Topic 7 - Animal coordination, control and homeostasis Flashcards
What is homeostasis?
The regulation of conditions inside your body (and cells) to maintain a stable internal environment, in response to changes in both internal and external conditions
Name the 6 endocrine glands?
- Pituitary gland
- Adrenal gland
- Testes
- Ovaries
- Thyroid gland
- Pancreas
What are hormones?
A chemical messenger which travels in the blood to activate target cells.
Where is the pituitary gland located?
Under the brain
What is the pituitary gland known as?
‘The master gland’
What do the hormones in the pituitary gland usually do?
Regulate body conditions
Where is the Thyroid gland located?
Near the throat
What does the Thyroid gland produce?
Thyroxine
What does the Ovaries produce?
Oestrogen
What does the Testes produce?
Testosterone
What does the Adrenal glands produce?
Adrenaline
What does the Pancreas produce?
Insulin
What does Adrenaline prepare the body for?
‘fight or flight’
Where are the Adrenal glands in the body
Just above the kidneys
What does the Adrenaline do?
1) Increases the heart rate and blood pressure
2) Increases blood flow to muscles
3) Increases blood sugar (glucose) levels
How does Adrenaline increase blood glucose levels?
Stimulates the liver to break glycogen down into glucose
How does Adrenaline increase the heart rate and blood pressure
It binds to specific receptors in the heart. This causes the heart muscle to contract more frequently and with more force.
Adrenaline causes the heart rate and blood pressure to increase, this also increases….
Blood flow to the muscles.
What does increasing the blood flow do to the cells?
Cells receive more oxygen and glucose for increased respiration
What does Adrenaline bind to?
- Receptors in the heart
- Receptors in the liver
Where is the Thyroid gland
In the neck
What is the hormone that the pituitary gland produces which stimulates the production of Thyroxine?
TSH - Thyroid Stimulating Hormone
What happens when Thyroxine levels are too low?
The pituitary will release TSH.
This stimlates the thyroid gland to release more thyroxine
So thyroxine levels in the blood increase back to normal.
What happens if Thyroxine levels are too high?
The thyroxine will inhibit (stop) the pituitary gland from producing TSH.
Less TSH means that the thyroid gland won’t release as much thyroxine.
So thyroxine levels in the blood fall back to normal.
negative feedback
hypothalamus
negative feedback
What is Thyroxine’s role?
Regulating metabolic rate
What is metabolic rate?
The speed at which chemical reactions in the body occur.
What is 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
What happens in Stage 1 of the Menstrual cycle?
Day 1 = Menstruation starts:
The lining of the uterus breaks down and is released
What happens in Stage 2 of the Menstrual cycle?
Day 4 - 14
Uterus lining is repaired
What happens when the uterus lining is repaired?
The lining builds up until it becomes a thick spongy layer full of blood vessels ready for a fertilised egg to implant there
What happens in Stage 3 of the Menstrual cycle?
Day 14 - Ovulation
What happens during Ovulation?
An egg develops and is released from the ovary
What happens in Stage 4 of the Menstrual cycle?
Day 14 - 28 = The uterus lining is maintained:
What causes the cycle to start over again?
If no fertilised egg lands on the uterus wall by day 28, the spongy lining starts to break down again.
What are the 4 Hormones that controls the Menstrual Cycle?
FSH
LH
Oestrogen
Progesterone
What are the 2 Hormones released by the Pituitary gland?
LH & FSH
What does the FSH do in the Menstrual cycle?
1) Released by the pituitary gland
2) Causes a follicle to mature in one of the ovaries
3) Stimulates oestrogen production
What does the Oestrogen do in the Menstrual cycle?
1) Released by ovaries
2) Causes the lining of the uterus to thicken and grow
3) Target organs are pituitary and uterus
4) A high level of oestrogen causes a rapid increase of LH (surge)
What does the LH do in the Menstrual cycle?
1) Released by pituitary
2) The LH surge stimulates ovulation (only at Day 14)
3) The follicle opens (ruptures) and the egg is released.
4) Remains of the follicle develop into corpus luteum
What does the Progesterone do in the Menstrual cycle?
1) Released by corpus luteum after ovulation
2) Maintains uterus lining
3) Inhibits FSH and LH
4) When the progesterone levels fall and there is a low oestrogen level the uterus lining breaks down.
5) Low progesterone allows FSH to increase and cycle restarts
What is the definition if Contraception?
