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- *located over kidneys (2 gland in 1)
- *Outer gland is adrenal cortex and inner gland is adrenal medulla.
are steroid hormones
- Outer layer secretes : mineralocorticoids
- 2nd layer: glucocorticoidsThird layer: glucocorticoids & gonadocroticoids
*Adrenal medulla (similar to posteriror pituitary to ensure the release of hormones) are non steroid hormones called catecholamines and are stimulated by the sympathetic nervous system.
Eg: enpinephrine and norpinephrine.
- *Function: regulate water and electrolyte levels in body
- *target cells are the kidney tubules
- * Aldesterone is a mineralocorticoids.
- *Sex hormones
- *produced in small amounts through out lifespan
- *cortisone and cortisol are the main hormones in this group.
- *Secreted in response to levles of ACTH.
- *Function of glucocorticoids is to maintain normal metabolism as well as increase BGL.
- *Responsible for metabolising lipids, proteins and converting them into glucose known as gyperglycemic.
- *When levels of glucocortiocids is prolonged, it causes wgt loss as the body uses protein
- *during stress; they ensure skeletal muscles receive an adequate supply of glucose during fight/flight response.
- *have anti inflammatory properties which reduce oedema and pain.
- *role in reducing bp via vasocostriction of vessels.
Epinephrine and Norepinephrine
- *effective in fight/flight response.
- *aids the body to cope with stressfull situations by increasing Hear rate, BP, BGL and respirations.
- *^ glucose and oxygen levels in blood
- *^ blood flow to vital organs (brain)
- *short term response to stress
- *located in abdominal cavity
- *glands: pancreatic islets or islets of langerhans.
- *Pancreatic islet cells mainly manufacture & secrete own hormones.
- Islet cells: alpha, beta, delta, pancreatic polypeptide cells. *Islet cells manufacture & secrete own individual hormones.
- *Alpha and beta islets are effective in sensing energy needs during fasting and feeding
- *BGL rises after a meal,2/3 of glucose is stored in liver when not needed.
- *Between meal BGL drops, liver release glucose to maintain homeostasis.
- *insulin and glucagon are digestive hormones.
Insulin and Glucagon
- *only hormone that reduces BGL, its action is hypoglycaemic.
- *acts on almost all body cells and ensure transportation of glucose across the cell membrane can be used for eneregy.
- *without insulin glucose is unable to enter cells
- *insulin is produced and released by beta cells in response to rising BGL*Insulin moves glucose out of the blood into tissues/cells for energy.
- *As glucose move into tissue BGL fall
- *In response to reduced BGL's insulin release ends
- *excess glucose is sent to liver and stored as glycogen until needed.
- *insulin increases protein synthesis
- *functions is to inhibit secretion of GH
- *action is to increases blood glucose levels (hyperglycaemic).
- *Produced by the alpha cells of the islets, occurs in response to low blood glucose.
- *target organ is the liver where it breaks down glycogen into glucose and then releases it into the bloood stream to maintain homeostasis.
What is diabetes?
Diabetes is defined by the body’s inability to control blood glucose. Diabetes is a chronic condition, which can cause kidney failure, eye disease, foot ulceration and a higher risk of heart disease if not well managed.
- *disorder that is characterised by a collection of problems/symptoms
- *involves insulin and glucagon
- * inadequate amount of insulin is produced or a diminished number of insulin receptors at target tissues imparing the ability of glucose to enter the cell.
- *result is hyperglycaemic due to inability/insufficient insulin production
Diabetes type 1
- *beta cells produce little or no insulin.
- *Without enough insulin, glucose builds up in the bloodstream instead of going into the cells.
- *The body is unable to use this glucose for energy.
- *Treatment involves person requiring insulin injections to control symptoms
*Diagnosed early stage in life.
Diabetes type 2
- *Your fat, liver, and muscle cells do not respond correctly to insulin resulting in insulin resistance.
- *blood glucose doesn't get into these cells
- *When glucose can't enter cells, high levels of glucose build up in the blood resulting in hyperglycemia.
- *Type 2 diabetes usually occurs slowly over time.
- *Diabetics tend to be overweight
- *Increased fat makes it harder for your body to use insulin the correct way.
- *diagnosed later on in life
- *treatment involved lifestyle changes/modification such as regular exercise and healthy diet.
- *doesn't require insulin injection
Other circulating hormones
- Gastrin> digestion
- Secretin> digestion
- Cholecytokini (CCK)> digestion
- atrial natriuretic peptide (ANP)> cardiovascular
- Erthropoietin> renal
- *Similar but not hormones
- *acts as chemical messagers
- *do not move to target sites, they manufactured by almost all cells in body and work locally at manufactured site.
- *action of prostaglandin is to activate the inflammatory response such as pain & fever
- *treatment is COX inhabitors/anti-inflammatories- works to reduce production of prostaglandin- reduce swelling.
- *aid in blood clotting processes
- *present in childbirth when labour begins/contractions causing pain
- *produced in GI tract and involved in mucous production
- *involved in blood flow in kidneys
- *Slower method of control
- *chemical communicator using hormones as chemical messengers.
- *hormones have widespread effect and primary responsible for reproduction, growth, development, mobilising body defences, maintain homeostasis
- *Endocrinology is study of hormones and endocrine glands.
*goals is to preserve homeostasis
- *Fast acting controller
- *nerves quickly response to stimuli and uses electrical/chemical transmitters (neurotransmitter) via action potentials to communicate between receptors at target site & brain
Receptors > identifies change to normal functioning occuring, and responds to change and monitors it. Change is named stimuli. It response by sending information along the affernt pathway to the control centre (brain).
