b11 - hormonal coordination Flashcards
what is the master gland and why?
where is it found?
the pituitary gland as if secretes many important hormones
- found in the brain and linked to the hypothalamus
endocrine system
the glands that produce the hormones which control many aspects of the development and metabolism of the body
hormones
chemicals produced that have effect on the functioning of target organs
- transported by blood plasma
role of the pituitary gland
- controls GROWTH in children
- stimulates the THYROID GLAND to make THYROXINE to control the rate of metabolism
- in women - stimulates the ovaries to produce and release eggs and make OESTROGEN
- in men - stimulates the testes to make sperm and TESTOSTERONE
role of the thyroid gland
controls the metabolic rate in the body, also controls heart rate and temperature
- found in the neck
role of the pancreas
controls the levels of glucose in the blood
- by releasing insulin and glucagon (which regulates those levels)
role of the adrenal gland
- prepares the body for stressful situations - ‘fight or flight’ response produce ADRENALINE
- has no feedback loop
- the two adrenal glands are found right above the kidneys
nervous system vs endocrine system
- the cns uses electrical impulses whilst the endocrine system responds to changes in the environment via hormones, which last for a longer period of time
- hormonal effects are slower than that of the nervous system
- cns is precise while the other can act on large areas of the body
examples of rapid response hormones
insulin and adrenaline
examples of slow response hormones
what is negative feedback
an opposite response to the effects of stimuli, which help to maintain the body’s stable conditions (homeostasis)
negative feedback loop or thyroxine
maintains a constant concentration of thyroxine in the blood
if too low: the production of TSH (thyroid stimulating hormone) is increased. this stimulates the thyroxine gland to secrete thyroxine
if too high: the production TSH is decreased
adrenaline
- triggers a fight or flight response in dangerous or stressful situations
- enlarges air passages and alters metabolism to enhance the delivery of oxygen and glucose to the brain and muscles
- increases heart rate and blood pressure and dilates our pupils
why is it important to regulate blood glucose levels?
- glucose is required for respiration so if there isn’t enough glucose, the organism will not be able to produce
enough energy - can have a negative impact on osmosis if the levels are too high as it alters the concentration gradients
negative feedback loop for blood glucose levels
if too low: the cells in the pancreas detect the change and glucagon is released into the bloodstream to rise the levels
if too high: the cells in the pancreas detect the change and insulin is released into the bloodstream to lower the levels
insulin
- the liver and muscles tissue detect insulin
- it then converts the excess glucose into glycogen until the pancreas detects a normal blood glucose conc.
glucagon
- the liver detects glucagon (it causes cells in the liver to do the below)
- the liver converts stores of glycogen into glucose to be released into the bloodstream and this process continues until the pancreas detects a normal blood glucose conc.
glycogen
a form of glucose that is insoluble and can be stored for later
type 2 diabetes
body still produces insulin but no longer responds to it
- develops later in life
type 1 diabetes
when the body doesn’t produce enough insulin
- develops as a child
ways of managing diabetes
- (1) injecting insulin when blood glucose becomes too high
- (1 and 2) manage their diet and exercise to keep blood glucose levels steady
risk factors for diabetes
- being overweight
- having an unhealthy diet
- not exercising regularly
symptoms of diabetes
- excess urine
- lack of energy
- feeling tired/fatigue
- losing weight
puberty in females
starts between 9-15
- the amount of oestrogen rises and triggers the menstrual cycle (mature eggs start to form)
- growth of underarm and pubic hair
- breasts enlarge
- uterus grows and becomes active
puberty in males
starts between 8-14
- testosterone rises, which triggers sperm production
- growth of underarm, facial and pubic hair
- voice deepens
- shoulders broaden
which 4 hormones are involved in the menstrual cycle?
- oestrogen
- FSH (follicle-stimulating hormone)
- LH (luteinising hormone)
- progesterone
how does female fertility work?
- the ovaries of a baby girl contain all the eggs she will ever have
- after puberty, those eggs mature and are released every month for 35-40 years, except if she’s pregnant
- approaching menopause, the woman is less fertile and has a higher chance of having a baby with genetic problems
FSH during the menstrual cycle
- released by the pituitary gland and causes the egg to mature
- also stimulates the production of oestrogen
oestrogen during the menstrual cycle
- produced in the ovaries and causes the development of the thick, spongy uterus lining
- stimulates the production of LH and inhibits the production of FSH
LH during the menstrual cycle
- secreted in the pituitary gland and releases the mature egg on day 14 of the cycle (OVULATION)
progesterone during the menstrual cycle
- produced in the ovaries
- responsible for maintaining the uterus lining during days 14-28
- when progesterone levels drop, the uterus lining will break down (day 1 of cycle)
- also inhibits the release of LH and FSH
what is a period
loss of the uterus lining and the release of a mature egg
what are oestrogen levels like during the menstruation cycle?
the blood oestrogen levels peak twice
how do the hormones interact with each other during the cycle?
