B7 - Animal Coordination, Control and Homeostasis Flashcards
Define
hormones.
chemicals which are released directly into the blood
Define
endorcine glands.
the glands that produce and secrete hormones
What are the 6 endorcine glands that you need to know?
- pituitary gland
- thyroid gland
- adrenal gland
- pancreas
- ovaries
- testes
What is the difference in action speed between
neurones and hormones?
neurones - very fast action
hormones - slower action
What is the difference between duration of action between
neurones and hormones?
neurones - act for a very short time
hormones - act for a long time
What is the difference between area acted on between
neurones and hormones?
neurones - act on a very precise area
hormones - act in a more general way
Where are the adrenal glands located?
just above the kidneys
What hormone do the adrenal glands release?
adrenalin
What two areas does adrenalin bind to the receptors of?
- heart
- liver
How does adrenalin affect the
heart?
and why?
it causes the heart muscle to contract more frequently and with more force, so heart rate and blood pressure increase
this increases blood flow to the muscles, so the cells receive more oxygen and glucose for increased respiration
How does adrenalin affect the
liver?
and why?
it causes the liver to break down its glycogen stores to release glucose
this increases the blood glucose level, so there’s more glucose in the blood to be transported to the cells
What hormone does the thyroid gland release?
thyroxine
What occurs when the blood thyroxine level is lower than normal?
(3 steps)
- The hypothalamus is stimulated to release TRH.
- TRH stimulates the pituitary gland to release TSH.
- TSH stimulates the thyroid gland to release thyroxine, so the blood thyroxine level rises back towards normal
(the opposite occurs when levels rise above normal)
Define
menstrual cycle.
the monthly sequence of events in which the female body releases and egg and prepares the uterus in case the egg is fertilised
What occurs during stage 1 of the menstrual cycle?
and how long is this stage?
menstruation starts
the lining of the uterus breaks down and is released
4 days long (on average)
What occurs during stage 2 of the menstrual cycle?
and how long is this stage?
the uterus lining is repaired until it becomes a thick spongy layer full of blood vessels ready for a fertilised egg to implant there
10 days long (on average)
What occurs during stage 3 of the menstrual cycle?
an egg develops and is released from the ovary
What occurs during stage 4 of the menstrual cycle?
and how long is this stage?
the uterus lining is maintained for about 14 days
if no fertilised egg has landed on the uterus wall by day 28, the spongy lining starts to break down again and the whole cycle starts over
14 days long (on average)
Define
ovulation.
the release of an egg from the ovary
What are the 4 key hormones in the
menstrual cycle?
- FSH (follicle-stimulating hormone)
- Oestrogen
- LH (luteinising hormone)
- Progesterone
What gland is FSH released from?
the pituitary gland
What gland is oestrogen released from?
the ovaries
What gland is LH released from?
the pituitary gland
What gland is progesterone released from?
the corpes luteum
Define
follicle.
an egg and its surrounding cells
What does FSH do?
(2 things)
- causes a follicle to mature in one of the ovaries
- stimulates oestrogen production
What does oestrogen do?
(2 things)
- causes the lining of the uterus to thicken and grow
- stimulates a rapid increase of LH (at a high level)
What does LH do?
(2 things)
- stimulates ovulation - the follicle ruptures and the egg is released
- stimulates the remains of the follicle to develop into a structure called a corpus luteum
What does progesterone do?
(2 things)
- maintains the lining of the uterus
- inhibits the release of FSH and LH
What does the drug clomifene do to help fertility?
it causes more FSH and LH to be released
(these stimulate egg maturation and ovulation)
What is the IVF process?
(5 steps)
- FSH and LH are given to a woman to stimulate egg production.
- Some eggs from the woman’s ovaries are collected.
- These are fertilised in a lab using the man’s sperm.
- These are then grown into embryos.
- Once the embryos are tiny balls of cells, one or two of them are transferred to the woman’s uterus to improve the chance of pregnancy.
Define
Assisted Reproductive Technology (ART).
a fertility treatment that involved eggs being handled (and usually fertilised) outside of the body
IVF is an example of this
How can oestrogen be used as a contraceptive?
it prevents the release of an egg if taken every day because permanently high levels of oestrogen inhibits the production of FSH
(so, after a while, egg development and production stop)
How can progesterone be used as a contraceptive?
it reduces fertility by stimulating the production of thick cervical mucus
(this prevents and sperm getting through the cervix and reaching an egg)
What are some positives of
hormonal methods of contraception?