Control centre > information is received, analysed, and identifies action that needs to be taken. Messenge is then send along efferent pathway to the effector.
Effector > site of reponse to stimuli. It either reduce the stimuli (-ve feedback) or increases it (+ve feedback).
- *ductless gland that release hormones into bloodstream
- *produce, control and modify release of specific hormones
- *Modify/change activities of their target tissue
- *most hormones comes in pair and have opposite effects.
- *Chemical messengers released by endocrine cells into blood.
- *Regulate metabolic activity of the cells.
- *Amino acid based or Steroids (steroid/non steroid)
- *Circulate throughout body
- *action is restricted to target cells/organs.
- *Attach to target cells/organ using receptor( protein) to ensure action.
- *excess hormones are excreted by kidney or broke down by liver.
- *secreted in small amount
- *have widespread effects
Cross cell membrane and enter cell nucleus, exerting their action inside the cell.
Non Seroid hormones
Bind with receptor on the cell membrane, resulting in activation of enzymes which act as second messenger commuication resulting in intracellular reaction
Stimuli activiated by other hormones
Stimulated by changing blood levels of ions/nutrients
involves hormones stimulated by nerves.
E.g: fight/flight whre sympathetic nervous sytem activates the release of adrenaline.
Organs of endocrine system
- Pituitary gland
- Thyroid gland
- Parathyroid glands
- Thymus gland
- Ovary & Testis
- Pineal gland
- Adrenal glands
- *major organ of endocrine system
- *The integrative centre for autonomic nervous sytem and endocrine system
- *Controls the pituitary gland
- *linked to posterior pituitary by neural pathways
- *Secretes hormones that stimulate or suppress the release of hormones in anterior pituitary gland
- *located base of the brain
- *control functions of other endocrine glands
- *anterior and posterior glands
- *release of pituitary hormones is controlled by hypothalamus
Anterior pituitary gland
- *all anterior hormones are amino acid (protein) or non-steroid
- *act by binding to receptors on cell membrane and mostly stimulated by -ve feedback.
- *6 hormones
- *2 act on non-endocrine organs> prolactin & growth hormone
- *4 are tropic hormones, stimulates their target organs to secrete hormones
- >adrenocorticotrophic hormone (ACTH)
- >thyroid stimulating hormone (TSH)
- >luteinizing hormone (LH)
- >follicle stimulating hormone (FSH)
- *metabolic hormone (protein)
- *determining factor of person body size
- *responsible for growth of skeletal muscles and long bones.
- *Stimulates gwoth and development of its target cells
- *production is stopped once certain age is reached.
- *GH increases uptake of glucose by the cells
- *protein hormone
- *stimulates and maintains breast milk in women
Regulates activity of cortex portion of adrenal gland
Influences growth & activity of thyroid gland
follicle and sperm development
- *Trigger ovulation
- *Produce progesterone, oestrogen
- *stimulates testosterone production
Posterior pituitary gland
- *doesn't produce hormones
- *acts as a storage department
- *Hormones produced in hypothalamus
- *stores two hormones until needed
- *ADH> acts on urin by reducing/inhibiting production of ADH therefore output is reduced.*ADH maintain the osmotic pressure of the blood at constant level
- *Oxytocin> responsible for childbirth
- *located infront of neck below larynx
- *body's major metabolic hormone
- *Produce thyroid T3 & T4, these are protein constructed with added iodine.
- *control over the rate of glucose conversion to energy
- *growth & development of tissue
- *Thyroid gland produce Calcitonin
- *can't produce thyroxin without iodine
- *deficiency of iodine result in goitre which is the enlargement of thyroid gland.
Maintains blood Ca levels by reducing blood Ca level.
- *located on posterior of thyroid gland, 2 on each side, 4 in total.
- *function is to secrete parathyroid hormones in order to regulate blood levels of Ca.
- *Parathyroid gland break down bone to release parathyroid hormones which is essential to maintain/release Ca into blood from bone.
- *PTH increasesexcretion of Ca by the kidneys
- * located in brain
- *produce melatonin which promotes sleep
- *secreted continuously peak at night
- *regulates body's biological clock
- *melatonin also affects skin pigmentation
- *located upper thorax, posterior to sternum
- *large in infant, decrease in size by adulthood
- *Produce thymosin necessary for blood development.
Gonads (ovaries and testes)
Produce steroid hormones
- *Placenta and embryo produce HCG during early stage of pregnancy
- *This hormones tests determine pregnancy
- *role of HCG is to continue production of estrogen and progesterone to prevent the shedding of uterus lining.
- *In third trimester, HPL (human placental lactogen) is produced to prepare the breast for lactation
- *produce relaxin responsible for relaxation of the pelvis & pubic regions, making them more flexible in preparation of birth.
What is the function of prolactin
Stimulates and maintains breast milk in women
Is prolactin -ve or +ve feedback?
Positive because it acts to increased rather than maintaining a steady state.
What are catecholamines?
Catecholamines are hormones produced by the adrenal glands. They are released into the blood during times of physical or emotional stress. The major catecholamines are dopamine, norepinephrine, and epinephrine
Name a common mineralocorticoid?
Cessation of mentruation
Hormones that affects menopause?
Progesterone and oestrogen
Common health issue assoicated with menopause?
breast cancer, endomentrial cancer and heart attacks
Where is thyroid located?
front of neck, below larynx
What hormones is produced by thyroid?
T3 and T4
What is hypothyroidism?
deficient activity of thyroid gland .
What signs and sympoms associated with hypothyroidism?
- *hard stool- constipation
- *painful muscles and joints
- *feel cold.
Why does thyroid cause weight gain?
Thyroid is a metabolising hormone.