FSH: causes egg to mature; stimulates release of oestrogen
oestrogen: causes the lining of the uterus to develop; inhibits the release of LH
LH: triggers ovulation
progesterone: maintains uterus lining; inhibits release of both FSH and LH
ways of treating diabetes (type 1)
- pancreas transplant
- stem cell treatment to replace the dysfunctional pancreatic cells
the menstrual cycle
1) menstruation: the uterus lining breaks down, resulting in a period if no fertilization has occurred (1-4)
2) the uterus lining begins to build up and thicken + is maintained (4-14)
3) ovulation: mature egg is released - travels from the oviduct towards the uterus
4) the uterus lining is maintained, and it is ready to accept a fertilized egg. if there isn’t a fertilised egg, the uterus breaks down and the cycle starts over
examples of hormone contraceptives
- progesterone only pill
- morning after pill/combined pill
- implant
- patch
- intrauterine device (IUD)
progesterone only pill
- stimulates the production of thick mucus which sperm cannot penetrate
- inhibits FSH so the eggs don’t mature
- fewer side effects than the combined pill
morning after pill
- contains both oestrogen and progesterone
- by taking it every day, enough oestrogen builds up in the female body to inhibit the production of FSH so no eggs mature
contraceptive implant
- lasts for three years
- is inserted under the skin (usually in the arm)
- regularly releases small amounts of progesterone
contraceptive injection
- contains progesterone
- lasts up to three months
contraceptive patch
- has to be changed every week
- steadily releases progesterone
- goes on the skin
diaphragm
- shallow plastic cup that is inserted into the vagina before intercourse - it sits at the entrance of the uterus
- is to prevent the sperm from reaching the egg
- can also be covered with spermicide to kill/disable the sperm
IUD
- small t-shaped devices that are inserted into the uterus aka coil 9 (by a medical professional)
- prevents the embryo implanting in the lining of the uterus
- release small amounts of progesterone
- lasts for 3-5 years
vasectomy
having the sperm ducts cut so that the sperm are not released
hysterectomy
having the fallopian tubes cuts so that the egg cannot reach the uterus
fertility treatment
- IVF (in-vitro fertilisation)
- fertility drugs
fertility drugs
- drugs that contain a mixture of LH and FSH
- boosting the levels of both hormones can cause an egg to be released in the ovaries
IVF
- LH and FSH ar egiven to stimulate the growth of lots of eggs
- the eggs are then collected before being fertilised in a petri dish (with the father’s sperm)
- when the fertilised eggs grown into embryos, they are implanted in the woman’s uterus
disadvantages of IVF
- can result in multiple pregnancies which can put both parties at risk
- it’s very expensive
- can involve emotional and physical stress for those partaking
reasons why people may have difficulty conceiving
male: blocked or damaged tubes that carry sperm, poor sperm quality, low sperm count
female: problem with uterus lining, blocked fallopian tubes, ovaries not releasing eggs, low levels of FSH (eggs dont mature)
both: hormonal problems
key plant hormones
auxins, gibberellins, ethene
auxins
- change growth patterns to allow roots and shoots to move towards or away from the stimulus (change in conditions)
- response to stimuli that involves directional growth = TROPISMS
gibberellins
important in beginning seed germination (the sprouting process)
ethene
a gas that controls cell division and the ripening of fruits
two types of tropisms
phototropisms and gravitropisms
positive phototropism
responses that involve growth towards a light source
negative phototropism
responses that involve growth away from a light source
positive gravitropism
responses that involve growth towards the direction of gravity
negative gravitropism
responses that involve growth away from the direction of gravity
tropism
response to stimuli that involve directional growth
distribution of auxins and phototropisms
- one side of the plant gets more sun than the others
- so the auxin is redistributed so that the conc is greater on the shaded side
- unequal distribution = cell elongation on the shaded side
- auxins PROMOTE cell elongation in shoots but DONT in roots
phototropism
growth either towards or away from a light source
gravitropism
growth either towards or away from the direction of gravity
REQUIRED PRACTICAL: light investigation
1) place the seeds in a petri dish with damp cotton wool, and leave them in a warm place to germinate
2)randomly divide the petri dish into 3 sections each with a different light condition: full sunlight (windowsill), partial sunlight. darkness
3) measure the height of the plant every day for a week
4) draw and label them to show the effects
independent variable: the light conditions
dependent: the growth of the plant
uses of gibberellins
promote flowering, increase fruit size and initiate germination
uses of ethene
used in the food industry to control the ripening of food during storage and transfer
uses of auxins
- used as weed killers as they can initiate such rapid growth that the weeds use up all of their resources and die
- rooting powder (growth supplement) to promote growth in tissue culture
