Nervous system II Flashcards
is the process
initiated by stimuli acting on
sensory receptors.
Sensation
is the conscious
awareness of those
sensations.
Perception
are the means by
which the brain receives
information about the
environment and the body
Senses
have receptors distributed over a large part of the body. General senses are touch, pressure, stretch, heat, cold, and pain. Receptors for general senses are located throughout the body.
General senses
are localized to localized to specific organs that have specialized receptors. Special senses are taste, smell, hearing, equilibrium, and vision. Special sense organs are located in the head.
Special senses
detect heat and cold.
Thermoreceptors
detect touch,
vibration, stretch, and pressure. They are stimulated by
mechanically disturbing the dendrite
of the neuron.
Mechanoreceptors
are pain receptors that detect tissue injury or potential tissue injury. These receptors may be stimulated by a chemical, temperature, or mechanical disturbance.
Nociceptors
respond to
changes in chemical concentrations.
Chemoreceptors
respond to light.
Photoreceptors
Are bare dendrites with no associated
connective tissue.
Free nerve endings
It widespread throughout the skin and mucous
membranes.
It functions as thermoreceptors for heat and
cold nociceptors for pain
Free nerve endings
It is located at dermal papillae of the skin; highly
concentrated in the fingertips and palmar skin.
Tactile corpuscles
It functions as
mechanoreceptors for light
touch and texture.
Tactile corpuscles
These are bare dendrites with
no associated connective tissue.
Hair receptors
It functions as
mechanoreceptors for any light
touch that bends a hair
Hair receptors
Single dendrites surrounded by flattened Schwann cells that in turn are surrounded by fibroblasts, giving a layered appearance like tree rings.
Lamellar corpuscles
It functions as
mechanoreceptors for deep
pressure, stretch, and vibration
Lamellar corpuscles
It is long, flattened capsules with
a few nerve fibers.
Bulbous (Ruffini) corpuscles
It functions as
mechanoreceptors for heavy
touch, pressure, and stretching
of the skin.
Bulbous (Ruffini) corpuscles
It functions as
mechanoreceptors for light touch.
Tactile disks
is the term for taste.
Gustation
There are approximately ____
taste buds in the human mouth.
10,000
The surface of the tongue is covered with
bumps called
lingual papillae.
These are banana-shaped and have
hairlike microvilli (taste hairs) on their
surface.
Taste cells
Taste hairs are exposed to molecules
taken into the mouth through a taste
pore of the taste bud.
Taste cells
These are stem cells in the taste bud
that develop to replace taste cells as
they die.
Basal cells
- They physically support the 50 to 150
taste cells in the taste bud. - They do not have a sensory role
Support cells
This taste sensation is caused
by ions from salts binding to the taste
hairs.
Salt
This taste sensation is
caused by sugars
Sweet
This taste sensation is
associated with acids.
Sour
This taste is associated with
alkaloids such as caffeine, nicotine,
and quinine found in tonic water. It is
also associated with spoiled food.
Bitter
This meaty taste is derived from some amino acids binding to the taste hairs. An example of umami is the taste of beef or chicken broth.
Umami
carries sensory
messages from taste buds in the
anterior two-thirds of the tongue
The facial nerve (CN VII)
carries sensory messages from taste
buds on the posterior one-third of the
tongue
The glossopharyngeal nerve (CN IX)
carries sensory messages for taste from the other taste
buds in the mouth..
The vagus nerve (CN X)
sense of smell
Olfaction
receptors for
olfaction that are located in the mucous
membranes of the roof of the nasal cavity,
called
Olfactory mucosa
The rest of the
mucous membrane lining the nasal
cavity. It has no sensory function.
Respiratory mucosa
Bipolar neurons.
Olfactory cells
is the interpretation of sound
waves travelling in air
Hearing
is measured in cycles per second, called Hertz (Hz)
Pitch