Somatic Senses Are Related to Detection of
Pressure, Chemicals, Proprioception, and Touch
the location and function
of receptors for the somatic senses
(tactile, thermal, pain).
the receptors for propriocep-
tion and describe their functions.
the neural pathways in-
volved in somatic senses.
ou know about the world around
. Sensations are detect-
ed by specialized nerve receptors
that detect a change in the body’s internal or external
environment. Each receptor is specific to a par-
ticular type of sensation. When a receptor is
stimulated, it initiates a signal in the associat-
ed dendrite, which conducts impulses related
to the sensation to the central nervous system
pain, temperature, and proprioception. Recep-
tors for the somatic senses are spread diffusely
around the body in structures such as the skin,
mucous membranes, muscles, tendons, and
joints (Figure 8.1a).
Visceral senses have receptors within the
walls of the internal organs that detect pain and
scious or subcon-
scious awareness of
changes in internal or
can occur in all parts
of the CNS.
scious awareness and
interpretation of sen-
sations; occurs only in
the cerebral cortex.
Tactile sensations: touch, pressure,
Proprioception: joint and muscle position,
movements of head and limbs
Thermal sensations: hot, cold
b. Visceral senses
(conditions within the
• Changes in
• Blood pressure
O verview o f se n satio n s • Figure 8.1
The neural pathway for sensations consists of the following: Stimulus ^ sensory receptor
^ neural pathway ^ brain (integrate nerve impulses) ^ sensation. For example, when
the skin of the cheek is touched, sensory receptors are stimulated, and a nerve impulse is
transmitted through the trigeminal nerve (cranial nerve V) to the cerebrum for integration
leading to perception of the sensation.
nose, eyes, ears
228 CHAPTER 8
Somatic Senses and Special Senses