Coordination and Control Flashcards
What is the nervous system?
A group of organs that work together to enable us to react to our surroundings and coordinate our behaviour.
Where are the receptors found and what are the receptors sensitive to in these areas?
Receptors are found in:
The eyes - sensitive to light
Nose and tongue - sensitive to chemicals
Ears - sensitive to sound and changes in position
Skin - sensitive to pressure, touch, pain and temperature
How does information from receptors get to the brain?
What then happens?
Information is transferred as electrical impulses that pass along neurons (nerve cells) in nerves to the brain.
The brain coordinates a response to the stimuli.
What are reflex actions? (In general terms)
What types of neurones do they involve?
Automatic and rapid actions that don’t require conscious thought.
Sensory, relay and motor neurones
What is a synapse?
A junction or gap between two neurones, over which a chemical (neurotransmitter) is secreted that causes an impulse to be sent
What is an effector?
What does each type of effector do?
Either a muscle or gland that brings about the response to stimulus.
Muscles contract to bring about movement.
Glands secrete hormones.
Explain the stages in a reflex action/reflex arc.
1) Recptor detects stimuli
2) Impulses from receptor pass along a sensory neurone to a relay neuron in spinal cord (CNS)
3) The impulse passes along the relay neuron.
4) A chemical is transmitted across the synapse between the relay neurone and the motor neurone.
5) The motor neuron is stimulated causing an impulse to be sent to the effector
6) Muscle would then respond by contracting; a gland by secreting (releasing) chemical substances
Give four examples of four internally controlled conditions.
Water content
Ion content
Temperature
Blood sugar
What do hormones do?
Where do they come from and how are they transported to their target organs?
They coordinate many bodily processes, especially the functions of many organs and cells.
They are secreted by glands and are transported by bloodstream.
Give the three main hormones involved in the menstrual cycle and explain what their function is and where they come from.
FSH (follicle stimulating hormone), secreted by the pituitary gland, causes eggs to mature in the ovaries, and stimulates the production of oestrogen.
Oestrogen is produced by the ovaries, it inhibits the production of FSH. It stimulates the production of LH and also stimulates the womb lining to develop to receive a fertilised egg.
LH (luteinising hormone) is made by the pituitary gland and stimulates the mature egg to be released from the ovaries (ovulation).
How are hormones used in oral contraceptives?
Oral contraceptives contain oestrogen and/or progesterone to inhibit FSH production, so that no eggs can mature.
What did the first birth-control pills contain that resulted in women suffering significant side effects?
What is different about modern birth-control pills?
High levels of oestrogen.
Less oestrogen and more progesterone, or only progesterone is now used.
Detail stages in In Vitro Fertilisation. (7)
Include details of how hormones are used in the process.
1) FSH causes the eggs to mature, LH stimulates ovulation.
2) The eggs are collected and placed in a special solution in a petri dish.
3) A sample of semen is collected.
4) The eggs and sperm are mixed in the petri dish.
5) The eggs are checked to ensure they have been fertilised and the early embryos are developing properly.
6) They then grow into embryos, one or two of which are implanted into the uterus at an early stage.
7) If all goes well at least one baby will grow and develop successfully.
How do plant shoots and roots respond to light, moisture and gravity?
What is the response to light called?
What is the response to gravity called?
What is the main plant hormone that controls these responses?
Plant shoots grow towards light (phototropism) and roots grow down towards the force of gravity (gravitropism). Roots also grow towards moisture.
Auxin
Explain how the unequal distribution of auxin causes unequal growth rates, and leads to gravitropism and geotropism. (3)
What happens to the auxin once the plant has grown and responded to light or gravity?
1) If a bean plant is laid on its side in the dark; in the roots and shoots more auxin gathers on the lower side.
2) The root grows more on the side with the least auxin, making it bend and grow down towards the force of gravity, when it has grown down, the auxin becomes evenly spread again.
3) The shoot grows more on the side with the most auxin, making it grow up towards light and away from the force of gravity, when it has grown up the auxin becomes evenly spread.
