Biology Paper 2 Topic 7 – Animal Coordination, Control and Homeostasis Flashcards
What two hormones control the menstrual cycle
Oestrogen and Progesterone
What is menstruation
The breakdown of the uterus lining
What day does menstruation start and how long does it usually last
Begins on day 1 of the cycle and usually lasts about 5 days
What happens during the second week of menstruation
The lining of the uterus is gradually built up
What is ovulation
The release of an egg from an ovary
What day does ovulation usually take place
Around day 14
What is more likely to take place on days 14 to 16
Fertilisation
What happens to the uterus lining if fertilisation occurs
It remains thick so that the embryo can embed in the lining and obtain the nutrients it needs
What happens throughout weeks 3 and 4
The lining of the uterus continues to build up
What happens if fertilisation does occur
Uterus lining is maintained.
Menstruation does not happen.
What are some examples of hormonal contraceptions
Hormone pills, implants or injections
How do hormonal contraceptions work and how do they prevent fertilisation
Works by releasing hormones to prevent ovulation and thicken mucus at the cervix, preventing sperm from entering
What is contraception
Contraception is the prevention of fertilisation
What are the two types of contraception
Hormonal contraception and Barrier methods
What are some examples of barrier methods
Male and female condoms.
The diaphragm.
Caps.
Sponges.
How do barrier methods prevent fertilisation
By stopping the sperm from reaching the egg
What is the cause of type 1 diabetes
The immune system has damaged the person’s insulin-secreting pancreatic cells, so the person does not produce insulin
How is type 1 diabetes controlled
They have to inject insulin into the fat just below the skin. They have to work out the right amount of insulin to inject so that the blood glucose concentration is kept within safe limits.
What is the cause of type 2 diabetes
The person does produce insulin but their liver and muscle cells have become resistant to it.
How is type 2 diabetes controlled
Most people can control their blood glucose concentration by eating foods that contain less sugar, exercising and using medication if needed.
Where are hormones produced and how do they reach their target organs
Hormones are produced by endocrine glands and released into the blood. They travel around the body in the blood until they reach their target organs. Each hormone causes its target organ(s) to respond, e.g. by releasing another chemical substance.
Difference between hormones and nerves
Both help to respond to changes in the environment and in your body.
Hormones usually have a long-lived effect while nerves have a short-term effect.
Nerve impulses work quickly while hormones take longer to work.
When is thyroxine released from the thyroid gland
When the Thyroid gland is stimulated by TSH (released from the pituitary gland).
What does thyroxine do
Causes the heart to contract more rapidly and strongly.
Increases the rate proteins and carbohydrates are broken down.
