THE SENSE You may think that you hear sounds with your ear, smell with your nose, or taste with your tongue, but that is not true. Your sensory organs only collect stimuli and send signals to your brain. Your brain interprets these signals as sounds, sights, smells, tastes, and so forth.

The nervous system’s two parts work together. The CNS includes the brain, brain stem, and spinal cord. The PNS includes four systems of nerves. Sensory neurons in receptors generates an impulse CNS interprets (interneurons) Motor neurons stimulate a response

The spinal cord controls reflexes. sensory neuron sends impulse to spinal cord spinal cord directs impulse to motor neuron does not involve the brain interneuron motor neurons sensory neuron

The senses help to maintain homeostasis. Senses gather stimuli, and send it to the nervous system. Nervous system responds to stimuli. Pupils shrink when too much light enters the eyes. Goose bumps when cold air touches skin.

Birds can also see in the Ultraviolet range We humans only see within a certain range of the electromagnetic spectrum Birds can also see in the Ultraviolet range What are some things we cannot see but we know are out there?

The ear contributes to hearing. mechanoreceptors called hair cells bend in response to vibrations

Dogs can hear at higher frequencies that we can Some animals can hear at lower frequencies (maybe sense earthquakes?) What are some things that we know are out there but that we cannot hear?

Taste and smell use chemoreceptors. Taste uses tongue, and smell uses nose. Chemoreceptors detect chemicals dissolved in fluid.

Mechanoreceptors detect pressure. The skin senses touch. Mechanoreceptors detect pressure. Pain receptors detect damaged tissue. Thermoreceptors detect temperature. pain receptor light pressure receptor hair follicle heavy pressure receptor

CIPA (Congenital Insensitivity to Pain with Anhydrosis) is a rare genetic disorder that affects the nervous system. It prevents the formation of nerve cells that transmit signals to the brain registering pain and temperature. People who suffer from CIPA are unable to feel pain, detect temperature, or even sweat.

Somatosensory cortex

The Primary Sensory Cortex This is part of the brain that receives information about your sense of touch from different parts of your body. Each body part sends information to a different place in your primary sensory cortex. Question: Does your finger or your forearm have more space devoted to it in the primary sensory cortex? 1) Have your partner close his or her eyes. Gently, touch the tip of your partner’s index finger with the tip(s) of 1, 2, or 3 Q-Tips at the same time. 2) Ask your partner how many points he or she feels. Repeat a couple more times, varying the number of toothpicks used. 3) Repeat steps 1 and 2 on your partner’s forearm. Did your partner’s finger or forearm receive more sensory information? Which are likely has more space in the primary sensory cortex?