B1 - Coordination And Control Flashcards
What is a receptor?
A cell that detects stimuli.
What is the purpose of the nervous system?
To enable the body to react quickly to the surroundings.
Give five of the receptors on the body.
Ears, eyes, nose and tongue, skin
Explain how information is passed to the brain.
Once a sensory receptor detects a stimulus, an impulse is sent along the sensory neurons up to the CNS.
How is information passed to the organs?
Impulses are sent from the CNS along motor neurons to the effector organs which are muscles or glands.
What is a reflex?
Some responses to stimuli are automatic and rapid.
Why are reflexes important?
Reflexes run everyday actions and prevent danger and damage.
What are the three types of neuron?
- Sensory
- Motor
- Relay
What is a synapse?
A gap between two nerves.
How do electrical impulses travel across the synapse?
- The impulse arrives at the synapse,
- chemicals are released into the gap between the neurons,
- the chemicals attach to the opposite neuron and form a new electrical impulse.
Give the general sequence of a reflex action.
Stimulus –> receptor –> coordinator –> effector –> response
How is the menstrual cycle controlled?
Hormones control the release of an egg and build of lining in the womb.
What are the three hormones that control the menstrual cycle?
FSH, oestrogen and LH.
Where is FSH released from?
The pituitary gland.
What is ovulation?
The maturing of an egg.
Where is the pituitary gland?
At the bottom of the brain.
What does FSH stand for?
Follicle stimulating hormone.
What two factors does FSH cause?
- Egg maturing
- Stimulates the ovary to produce oestrogen
Where is oestrogen released from?
The ovaries.
What three factors does oestrogen cause?
- The lining of the womb to develop
- The inhibition of FSH production
- Stimulates the release of the mature egg.
What does LH stand for?
Luteinising hormone.
How can hormones prevent pregnancy?
Some contraceptives contain hormones which stop FSH production.
How can hormones be used to improve fertility?
FSH can be used to stimulate eggs to mature which can be used for IVF.
What does IVF stand for?
In vitro fertilisation
What is the Fallopian tube?
The tube between the ovary and womb.
Give three advantages of using fertility treatment.
- Families can be much smaller.
- Population growth can be controlled.
- The eggs can be stored for later use.
Give three disadvantages of using fertility treatment.
- The pill can cause health problems.
- The pill can be expensive.
- Some religious groups dislike contraception.
Give four conditions that have to be controlled in the body.
- Core body temperature
- Water level
- Ion level
- Blood sugar level.
What is homeostasis?
The controlling of conditions in the body.
How are the levels of water and salts controlled?
The kidneys control how much salt and water is lost in the urine.
What stimuli are plants responsive to?
Light, moisture and gravity.
Which hormones cause responses in plants?
Auxin
How do plants react to gravity?
Plant roots grow downwards into soil to get water and minerals.
How do plant shoots react to different conditions?
Shoots are sensitive to light and gravity so the plant grows towards the light.
What is phototropism?
The response of a plant to light.
What is geotropism/gravitropism?
The response of a plant to gravity.
How does auxin control the response of a plant?
The auxin hormone is unevenly distributed causing an unequal growth rate.
How does auxin relocate in accordance to light?
- Auxin moves to the unlit side so the shoot bends.
- When whole of the shoot is lit, the levels of auxin is even meaning the shoot grows straight.
How does auxin effect roots and shoots?
Auxin inhibits growth in roots and promotes growth in shoots.
How can plant hormones be used?
- Gardeners use hormones as rooting powder for cuttings.
- Farmers can use hormones as weed killer.
How do plant hormones kill weeds but not other crops?
- Weeds are broad leafed and absorb a lot of hormones making them grow uncontrollably, hence killing them.
- Narrow leafed plants such as grass and cereal are unaffected.
Give an advantage of using FSH for older women.
They are able to have a baby.
Give one example of when the use of a plant hormone has caused excessive damage.
Agent Orange
