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Palmar may refer to:
In biology, a reflex, or reflex action, is an involuntary, unplanned sequence or action and nearly instantaneous response to a stimulus.
The pharyngeal reflex or gag reflex is a reflex muscular contraction of the back of the throat, evoked by touching the roof of the mouth, back of the tongue, area around the tonsils, uvula, and back of the throat. It, along with other aerodigestive reflexes such as reflexive pharyngeal swallowing, prevents objects in the oral cavity from entering the throat except as part of normal swallowing and helps prevent choking, and is a form of coughing. The pharyngeal reflex is different from the laryngeal spasm, which is a reflex muscular contraction of the vocal cords.
The pupillary light reflex (PLR) or photopupillary reflex is a reflex that controls the diameter of the pupil, in response to the intensity (luminance) of light that falls on the retinal ganglion cells of the retina in the back of the eye, thereby assisting in adaptation of vision to various levels of lightness/darkness. A greater intensity of light causes the pupil to constrict, whereas a lower intensity of light causes the pupil to dilate. Thus, the pupillary light reflex regulates the intensity of light entering the eye. Light shone into one eye will cause both pupils to constrict.
In neuroanatomy, the optic tract is a part of the visual system in the brain. It is a continuation of the optic nerve that relays information from the optic chiasm to the ipsilateral lateral geniculate nucleus (LGN), pretectal nuclei, and superior colliculus.
The patellar reflex, also called the knee reflex or knee-jerk, is a stretch reflex which tests the L2, L3, and L4 segments of the spinal cord. Many animals, most significantly humans, have been seen to have the patellar reflex, including dogs, cats, horses, and other mammalian species.
Reciprocal inhibition describes the relaxation of muscles on one side of a joint to accommodate contraction on the other side. In some allied health disciplines, this is known as reflexive antagonism. The central nervous system sends a message to the agonist muscle to contract. The tension in the antagonist muscle is activated by impulses from motor neurons, causing it to relax.
Tendon reflex may refer to:
The vestibulospinal tract is a neural tract in the central nervous system. Specifically, it is a component of the extrapyramidal system and is classified as a component of the medial pathway. Like other descending motor pathways, the vestibulospinal fibers of the tract relay information from nuclei to motor neurons. The vestibular nuclei receive information through the vestibulocochlear nerve about changes in the orientation of the head. The nuclei relay motor commands through the vestibulospinal tract. The function of these motor commands is to alter muscle tone, extend, and change the position of the limbs and head with the goal of supporting posture and maintaining balance of the body and head.
The stretch reflex, or more accurately "muscle stretch reflex", is a muscle contraction in response to stretching a muscle. The function of the reflex is generally thought be maintaining the muscle at a constant length but the response is often coordinated across multiple muscles and even joints. The term deep tendon reflex is often wrongfully used by many health workers and students to refer to this reflex. "Tendons have little to do with the response, other than being responsible for mechanically transmitting the sudden stretch from the reflex hammer to the muscle spindle. In addition, some muscles with stretch reflexes have no tendons ".
In the fields of optometry and ophthalmology, the Hirschberg test, also Hirschberg corneal reflex test, is a screening test that can be used to assess whether a person has strabismus.
The Snout reflex or a "Pout" is a pouting or pursing of the lips that is elicited by light tapping of the closed lips near the midline. The contraction of the muscles causes the mouth to resemble a snout.
The asymmetrical tonic neck reflex (ATNR) is a primitive reflex found in newborn humans that normally vanishes around 6 months of age. It is also known as the bow and arrow or "fencing reflex" because of the characteristic position of the infant's arms and head, which resembles that of a fencer. When the face is turned to one side, the arm and leg on that side extend, and the arm and leg on the opposite side flex. It is more likely to be seen in premature infants than full-term babies. It is rare in newborns but can be stimulated from infants to up to 3 months old. It is believed to help develop hand-eye coordination and help with awareness of both sides of the body.
The tonic labyrinthine reflex (TLR) is a primitive reflex found in newborn humans. With this reflex, tilting the head back (extension) while lying on the stomach causes the back to stiffen and even arch backwards, the legs to straighten, stiffen, and push together, the toes to point, the arms to straighten. The reverse happens to arms and legs with neck flexion. The presence of this reflex beyond the newborn stage is also referred to as abnormal extension pattern or extensor tone.
Primitive reflexes are reflex actions originating in the central nervous system that are exhibited by normal infants, but not neurologically intact adults, in response to particular stimuli. These reflexes are suppressed by the development of the frontal lobes as a child transitions normally into child development. These primitive reflexes are also called infantile, infant or newborn reflexes.
Frontal release signs are primitive reflexes traditionally held to be a sign of disorders that affect the frontal lobes. The appearance of such signs reflects the area of brain dysfunction rather than a specific disorder which may be diffuse, such as a dementia, or localised, such as a tumor.
The palmomental reflex (PMR) or Marinesco-Radovici Sign or Kinn reflex or Marinesco Reflex is a primitive reflex consisting of a twitch of the chin muscle elicited by stroking a specific part of the palm. It is present in infancy and disappears as the brain matures during childhood but may reappear due to processes that disrupt the normal cortical inhibitory pathways. Therefore, it is an example of a frontal release sign.
The palmar grasp reflex is a primitive and involuntary reflex found in infants of humans and most primates. When an object, such as an adult finger, is placed in an infant's palm, the infant's fingers reflexively grasp the object. Placement of the object triggers a spinal reflex, resulting from stimulation of tendons in the palm, that gets transmitted through motor neurons in the median and ulnar sensory nerves. The reverse motion can be induced by stroking the back or side of the hand. A fetus exhibits the reflex in utero by 28 weeks into gestation, and persists until development of rudimentary fine motor skills between two and six months of age.
The Golgi tendon organ (GTO) is a proprioceptor – a type of sensory receptor that senses changes in muscle tension. It lies at the interface between a muscle and its tendon known as the musculotendinous junction also known as the myotendinous junction. It provides the sensory component of the Golgi tendon reflex.
References
- ↑ Gieysztor, Ewa Z.; Sadowska, Ludwika; Choińska, Anna M.; Paprocka-Borowicz, Małgorzata (2018). "Trunk rotation due to persistence of primitive reflexes in early school-age children". Advances in Clinical and Experimental Medicine. 27 (3): 363–366. doi: 10.17219/acem/67458 . ISSN 1899-5276.
- Galant's reflex - whonamedit.com
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