Any artificial method people use to prevent pregnancy
What are the two categories for contraception?
- Hormonal methods
- Non-hormonal methods
What hormones do the hormonal methods of contraception rely on?
Oestrogen and Progesterone
How does Oestrogen prevent pregnancy?
If oestrogen is released steadily every day, it inhibits FSH which means that no egg will be developed or released
How does Progesterone prevent pregnancy?
It stimulates the production of thick mucus in the cervix - prevents the sperm from reaching the egg
What is the most common hormonal contraceptive?
Combined Oral Contraceptive Pill
What does the Combined Oral Contraceptive Pill contain that helps prevent pregnancy?
Oestrogen and Progesterone
How effective is the Combined Oral Contraceptive Pill?
99%
What are the side effects of the Combined Oral Contraceptive Pill?
- Headaches
- Nausea
What other hormonal contraceptives are there (excluding the pill)
- Progesterone only pill
- Contraceptive patch
- Contraceptive injection
- Contraceptive implant
- Intrauterine device
What is an advantage of the Progesterone only pill?
Has fewer side effects
What is an advantage of the Combined Oral Contraceptive Pill?
It is 99% effective
What is an disadvantage of the Combined Oral Contraceptive Pill?
It has more side effects (headaches & nausea)
How does the Contraceptive patch work?
Sticker on arm the slowly releases oestrogen and progesterone.
How does the Contraceptive injection work?
Injection of progesterone into the upper arm
How does the Contraceptive implant work?
Small device under the skin of the arm, slowly releasing progesterone.
How does the (plastic) Intrauterine device work?
Placed inside the uterus, releases progesterone
How long does the Contraceptive patch last?
1 week
How long does the Contraceptive injection last?
2-3 months
How long does the Contraceptive implant last?
Up to 3 years
How long does the Intrauterine device last?
Over 3 years
What is a non-hormonal (barrier) contraceptive?
They work by preventing the sperm from meeting the egg
What are the non-hormonal methods of contraception?
- Male condom
- Female condom
- Diaphragm
- Sterilisation
What do condoms do?
Trap the sperm to prevent fertilisation
What else do condoms do?
Protects against STDs
How does a diaphragm work?
Fits over the cervix to block the sperm
Are diaphragms reliable
They are unreliable
What are diaphragms’ used with?
Spermicide which kills sperm (not too effective
What is the permanent contraceptive method?
Sterilisation
How does Sterilisation work?
By cutting the fallopian tubes or sperm ducts
Are natural methods reliable?
They are unreliable
What is the most reliable way to prevent pregnancy (100%)?
Abstaining from sex
What is the other non-hormonal type of Intrauterine divide?
Copper IUD/Copper coil - contains no hormones and kills sperm.
What does Infertile mean?
The woman (or animal) cannot reproduce
What is the main reason for infertility?
Low levels of FSH which means that the eggs wont mature.
How can you restore fertility using hormones?
Give FSH in the from of a pill and then give LH to stimulate ovulation.
What is the other solution for infertility if hormones don’t work?
IVF
What does IVF stand for and mean?
In Vitro Fertilisation - meaning that it happens outside the body
How many stages of IVF are there?
5 stages
What happens in Stage 1 of IVF?
Women are given FSH and LH to stimulate their eggs to mature.
What happens in Stage 2 of IVF?
Eggs are collected from the ovaries and fertilised using sperm from the father
How are the eggs and the sperm fertilised during IVF?
In the Lab
What happens if the father has a low sperm count?
Doctors use a technique called ICS1 - sperm is injected into the egg cell using a tiny needle.
What happens in Stage 3 of IVF?
Once fertilised, the sperm and the egg cell are left in an incubator. to form into embryos
What happens in Stage 4 of IVF?
The egg and sperm form into embryos, in the incubator
What happens in Stage 5 of IVF?
1 or more embryos are inserted into the mothers uterus to grow into a foetus.
What is an advantage of IVF?
Infertile couples can have kids.
What are the disadvantages of IVF?
- It does not always work
- Stressful
- Emotionally upsetting
- Painful - abdominal pain & vomiting
- Often leads to multiple births (twins/triplets0
What is the chance of success for IVF in the UK?
1 in 4
Why do doctors put multiple embryos in the uterus during IVF?
To increase the chance of success.
What is the possible outcome of having multiple embryos in the uterus?
Twins or triplets (maybe more)
What is the risk of having multiple births?
a higher risk of complications such as miscarriage or still-birth.
