Nerves and Hormones Flashcards
What does the nervous system enable?
The nervous system enables humans to react to their surroundings and coordinate their behaviour.
What is the name for cells that detect stimuli?
Receptors.
What is a stimulus?
A change in the environment.
What three features do light receptor cells contain?
A nucleus, cytoplasm and a cell membrane.
How do receptors get information to the brain?
Using nerve cells/neurons.
What happens in a basic reflex arc?
What is a synapse and how does it work?
A synapse is a gap between two neurons. When an impulse arrives at the junction between two neurons, chemicals are released which cross the synapse and arrive at the receptor sites on the next neuron. This starts an electrical impulse in the next neuron.
What is a hormone?
Hormones are chemical messengers secreted by glands and are usually transported to their target audience by the blood stream.
Which out of the below is data about hormones and which is data about nerves?
A=nerves B=hormones
What is ovulation and what day of the menstural cycle does it occur at?
Ovulation is the release of a mature egg from the ovary and it occurs at day 14.
How long is the menstrual cycle?
28 days long.
What is menstruation and how long does it last for?
Menstruation lasts for 5 days and it is the breaking down of the lining of the uterus.
FSH is a hormone secreted by the pituitary gland. Give the two roles of FSH.
- Causes an egg to mature in one of the ovaries
- Stimulates the production of oestrogen in the ovaries.
Oestrogen is a hormone that is secreted by the ovaries. What are its three main roles?
- Causes the pituitary gland to produce LH
- Inhibits the release of FSH
- Builds up the lining of the uterus.
LH is a hormone involved in the menstrual cycle that is produced in the pituitary gland. Describe its role.
Stimulates the release of an egg at around the middle of the menstrual cycle from the ovary.
What is the contraceptive pill?
This stops somone from becoming pregnant. It may contain oestrogen and progesterone to stop eggs from becoming mature or to stop egg production.
What is the difference between early birth control pills and ones used today.
Early birth control pills contained large amounts of oestrogen which caused women to suffer significant side effects however now they contain very low doses of oestrogen and you can even get progesterone only pills.
What are fertility treatments? How do they work?
They are ways to help increase fertility. Giving FSH and LH in a fertility drug can stimulate egs to mature and stimulates oestrogen production. They are used to make lots of eggs mature at the same time time. The eggs are then collected and placed in to a petri dish where they are mixed with a sample of semen. The sperm and eggs mix. Once the eggs have been checked to ensure that they are developing correctly they are inplanted in to the uterus.
Describe which internal conditions need to be kept constant.
- The water content of the body – water leaves
the body via the lungs when we breathe out and via the skin when we sweat to cool us down, and excess water is lost via the kidneys in the urine - The ion content of the body – ions are lost via the skin when we sweat and excess ions are lost via the kidneys in the urine
- Temperature – to maintain the temperature at
which enzymes work best - Blood sugar levels – to provide the cells with
a constant supply of energy.
How do plant shoots respond to light and gravity?
How do plant roots respond to gravity and moisture?
What is auxin?
Auxin is a plant growth hormone