(2)
- they are generally (when used correctly) more effective at preventing pregnancy than barrier methods
- the couple don’t have to stop and think about contraception each time they intercourse
What are some negatives of
hormonal methods of contraception?
(2)
- they can have unpleasant side-effects
- they don’t protect against STIs
What are three examples of
homeostasis?
- Osmoregulation (regulating water content)
- Thermoregulation (regulating body temperature)
- Blood glucose regulation
What occurs to stabilise blood glucose concentration when the
blood glucose concentration is too high?
(3 steps)
- Insulin is secreted by the pancreas.
- This makes the liver turn glucose into glycogen.
- So more glucose moves from blood into liver and muscle cells.
What occurs to stabilise blood glucose concentration when the
blood glucose concentration is too low?
(3 steps)
- Glucagon is secreted by the pancreas.
- This makes the liver turn glycogen into glucose.
- This glucose is released into blood by the liver.
What is
type 1 diabetes?
and what can this lead to?
a condition where the pancreas produces very little or no insulin
a person’s blood glucose can rise to a level that can kill them
How can type 1 diabetes be ‘treated’?
Insulin therapy:
insulin is regularly injected into fatty tissue where it will enter the bloodstream
(e.g. at mealtimes)
What is
type 2 diabetes?
a condition where a person becomes resistant to insulin
so blood glucose level rises
What is the formula for
BMI?
mass (kg) / height (m) ^2
What is the formula for
waist to hip ratio?
waist circumference (cm) / hip circumference (cm)
What waist to hip ratios would be associated with an increased risk of type 2 diabetes?
1 for males
and
0.85 for females
How can type 2 diabetes be controlled?
(5 ways)
- eating a healthy diet
- getting regular exercise
- losing weight
- medication
- insulin injections
What should our
core body temperature be?
37°C
What occurs when you are
too hot?
(3 things)
- erector muscles relax (so hairs lie flat)
- lots of sweat is produced in sweat glands
- blood vessels close to the surface of the skin dilate (widen)
How does
sweat work to cool you down?
when the sweat evaporates it transfers energy from your skin to the environment, cooling you down
What is
vasodilation?
and what does this do?
when blood vessels close to the surface of your skin dilate (widen)
it allows more blood to flow near the surface so it can transfer more energy into the surroundings, which cools you down
What occurs when you are
too cold?
(4 things)
- erector muscles contract (hairs stand on end to trap an insulating layer of air near the surface of the skin, which helps keep you warm)
- very little sweat is produced
- blood vessles near the surface of the skin constrict (vasoconstriction)
- you shiver (your muscles contract automatically)
How does
shivering work to warm you up?
this increases your rate of respiration, which transfers more energy to warm the body
What are the
three main roles of kidneys?
- Remove urea from the blood
- Adjust the ion levels in the blood
- Adjust the water content of the blood
What happens in each
nephron of a kidney?
(3 steps) (good luck with this one)
- The liquid part of the blood is forced out of the glomerulus and into the Bowman’s capsule at high pressure (ultrafiltration). Bigger molecules and blood cells can’t pass through the membranes and are not forced out.
- As the liquid flows along the nephron useful substances are reabsorbed. (e.g. glucose, sufficient ions, sufficient water)
- Whatever isn’t reabsorbed continues out of the nephron via the collecting duct. It then passes into the ureter and down to the bladder as urine. Urine is released through the urethra.
State the
journey of urine.
(starting from the renal artery) (10 stages)
- Renal artery
- Glomerulus
- Bowman’s capsule
- Proximal convoluted tubule
- Loop of Henle
- Distal convoluted tubule
- Collecting duct
- Ureter
- Bladder
- Urethra
What is the role of
ADH?
and what does it stand for?
to control the amount of water reabsorbed by the kidney nephrons
anti-diuretic hormone
How is
water content regulated?
(3 steps)
- The brain monitors the water content of the blood.
- It instructs the pituitary gland to release ADH into the blood according to how much is needed.
- ADH makes the collecting ducts of the nephrons more permeable so that more water is reabsorbed back into the blood.
What gland is
ADH released from?
the pituitary gland
What cures are there for
kidney disease?
kidney transplant
What precautions are taken to
reduce the risk of a donor kidney being rejected by the patient’s immune system?
(2 things)
- a donor with a tissue type that closely matches the patient is chosen
- the patient is treated with drugs that suppress the immune system, so that their immune system won’t attack the transplanted kidney
