The Sensory Nervous System: Internal Senses
The Internal Senses include Proprioception and inputs responsible for regulating homeostasis. Homeostasis is a state or tendency towards equilibrium.
Proprioceptors: Proprioception: Sensors that keep track of where the body is in space. The sensory nervous system includes internal monitoring systems that allow us to coordinate movement.
- Mechanoreceptors: Proprioception is carried out by Mechanoreceptors: In the joints, Pacinian Corpuscles detect deformation of the joints In the muscles, Muscle Spindles detect stretching of the muscle fibers In the muscles where tendons connect, Golgi Organs detect stretching of the tendons.
- Vestibular system: An aspect of knowing where you are in space is knowing your orientation One component of your ears, the vestibular system informs your brain of how your body is oriented in space.
The Sensory Nervous System: External Senses
Sight: The retina is the neural portion of the eye Photons (light) activates receptors on the retina and the signal is transported to the CNS via the optic nerve.
- Smell: Aromatic compounds are passed over the olfactory epithelium when you breathe. The olfactory epithelium contains nerve endings that signal to the olfactory bulb and other centers in the brain.
- Touch: Skin: Three separate kinds of nerves detect sensations on the skin 1. Mechanoreceptors: Detect pressure and tension on the skin 2. Thermoreceptors: Detect the temperature of the stimulus 3. Nociceptors: Detect painful stimuli.
- Hearing: Detect sounds and air pressure. Organ of Corti Sound in the form of pressure waves enter the ear, pass through the middle ear and vibrate a membrane in an elegant organ called the Organ of Corti.
- Taste: Receptors on our tongue act in concert with the olfactory system to distinguish taste. There are five basic taste receptors: Salty, Sour, Bitter, Sweet and Umami.