Reflex Arc: From 1 Different Sources
the nervous circuit involved in a *reflex, being at its simplest a sensory nerve with a receptor, linked at a synapse in the brain or spinal cord with a motor nerve, which supplies a muscle or gland (see illustration). In a simple reflex (such as the *patellar reflex) only two neurons may be involved, but in other reflexes there may be several *interneurons in the arc.
See under EYE, DISORDERS OF.... arcus senilis
Weakness in the muscles that support the bony arches of the foot. The result is ?at feet, a condition that can adversely affect a person’s ability to walk and run normally.... fallen arches
The arch of bone, commonly known as the cheek bone, on either side of the skull just below the eye socket. The zygomatic arch is formed of the zygomatic and temporal bones.... zygomatic arch
(Greek / Spanish) Feminine form of Arkadios; woman from Arcadia / one who is adventurous Arcadiah, Arkadia, Arcadya, Arkadya, Arckadia, Arckadya... arcadia
(Greek) Angel of high rank Arcangel, Archangela, Archangelia, Archangelica... arcangela
Salix arcticaDescription: The arctic willow is a shrub that never exceeds more than 60 centimeters in height and grows in clumps that form dense mats on the tundra.Habitat and Distribution: The arctic willow is common on tundras in North America. Europe, and Asia. You can also find it in some mountainous areas in temperate regions.Edible Parts: You can collect the succulent, tender young shoots of the arctic willow in early spring. Strip off the outer bark of the new shoots and eat the inner portion raw. You can also peel and eat raw the young underground shoots of any of the various kinds of arctic willow. Young willow leaves are one of the richest sources of vitamin C, containing 7 to 10 times more than an orange.... arctic willow
When a sharp body is drawn along the sole of the foot, instead of the toes bending down towards the sole as usual, the great toe is turned upwards and the other toes tend to spread apart. After the age of about two years, the presence of this re?ex indicates some severe disturbance in the upper part of the central nervous system. The Babinski re?ex may occur transiently during COMA or after an epileptic ?t and need not indicate permanent damage.... babinski reflex
The development of a speci?c response by an individual to a speci?c stimulus. The best-known conditioned re?ex is the one described by Ivan Pavlov, in which dogs that became accustomed to being fed when a bell was sounded salivated on hearing the bell, even if no food was given. The conditioned re?ex is an important part of behavioural theory.... conditioned reflex
Instinctive closing of the eyelids when the surface of the cornea (see EYE) is lightly touched with a ?ne hair.... corneal reflex
A cough induced by intestinal, gastric or uterine irritation, and not from respiratory causes.... cough, reflex
Assessment of victims of major trauma must include maintenance of their airways and breathing. Any false teeth, vomitus and foreign bodies should be removed, and the response to digital stimulation of the posterior pharyngeal wall – the ‘gag re?ex’ – assessed. Even with a normal gag re?ex, the airway may be seriously threatened if vomiting occurs. During the initial stages of resuscitation, careful and constant supervision of the airway is essential, with a high-volume sucker immediately available. If the gag re?ex is absent or impaired, an endotracheal tube should be inserted (see ENDOTRACHEAL INTUBATION).... gag reflex
Get a taste of South America by drinking pau d’arco tea. It has a pleasant, earthy taste, astringent and just a bit bitter. Find out more about its health benefits and side effects!
About Pau D’Arco Tea
Pau D’Arco tea uses the inner bark of the Pink Ipê tree, also known as Pink Lapacho. The tree can be found in many South American countries.
The Pink Lapacho is a large tree which can grow up to 30m tall. Usually, the trunk represents a third of that height, while the rest is used by the tree’s branches. The bark is dark brown, tough and hard to peel, and its branches spring up with opposite and petiolate leaves, and large, tubular-shaped pink flowers which bloom between July and September.
How to make Pau D’Arco Tea
To enjoy some pau d’arco tea, add 3 tablespoons to a pot containing 1 liter of water and bring it to boiling point. Once it reaches boiling point, lower the heat to medium-low and leave it like this for about 20 minutes. Once that’s done, strain the tea and pour it into cups.
Pau d’arco tea can be served both hot and cold. If you want to, you can sweeten it with honey, stevia or fruit juice.
