Topic 7- Animal Coordination, Control And Homeostasis Flashcards
Hormones
Chemicals released directly into the blood affecting particular cells in target organs to control organs/cells need for constant adjustment.
What system is involved in the secretion of hormones?
The endocrine system
What glands produce hormones?
Endocrine glands
Examples of endocrine glands
The pituitary gland Thyroid gland Adrenal glands Ovaries Testes Pancreas
Pituitary gland
Location and function
Located in brain
master gland
Produce many hormones regulating body conditions and acting on other glands to release hormones that bring about change.
Thyroid gland
What does it produce?
THYROXINE (controlling metabolism, heart rate, temperature)
Ovaries
What do they produce?
OESTROGEN (involved in menstrual cycle)
Testes
What does it produce?
TESTOSTERONE (controls puberty and sperm production)
Adrenal glands
What does it produce?
ADRENALINE (prepares body for ‘fight or flight’ response)
pancreas
What does it produce?
INSULIN (regulates blood glucose levels)
Difference between hormones and neurones
Neurones = fast while hormones = slow action
Neurones= short time while hormones= long lasting
Neurones act on precise area while hormones act in a general area
Where are adrenal glands located?
Just above kidneys.
How does adrenaline prepare your body for, ‘flight/fight’?
Binds to specific heart receptors, causing heart muscle to contract more frequently w more force so heart rate/blood pressure increase.
Increases blood flow to muscles (more oxygen/glucose for respiration)
Also binds to receptors in liver, causing liver to break down glycogen stores and release glucose, increasing blood glucose level
What does your brain do when it detects a stressful situation
Sends nervous impulses to the adrenal glands which secrete adrenaline.
How does the body uses negative feedback systems?
When it detects a substance level has gone above/below the normal level, it triggers a response to bring the level back to normal again.
Metabolic rate
The speed at which chemical reactions in the body occur.
What happens when your blood thyroxine level is lower than normal?
The hypothalamus is stimulated to release THYROTROPIN RELEASING HORMONE.
What does thyrotropin releasing hormone do?
Stimulates the pituitary gland to produce thyroid stimulating hormone which stimulates the thyroid gland to release thyroxine so the thyroxine level rises back to normal.
What happens when the blood thyroxine levels are higher than normal?
TRH production in the hypothalamus is inhibited .
The menstrual cycle
The monthly sequence of events in which the female body releases an egg and prepares the uterus in case the egg is fertilised.
Stage 1 of menstrual cycle
Uterus lining breaks down and is released
Uterus lining
Endometrium
Stage 2 of menstrual cycle
Uterus lining is repaired (day 4 to 14)
Until becomes spongy layer of blood vessels ready for fertilised egg to implant there.
Stage 3 of menstrual cycle
Egg develops and is released from ovary
Ovulation
Day 14
Stage 4 of menstrual cycle
Lining is maintained until day 28 (w no fertilised egg)
Spongy lining breaks down again
Whole cycle repeats
4 hormones controlling menstrual cycle
FSH (follicle stimulating hormone)
Oestrogen
LH (luteinising hormone)
Progesterone
Where’s follicle stimulating hormone produced ?
Function?
Pituitary gland
Causes a follicle to mature in ovaries and stimulates oestrogen production.
Follicle
An egg and its surrounding cells
Where’s oestrogen released?
Function?
Released by ovaries
Causes uterus lining to thicken / grow
Stimulates LH surge
Where’s luteinising hormone released?
Function?
Pituitary gland
Stimulates ovulation at day 14 so follicle ruptures and egg is released.
Stimulates remains of follicle to be a corpus luteum (secretes progesterone)
Where’s progesterone released?
Corpus Luteum (after ovulation ) Maintains uterus lining/ inhibits release of FSH and LH Fall in progesterone levels = endometrium breakdown = FSH increase
What will happen to progesterone levels if a fertilised egg implants in the uterus?
Progesterone levels will stay high to maintain endometrium during pregnancy
Infertile
Unable to reproduce naturally
2 ways in which an infertile couple can become pregnant
Clomifene therapy
IVF (in vitro fertilisation)
Clomifene therapy
Drug causing more FSH/ LH release, stimulating egg maturation/ovulation.
IVF
Collecting eggs and lab fertilising them w sperm, growing into embryos.
Transferred to uterus to improve pregnancy chance. FSH/LH given before to stimulate egg production.
Example of assisted reproductive technology
Assisted reproductive technology
Fertility treatment involving egg fertilisation outside of body.
Contraceptives
Hormones (eg, progesterone/ oestrogen) to prevent egg release, minipill, injection, patch or barrier methods (condoms/diaphragms )
How does oestrogen contraceptive work?
Keeps levels high to inhibit FSH production so egg development/production stops
How does progesterone hormone work?
Stimulates thick cervical mucus production, preventing sperm getting through uterus entrance.