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While walking in the bush Paul hears a sound which he thinks is the roar of a lion - NSC Life Sciences - Question 4 - 2016 - Paper 1
Question 4
While walking in the bush Paul hears a sound which he thinks is the roar of a lion. He immediately runs to safety. Describe how he hears the sound and describe the ... show full transcript
Worked Solution & Example Answer:While walking in the bush Paul hears a sound which he thinks is the roar of a lion - NSC Life Sciences - Question 4 - 2016 - Paper 1
Step 1
How he hears the sound
Answer
- The sound is initially captured by the pinna, the outer part of the ear, which directs the sound waves into the ear canal.
- These sound waves cause the tympanic membrane (eardrum) to vibrate.
- The vibration is then transmitted to the auditory ossicles (malleus, incus, and stapes) which amplify the sound.
- The stapes transmits this vibration to the oval window of the cochlea.
- The oval window vibrates, creating waves in the fluid (endolymph) within the cochlea.
- These waves stimulate the Organ of Corti, which converts the wave into an electrical impulse.
- The impulse travels along the auditory nerve to the cerebrum, where it is interpreted as the roar of the lion.
Step 2
Describe the role of adrenalin
Answer
- When the sound is perceived as a threat, more adrenalin is secreted into the bloodstream.
- Adrenalin increases muscle tone, preparing the body for rapid action.
- It stimulates the liver to convert glycogen into glucose, providing quick energy sources for the muscles.
- The heart rate increases, ensuring that the muscles receive more glucose and oxygen needed for cellular respiration.
- The rate of breathing increases, allowing for a higher oxygen intake to meet the energy demands.
- Adrenalin causes the constriction of blood vessels to the gut/skin, directing more blood to vital organs and muscles, ensuring they function efficiently during escape.