Outer ear consists of auricle, external auditory canal, and tympanic membrane. Ear resides in temporal bone, meeting with other skull bones. Healthy ear can hear frequencies between 20-20,000 Hz
The auricle, also known as the pinna, is the visible part of the ear outside the head. It develops from auricular hillocks during the sixth week of fetal development. The first three hillocks form the tragus, crus of the helix, and helix. The final three hillocks form the antihelix, antitragus, and lobule
Most mammals have main and accessory olfactory systems. Peripheral system includes nostrils, ethmoid bone, nasal cavity, and olfactory epithelium. Olfactory neurons detect dissolved odor molecules in mucus. Olfactory nerves transmit information to brain through cribriform plate
The inner ear is the innermost part of vertebrates responsible for sound detection and balance. In mammals, it consists of a bony labyrinth with cochlea and vestibular system. The cochlea converts sound pressure into electrochemical impulses. The vestibular system detects head position, rotation, and linear motion
Auditory pathway conveys hearing from inner ear to central nervous system. Pathway consists of primary (lemniscal) and non-lemniscal pathways. Information travels from spiral ganglion to cochlear nerve through brainstem
Absolute threshold is the smallest detectable stimulus level at least half the time. It applies to all human senses including sound, touch, taste, sight, and smell. No single absolute threshold exists for any sensory experience