EQ: How does an individual smell odors and hear things? The Senses Part 2 EQ: How does an individual smell odors and hear things?

Sense of Smell

Olfactory Receptor cells Bipolar neurons surrounded by columnar epithelial cells Hair like cilia cover distal ends of neuron’s dendrites

Olfactory Bulb Structure above nasal cavity that analyze impulses from receptor cells.

Humans use about 12 million olfactory receptors Bloodhounds have about 4 billion

Sense of Hearing

Organs for hearing Outer Ear Middle Ear Inner Ear

Outer Ear

Pinna Outer flap used for catching sound waves

External Acoustic Meatus AKA Ear Canal Adult runs about 2.5 cm

Tympanic Membrane AKA Eardrum Sound waves change the pressure of eardrum, thus producing vibrations

Middle Ear

3 Main structures Eardrum Tympanic Cavity Ossicles (3 bones

3 Bones of Middle Ear Malleus: Long handle attached to eardrum

3 Bones of Middle Ear Incus: The bridge bone between malleus and Stapes

3 Bones of Middle Ear Stapes: smallest bone that attaches to Cochlea

Sound travels through middle ear causing eardrum and ossicles to vibrate.

Inner Ear Includes: Semicircular Ducts Cochlea Eustachian Tube

Semicircular Ducts Filled with fluid Attached to Cochlea Sends information about balance

Cochlea Spiral shaped organ filled with fluid. Transforms sound into signal using pressure Signal sent through the Vestibular Nerve and Cochlear Nerve

Eustachian Tube Canal that drains fluid from middle ear into throat behind the nose

LEFT SIDE ACTIVITY Draw a diagram of an ear and a nose. Label all of the parts and a description of their functions