Chapter 13

Mechano-receptors

Respond to touch, pressure, vibration, stretch, and itch.

Thermo-receptors

Sensitive to changes in temperature.

Photo-receptors

Respond to light energy, located in the retina.

Chemo-receptors

Respond to chemicals such as smell, taste, and changes in blood chemistry.

Noci-receptors

Sensitive to pain-causing stimuli.

Extero-receptors

Respond to stimuli arising outside the body; receptors in the skin for touch, pressure, pain, and temperature.

Intero-receptors

Respond to stimuli arising inside the body; also known as visceroreceptors.

Proprio-receptors

Stretch receptors located in muscles, tendons, ligaments, joints, and connective tissues.

Kinesthetic receptors

Related to the sense of body position and movement.

Epineurium

Connective tissue that surrounds groups of fascicles and blood vessels.

Perineurium

Connective tissue that surrounds a group of axons, forming a fascicle.

Endoneurium

Connective tissue that surrounds an individual axon.

Ventral spinal nerves

Motor (efferent) fibers that innervate skeletal muscles.

Dorsal spinal nerves

Sensory (afferent) fibers that carry impulses from peripheral receptors.

Intrinsic reflexes

Rapid, involuntary, predictable motor responses to a stimulus.

Acquired reflexes

Reflexes that result from practice or repetition, such as driving skills.

Components of a reflex arc

Receptor, sensory neuron, integration center, motor neuron, effector.

Receptor in a reflex arc

The site of stimulus action.

Sensory neuron in a reflex arc

Transmits afferent impulses to the CNS.

Integration center in a reflex arc

The monosynaptic or polysynaptic region within the CNS.

Motor neuron in a reflex arc

Conducts efferent impulses from the integration center to an effector organ.

Effector in a reflex arc

Muscle fiber or gland cell that responds to efferent impulses by contracting or secreting.