5.3 Hormonal Coordination in Humans Flashcards

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1
Q

give the name of the body’s coordination system which involves hormones

A

the endocrine system

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2
Q

what is a hormone?

A

a hormone is a chemical messenger secreted by a gland. it travels in the blood to a target organ, where it causes a response.

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3
Q

what type of organ secretes hormones?

A

glands

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4
Q

which gland controls many other glands in the body?

A

the pituitary gland

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5
Q

why is the pituitary gland considered a ‘master gland’?

A

it secretes a wide range of hormones, some of which may stimulate other endocrine glands.

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6
Q

what is the role of the pituitary gland in the endocrine system?

A
  • secretes human growth hormone - controls human growth.
  • stimulates the thyroid gland.
  • stimulates ovulation and the production of oestrogen in the ovaries.
  • stimulates the production of sperm and testosterone in the testes.
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7
Q

what is the role of the thyroid gland in the endocrine system?

A

secretes the hormone thyroxine - controls metabolism, heart rate and body temperature.

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8
Q

what is the role of the pancreas in the endocrine system?

A

secretes the hormone insulin - controls blood glucose levels.

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9
Q

what is the role of the adrenal gland in the endocrine system?

A

secretes adrenaline - controls the body’s ‘fight or flight’ response.

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10
Q

what is the role of the overies in the endocrine system?

A

secrete oestrogen, which coordinates the menstrual cycle and the development of female secondary sexual characteristics.

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11
Q

what is the role of the testes in the endocrine system?

A

secrete testosterone, which coordinates the production of sperm and the development of male secondary sexual characteristics.

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12
Q

which organ monitors and controls blood glucose concentration?

A

the pancreas

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13
Q

how does the pancreas respond when blood glucose levels are too high?

A

the pancreas secretes the hormone insulin. insulin binds to receptors on the liver and muscles, causing excess glucose to be converted into glycogen and stored.

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14
Q

how does the pancreas respond when blood glucose levels are too low?

A

the pancreas secretes the hormone glucagon. glucagon binds to liver cells, causing glycogen to be converted into glucose and released into the blood.

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15
Q

how is blood glucose concentration controlled using a negative feedback loop?

A
  • when the blood glucose concentration rises or falls below the optimum, a hormone is secreted by the pancreas.
  • the action of either hormone (insulin or glucagon) helps bring back the concentration to the correct level.
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16
Q

what is type 1 diabetes?

A

type 1 diabetes is an autoimmune disorder in which the pancreas does not produce sufficient insulin to control the blood glucose concentration. as a result, blood glucose levels are often very high, leading to excessive urination, tiredness and weight loss.

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17
Q

how can type 1 diabetes be treated?

A
  • insulin injections before meals - allows glucose to be converted into glycogen.
  • limiting carbohydrate intake.
  • attemps using pancreas and pancreatic cell transplants; investigations into genetic engineering of pancreatic cells.
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18
Q

what is type 2 diabetes?

A

type 2 diabetes is a disorder in which the body’s cells stop responding to insulin, leading to an uncontrolled blood glucose concentration. its onset is linked with increasing age and obesity.

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19
Q

how can type 2 diabetes be treated?

A
  • following a carefully-controlled diet
  • doing regular exercise
  • losing weight
  • use of drugs which increase insulin production and effectiveness
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20
Q

what is osmosis?

A

osmosis is the movement of water from a dilute solution to a concentrated solution through a partially permeable membrane.

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21
Q

in what ways is water lose from the body?

A
  • during exhalation via the lungs
  • sweating
  • urie (some reabsorded in the kidney)
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22
Q

in what ways are ions lost from the body?

A
  • sweating
  • urine (some reabsorded in the kidney)
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23
Q

how are excess amino acids excreted from the body?

A
  • excess amino acids are deaminated in the liver to form ammonia.
  • ammonia is toxic, therefore it is converted into urea.
  • urea is excreted from the body via sweat and urine.
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24
Q

how do the kidneys maintain the balance of water and other substances in the body?

A
  • filter blood in order to remove waste products e.g. urea.
  • selectively reabsorb useful molecules e.g. glucose, water, ions.
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25
Q

what is the full name for the hormone ADH?

A

anti-diuretic hormone

26
Q

where is ADH secreted in the body?

A

the pituitary gland of the brain

27
Q

how does ADH affect the reabsorption of water in the kidneys?

A
  • when the blood is too concentrated, the pituitary gland secretes more ADH.
  • ADH travels in the bloodstream to the kidney and increases the permeability of kidney tubules to water.
  • more water is reabsorbed in the kidneys, resulting in a smaller volume of more concentrated urine.
28
Q

what is kidney failure dangerous?

A

when the kidneys are damaged, they may be unable to filter the blood properly. this may lead to:
- a build-up of tocis molecules (e.g. urea) in the body.
- an uncontrolled ion and water balance and cells being damaged as a result of osmosis.

29
Q

what are the two main ways of treating kidney failure?

A
  • dialysis
  • transplant
30
Q

what is kidney dialysis?

A

kidney dialysis is the use of a specialist machine to carry out the function of kidneys. dialysis fluid contains the same concentration of glucose and ions as healthy blood. as a result, only excess and waste molecules are lost from the blood, and glucose and ions remain.

31
Q

what is the function of reproductive hormones during puberty?

A
  • males: cause the development of secondary sexual characteristics.
  • females: cause the development of secondary sexual characteristics and the maturation of eggs.
32
Q

what is the main male reproductive hormone?

A

the main male reproductive hormone is testosterone, which is produced by the testes and controls sperm production.

33
Q

what is the main female reproductive hormone?

