Topic 5 - Homeostasis and response - hormonal coordination Flashcards
(42 cards)
1
Q
What is the endocrine system?
A
network of glands that produce and release hormones that act as chemical messengers to regulate various bodily functions
2
Q
What are hormones?
A
- chemical molecules released directly into the blood
- carried in blood to other parts of body - only affect target organs
3
Q
Thyroid gland function?
A
- produces thyroxine
- regulates metabolic rate of the body
4
Q
Adrenal gland function?
A
- produces adrenaline
- prepares body for flight or fight response
5
Q
Pancreas function?
A
- produces insulin
- used to regulate blood glucose level
6
Q
Testest function?
A
- produce testosterone
- controls puberty and sperm production in males
7
Q
Ovaries function?
A
- produces oestrogen
- involved in menstrual cycle
8
Q
Pituitary gland function?
A
- controls growth in children
- stimulates thyroid gland to make thyroxine - control rate of metabolism
- in women stimulates ovaries
- in men stimulates tests
- known as “master gland”
9
Q
Comparing hormones and nerves?
A
- nerves are very fast action - hormones slower action
- nerves act for very short time - hormones act for long time
- nerves act on very precise area - hormones act in more general way
10
Q
How is glucose removed from blood?
A
- normal metabolism of cells removes glucose from blood
- vigorous exercise removes a lot of glucose from blood
11
Q
How can excess glucose be stored?
A
stored as glycogen in liver and in muscles
12
Q
What is added when blood glucose level is too high?
A
insulin added
13
Q
What is added when blood glucose level is too low?
A
glucagon added
14
Q
What happens when blood glucose is too high?
A
- blood with too much glucose detected
- insulin secreted by pancrea
- insulin allows glucose to move from blood into cells to be used
- insulin also makes liver turn glucose into glycogen
- blood glucose level reduced
15
Q
What happens when blood glucose is too low?
A
- blood with not enough glucose detected
- glucagon secreted by pancreas
- glucagon makes liver break down glycogen - coverting it into glucose - released back into blood
- blood glucose level increased
16
Q
Where is glucose stored when glycogen stores are full?
A
- converted into lipids and stored
- if you regularly take in food that results in having more glucose than the livers and muscles can store as glycogen - gradually store more and more of it as lipids - may become obese
17
Q
What is type 1 diabeties?
A
- pancreases produces very little or no insulin
- blood glucose level can rise to level that will kill them
- kidney excretes glucose in urine - urinate a lot + feel thirsty all the time
- glucose cant get into cells - lack energy and feel tired
- break down fat and protein to use as fuel instead - lose weight
- genetic
18
Q
What is type 2 diabeties?
A
- pancreas still makes insulin - body cells stop responding to it
- linked to obesity
19
Q
How to treat type 1 diabeties?
A
- insulin therapy - injections of insulin throughout the day - commonly at meal times
- stops concentration of glucose in blood getting too highi
- limit intake of food rich in simple carbohydrates and carry out regular exercise
20
Q
How to treat type 2 diabeties?
A
- eating balanced diet with controlled amount of carbs
- regular exercise
21
Q
What is the main reproductive hormone in men?
A
- testosterone
- produced by testes and stimulates sperm production
22
Q
What is the main reproductive hormone in women?
A
- oestrogen - produced in ovaries
- brings about physical changes + involved in menstrual cycle
23
Q
What are the 4 stages of the menstrual cycle?
A
- day 1 - menstruation starts - uterus lining breaks down for about 4 days
- uterus lining builds up again - from day 4 to 14 - into thick spongy layer full of blood vessels - ready to receive fertilised egg
- egg develops and released from ovary at day 14 - ovulation
- wal maintainted for about 14 days until day 28 - if no fertilised egg has landed on uterus wall by day 28 - spongy lining starts to break down - whole cycle starts again
24
Q
What does FSH (Follicle-stimulating hormone) do?
