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B5 - Progress Check - Coggle Diagram
B5 - Progress Check
L5 - The Eye
The eye contains two types of receptor cells: rods (detect light intensity) and cones (detect different wavelengths).
- Light enters the eye first by refracting most in the cornea.
- It then passes through the iris, pupil and is refracted by the convex lens, converging on the retina.
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Close object:
- Ciliary muscles contract.
- Suspensory ligaments loosen.
- Lens becomes thicker.
Distant object:
- Ciliary muscles relax.
- Suspensor ligaments pulled tight.
- Lens becomes thinner.
L2 - The Nervous System
The reflex arc consists of a stimulus, receptor, sensory neurone, relay neurone, motor neurone and response.
Reflex actions are involuntary and rapid, they do not involve the conscious part of the brain.
Sensory neurones contain a cell body that stores the cell's genetic information, axons that carry the electrical impulse, a myelin sheath which insulates the axons so that the impulse is not interrupted and dendrites that receive impulses from other neurones.
A synapse is the space between two axon terminals. Neurotransmitters (stored in vesicles) allow for the transmission of electrical impulses from the pre- to post-synaptic neurone. These are then received by the receptor molecules.
L4 - The Brain
Cerebral Cortex:
- Responsible for thought and action.
- Largest part of the human brain.
Cerebellum:
- Regulates motor movements.
- Coordinates voluntary movements such as posture, balance and speech.
Medulla:
- Regulates involuntary processes such as breathing, circulation, sneezing and swallowing.
L7 - Thermoregulation
Thermoregulation is controlled by the hypothalamus; it contains temperature receptors sensitive to blood temperature (as does the skin for external temperatures).
Above 37C:
- Vasodilation (more blood to surface).
- Sweating (large amount of energy requires to evaporate water).
- Hairs lie flat.
Below 37C:
- Vasoconstriction (less energy radiated through skin).
- Shivering (muscle twitches release energy through cellular respiration).
- Hairs stand up (layer of insulating air).
L3 - Reaction Time
Reaction time is the time taken to respond to stimulus; it can be affected by such factors as age, drugs, tiredness, etc...
Control variables:
- Starting distance between thumb and first finger.
- Room's lighting.
- Background noise.
L6 - Eye Disorders
Myopia (short sightedness):
- Light converges before the retina.
- Fixed with a concave lens (spectacles, contact lenses).
Hyperopia:
- Light converges behind the retina.
- Fixed with a convex lens.
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