Illustration of the reflex action of an animal. SE is the sensory nerve-ending. A stimulus passes through the sensory nerve-fiber SF to a nerve-cell SC in the ganglion of a dorsal or afferent (convey towards the center) root (DR) of a spinal nerve. The fiber divides in the spinal cord (SP C) where the message is relayed to an internuncial nerve-cell (A). MO is motor nerve-cell, VR is ventral or efferent nerve, ME is nerve plate, and MU is muscle fiber.

Reflex Action

Illustration of the reflex action of an animal. SE is the sensory nerve-ending. A stimulus passes through…

An illustration showing acute, obtuse, straight, right, and reflex angles.

Acute, Obtuse, Straight, Right, And Reflex Angles

An illustration showing acute, obtuse, straight, right, and reflex angles.

An illustration showing an angle the is greater than a right angle and less than a straight angle. This is an obtuse angle (solid curved arrow). The angle that is greater than a straight angle and less than two straight angles is called a reflex angle (dashed curved arrow).

Obtuse And Reflex Angles

An illustration showing an angle the is greater than a right angle and less than a straight angle. This…

"Illustrating the path of a simple nervous reflex action." — Blaisedell, 1904

Reflex action

"Illustrating the path of a simple nervous reflex action." — Blaisedell, 1904

"Diagram of the simple reflex arc. R, receptor; A, afferent (sensory) neuron; E, efferent (motor) meuron; M, muscle." —Martin, 1917

Reflex Arc

"Diagram of the simple reflex arc. R, receptor; A, afferent (sensory) neuron; E, efferent (motor) meuron;…