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biology > topic 7 > Flashcards

topic 7 Flashcards

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1
Q

how does the endocrine system work

A

hormones (chemical messengers) are released from glands directly into the blood and carried in it to parts of the body, they produce a response when they reach a target tissue

slower than the nervous system but it acts for longer

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2
Q

the pituitary gland

A
  • the master gland
  • secreted hormones into blood to have an effect on the body/act on other glands to stimulate production of different hormones
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3
Q

pancreas

A

secretes insulin

controls blood glucose

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4
Q

thyroid

A

secretes thyroxine

controls metabolic rate, heart rate and temperature

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5
Q

adrenal gland

A

secretes adrenaline

involved in fight or flight response

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6
Q

ovary

A

secretes oestrogen

involved in menstrual cycle and development in female secondary sexual characteristics

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7
Q

testes

A

secrete testosterone

involved in sperm production and development of male secondary sexual characteristics

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8
Q

aspects of the fight or flight response

A
  • adrenaline is released from the adrenal glands
  • increased heart rate - oxygen reaches muscles quicker so we can move away from danger
  • increased blood pressure - ^
  • increased blood flow to muscles - blood vessels dilate, allowing more blood to reach muscles so they can contract faster with greater strength
  • increased blood sugar levels - liver is stimulated to break down glycogen into glucose, muscles can use it to contract
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9
Q

thyroxine negative feedback loop

A
  • low thyroxine levels stimulate TRH production in the hypothalamus
  • TRH stimulates the release of TSH from the pituitary gland
  • TSH stimulates the thyroid gland to release thyroxine
  • thyroxine levels exceed the normal level and the release of TSH is inhibited, causing thyroxine levels to form
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10
Q

oestrogen as contraception

A

permanently high oestrogen means FSH production is permanently inhibited, so after a while egg development stops and stays stopped

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11
Q

progesterone as contraception

A

progesterone prevents FSH production so that no eggs mature in the ovaries

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12
Q

FSH in menstrual cycle

A

it’s produced in the pituitary gland, stimulates an egg to mature in the follicle and stimulates ovaries to produce more oestrogen

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13
Q

oestrogen in menstrual cycle

A

releases due to FSH, it’s released from the ovaries and causes the growth of the uterus lining, high levels then stimulate LH production and inhibit FSH secretion

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14
Q

LH (luteinising hormone) in menstrual cycle

A

LH is produced in the pituitary gland as a result of oestrogen, it triggers ovulation at day 14 where the follicle ruptured and the egg is released, the remains are then stimulated to form a structure called corpus luteum that secretes progesterone

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15
Q

progesterone in the menstrual cycle

A
  • released from corpus luteum post ovulation, maintains uterus lining and if an egg is implanted would maintain high levels
  • high oestrogen and progesterone levels inhibit LH and FSH production, low levels then restart the cycle
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16
Q

order of hormones in the menstrual cycle

A

FSH
oestrogen
LH
progesterone

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17
Q

metabolic rate

A

the amount of energy expended by an organism in a given time period, usually daily

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18
Q

outline the menstrual cycle

A

it is the process the body undergoes each month to prepare for a potential pregnancy

  • the uterus lining breaks down, and the person has their period
  • the layer builds until ovulation on day 14 where an egg is released
  • if a fertilised egg hasn’t been embedded in the uterus lining after 28 days, it breaks down and the cycle continues
19
Q

the mixed contraceptive pill

A

has to be taken regularly or the body’s hormones will be released and an egg will mature

  • has oestrogen and progesterone
  • constantly high oestrogen levels inhibit FSH so eggs can’t mature
  • lining stops developing and cervical mucus becomes thick to stop sperm from moving through
  • side effects: mood swings, depression, breast pain/enlargement, increased blood pressure
20
Q

progesterone only pill

A

has to be taken regularly to prevent the body’s own hormones releasing and an egg maturing

  • high progesterone levels inhibit FSH and LH release, so an egg can’t mature
  • it has less side effects than the mixed pill
21
Q

contraceptive patch

A
  • oestrogen and progesterone
  • small, stuck on the skin
  • lasts for 1 week
22
Q

contraceptive implant

A
  • releases a continuous amount of progesterone
  • lasts for 3 years
  • prevents release of eggs from ovaries, thickens cervical mucus, stops eggs embedding in uterus
23
Q

contraceptive injection

A
  • progesterone
  • prevents release of egg from ovaries, thickens cervical mucus, stops fertilised eggs from embedding in the uterus
  • lasts 2-3 months
24
Q

intra-uterine device (IUD)

