Homeostasis, Variation And Evolution Flashcards
What does homeostasis maintain
It maintains optimal conditions for enzyme action and all cell function
What does the nervous system enable
The nervous system enables humans to react to the surroundings and coordinate their behavior
What are reflex actions
Reflex actions are automatic and rapid it they do not involve the conscious part of the brain
What is the endocrine system composed
It’s composed of glands which secrete chemicals
What chemicals are secreted from the gland’s
Hormones 
The endocrine system is composed of glands which secrete chemicals called hormones. Where are the hormones transferred to?
Hormones go directly into the bloodstream and trigger effects in specific target organs
What is the pituitary gland
It’s called the ‘master gland’ and its in the brain
What does the pituitary gland secrete
It secretes several hormones into the blood in response to body conditions
The purity gland secretes several hormones. what do these hormones do?
These hormones act on other glands to simulate other hormones to be released to bring about effects.
Where is blood glucose concentration monitored and controlled by
The pancreas
What is the main male reproductive hormone called
Testosterone
What do enzymes and cells require
A stable condition in order to work
Define homeostasis
The regulation of internal conditions of a cell or organism to maintain optimal conditions for function in response to internal and external changes
Respiration will use glucose to generate what
Energy
In the human body what does homeostasis control (other than the optimum level)
Blood glucose concentration
body temperature
water levels
Homeostasis consist of a automatic control systems making sure for what
that the internal conditions of the body stay consistent as possible
What does the automatic control system involve in the human body
the nervous system or hormones
What are the features of an automatic control system
Receptor cells
Coordination center
Effector
What’s the use of receptor cells
They detect changes in the environment like the body’s internal conditions for example the concentration of glucose in the blood
or
the bodies external conditions for example the temperature of the skin
What do scientists call changes in the environment
A stimulus
Give an example of a coordination center
The brain
The spinal cord
what does the coordination center do
It receives and processes the information from the receptor cells
What is an example of an effector
A muscle
A gland 
What is the job of the effector
It’s receives information from the coordination center and carries out a response which restores optimum levels
Explain the process of an Automatic control system
A stimulus gets sent to the receptor cells
Then to the coordination center then to the effector
Then it’s produces a response and continues
What is the role of the nervous system
It enables humans to react to their surroundings 
Why are reflex actions important
They help protect us from danger and they are rapid
What two parts does the nervous system consists of
The central nervous system (CNS) = Brain and spinal cord
And other nerves running to and from the nervous system
What is the independent variable
Some thing that has changed
What’s the control variable
Something that cannot change
What’s the difference between the nervous system and the endocrine system
The nervous system is faster but shorter
The endocrine system is slower but acts for longer
What’s the use of the pancreas
The pancreas controls the concentration of glucose in the blood
What’s the use of the ovaries (female) and Tasteas (male)
They release hormones and puberty and in reproduction
What’s the use of the thyroid gland
It produces hormones involved in growth and regulating the body’s metabolic rate (Metabolic rate = how rapidly the body’s reaction takes place)
What’s the use of the adrenal glands
Releases hormones in times of fear or stress
Where is the pituitary gland located
In the brain
What does the pituitary gland do
It’s releases different hormones into the blood depending on the conditions and they react on other glands and cause other hormones to be released
Why is glucose needed by every cell
To release energy by respiration
This is why it’s very important to keep the concentration of glucose constant
What does the pancreas produce
Insulin 
Where does insulin travel
In the bloodstream all around the body
What does insulin trigger for the liver and muscle cells
To store excess glucose as a storage molecule this is called glycogen
What is metabolism
Metabolism is the sum of all reactions in a cell or the body
What is contraception
Preventing fertilization
What’s a common method of contraception
The use of oral contraceptives such as a pill
An implant
A skin patch
Injection
Condom
Diaphragm
In contraception what does the pill do
It contains hormones which prevents the body from producing the hormone FSH
What does FSH (follicle simulating hormone) do
It causes an egg to mature in the ovary
What are the advantages and disadvantage of a contraceptive pill
It is highly effective if taken correctly although it must be taken every day
What happens if a woman forgets to take her contraceptive pill
A risk of pregnancy
What side effects do the contraceptive pills have
A very small risk of breast cancer or blood clots
What does the implant, injection and skin patch contain
Progesterone 
What does the progesterone do
It stops eggs from maturing or being released
What are the advantages of an injection, implant and skin patch
It is more convenient than taking a daily pill
The injection lasts for 13 weeks
The implant lasts for 3 years
The patch lasts for 1 week
What are the disadvantages of an injection, implant and skin patch
They don’t protect against sexually transmitted infections for example HIV
What is oestrogen
It’s the main female reproductive hormone produced in the Overy
At puberty several hormones work together to begin to mature what is released
An egg every 28 days (Ovulation)
What is ovulation
When eggs begin to mature at puberty and a egg is released every 28 days
What does FSH trigger
It triggers an egg to mature in one of the ovaries
What does LH trigger
The mature egg to be released this is called ovulation
What’s 2 fertility treatment for women
When FSH and LH is given in a “fertility drug” to a woman she may then become pregnant in the normal way
In vitro fertilization (IVF)
What does the fertility drug do
It causes the woman to ovulate more than usual
Explain the process of IVF
Fertilization takes place outside the body and the mother is treated with FSH and LH to cause several eggs to mature then they are collected from the mother and a sperm from the father is collected and used to fertilize the egg in the laboratory.
