REFLEX ACTION MECHANISM , for Instance, Patellar Reflex = Knee-Jerk

REFLEX ACTION MECHANISM, for instance, patellar reflex = knee-jerk

Striking thepatellar tendonwith areflex hammer[4] just below thepatella [11]stretches [1] thequadriceps muscle. This produces a signal (an afferent [9] impulse) which travels back, through a sensory neuron, to the spinal cord [3] and synapses [5] in the spinal cord, completely independent of any higher centre [10]. From there, a motor neuron[6] conducts an efferent [8] impulse back to thequadriceps muscle, triggering [7] contraction. This contraction, coordinated with the relaxation of the flexor hamstring [2] muscle causes the leg to kick. This reflex is a reflex of proprioception [12] which helps maintainpostureandbalance, allowing to keep one's balance with little effort or conscious thought.

The patellar reflex is a clinical and classic example of the monosynapticreflex arc. The bipolar sensory neuron synapses directly on a motor neuron in the spinal cord.

1.- To pull something so that it becomes longer / 7.- To make something function
2.- A muscle at the back of the upper part of your leg / 8.- An impulse that comes
3.- A set of nerves that connect the brain to other nerves in the body (it's made of gray and white matter) / 9.- An impulse that goes
4.- A tool with a rubber part at the top that a doctor uses to hit a tendon and test a reflex / 10.- The brain, for instance
5.- To establish a connection between nerve cells / 11.- The kneecap or knee bone
6.- A nerve cell that conducts an impulse / 12.- Perception of your own position or movement

THE FIVE SENSES

STIMULUS / Receptor / Type / Organ / Sense
Light / Cones and rodes in the retina. / Photoreceptors / Eye / Sight or vision
Sound vibrations / Receptor cells in cochlea. / Mechanoreceptors / Inner ear / Hearing or audition
Contact, pressure or puncture / Receptors and nerve endings of the dermis. / Skin / Touch
Changes of temperature / Specific receptors in the dermis. / Thermoreceptors / Skin / Touch
Substances dispersed in the air / Receptor cells in the olfactory epithelium / Chemoreceptors / Olfactory epithelium / Smell
Molecules dissolved in water or saliva / Receptor cells in taste buds / Tongue / Taste