A
  • releases progesterone
  • T-shaped, inserted into uterus
  • lasts 5-10 years
  • prevents release of egg from ovaries, thickens cervical mucus, stops fertilised eggs from embedding in the uterus
25
Q

clomifene therapy

A
  • clomifene is a drug
  • it increases FSH and LH released from pituitary, increasing chances of a woman ovulating
  • woman can then get pregnant naturally
26
Q

IVF

A
  • FSH and LH is given to encourage the maturation and release of eggs
  • these are extracted and then fertilised using sperm in the lab
  • fertilised eggs developing into embryos and 1/2 are inserted into the uterus
27
Q

cons of IVF

A
  • physically stressful bc she may have reactions to the hormone eg. feeling sick
  • emotionally stressful bc it may not work, 26% success
  • can lead to multiple births, may be a risk to mother+babies
  • can be £££ if process needs repeating
28
Q

define homeostasis

A

the maintenance of a constant internal environment

29
Q

why is thermoregulation important

A

if the temp exceeds 37 ˚C, enzymes will become less effective and eventually denature

30
Q

why is osmoregulation important

A
  • blood is too dilute = water will move into cells by osmosis an they’ll burst under the pressure
  • blood is to concentrated - water moves out of cells and they shrink

in either case, they can’t perform their function

31
Q

how does the body know when to thermoregulate

A
  • receptors monitor blood temperature

* receptors in the skin send impulses to the thermoregulatory centre (found in the hypothalamus)

32
Q

negative feedback loop with blood glucose

A
  • eating carbs increases blood glucose
  • high glucose levels - pancreas produces the hormone insulin
  • insulin binds to cells in muscles and liver
  • excess glucose is converted into glycogen which is stored in the liver
  • blood glucose concentration reduces
  • pancreas produces the hormone glucagon
  • it binds to liver cells and causes glycogen to be broken down to glucose
  • glucose is released into the blood and the conc increases

REPEAT!

33
Q

type 1 diabetes

A

the pancreas can’t produce enough insulin

  • blood glucose can rise fatally
  • glucose is excreted with urine –> lots of urine –> thirsty
  • insulin injections at mealtimes + advised to limit simple carbohydrates with lots of glucose
34
Q

type 2 diabetes

A

body cells no longer respond to insulin

  • blood glucose levels can rise to a fatal amount
  • obesity is a risk factor
  • limit simple carbohydrates, lose weight, exercise
  • there are drugs to make insulin more effective on body cells/ make more insulin/ reduce amount o glucose absorbed by gut
35
Q

how is BMI calculated

A

mass (kg)/height^2(m)

36
Q

what BMI is considered as obese

A

30+

37
Q

what is the urinary system

A

the bodily system that removes impurities and waste products from our blood, which are excreted in urine

38
Q

what is the route that blood takes to be purified

A
  • blood to the kidneys through the renal artery
  • the kidneys regulate salt, ion and urea levels in the blood
  • excess is sent to the ureter for excretion and eventually the bladder
  • the purified blood returns for circulation through the renal vein
39
Q

structure and function of nephrons

A
  • glomerulus - ultrafiltration occurs, urea, water, ions and glucose (not protein/cells) pass out of the capillaries into the Bowman’s capsule
  • proximal convoluted tubule - selective reabsorption of glucose and ions (all glucose is reabsorbed bc its needed for energy)
  • loop of Henle and collecting duct - reabsorption of some water and ions
40
Q

how does ADH work

A
  • ADH is produced and released from the pituitary gland
  • too much water in the blood - less ADH is released, the collecting duct becomes less permeable and more water is released in urination

and vice versa

41
Q

kidney dialysis

A
  • blood is taken from an arm vessel and mixed with an anticoagulant
  • the dialysis fluid contains similar glucose and ion levels but no urea
42
Q

kidney transplants

A
  • risk of rejection which can lead to severe illness or even death
  • immunosuppressants have to be taken for the rest of the patients life
  • tissue typing prevents rejection but often leads to long waits
43
Q

how is urea produced

A

by the breakdown of excess amino acids in the liver

biology (10 decks)

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