Pau D’Arco Tea Benefits
The inner bark of the Pink Lapacho tea has important active constituents, such as lapachol, lapachone and isolapachone, as well as various flavonoids and tannins. They are transferred to the pau d’arco tea; this way, the beverage helps us stay healthy.
Pau d’arco tea plays an important role in the help against cancer. Cancer patients who have consumed this tea have shown progress, from alleviation of chemotherapy symptoms to complete remission of the cancerous tumors. Pau d’arco tea is also useful in the treatment of other diseases, such as diabetes, fibromyalgia, and lupus.
Drinking pau d’arco tea can help if you’ve got a cold or the flu. It is also useful as a remedy for smoker’s cough, and acts as an expectorant, stimulating coughing in order to get rid of mucus.
It was also discovered that pau d’arco tea increases the production of red blood cells. Although researches are still being made in this area, it is recommended in the treatment for leukemia, anemia and other blood disorders.
Pau d’arco tea is also useful in fighting fungi. It is used to treat yeast infection and candida, due to its antifungal nature. It can help in the treatment for stomach ulcers, tuberculosis, pneumonia, and dysentery. It also protects you against tropical diseases (malaria, schistosomiasis).
Pau D’Arco Tea Side Effects
Pau d’arco tea may act like a blood thinner. Don’t drink this tea at least two weeks before a surgery, otherwise it might increase the risk of bleeding both during and after the surgery, and can decrease the blood clotting speed. You also shouldn’t drink pau d’arco tea if you’ve got a bleeding disorder (hemophilia) or if you’re taking anticoagulants.
If you’re taking any medication, talk to your doctor first before drinking pau d’arco tea. It may interfere with various medications, for example aspirin, enoxaparin, warfarin, and dalteparin.
It is also recommended that you not drink pau d’arco tea if you’re pregnant or breastfeeding. During pregnancy, it can lead to child defects or even death of the baby. It can also affect the baby during breastfeeding.
Be careful with the amount of pau d’arco tea you drink a day. The maximum amount of tea you can drink a day is 1 liter. If you drink more, it might lead to nausea, vomiting or bleeding (in which case you should consult a doctor). Other symptoms include headaches, dizziness and diarrhea.
Pau d’arco tea has lots of important health benefits, but it also has a few side effects which you should remember. If you make sure it’s safe to drink this tea, you can enjoy it with no worries!... drink pau d’arco tea from south america
A ‘protective’ cough occurring as a result of irritation of the LARYNX – for example, a small particle of food may be accidentally ‘inhaled’ into the larynx, which reacts with an expulsive cough to prevent the food from entering the lungs.... laryngeal reflex
Pupillary constriction in the EYE in response to light. The direct light re?ex involves pupillary constriction in the eye into which a light is shone; the consensual light re?ex is the pupillary constriction that occurs in the other eye. The a?erent or inward pathway of the re?ex is via the optic nerve, and the e?erent or outward pathway is via the occulomotor nerve.... light reflex
A primitive REFLEX ACTION occurring in newly born infants in response to a sudden movement or noise. Also known as the startle re?ex, the baby will throw its arms and legs wide and sti?en its body. This is followed by ?exion of the arms and legs. The re?ex disappears by four months; its persistence suggests a possible neurological condition such as CEREBRAL PALSY.... moro reflex
See REFLEX ACTION.... patellar reflex
Eye movement that occurs after or during the slow injection of 20 ml of ice-cold water into each external auditory meatus (see EAR) in turn.... vestibulo-ocular reflex
An automatic movement in response to a stimulus that is present in newborn infants but disappears during the first few months after birth. Primitive reflexes are believed to represent actions that were important in earlier stages of human evolution. They include the grasp reflex when something is placed in the hand and the rooting reflex, which enables a baby to find the nipple. The rooting reflex can be evoked by touching the baby’s cheek with the fingertip. These reflexes are tested after birth to give an indication of the condition of the nervous system.... reflex, primitive
The use of digital imaging systems to replace conventional X-ray pictures and other imaging techniques. Though expensive to operate, digital imaging and storage systems o?er promising possibilities for transmission of clinical images within and between hospitals and community health-care units, providing fast access and remote working that will bene?t patients and health-care sta? alike. When security and con?dentiality are assured, images could be transferred via the Internet and teleradiology. In future, hospitals might be able to eliminate the costly physical transfer and storage of X-ray ?lms. The integration of PACS with hospital information systems in the NHS will (hopefully) facilitate the introduction of electronic radiology.... picture archiving and communications system (pacs)