A

the main female reproductive hormone is oestrogen, which is produced by the ovaries and is involved in the menstrual cycle.

34
Q

what is the menstrual cycle?

A

the mentrual cycle is the monthly cycle of physiological changes that occur in females, involving the shedding of the uterus lining (menstruation) and ovulation.

35
Q

describe the events of the menstrual cycle

A
  • uterus lining thickens and eggs begins to mature in the ovaries.
  • an egg is released from one of the ovaries (ovulation) - uterus lining remains thick.
  • if the egg iosz fertilised, pregnancy may occur. if not, both the egg and the uterus lining are shed during menstruation.
36
Q

what is ovulation?

A

ovulation is the release of a mature egg from the ovaries, which occurs approximately every 28 days.

37
Q

name the four main hormones involved in the menstrual cycle

A
  • oestrogen
  • progesterone
  • follicle stimulating hormone (FSH)
  • luteinising hormone (LH)
38
Q

what is the role of FSH in the menstrual cycle?

A

FSH is secreted by the pituitary gland. it contr#ols the maturation of eggs within the ovaries (inside a follicle) and triggers the production of oestrogen by the ovaries.

39
Q

what is the role of oestrogen in the menstrual cycle?

A

oestrogen is produced by the ovaries and released due to the action of FSH - it causes the regrowth of the uterus lining.
it triggers the production of LH and restricts the release of more FSH.

40
Q

what is the role of LH in the menstrual cycle?

A

LH is produced in the pituitary gland as a result of oestrogen. its release triggers ovulation.

41
Q

what is the role of progesterone in the menstrual cycle?

A

progensterone is secreted from the follicle of the ovary. it sustains the uterus lining and inhibits FSH and LH.

42
Q

what is contraception?

A

contraception refers to any method of preventing pregnancy.

43
Q

what are the two types of oral contraceptives?

A
  • combines contraceptive pill (contains oestrogen and progesterone).
  • mini pill (contains only progesterone).
44
Q

how does the contaceptive pill prevent pregnancy?

A
  • inhibits FSH - eggs do not mature.
  • prevents the development of the uterus lining - eggs cannot impant.
  • increases the thickness of cervical musuc - immubilises sperm cells.
45
Q

what is the conctraceptive patch?

A
  • contains bnoth oestrogen and progesterone.
  • it is a patch that is placed onto the skin for 7 days at a time.
46
Q

what is the contraceptive implant?

A

a small rod inserted under the skin whicgh continously releases the hormone progesterone - lasts for 3 years.

47
Q

what is the contraceptive injection?

A

an injection contains the hormone progesterone - lasts for approximately 3 months.

48
Q

what is the IUS?

A

the IUS (intrauterine system) is a small plastic device that is inserted into the uterus. it releases progesterone which thickens cervical mucus and prevents the build-up of the uterine lining.

49
Q

what is the IUD?

A

the IUD (intrauterine device) is a small copper-containing device inserted into the uterus, which prevents the implantation of embryos.

50
Q

what is a spermicide?

A

a spermicide is a chemical that kills or immobilises sperm cells - however, they are not very effective, and work better when combined with barrier methods.

51
Q

what is a barrier method of contraception?

A

a barrier method of contraception involves a physical separation between the sperm and the egg. they include:
- condoms - thin sheath worn on the penis or inside the vagina - protects against STIs but may tear/break.
- diaphragms - a thin cap placed over the cervix - prevent entry of sperm.

52
Q

what surgical methods of contraception are available?

A

sterilisation - in males, the sperm ducts are tied (vasectomy) and in females, the oviducts are tied.

53
Q

what is abstinence?

A

abstinence is the practice of not having sex, which also avoids pregnancy. some people abstain from sex around the time of ovulation - this is known as the rhythm method, but it is quite unreliable.

54
Q

how do fertility drugs increases the chance of pregnancy?

A

many fertility drugs contain FSH - which stimulates oestrogen production and the maturation of eggs in the ovary. they also contain LH which triggers ovulation.

55
Q

what is IVF?

A

IVF (in vitro fertilisation) is type of fertility treatment:
- mother is given FSH and LH - stimulates maturation of eggs and ovulation.
- eggs are fertilised using sperm in a laboratory - develop into embryos.
- 1 or 2 embryos are inserted into the mother’s womb.

56
Q

what are the advantages of fertility treatment?

A
  • allows infertile couples to have children
  • can store a woman’s eggs for later
57
Q

what are the disadvantages of fertility treatment?

A
  • it can be a very expensive process.
  • it has a low success rate - especially fopr older couples.
  • increases chance of multiple pregnancies - dangerous for mothers and babies.
  • side effects of fertility drugs.
58
Q

what is negative feedback?

A

negative feedback is a type of control where the body responds to an increase or decrease in a factor by returning it to the optimum level.

59
Q

what is thyroxine?

A

thyroxine is a hormone released by the thryoid gland. its release is triggered by the thyoid stimulating hormone (TSH). thyroxine controls the body’s metabolic rate, growth and development.

60
Q

how is the release of thyroxine controlled by negative feedback?

A
  • levels of blood thryoxine falls - detected by receptors in the brain.
  • pituitary gland releases more TSH.
  • more thyroxine produced and released by the thryoid gland.
  • blood thryoxine level returns to normal.
61
Q

what is adrenaline?

A

adrenaline is a hormone secreted by the adrenal gland in times of stress. it is responsible for the ‘fight of flight response’.

62
Q

what are the effects of adrenaline?

A
  • increase in heart and breathing rate - delivers oxygen and glucose to the body.
  • stored glycogen converted to glucose.
  • dilation of pupils.
  • increased mental awareness.
  • blood diverted away from digestive system to muscles.