Coordination and Control Flashcards
What is a ‘receptor’?
Special sensory cell/organ that detects changes in the environment
What is a ‘stimuli?
A change in the environment that is detected by sensory receptors
Complete the sentence:
The nervous system has…
…receptors to detect stimuli
Where are receptors found?
In sense organs such as the eye, ear, nose, tongue, and skin
What is a sense organ?
A collection of special cells known as receptors which responds to stimuli
What does light stimulate?
Receptors in the eye. Electrical impulses are then produces and pass to the brain along neurons.
Give some examples of different stimuli.
- Sound
- Chemicals
- Temperature changes
- Touch
- Pain
- Smell
What does the brain coordinate?
Responses to many stimuli
What does the nervous system allow humans to do?
Detect and react to their surroundings and coordinate behaviour accordingly
What is the central nervous system (CNS)?
Made up of the brain and spinal cord and is where information is processed.
It coordinates resonses to stimuli
What do nerves contain?
Neurons
What are nerves?
Bundles of hundreds, or even thousands, or neurons
What are neurons?
Nerve cells which carry minute electrical impulses around the body
What are sensory neurons/what do they do?
Neurons which carry impulses from the sensory organs/receptors to the CNS
What are motor neurones/what do they do?
Neurons which carry impluses from the CNS to effector organs
What are effector organs?
Muscles/glands that respond to impulses from the nervous system (specifically motor neurons)
How do muscles and glands respond to imulses from the nervous system?
Muscles contract, glands secrete chemicals
Describe the stages/order of the nervous system/how it works.
- Sense organs/receptors detect external stimuli
- Sensory neurons then carry electrical impulses from these receptors to the CNS
- The CNS coordinates a response (reflex or thought through)
- Motor neurons then carry impulses from the CNS to effector organs
- The effector organs then carry out the response to the initial stimuli
What are reflexes?
Rapid, automatic responses of the nervous system that do not involve conscious thought
What are the main steps of a reflex action?
- Receptor detects stimulus
- Sensory neuron transmits impulse to the CNS
- Relay neuron passes the impulse on
- Motor neuron is stimulated
- Impulse passes to an effector
- Action/response is taken
What is the name of the junction between two neurons?
A synapse
What is a synapse?
A junction/gap bwteeen two neurons where the transmission of information is chemical rather than electrical
What is a reflex arc?
The name for the sequence from receptor to effector when performing a reflex action
How long does the menstrual cycle take?
About 28 days (1 month)
When does ovulation occur in the menstrual cycle?
About 14 days into the cycle
What is FSH and what does it do?
Follicle stimulating hormone is made by the pituitary gland and causes the egg to mature and oestrogen to be produced.
What is the pituitary gland/what does it do?
Small gland in the brain which produces a range of hormones controlling body functions
What is oestrogen and what does it do?
Hormone produced in the ovaries. Inhibits further production of FSH and stimulates the production of LH + the womb lining to develop to recieve a fertilised egg
What is LH and what does it do?
Luteinising hormone made by the pituitary gland. It stimulates the mature egg to be released from the ovary (ovulation)
What is ovulation?
When the mature egg is released from the ovary
Describe the stages of the menstrual cycle.
- FSH, made in the pituitary gland, causes egg to mature + production of oestrogen
- Oestrogen, produced by the ovaries, inhibits further FSH production. Stimulates LH production + development of womb lining ready for ovulation.
- LH, produced in the pituitary gland, stimulates ovulation.
What is the contraceptive pill?
Pill containing female sex hormones, such as oestrogen and progesterone, used to prevent contraception
What is progesterone?
Female sex hormone used in the contraceptive pill
Why are some contraceptive pills progesterone-only?
Because this has fewer side effects than also using oestrogen
How do contraceptive pills work?
Inhibits production of FSH so no eggs can mature. This means that ovulation does not occur, and subsequently neither can pregnancy.
What is a ‘fertility treatment’?
When a woman is given FSH and LH to help produce mature eggs and release them (ovulation) respectively
Describe how IVF works.
- Fertility drugs (containing FSH) are used to make lots of eggs mature at the same time for collection
- The eggs are collected and places in a special solution in a Petri dish
- A sample of semen is collected
- The eggs and sperm are mixed in the Petri dish
- The eggs are checked to make sure they’ve been fertilised and the embryos are developing properly
- 1 or 2 embryos are then placed inside the uterus of the mother. Hopefully, at least one baby will grow + develop successfully.
What are the advantages of contraceptive pills?
- Have helped reduce family size which has helped reduce poverty in some areas
- Allows women to control their pregnancies
What are the disadvantages of contraceptive pills?
- Can cause side effects
- Some people object to it for moral/ethical/religious reasons
What are the advantages of fertility treatments/drugs?
- Fertility drugs can help infertile couples who are having IVF
- IVF can help couples have a baby
What are the disadvantages of fertility treatments/drugs?
- IVF is expensive
- Some people think it is unethical when women have babies using IVF
- Extra embryos produced may be stored/destroyed (unethical/against religions/morals, wasteful)
What is ‘internal environment’?
The conditions inside the body
What internal conditions are controlled by the body?
- Water content
- Ion content
- Temperature
- Blood sugar level
What controls the level of sugar in our blood?
The pancreas
Why must we keep our body temperature constant?
So that enzymes in the body are not denatured/work as efficiently as possible
How do we lose water?
- Breathing
- Sweating
- Excess is lost in urine (produced by kidneys)
How do we lose ions?
- Sweat
- Kidneys
- Urine
How do we lose sugar?
Through respiration
What are plants sensitive to/what do they respond to?
- Light
- Gravity
- Moisture
What is phototrophism?
The response of a plant shoot growing towards light.
It is controlled by auxin
What is gravitrophism?
The response of a plant root growing towards gravity.
It is controlled by auxin
How do plants respond to light, gravity, and moisture?
- Phototrophism
- Gravitrophism
- Roots grow towards water
What is auxin?
A plant hormone which controls phototrophism and gravitrophism
What does unequal distribution of auxin cause?
Unequal plant growth.
This, in turn, results in the bending of the shoot or root
What are the uses of plant growth hormones?
- Can be used as weed killers
- To stimulate root growth
Horticulture + agriculture (respectively)
Describe an experiment that could be used to demonstrate gravitrophism.
- Normal young bean is laid on its side in the dark. The auxin is equally spread
- In the root, more auxin gathers on the lower side
- The root grows more towards the side with the least auxin, making it bend and grow down towards the force of gravity.
- When it has grown downwards, the auxin becomes evenly spread again
- The shoot grows more on the side with the most auxin, away from the force of gravity
- When it has grown upwards, the auxin become evenly spread again
How are hormones used in women?
- Use contraceptive pills to plan + prevent pregnancies
- To help them become pregnant
- To help older women have babies. May involve using an egg donor being given hormones to produce egg-stra eggs.
(It can also be used to write objectifying exam-style questions)
How are hormones used in plants?
- Weedkillers are used to kill unwanted plants
- When cuttings are taken, hormones can be used to encourage root growth before planting
- Can encourgae fruit to ripen
- If used incorrectly can damage the environment. E.g. weedkillers may harm other plants.