Then the fertilized eggs develop embryos and once the embryos are tiny balls of cells
They are inserted into the mothers uterus (womb) then they develop inside the mother
What is the benefit of IVF
It gives the woman a chance to have a baby of her own
What are the problems of IVF
Very low success rates
Very stressful
Physically demanding on the mother
Could cause multiple births
Not all embryos are transferred to the mother meaning many embryos are destroyed
IVF is expensive
What’s the difference between type 1 and type 2 diabetes
In type 1 the pancreas fails to produce insulin
In type 2 the body no longer responds to insulin
What happens if the blood glucose concentration is too low
If it’s to low the pancreas produces the hormone glucagon that causes glycogen to be converted into glucose and released into the body
What is type 1 diabetes
A disorder where the pancreas fails to produce a certain amount of insulin.
Type 1 diabetes is characterized by controlled high blood glucose levels. How can you treat type one diabetes?
By injecting insulin
What is type 2 diabetes
The body cells no longer respond to insulin produced by the pancreas
What is one risk factor for type 2 diabetes
Obesity
How can you treat type 2 diabetes
By having a controlled diet of carbohydrates and exercise
If the blood glucose concentration is too high what happens
The pancreas produces the hormone insulin that causes glucose to move from the blood into the cells
Give an example of negative feedback
If the blood glucose level is too low, the pancreas releases the hormone glucagon. This travels to the liver in the blood and causes the break-down of glycogen into glucose. The glucose enters the blood stream and glucose levels increase back to normal.
During puberty reproductive hormones cause what
Reproductive hormones cause secondary sex characteristics to develop eg. Pubic hair
Testosterones for the male produces what
Testosterones stimulates the testes to produce sperm
How does the uterus respond to hormones 
The uterus lining becomes thick and spongy
How does an egg become fertilized
If a sperm is present a egg implants into the uterus wall and develops into a baby
If the egg does not become fertilized what happens
The egg and the uterus lining are released this causes a period
What does the Luteinizing hormone (LH) cause
It causes an egg to be released (ovulation)
How is oestrogen produced
By the ovary
What is the function of oestrogen and progesterone
They are involved in maintaining the uterus lining in case the egg is fertilized 
Explain the interactions of FSH, oestrogen, LH, and progesterone in control of the menstrual cycle
In the first stage FSH is released by the pituitary gland
FSH travels in the blood to the ovaries
where it causes an egg to mature
at the same time FSH triggers the ovaries to make Oestrogen
then the pituitary gland releases LH releasing a egg
once the ovary has released its egg in the ovary now produces the hormone progesterone
What does progesterone stop
It stops the pituitary glands from releasing FSH and LH this is to prevent more eggs from maturing or being released
Fertility can be controlled by a variety of
Hormonal and non-hormonal methods of contraption
What are the advantages and disadvantages of condoms and diaphragms
Condoms reduce the risk of STI’s but it can break or slip off
What’s the use of spermicides
They killed or disable sperm and they reduce the chances of fertilization
What’s the use of intrauterine device/IUD for women
It prevents the implementation of an embryo or releases a hormone to reduce the chances of fertilization
What are the advantages and disadvantages of IUD
Highly effective and prevents pregnancy for up to 10 years but it doesn’t protect against sexually transmitted infections 
What do surgical methods of male and female sterilization cause 
In woman it’s prevents the egg from reaching the uterus
In man it’s prevents the sperm from leaving the penis
What are the advantages and disadvantages of surgical methods
It’s highly effective but It’s not easy to reverse so the person has to be certain that they never want children and they do not protect against STI
Abstaining from sexual intercourse during the time after ovulation what is this called
A natural form of contraception
What are the problems of a natural form of contraception
It’s hard to tell when a woman has ovulated and it does not protect us against STI
Name two glands
Adrenal gland
Thyroid gland
Where are the adrenal glands located and what do they produce
They are located on top of the kidneys and in times of fear or stress they produce a hormone called adrenaline that gets released into the blood
What are the main factors of Adrenaline 
It increases the heart rate and boosts the delivery of oxygen and glucose to the brain and muscles preparing the body for ‘fight or fight’ (To run away or fight)
Why is oxygen and glucose needed for Adrenaline 
For aerobic respiration (Respiration=Energy)
Where is the thyroid gland found and what does it release
It’s found in the base of the neck and releases the hormone called thyroxine
What are the effects of thyroxine
It stimulates the bodies basal metabolic rate
Thyroxine plays an important role in growth and development
Explain negative feedback for thyroxine
The level of thyroxine in the blood is monitored by the brain
when the thyroxine levels fall the purity gland releases the hormone TSH into the bloodstream
TSH triggers the thyroid gland to release more thyroxine into the blood
The increased level of thyroxine is detected by the brain
Preventing the purity gland from releasing TSH
As the TSH level falls the thyroid gland releases less thyroxine
But as TSH level increases the thyroid gland releases more thyroxine