Why might IVF be unethical?
It leads to unused embryos which are eventually destroyed - this was a potential for human life.
What does the recent advancments in microsope technology do?
- Increases the success rate
- Can remove single cells from an embryo to test for diseases
What is the disadvantage to the advancements in microscope technology?
Can find out characteristics of the future babies (gender or eye colour) - which may lead to people choosing the babies they like (illegal )
What is the other reason for Infertility?
They don’t ovulate regularly or at all
What is the solution to infertility due to the inability to ovulate?
Clomifene Therapy
What is Chlomifene?
A drug used to stimulate ovulation
How does Chlomifene Therapy work?
Clomifene blocks the action of oestrogen’s negative feedback on LH, so that more LH is released. This mimics the LH surge and stimulates the release of the eggs.
Why are embryos kept in an incubator whilst in the laboratory?
To provide the optimum temperature for enzymes and thus cell growth
What does our body use to regulate conditions?
Automatic control systems
What are the 3 main components of Automatic control systems?
1) Receptors
2) Coordination centres
3) Effectors
What do the receptors do?
Detect a change
What do the coordination centres do?
Interpret the change and what needs to be done
What do the effectors do?
Carry out the change
Through muscles or glands that release hormones.
What does the Nervous system do?
Sends very fast and precise electrical impulses through nerves. Which allows us to respond to things very quickly.
What does the Endocrine system do?
Release hormones in the bloodstream which travel throughout the body.
What is the main difference between the Nervous and Endocrine system?
Nervous system allows us to respond to things quickly whereas the endocrine system only affects certain cells
What are the other differences between the Nervous and Endocrine system?
Nervous - very fast, precise and quick responses
Endocrine - slower, loger-lasting and more genralised.
What is the process that allows Automatic Control Systems to work?
Negative Feedback
What does negative feedback do?
Decreases or Increases the levels of something to the normal.
What happens if the receptors in the skin detect the cold climate?
Nervous system sends the impuse
To coordination centres (like brain and spinal chord) which interpret the information
Send more signals to effectors (muscles)
Which carry out useful responses such as shivering to return the body tem back to normal.
What would happen if the temperature (or other condition) rises too high?
The cycle would repeat to cool (or lower) the body conditions using different receptors, signals and effectors.
What is blood glucose concentration?
The amount of sugar in our blood stream
What happens if the blood glucose conc is too high?
Damages tissues
What breaks down the carbs from a meal?
Small Intestines
What do the small intestines break down the cabs into?
Lots of glucose
Where does the glucose go after it has been broken down by the small intestine?
Absorbed into the bloodstream.
What organ/gland detects the increase in glucose?
Pancreas
What does the pancreas release when high levels of glucose are detected?
Insulin
How does insulin lower blood glucose?
Binds to receptors of certain cells - mostly liver and muscle cells.
What happens after the insulin binds to the receptors on liver and muscle cells?
Combine the glucose molecules to form glycogen
What is the glycogen used for?
Long term storage
What is the difference between glucagon and glycogen?
Glucagon is a hormone and glycogen is a large molecule made up of glucose molecules.
What does Glucagon do?
Increases blood glucose
What happens when you have low blood glucose?
The pancreas detects it and secretes glucagon into the bloodstream.
What happens when the glucagon is in the bloodstream?
It travels around the body and minds to mainly liver cells
What happens after the glucagon has binded to the liver cells?
It breaks down the glycogen back into glucose and releases it back into the bloodstream
What does Insulin and Glucagon produce?
A negative feedback loop.
How is Type 1 diabetes started?
Occurs in childhood or teenage years and is lifelong
What is Type 1 diabetes caused by?
When the pancreas stops producing insulin (or only small amounts)
What is the treatment for Type 1 diabetes?
Inject Insulin
Where do you inject the insulin for Type 1 diabetes?
Into their abdomen or thigh.
When do they inject insulin?
After a meal
In what case would they need to inject high amounts of insulin?
After a meal that contains high amounts of carbohydrates and sugars
In what case would they need to inject low amounts of insulin?
If they are exersising regularly as muscles will absorb more glucose from the blood
How and when does Type 2 diabetes happen?
Happens in older people who have had an unhealthy diet for a long time.
What happens in the body of someone with Type 2 diabetes?
They don’t t respond to insulin so cells wont take in glucose from the blood stream.
What are the best ways to treat Type 2 diabetes?
- Have a healthy low-sugar diet
- Exercise regularly
