SB7- Animal coordination, control and homeostasis Flashcards
What’s the hormonal system
Another response other than the nervous system - it works more slowly than the nervous system but can cause responses in many parts of the body
What does the hormonal system use
Chemical messengers callee hormones are carried by the blood and so take time to get around the body
Different hormones are released by a range of endocrine glands
What are the endocrine glands
Include pituitary, thyroid, adrenals, ovaries, tested and pancreas
What does the pituitary gland release
Many hormones including
ACTH
FSH
LH
And growth hormone
What does the thyroid gland produce
Several hormones including thyroxine
What gland does the pancreas produce
Some cells produce insulin and other produce glucagon
What hormone do the ovaries produce
The was hormones oestrogen and progesterone
What hormone do the testes produce
Testosterone
What hormone do the adrenal glands produce
Several hormones including adrenalin
What’s a target organ
An organ specially affected by a specific hormone
The hormone affects the organ by changing what the organ is doing - eg growth hormone stimulates cells in muscles and bones to divide, it also stimulates the digestive system to absorb calcium ions - also used to help make strong bones
Tell me about some endocrine glands being the target organs for other hormones
For the sex hormones oestrogen and testosterone which are released by reproductive organs, stimulate the release of growth hormone
The release of sex hormones increases during puberty which helps to increase the growth rate at this time
What’s your metabolic rate
Is the rate at which the energy stored in your food is transferred by all the reactions that take place in your body to keep you alive
How is resting metabolic rate measured
Measured with the body at rest in a warm room and long after the person last had a meal
Tell me about thyroxine and metabolic rate
Thyroxine is taken into, and affects many different kinds of cell
It causes heart cells to contract more rapidly and strongly and it also increases the rate at which proteins and carbohydrates to break down inside cells
Why is thyroxine concentration in the blood an example of negative feed back
An increase in thyroxine concentration directly causes changes that bring a decrease in amount of thyroxine being released into blood
Negative feedback loops
Check pg 144 diagram
What is adrenalin
A hormone that is released from the adrenal glands - normally very little is released into the blood
When do amounts of adrenalin in blood change
In frightening or exciting situations - an increase in impulses from the neurones reaching the adrenal glands from the spinal cord triggers the release of large amounts of adrenalin into the blood
What are the target organs of adrenalin
Including the liver in which causes the breakdown of a storage substance called glycogen
Glycogen is a polymer made of glucose molecules, when glycogen is broken down, the glucose molecules can be released into the blood providing additional glucose for respiration
What’s the fight or flight response
Some of the other target organs and effects of adrenalin together these effects prepare the body to fight or run away from danger
Hear muscle cells contract more rapidly to increase heart rate and more strongly to increase blood pressure
Diameter of blood vessels to muscles increase and to organs decease
Liver cells change glycogen to glucose
What’s the menstrual cycle
A cycle of changes in a woman’s reproductive system
It prepares the body for fertilisation of an egg cell, leading to pregnancy
How long does the menstrual cycle last for
28 days
When does the cycle start and end
Around 12 at puberty and ends in early 50s (menopause)
What happens in days 1 to 5 of the cycle
This is menstruation - when the uterus lining breaks down and is lost with the unfertilised egg cell
Progesterone levels are low
Oestrogen levels are lol
At day 4, low levels of progesterone allow FSh to be released to cause the growth and maturation of egg
When and what happens when menstruation ends
Menstruation ends at day 10, the uterus lining start to thicken again
Oestrogen levels are now rising a lot, progesterone levels still low
Oestrogen levels stimulate release of more LH - LH surge triggers ovulation
When and what happens in ovulation
Days 13-15, the ovary releases the egg
Oestrogen levels are high and progesterone levels begin to rise now
As progesterone begins to be released - this inhibits FSH and LH being released
What happens from days 16 to 28!
Fertilisation lead if to pregnancy is most likely around days 18 to 20
The uterus lining continues to thicken
Around day 25 the egg cell travels along the oviduct to the uterus, progesterone levels high and start to fall around 28 and cycle starts again, oestrogen levels have decreased from day 14 and then stayed the same and now are falling a bit too and cycle ends
What hormones is the cycle controlled by
Oestrogen and progesterone- which are released by the ovaries in to the blood
How can fertilisation occur
During sexual intercourse, sperm cells are deposited in the vagina, they then pass through the cervix to the uterus and into the oviducts - if a sperm cell meets an egg cell fertilisation can occur
What’s contraception
Is the presentation of fertilisation- there are hormones and then physical barriers
What’s the success rate and how does the male condom work
98% succes
It’s placed over an erect penis to prevent sperm entering the vagina
Tell me about the success and how a diaphragm or cap works
92-6% success
It’s placed over the cervix (entrance to the uterus) prevents sperm in the vagina entering the uterus
Tell me about the success and what the hormone pill or implant placed under the skin
> 99% success rate
It releases hormones to prevent ovulation and thickens mucus to the cervix making it difficult for sperm to pass through
What is FSH and LH
Follicle stimulating hormone - FSH and Luteinisong hormone is released from pituitary gland, release of hormones are controlled by concentration of oestrogen and progesterone released after ovulation when egg cell becomes a corpus luteum structure
When do levels of oestrogen increase
Levels increase as the egg follicle matures
When can FSH be released
When there are low levels of progesterone
What does increasing progesterone do to levels of FSH and LH
Increasing progesterone inhibits FSH and LH
What do high levels of oetrogen allow
Stimulate release or more LH
Oestrogen levels are stimulated to rise from maturing follicles
What does increasing oestrogen levels do to uterus lining
It causes it to thicken
What hormone does the corpus luteum release
Progesterone
What do falling levels of oestrogen and progesterone cause
Menstruation