BIOD 152 AP2
Lab 2 Exam
A&P 2 Lab 2
Special Senses
They are essential for our intellectual functioning (EX: prisoners in solitary
... [Show More] confinement),
personality development, and for life sustaining properties (EX: pain).
How do we detect changes in the environment through our body?
Sensory Receptors- 1st line of reception. They are structures specialized to detect the senses and
also to convert one form of energy into another.
o EX: sensory receptor gathers in information from the environment, converts that energy
into a nerve signal, and then that signal is sent to the brain for processing
Sense Organs: specialized structures composed of nervous tissue and other types of tissues that
work together to enhance the responses we gather from the environment and the sensory
receptors.
RECEPTORS
Thermoreceptors- respond to heat or cold
Photoreceptors- respond to light (found in eyes)
Chemoreceptors- respond to a chemical like an odor or taste
Nociceptor- respond to tissue injuries (pain receptors)
2 broad types of senses:
General Sense- the receptors are widely distributed through the body; muscles, joints,
organs
o Respond to stimuli like general touch, pain, temperature.
Special Sense- limited to the head and innervated by the cranial nerves.
o The sense organs that go along with the sense organs are much more complex,
o EX: vision, hearing, taste, equilibrium, and smell
AUDITORY SYSTEM
Responsible for senses of hearing and equilibrium (balance).
Cranial Nerve VIII (8) vestibulocochlear nerve: responsible for the auditory system
Ear is divided into 3 sections: outer, middle, and inner
o All 3 are responsible for hearing but just the inner ear is responsible for
equilibrium.
o Outer and inner ear are more concerned with conducting the sound waves into
the inner ear where they are processed as sound.
External Ear: a funnel for collecting sound
o Auricle (Pinna)- the ear lobe; its shaped and supported by a very thick skin and elastic
cartilage, no bone present. (no cartilage in the ear lobe at the bottom)
o External Acoustic Meatus- opening in the auricle where the sound waves enter
o Auditory Canal- formed out of the temporal bone of the skull; lined with thick skin and
cartilage.
Guard hairs- present to protect the ear from any debris
Sebaceous glands- secrete oil
Cerumen- earwax; mixture of oil and dead skin; they will coat the guard hairs
and help them do their job
o Tympanic membrane- ear drum; marks the end of the outer ear and beginning of the
middle ear
The surface that faces the auditory canal is a concave shape (turns in)
The inner surface is more convex (turns out)
Middle Ear: about 2-3 mm wide (very small)
o Eustachian Tube: a.k.a auditory tube
Connects the middle ear to the nasopharynx. (which allows air into the
middle ear)
Disadvantage: if there is an infection in the throat region or the
upper respiratory tract, it can travel through the tube and into the
ear.
Also permits pressure equalization. At rest-the tube is closed. When
yawning or swallowing, it will open.
o Auditory ossicles- 6 (3R/3L); smallest bones found in the body; they connect the
tympanic membrane to the inner ear structures. Serve as a bridge for the sound waves
to travel
Malleus (hammer)- attached to [Show Less]