Crossed Extensor Reflex

picture info	Crossed Extensor Reflex The crossed extensor reflex or crossed extensor response or crossed extension reflex is a reflex in which the contralateral limb compensates for loss of support when the ipsilateral limb withdraws from painful stimulus in a withdrawal reflex. During a withdrawal reflex, the flexors in the withdrawing limb contract and the extensor In anatomy, extension is a movement of a joint that increases the angle between two bones or body surfaces at a joint. Extension usually results in straightening of the bones or body surfaces involved. For example, extension is produced by extendin ...s relax, while in the other limb, the opposite occurs as part of the crossed extensor reflex. Besides shifting the body weight to the other side, the reflex pathway is also associated with leg coordination when walking by flexing muscle on one side, while extending muscle on the other side. This crossed extensor response is properly part of the withdrawal reflex. An example of this is when a person steps on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Reflex In biology, a reflex, or reflex action, is an involuntary, unplanned sequence or action and nearly instantaneous response to a stimulus. Reflexes are found with varying levels of complexity in organisms with a nervous system. A reflex occurs via neural pathways in the nervous system called reflex arcs. A stimulus initiates a neural signal, which is carried to a synapse. The signal is then transferred across the synapse to a motor neuron which evokes a target response. These neural signals do not always travel to the brain, so many reflexes are an automatic response to a stimulus that does not receive or need conscious thought. Many reflexes are fine-tuned to increase organism survival and self-defense. This is observed in reflexes such as the startle reflex, which provides an automatic response to an unexpected stimuli, and the feline righting reflex, which reorients a cat's body when falling to ensure safe landing. The simplest type of reflex, a short-latency reflex, has a s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Noxious Stimulus A noxious stimulus is a stimulus strong enough to threaten the body’s integrity (i.e. cause damage to tissue). Noxious stimulation induces peripheral afferents responsible for transducing pain (including A-delta and C- nerve fibers, as well as free nerve endings), throughout the nervous system of an organism. The ability to perceive noxious stimuli is a prerequisite for nociception, which itself is a prerequisite for nociceptive pain. A noxious stimulus has been seen to drives nocifensive behavioral responses, which are responses to noxious or painful stimuli. These include reflexive, escape behaviors, to avoid harm to an organism's body. Because of rare genetic conditions that inhibit the ability to perceive physical pain, such acongenital insensitivity to pain and anhydrosis (CIPA) noxious stimulation does not invariably lead to tissue damage. Noxious stimuli can either be mechanical (e.g. pinching or other tissue deformation), chemical (e.g. exposure to acid or irritan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Withdrawal Reflex The withdrawal reflex (nociceptive flexion reflex or flexor withdrawal reflex) is a spinal reflex intended to protect the body from damaging stimuli. The reflex rapidly coordinates the contractions of all the flexor muscles and the relaxations of the extensors in that limb causing sudden withdrawal from the potentially damaging stimulus. Spinal reflexes are often monosynaptic and are mediated by a simple reflex arc. A withdrawal reflex is mediated by a polysynaptic reflex resulting in the stimulation of many motor neurons in order to give a quick response. Example When a person touches a hot object and withdraws their hand from it without actively thinking about it, the heat stimulates temperature and pain receptors in the skin, triggering a sensory impulse that travels to the central nervous system. The sensory neuron then synapses with interneurons that connect to motor neurons. Some of these send motor impulses to the flexors that lead to the muscles in the arm to contract, whi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Flexor A flexor is a muscle that flexes a joint. In anatomy, flexion (from the Latin verb ''flectere'', to bend) is a joint movement that decreases the angle between the bones that converge at the joint. For example, one’s elbow joint flexes when one brings their hand closer to the shoulder. Flexion is typically instigated by muscle contraction of a flexor. Flexors Upper limb of the humerus bone (the bone in the upper arm) at the shoulder Pectoralis major Anterior deltoid Coracobrachialis Biceps brachii of the forearm at the elbow Brachialis Brachioradialis *Biceps brachii of carpus (the carpal bones) at the wrist flexor carpi radialis flexor carpi ulnaris *palmaris longus of the hand flexor pollicis longus muscle flexor pollicis brevis muscle flexor digitorum profundus muscle flexor digitorum superficialis muscle Lower limb Hip The hip flexors are (in descending order of importance to the action of flexing the hip joint):Platzer (2004), p 246 Coll ... [...More Info...] [...Related Items...] OR:* [Wikipedia] [Google] [Baidu]
	Extensor In anatomy, extension is a movement of a joint that increases the angle between two bones or body surfaces at a joint. Extension usually results in straightening of the bones or body surfaces involved. For example, extension is produced by extending the flexed (bent) elbow. Straightening of the arm would require extension at the elbow joint. If the head is tilted all the way back, the neck is said to be extended. Muscles of extension Upper limb of arm at shoulder Axilla and Shoulder Latissimus Dorsi * Posterior Fibres of Deltoid **Teres Major of forearm at elbow Posterior compartment of the arm Triceps Brachii *Anconeus of hand at wrist Posterior compartment of the forearm * Extensor carpi radialis longus *Extensor carpi radialis brevis Extensor carpi ulnaris *Extensor digitorum of phalanges, at all joints Posterior compartment of the forearm Extensor digitorum Extensor digiti minimi (little finger only) Extensor indicis (index finger only) ... [...More Info...] [...Related Items...] OR:* [Wikipedia] [Google] [Baidu]