Endocrine System Flashcards
What term is used for glands that secrete hormones?
Endocrine
How do endocrine glands differ from those that do not secrete hormones
Ductless
Explain why the pancreas may be described as a dual-function gland
Both an endocrine and exocrine gland
Endocrine - in islets of langerhaun produces hormone insulin
Exocrine - rest of pancreas produces enzymes for digestion
What is the chemical nature of many hormones?
Protein
Give the precise location of adrenaline
Adrenal gland, on Kidney
Give the precise location of thyroxine
Thyroid gland, Neck
Give a function of adrenaline
Cope with stress by increasing blood flow to heart, muscles and brain and opening bronchioles to allow increase air flow
“Fight or flight hormone”
Give a function of thyroxine
Stimulates metabolism
Give a deficiency symptom of thyroxine
Lack of energy, weight gain
Give a symptom of excess secretion of thyroxine
Bulging eyes, loss of weight
Give a corrective measure of thyroxine deficiency
Hormone supplement - tablet form
Give a corrective measure of thyroxine excess
Surgically removing part of thyroid
Explain why hormonal responses are slower than nervous responses
Hormones travel in blood whereas electrical transmissions in nerves
Describe what happens if the body experiences a deficiency of thyroxine
Reduce rate of metabolism
Lead to - lack of energy, tiredness, slow mental and physical activity
causes thyroid gland to swell = goitre
Give two examples of the use of hormone supplements
Insulin - treatment of diabetes
Oestrogen and progesterone - contraceptives
State the gland that produces insulin
Islets of langerhaun
State the extact location of production of insulin
Pancreas [islets of langerhaun]
Role of insulin
Stimulates cells to absorb glucose and store as glycogen
State ways in which hormone action differs from nerve action
Chemical transmission
Slower reaction
Longer lasting effect
What are exocrine glands and give an example
Release products into ducts eg, salivary glands, sweat glands
What are endocrine glands
Ductless glands that produce hormones
What is the endocrine system
A group of specialised tissues [glands] that produce chemicals called hormones, many of which are proteins
What do endocrine glands have that allow hormones to be transported by blood?
A rich supply of capillaries
What is a hormone?
Chemical messenger produced by endocrine gland and carried by the bloodstream to another part of the body where it has a specific effect
Why is the pituitary gland often known as the master gland?
Produces a range of hormones that trigger other glands to release theirs
What is most hormone activity controlled by?
Hypothalamus and pituitary gland
What hormones does the pituitary gland produce and what are their functions?
ADH -stimulate water reabsorption in kidneys
TSH - stimulates thyroid gland to release thyroxine
FSH
What do endocrine glands have that allow hormones to be transported by blood?
A rich supply of capillaries
What is a hormone?
Chemical messenger produced by endocrine gland and carried by the bloodstream to another part of the body where it has a specific effect
Why is the pituitary gland often known as the master gland?
Produces a range of hormones that trigger other glands to release theirs
What is most hormone activity controlled by?
Hypothalamus and pituitary gland
What hormones does the pituitary gland produce and what are their functions?
TSH - stimulates thyroid gland to release thyroxine
FSH - controls functions of reproductive organs
Growth hormone [somatropin]
What is the function of the growth hormone?
Causes body to absorb amino acids and from proteins which allows growth and elongation of the bones of the skeleton
What occurs when there is overproduction/underproduction is growth hormone [somatropin]
Overproduction - gigantism
Underproduction - dwarfism
What does the hypothalamus gland produce and give example
Hormones that control pituitary gland in response to messages from the brain and other hormones
Example -
GHRF - causes production of growth hormone in pituitary
Where is the pileal gland located?
Within the brain
What does the pileal gland produce and what is it’s function?
Melatonin, the hormone produced in the dark
Involved in sleep and activity patterns, biological rhythms [ovulation], sexual maturity
What gland links the nervous and endocrine systems?
Hypothalamus
Where is ADH produced and stored?
Produced - hypothalamus
Stored - pituitary gland
What does parathyroid gland produce?
Parathormone, which increases blood calcium levels
How does insulin reduce blood glucose levels?
Stimulates cells to absorb glucose from the blood and store it as glycogen
How many parathyroids are there?
Four
What hormone does thymus gland release and what is it’s function
[location]
Thymosin - causes lymphocytes to mature and become active
[behind breastbone]
What is the name given to the method of control of thyroxine level?
Negative feedback - correct level of one item has a negative effect on a previous step in the cycle
What occurs when there are normal concentrations of thyroxine?
Inhibits pituitary gland from releasing TSH so no further thyroxine is made
What occurs when there are low concentrations of thyroxine?
Pituitary gland produces TSH [thyroid stimulating hormone] which causes more thyroxine to be made by thyroid gland, until thyroxine concentration is returned to normal again
What’s goitre?
An enlargement of the thyroid gland caused by underproduction of thyroxine
What is goitre caused by?
Lack of iodine in diet leads to underproduction of thyroxine
How does goitre occur?
There is low concentration of thyroxine in blood - causes pituitary gland to produce TSH
TSH normally combines with iodine to produce thyroxine however it there is a shortage of iodine this cannot happen so it is stored in thyroid
Causes thyroid to swell = goitre
How can goitre be treated?
Intake of iodine in diet
