in the upper chest. produces thymosin which causes lymphocytes to mature and become active
what are adrenals
two glands located on top of the kidneys that produce hormones that help the body cope with stress- adrenaline, which is produced when we are in an emergency and affects the body to help us to respond more efficiently to stress
write a short note on the pancreas
it is a dual functioning gland meaning it has an exocrine and an endocrine function. its exocrine funtion is to produce enzymes which flow to the duodenum through ducts. its endocrine function is to produce insulin by these cells called islets of langerhans (are a tissue) and are transported by the blood
write a short note on the funtion of insulin
vital hormone that reduces blood glucose which is absorbed into muscle and fat cells. the absorbed glucose is either used in respiration or converted to glycogen to be stored in liver and muscles
what occurs when there is low insulin in the body
diabetes may from as a result of low insulin production it an inability of cells to take up insulin. in young people it is generally caused by the faiure of the islets of Langerhans to work properly
what are the symptoms of diabetes
high glucose concentration in blood + urine, production of large amounts of urine, severe thirst, loss of weight, tiredness
how may diabetes be treated
regular insulin injections
why can’t insulin be taken into the digestive system
it is a protein and would be broken down by digestive enzymes
write a short note on anabolic steroids
drugs that build up protein or muscle and are similar to the mle sex hormone testosterone. they speed up muscle recovery after an injury and help strengthen bonds. they have been widely abused in sports and are now illegal. risk of abusing these incllude liver and adrenal gland damage + infertility.