(convergence reflex) a reflex that occurs when an individual focuses on a near object, in which the crystalline lens becomes more convex, the pupils constrict, and the eyes turn inwards.... accommodation reflex
that part of the aorta that extends from the ascending aorta, upward over the heart and then backward and down as far as the fourth thoracic vertebra. *Stretch receptors in its outer wall monitor blood pressure and form part of the system maintaining this at a constant level.... aortic arch
(arche-, archi-, archo-) combining form denoting first; primitive; ancestral. Example: archinephron (first-formed embryonic kidney).... arch
n. a cavity that forms in the very early embryo as the result of gastrulation (see gastrula). In humans it forms a tubular cavity, the archenteric canal, which connects the amniotic cavity with the yolk sac. —archenteric adj.... archenteron
n. (in Jungian psychology) an inherited idea or mode of thought supposed to be present in the *unconscious mind and to derive from the experience of the whole human race (the collective unconscious), not from the life experience of the individual. Anima is the feminine component of a male’s personality; animus is the masculine component of a female’s personality.... archetype
n. the *hippocampal formation of the cerebrum. The term is seldom used.... archipallium
a curved incision made in the periphery of the cornea. It is usually performed in the region of greatest curvature of the cornea in order to flatten it and hence reduce *astigmatism.... arcuate keratotomy
an anomaly or anatomical variation in which there is a slight indentation of the endometrium at the top of the uterus. Unlike a septate uterus, in which the indentation extends into a septum that divides the interior of the uterus, and a *bicornuate uterus, it does not normally affect reproductive function. See also uterus didelphys.... arcuate uterus
n. an arch; for example the arcus aortae (*aortic arch) or an arcus senilis or arcus juvenilis (see corneal arcus).... arcus
a primitive reflex that is present from birth but should disappear by six months of age. If the infant is lying on its back and the head is turned to one side, the arm and leg on the side to which the head is turned should straighten, and the arm and leg on the opposite side should bend (the ‘fencer’ position). Persistence of the reflex beyond six months is suggestive of *cerebral palsy.... asymmetric tonic neck reflex
see plantar reflex. [J. F. F. Babinski (1857–1932), French neurologist]... babinski reflex
see pharyngeal arch.... branchial arch
reflex control of the heart rate. Sensory fibres in the walls of the heart are stimulated when the heart rate increases above normal. Impulses are sent to the cardiac centre in the brain, stimulating the vagus nerve and leading to slowing of the heart rate.... cardiac reflex
a reflex in which the response occurs not to the sensory stimulus that normally causes it but to a separate stimulus, which has been learnt to be associated with it. In Pavlov’s classic experiments, dogs learned to associate the sound of a bell with feeding time and would salivate at the bell’s sound whether food was then presented to them or not.... conditioned reflex
a white or greyish line in the periphery of the cornea, concentric with but separated from the edge by a clear zone. It begins above and below but may become a continuous ring. It consists of an infiltration of fatty material and is common in the elderly (arcus senilis). When it occurs in younger people (arcus juvenilis) it may indicate *hyperlipidaemia. It does not affect vision.... corneal arcus
reflex blinking of both eyes normally elicited by lightly touching the cornea of one eye. This reflex is lost in deep coma, during general anaesthesia, and in death; it is therefore one of the tests used to confirm brainstem death.... corneal reflex
a superficial reflex in males elicited by stroking the inner side of the upper thigh with a sharp object. If the reflex is intact the scrotum on that side is pulled upwards as the cremaster muscle contracts. Absence or reduction of both cremasteric reflexes indicates an upper *motor neuron lesion; absence of the reflex on one side suggests a lower motor neuron lesion at the level of the first lumbar spinal nerve.... cremasteric reflex
see Hoffmann’s sign.... finger-flexion reflex
a reflex action of the body that develops by five to six months and never disappears. If the body is held by the waist face down and lowered, the arms and legs extend automatically.... forward parachute reflex
