CHAPTER 11 Flashcards
what is the endocrine system
a collection of glands that secrete hormones into the blood stream
how does the endocrine system work
a gland secretes a hormone to the blood stream the blood carries the hormone to an organ
the organ carries out the desired action
differences between hormones and nerves 3
nerves are very fast, hormones are slower
nerves act for a short time, hormones last longer
nerves act on a very precise area, hormones act in a more general way
what does insulin do
controls blood glucose levels
what does adrenaline do
prepares body for fight or flight
examples of hormones 2
insulin
adrenaline
what is the main gland in the endocrine system
the pituitary gland in the brain
4 examples of hormones produced by the pituitary gland
growth hormones in children
ADH
FSH
TSH
what is fsh
follicle stimulating hormone
stimulates ovaries to make oestrogen
what is tsh
stimulates thyroid to make thyroxine which controls metabolism
function of hormones produced by the thyroid
controls metabolism
function of hormones produced by the pancreas
controls glucose levels
function of hormones produced by adrenal gland
prepares body for fight or flight
function of hormones produced by ovaries
menstrual cycle
function of hormones produced by testes
sperm production
where is insulin produced
pancreas
what does insulin do
it allows or restricts the movement of glucose into cells
what are gibberellins
they initiate seed growth
what are plant shoots sensitive to
light and gravity
what are tropisms
the response of plants to light and gravity
what is the response of plants to light called
phototropism
what is the response of plants to gravity called
gravitropism
what is auxin
a hormone that makes plants grow
what happens when a shoot responds to light
auxin moves to the unlit side
makes this side grow more
unequal growth shoot brands towards light
what effect does auxin have on root hair cells
inhibit growth
what effect does auxin have on shoot cells
accelerated growth
what happens if there is no auxin in a plant
no growth
what causes root cells to act towards gravity
more auxin on lower side
more growth on upper side so shoot bends towards side with least auxin facing down
when shoot grows down, auxin is spread evenly
what causes shoot cells to grow up
auxin gathers on lower side, grows more on side with auxin bends upwards
auxin is redistributed normally
shoot continues growing up
what are cuttings dipped in to stimulate growth
auxin
how is auxin used as a weed killer
it makes the plant grow rapidly and uncontrollably
how does weed killer not affect crops
narrow leafed crops don’t absorb as much auxin as broad leaved weeds so they don’t die
why are weed killers important
kills competition so crops thrive
what are gibberellins used for 3
used in brewing industry to speed up germination of barley
promotes flowering throughout the year
increased size of fruit
what chemical is used to control the ripening of fruit
ethene
one common cause of infertility
lack of ovulation
when and why does lack of ovulation occur
women don’t produce enough FSH to mature eggs in ovaries
how can lack of ovulation be treated naturally
artificial FSH stimulates maturation of eggs
artificial LH can be used to encourage ovulation
what does IVF stand for
in vitro fertilisation
when is IVF used 4
no obvious cause of infertility
if donor eggs is used
if oviducts are block
man produces very few sperm
how does IVF work
they give the mother FSH to mature eggs and LH to bring to point of ovulation
they collect eggs and fertilise with sperm in a lab eggs grow into embryos
embryos transplanted into uterus
advantages of IVF
allows couples to have a child
disadvantages of IVF 5
very expensive not always successful can have health risk for mother increases chance of multiple pregnancy ethical issues
what is contraception
a method that prevents sperm and egg meeting
what are the 6 main methods of contraception
chemical intrauterine devices abstinence barrier hormonal surgical
how does abstinence work
people don’t have sex to avoid getting pregnant or don’t have sex around ovulation
how does a barrier method work
forms a physical barrier between sperm and egg
how do surgical methods of contraception work
vasectomy (sperm ducts are cut and tied)
oviducts are cut and tied in women
how do copper IUDs work
prevent embryos implanting in womb
how do hormonal IUDs work
contain progesterone to stop lining of womb building up
examples of barrier methods
cervical cap
condom
how do chemical methods of contraception work
they kill sperm to stop fertilisation
how does the pill work
contains oestrogen and LH
stops production of FSH
no eggs mature
also stop lining thickening for embryo
where are oestrogen and progesterone made
ovaries
where are FSH and LH made
pituitary gland
how long does the menstrual cycle last
28 days
function of FSH 2
makes egg mature
stimulates release of oestrogen
function of oestrogen 3
thickness
womb lining
stops release of FSH
stimulates release of LH
function of LH 1
ovulation
function of progesterone 1
keep womb lining thick
what does LH stand for
luteinising hormone
why does the lining of the womb build up
to prepare for the baby
main reproductive hormone in men
testosterone
3 similarities between puberty in girls and boys
growth spurts
underarm hair
brain matures
4 differences between puberty in boys and girls
boys happen later
boy voice breaks
girls breasts develop
start menstruation
where is testosterone produced
testes
function of testosterone
sperm production
what is menopause
when a woman’s eggs run out so she doesn’t menstruate
what is negative feedback
the body’s attempt to restore optimum conditions when conditions change
what does thyroxine do
controls metabolism
what happens when levels of thyroxine falls
detected by sensors in the brain, stimulates release of TSH from pituitary gland
TSH stimulates release of thyroxine from thyroid
what does TSH stand for and do
thyroxine stimulating hormone
stimulates release of thyroxine from thyroid
changes that happen when adrenaline is released
increased heart rate boosts delivery of oxygen an glucose to brain prepares body for fight or flight
is adrenaline controlled by negative feedback and why
no you don’t constantly need adrenalin, only in times of stress
cause of type 1 diabetes
genetics
cause of type 2 diabetes
lifestyle
when does type 1 diabetes occur
childhood / birth
when does type 2 diabetes occur
adulthood
treatment of type 1 diabetes
insulin injections allows glucose to be taken into body cells and converted to glycogen in liver and stops levels getting too high
it also allows glycogen to be made back into glucose - stops levels getting too low
why is type 1 diabetes not always treated with insulin
many other techniques such as pancreas transplant or pancreatic cells to make insulin
diet
weight
exercise
treatment of type 2 diabetes
changing lifestyle to be more healthy drugs can help insulin work better
what is type 1 diabetes
when the pancreas doesn’t produce enough insulin to monitor glucose levels
what is type 2 diabetes
when body doesn’t respond to insulin
why isn’t type 2 diabetes treated with insulin
body doesn’t respond to it
why do you lose weight with type 1
using fats as fuels rather than sugar
why do you urinate more with type 1
to excrete glucose
why are you thirsty with type 1
to replace water lost by urinating
why are you tired with type 1
no glucose for respiration for energy
what does insulin do and what happens without it
allows glucose into body cells rather than in blood without it levels get too high in blood stream
what is glucose
sugar used in respiration
what is glycogen
how is glucose stored as a carbohydrate
what is glucagon
a hormone that stimulates the liver to break down glycogen to glucose
what does your pancreas do after eating
produces insulin to move glucose into cells rather than in blood
when is glucagon used
when your blood sugar level is too low it converts glycogen back to glucose
name 3 plant hormones
ethene , auxin , gibberellins
what is an endocrine gland
secretes hormones directly into blood
why is the pituitary gland so powerful
not only secretes hormones, but stimulates other glands to do so
what is an allele
a form of a gene
