Biology AQA Unit B1a Human Biology - Respoundi
Respounding To Change
The body respounds to external and internal conditions.
- You have glands that produce hormones that are transported around the body by the blood.
- You have electrical impulses that pass along the nervous system.
- All responses are co-ordinated.
Ears - Senstive to sound and change in position. Eyes - sensetive to light. Skin - sensitive to touch, pressure, pain and temperature. Nose and tounge - sensitive to chemicals.
Control of the body's functions and responses involves hormones (chemicals) and the nervous system (electrical impulses.)
REMEMBER: Nervous system impulses are transmitted by electrical impulses. Impulses are transmitted by chemicals in hormone system.
Biology AQA Unit B1a Human Biology - Reflex A
Steps in a reflex action:
- A receptor detects a stimulus (e.g sharp pain.)
- Sensory neurone transmits the impulse.
- Relay neurone passes the impulse on.
- A motor neurone is stimulated.
- Impulse sent to effector (muscle or gland).
- Action is taken.
At the junction between two neurons is a synapse. Chemicals transmit the impulse across the gap.
Biology AQA Unit B1a Human Biology - The Men
The Menstrual Cycle
- FSH - made by the pitutary gland and causes an egg to mature and oestrogen to be produced.
- Oestrogen - produced by ovaries and inhibits further production of FSH. Stimulates production of LH and stimulates the linning of the womb to develop ready to recieve a fertilised egg.
- LH - made by pituitary gland and stimulates a mature egg to be released.
The Menstrual Cycle takes place every 28 days with ovualtion taking place about 14 days into the cycle.
The cycle is controlled by three hormones.
Biology AQA Unit B1a Human Biology - The Art
The Artificial Control of Fertility
The contraceptive pill contains oestrogen, this prevents the production of FSH so no eggs mature.
If a women cannot produce mature eggs then FSH can be given. This is known as fertility treatment.
Stages to artificial control of fertility:
- Fertility drug are used to make lots of eggs mature at the same time.
- Eggs are collected and places in a petri dish.
- A ***** sample is taken.
- Semen and eggs mixed in petri dish.
- Eggs are checked to check they are fertilised and developing.
Eggs are placed into mothers uterus ones a few cells thick, if all goes well a baby or two will grow.
Biology AQA Unit B1a Human Biology - Controll
Internal conditions that are controlled are:
- Water content - lost in breathing, sweat and urine.
- Ion content - lost in sweat and urine.
- Temperature - if not controlled enzymes in body will not work properly.
- Blood sugar level - is an energy sourse for cells, level of sugar in our blood must be controlled.