NERVE CONDUCTION & HEARING
What frequency travels furthest up the cochlea?
Low-frequency sounds travel further along the basilar membrane before causing maximal vibration, so they stimulate hair cells near the apex, also have longer wavelengths
What are the two phases of the breathing cycle?
Inspiration and expiration
Give a brief overview of how sound waves travel through the ear.
Outer Ear: Pinna collects sound and funnels it through the external auditory canal to the tympanic membrane.
Middle Ear: Vibrations of the eardrum are transmitted through the ossicles to the oval window.
Inner Ear: Vibrations enter the cochlea; the basilar membrane responds to specific frequencies, and hair cells convert them into electrical signals.
Auditory Nerve: Signals travel via the cochlear branch of CN VIII to the brainstem and auditory cortex for sound perception.
What are factors that can influence your breathing?
Lung stretch response
Chemicals
Higher brain centers
Irritant response
How is an action potential triggered in the neuron?
Multiple presynaptic neurons release neurotransmitters onto the same postsynaptic neuron at the same time. The graded potentials from different synapses add together at the dendrites or soma. If the combined effect reaches threshold at the axon hillock, an action potential is triggered.
What two areas of the brain are the respiratory centers located?
Medulla oblongata and pons in the brainstem
What is the difference between a signal and synaptic transmission?
Signal- location= inside a neuron, mechanism= electrical (graded potential/action potential), example= Depolarization moving from dendrite to axon hillock
synaptic transmission- location= between neurons, mechanism= Chemical (neurotransmitters) → electrical in next neuron, example= Glutamate released by presynaptic neuron triggers EPSP in postsynaptic neuron
What is the structure where gas exchange occurs?
Alveoli
What is the resting potential of an action potential, and what exactly does that mean? (ie charges inside/outside, which ions where etc)
Na+- Inside neuron= low, Outside neuron= high
K+- Inside neuron= high , Outside neuron= low
RMP (resting membrane potential)- Inside neuron=Negative (-70 mV), Outside neuron= Positive relative to inside
Explain how partial pressures of O₂ and CO₂ determine their diffusion between alveoli and blood.
Partial pressures determine gas diffusion by creating a gradient: oxygen diffuses from the alveoli (high partial pressure) into the blood (low partial pressure), while carbon dioxide diffuses from the blood (high partial pressure) into the alveoli (low partial pressure). This movement of gases down their respective partial pressure gradients is the fundamental principle of gas exchange in the lungs