A
- produced in pituitary gland
- causes egg to mature in one of the ovaries in structure called follicle
- stimulates ovaries to produce oestrogen
25
What does oestrogen do?
- produced in ovaries
- causing lining of uterus to grow
- stimulates release of LH (causes release of egg) + inhibits release of FSH
26
What does LH (luteinising hormone) do?
- produced by pituitary gland
- stimulates release of an egg at day 14 (ovulation)
27
What does progesterone do?
- produced in ovaries by remains of follicle after ovulation
- maintains lining of uterus during second half of cycle - when level of progesterone falls - lining breaks down
- inhibits release of LH and FSH
28
How can oestrogen be used as a method of contraception?
- prevents release of egg
- if oestrogen taken every day to keep its level permanently high - inhibits production of FSH
- egg development and production stop
29
How can progesterone be used as a method of contraception?
stimulates production of thick mucus that prevents any sperm getting through and reaching an egg
30
How can mixed pill be used as a method of contraception?
- contains low doses of oestrogen and progesterone
- inhibits production and release of FSH by putuitary gland - no eggs mature - preventing pregnancy
- over 99% effective - side effects like headaches and nausea - doesnt protect against STD's
31
What is the progesterone only pill?
- fewer side effects than mixed pill
- must be taken regularly
- if they dont - artificial hormone levels drop - body's hormones take over quickly - unexepected release of egg
32
What is the contraceptive patch?
- contains mixture of oestrogen and progesterone
- hormones absorbed directly into bloodstream
- must be replaced every week
33
Barrier methods to stop contraception?
- condoms prevent sperm entering vagina - also protect against STDs
- diaphragm - shallow plastic cup fits over cervix - must be used with spermicide
- spermicide can be used - not effective - only about 70-80%
34
How is sterilisation used as contraception?
- cutting or tying fallopian tubes in females
- cutting or tying sperm duct in males
- permanent procedure - small change tubes can rejoin
35
How can abstinence be used as contraception?
never have intercourse - sperm cannot meet egg
36
Pros and cons of using fertility drug containing FSH and LH to stimulate ovulation?
- helps a lot of women get pregenant
- doesnt always work - some women may have to do it many times - expensive
- too many eggs could be stimulated - unexpected multiple pregnancies
37
How can IVF be used as infertility treatment?
- mother given synthetic FSH to stimulation maturation of a number of eggs - followed by LH to bring eggs to point of ovulation
- eggs from ovaries collected and fertilised with sperm from father in a lab
- fertilised eggs kept in special solutions in warm environment to develop into tiny embryos
- once embryos are tiny balls of cells - one or two of them inserted into uterus to improve change of pregnancy
38
Pros and cons of IVF?
- can give infertile couple a child
- IVF expensive for NHS and individuals - thousands of pounds for repeated cycles of treatment
- success rate of IVF low - average success rate in UK 26%
- IVF increases change of mulitple pregnancies - on average 1 in 5 IVF pregnancies is a multiple pregnancy - compared to 1 in 80 for natural pregnancies
39
Why are some people against IVF?
process results in unused embryos that are destroyed - people think it is unethical
40
Effect of adrenaline on body?
- heartrate and breathing rate increase
- stored glycogen in liver converted to glucose for respiration
- pupils of eye dilate to let in more light
41
What is thyroxine?
- hormone released by thyroid gland - plays important role in regulating metabolic rate - speed at which chemical reactions in the body occur while body is at rest
- important for lots of processes in body - stimulates protein synthesis for growth and development
42
How does negative feedback keep the amount of thyroxine in the blood at the right level?
- thyroxine released in response to thyroid stimulating hormone (TSH) - released from pituitary gland
- negative feedback keeps amount of thyroxine in the blood at the right level
- when level of thyroxine in blood is too highi - secretion of TSH from pituitary gland is inhibited
- this reduces amount of thyroxine released from thyroid gland - level in blood falls back to normal
