Human biology - Endocrine system
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Human biology - Endocrine system - Leaderboard
Human biology - Endocrine system - Details
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Hyperthyroidism | Over active thyroid |
Negative feedback | Feedback is opposite to feedback |
Endocrine system main purpose | Maintain home stasis by influencing cellular activity through chemical messengers-hormones, and using feedback- responding to stimulus by secreting more/less of a hormone to alter original stimulus |
Hormone types and descriptions | Protein (made of protiens) eg. insulin. -water soluble steroid (made of lipids :. lipid soluble) eg. cortisol amine(amino acids ) eg. adrenalin and epinephrin. -water soluble (and paracrines (local hormones via which two adjacent organs communicate)) can effect all cells, target cells or target organs. only able to influence cells with specific receptors |
How do hormones change cell function | Via changing the type, activity or quantities of protiens/enzymes produced by: activating genes in nucleus to protiens are produced changing enzyme shape/ structure to turn function on/off changing rate of production of enzyme or protein by increasing/decreasing transcription/translation |
Enzyme amplification | One hormone can activate thousands of enzymes. hormones trigger a cascade of reactions small amount of hormone/ stimulus can produce large effect saturation can occur so additional hormones will no longer take effect |
Paracrine action | Hormone acts locally diffusing from its source to neighbouring target cell |
Autocrine action | Hormone effects the same cell that produced it |
Water soluble hormones enter the cell and take effect by: | Amines and protiens are hydrophilic, cannot pass through hydrophobic tails :. they attach to receptor protiens in target cells membrane causes secondary messenger(g protein) to be released into cell and activate enzyme via nucleus (signal transduction) cytoplasmic response |
Lipid soluble hormones enter cell and take effect by: | Steroids defuse through cell membrane and combine with receptor within cell hormone receptor complex alters gene expression by activating genes controlling the formation of particular protiens |
How are hormones controlled | Secretions are regulated by negative feedback - response is opposite of feedback -sometimes involves the nerves system stimulating the hypothalamus to secrete inhibiting or restricting factors hormones must turn off after producing desired effect- done by breaking down hormone molecules in target cell, kidney or liver then excreted in bile, urine |
Exocrine gland | Secrete hormones into a duct , caries the secretion to surface/body cavities. eg. sweat, saliva |
Endocrine glands | Secrete hormones into extracellular fluid , passes into capillaries to circulate body |
The bodies gland names | Hypothalamus pituitary gland adrenal glands ovaries testies pancreas parathyroid glands thyroid glands pineal gland |
Hypothalamus | Base of brain regulates bodies basic functions, eg wate balance, heart rate many functions varied out through the pituitary gland produces many hormones-travel via blood and nerve fibres to pituitary where they are secreted |
Pituitary gland | Lies under hypothalamus , connected via infundibulum -vital secretes hormones produced by hypothalamus master gland- due to its nature to |
Element connecting hypothalamus and pituitary | Infundibulum |
Segments of the pituitary gland | Anterior and posterior lobes anterior = front, connected to hypo via blood vessels controlled by hypothalamus' restricting and inhibiting hormones posterior =back lobe does not secrete anything (not real gland) joint by nerve fibres stores oxytocin's and antidiuretic hormones produced in hypothalamus |
Hormones released by anterior pituitary | Follicle stimulating hormone (fsh) -overies, testes luteinising hormones (LH) -overies testes growth hormone (GH) -all cells thyroid stimulating hormone (TSH) -thyroid gland Adrenocorticotropic hormone -adrenal cortex Prolactin -mammary glands (initiate and maintain milk secretion) FLAG ToP FLaP -reproductive hormones |
Tropic hormones | Hormones that regulate other hormones non tropic directly stimulate target cells |
The posterior pituitary secretes? | Travelled via nerves from hypo antiduretic -causes kidney to remove water from urine + return to blood, at high conc also constricts small arteries oxytocin -contractions during labor and milk let down |
Peneal gland secretes? targets? achieves? | Hormone :melatonin target: the hypothalamus regulates sleep patterns, released at night |
Pancrease exo end endo functions , hormone | Produces enzymes release into small intestines hormones produced in cluster of cells called islets of langerhans hormone: glucagon target: liver raises blood sugary stimulating breakdown of glycogen to glucose hormone: insulin target: liver, muscle cells and fat stores lowers blood sugar by promoting glucose to glycogen conversions (liver + skeletal muscles)+ glucose to fat in fat stores. |
Adrenal glands - adrenal cortex is affected by? produces? hormones (2) , target and function. | Affected by ACTH from anterior pituitary produces corticosteroids hormones include cortisol: targets liver, promotes normal liver function and adaptation to stress + tissue repair aldosterone: targets kidney , reduces sodium and increases urine potassium |
ADRENAL GLANDS – ADRENAL MEDULLA 2 hormones and target | Adrenalin (epinephrine ) -fight or flight response Noradrenalin-similar effect targets most cells and tissues |
Gonads -ovaries | Hormone: oestrogen target: many tissues |
Thyroid hormone | Thyroxine -controls body metabolism by regulating catabolic and anabolic reactions - release and maintain body temp secreted in response to TSH targets all cells |
Parathyroids | 4 on rear surface of thyroid gland -size of peas hormone -parathyroid hormone (PTH) targets bones and kidneys controls calcium and phosphate levels in blood. |
Thymus | Hormone- thymosins (hormone group) Target : T lymphocytes. -influences their maturation |
Gonads- Ovaries (2 hormones) | Hormone: oestrogen effects: many tissues regulates menstruation Progesterone targets uterus and mammary glands regulates period and milk production |
Gonads- Testes | Hormones: Androgens (e.g testosterone) target: many tissues stimulates sperm production growth of skeletal muscles development of male sex characteristics |
Feedback system steps | Stimulus receptor message modulator message effector -mucle glands response -effector organ brings a reaction feedback srmmmerf smurf |
Positive feedback | Reinforces and intensifies the stimulus |
Negative feedback | Feedback is opposite to feedback |
Hyperthyroidism | Over active thyroid, produces to much thyroxin -auto immune disorder |
Hypothyroidism | Under active thyroid, to little thyroxin -auto immune disorder |
Carb foods | Starch, sugary, milk and dairy, fruit |
In response to injecting carbs: | Carbs-> glucose in stomach in response pancreas releases insulin blood carries glucose+insulin to all required cells blood glucose level decreases as glucose is stored can be risen again through the liver releasing extra stored glucose |
Diabetes type 1 | Body makes no insulin at all due to an auto immune response all insulin producing cells are destroyed 10% of cases, occurs under 40s. glucose in blood stream cannot enter cells so BS consistently increases body attempts to remove excess through kidneys = frequent eurination and dehydration. glucose also leads to area for bacteria to bread=thrush and long lasting wounds glucose also builds in eyes=blindness tiredness, breaks down fat stores for energy= fat loss |
Type 2 diabetes | 90% cases, over 40s either body isn't producing enough insulin or insulin isn't working properly. can be due to build up of fat blocking insulin receptors regular processes occur, but insulin and glucose don't enter cells, bs levels ^ in response body makes more insulin ^ cells send signals to liver to produce more insulin from storage leading to a further increase. pancreas can't cope and tires out similar symptoms to type 1 slow or non noticeable symptoms can be treated by diet and lifestyle, medication |
Glucocorticoids | Steriod hormones produced from adrenal glands cortex |