Chapter 14

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What are endocrine glands?
They secrete hormones into the bloodstream
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Name the main endocrine glands and their function
Pituitary gland- growth hormone, anti diuretics, gonadotrophins, Adrenal gland-adrenaline, Testis- testosterone, Pineal gland-melatonin, Thyroid gland-thyroxine rate of metabolism, Thymus-thymosin production and maturation of white blood cells,
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Name the main endocrine glands and their function
Pancreas produces insulin, Ovaries produce oestrogen for ovulation and progesterone for secondary sexual characteristics
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What are the 2 types of hormones?
Steroid and non steroid hormones
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What is the difference between them?
Steroid hormones are lipid soluble, bind to form hormone receptor complex, acts as a transcription factor. Non steroid hormones are hydrophilic cannot pass through membrane bind to receptor on cell surface and triggers a cascade reaction
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What is the structure of the adrenal glands and their function?
Adrenal cortex is the outer region, produces essential hormones eg mineralocorticoids, glucocorticoids and androgens. The inner part is called the adrenal medulla and produces non essential hormones eg adrenaline and noradrenaline
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Hormones released by the adrenal cortex and their function
Glucocorticoids- eg cortisol regulates metabolism, Mineralocorticoids- eg aldosterone control blood pressure by regulating water and salt conc. Androgens- small amount of female and male sex hormones
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Hormones released by the adrenal medulla and their function
Adrenaline- fight or flight blood pressure. Noradrenaline- works with adrenaline to produce effects eg widening pupils.
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The pancreas as an exocrine gland
Made up of exocrine glandular tissue produces digestive enzymes and pancreatic fluid secreted into ducts leading to pancreatic duct and to the top of the intestine called the duodenum
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The pancreas as an endocrine gland
Inside exocrine tissue there are endocrine cells called the islets of langerhans- A cells secrete insulin, B cells secrete glucagon
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Ways of increasing blood glucose concetration
Eating carbohydrates, Glycogenolysis (breaking up of gylcogen into glucose), Gluconeogenesis (production of glucose from non carbohydrate sources)
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Ways of decreasing blood glucose concentration
Respiration, Glycogenesis (production of glycogen)
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What is the role of insulin and how does it work?
Insulin binds to glycoprotein receptors and causes a change to the tertiary structure of the glucose transport gates, channels open glucose enters
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What is the role of glucagon and how does it work?
Raises blood glucose concentration by increasing the rate of gluconeogenesis and glycogenolysis
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How is insulin secreted?
At normal blood glucose conc. K channels are open and potassium diffuses out. Potential difference is at -70mv. As blood glucose conc rises, glucose enters by glucose transporters and gets metabolised in mitochondria to produce ATP.
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How is insulin secreted?
ATP binds to ATP sensitive potassium channels and closes them so K cant diffuse out. Depolarisation occurs, pd falls to -30mv, depolarisation causes voltage gated C channels to open, C enters and secretory vesicles release insulin
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What are the 2 types of diabetes and their differences?
Type 1- unable to produce insulin autoimmune attack B cells, Type 2- unable to respond to insulin- glycoprotein receptors dont work
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What are the treatments?
Type 1- regularly checking blood glucose c. and insulin injections,cannot be taken orally as it would be digested in stomach, Type 2- exercise, diet. loose weight, drugs
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Why is medically produced insulin (genetically modified bacteria) better than insulin from pigs
Cheaper, less likely to cause allergic reactions, more ethical, larger quantities
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Explain fight or flight
Threat is detected by the autonomic nervous system. Hypothalamus activates the sympathetic n system, sends impulses to smooth muscles and glands, also activates adrenal medulla which releases adrenaline and noradrenaline
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Explain fight or flight
Hypothalamus activates adrenal cortical region by releasing CRF, pituitary gland secretes hormone ACTH, ACTH arrives at the adrenal cortex and releases 30 hormones into bloodstream
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What are physical responses to fight or flight?
Increased heart rate, widened pupils,
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How does adrenaline work?
Adrenaline is hydrophilic so it cant enter the membrane, it binds to receptors on the surface and activate enzyme inside (adenylyl cyclase) which turns ATP into AMP
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How is heart rate controlled?
Heart rate is involuntary and controlled by autonomic nervous s. Medulla oblongata has 2 centres, to increase it sends impulse thru sympathetic via accelarator nerve to SAN, to dercrease impulse thru parasympathetic via vagus nerve to SAN
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What are the 2 types of receptors involved in controlling heart rate?
Baroreceptors detect pressure, chemoreceptors detect chemicals
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How do baroreceptors work?
Detect fall or rise in blood pressure, send impulse to medulla oblongata
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How do chemoreceptors work?
If level of co2 rises in blood the ph falls, chemoreceptors detect change in ph, signal mo to increase heart rate to get rid of co2 and ph returns to normal
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Hormonal control of heart rate
Hormones can also affect heart rate eg adrenaline or noradrenaline affect pacemaker region
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Card 2

Front

Name the main endocrine glands and their function

Back

Pituitary gland- growth hormone, anti diuretics, gonadotrophins, Adrenal gland-adrenaline, Testis- testosterone, Pineal gland-melatonin, Thyroid gland-thyroxine rate of metabolism, Thymus-thymosin production and maturation of white blood cells,

Card 3

Front

Name the main endocrine glands and their function

Back

Preview of the front of card 3

Card 4

Front

What are the 2 types of hormones?

Back

Preview of the front of card 4

Card 5

Front

What is the difference between them?

Back

Preview of the front of card 5
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