(pharyngeal reflex) a normal reflex action caused by contraction of pharynx muscles when the soft palate or posterior pharynx is touched. The reflex is used to test the integrity of the *glossopharyngeal and *vagus nerves.... gag reflex
a wave of peristalsis produced in the colon by introducing food into a fasting stomach.... gastrocolic reflex
the relaxation of the *ileocaecal valve caused by the presence of food in the stomach.... gastroileac reflex
involuntary grasping in response to anything that touches the palm of the hand. This is a normal reflex in babies that is lost in early childhood. In adults it is a sign of damage to the *prefrontal lobes of the brain.... grasp reflex
the normal physiological reflex to breathe out when the breath is held in inspiration and to breathe in when it is held in exhalation. [H. E. Hering (1866–1948), German physiologist; J. Breuer (1842–1925), German physician]... hering–breuer reflex
an abnormal reflex elicited by lightly placing the index finger across the chin of the patient and tapping it with a tendon hammer while the jaw hangs loosely open. A brisk upward movement of the jaw indicates an upper *motor neuron disorder above the brainstem.... jaw-jerk reflex
a reflex seen in normal babies from three months until one year, when it disappears. If the baby is held horizontally, face down, it will straighten its legs and back and try to lift up its head. The presence of this reflex beyond one year may be suggestive of a developmental disorder.... landau reflex
a cough produced by irritating the larynx.... laryngeal reflex
see pupillary reflex.... light reflex
involuntary contraction of the stapedius and/or tensor tympani muscles in the middle ear in response to various stimuli. The stapedius contracts in response to sound (see stapedial reflex). The tensor tympani is thought to contract during chewing. The sound-evoked middle ear reflex can be detected using a *tympanometer.... middle ear reflex
(startle reflex) a primitive reflex seen in newborn babies in response to the stimulus of a sudden noise or movement: the baby will fling its arms and legs wide and will appear to stiffen; the arms and legs are then drawn back into flexion. The Moro reflex should disappear spontaneously by four months. Its presence beyond this age is suggestive of an underlying neurological disorder, such as cerebral palsy. [E. Moro (1874–1951), German paediatrician]... moro reflex
a reflex action of the intestine in which a physical stimulus causes the intestine to contract above and relax below the point of stimulation.... myenteric reflex
see stretch reflex.... myotatic reflex
see vertebra.... neural arch
(knee jerk) reflex contraction of the quadriceps (thigh) muscle so that the leg kicks, elicited in a patient sitting with one knee crossed over the other by sharply tapping the tendon of the muscle below the kneecap. The reflex is mediated through nerves emanating from the third and fourth lumbar spinal levels (see spinal nerves). This is a test of the connection between the sensory nerves attached to stretch receptors in the muscle, the spinal cord, and the motor neurons running from the cord to the thigh muscle, all of which are involved in the reflex. The patellar reflex is reduced or absent when there is disease or damage of the spinal cord at or below the level of the reflex and exaggerated in disorders above the level of the reflex.... patellar reflex
(branchial arch, visceral arch) any of the paired segmented ridges of tissue in each side of the throat of the early embryo that correspond to the gill arches of fish. Each arch contains a cartilage, a cranial nerve, and a blood vessel. Between each arch there is a *pharyngeal pouch.... pharyngeal arch
see gag reflex.... pharyngeal reflex
see PACS.... picture archiving and communication system
the arch in the sole of the foot formed by anastomosing branches of the plantar arteries.... plantar arch
a reflex obtained by drawing a bluntly pointed object (such as a key) along the outer border of the sole of the foot from the heel to the little toe. The normal flexor response is a bunching and downward movement of the toes. An upward movement of the big toe is called an extensor response (or Babinski reflex or response). In all persons over the age of 18 months this is a sensitive indication of damage to the *pyramidal system in either the brain or spinal cord.... plantar reflex
(light reflex) the reflex change in the size of the pupil according to the amount of light entering the eye. Bright light reaching the retina stimulates nerves of the *parasympathetic nervous system, which cause the pupil to contract. In dim light the pupil opens, due to stimulation of the *sympathetic nervous system. See also iris.... pupillary reflex
flexion of the forearm (and sometimes also of the fingers) that occurs when the lower end of the radius is tapped. It is due to contraction of the brachioradialis muscle, which is stimulated by tapping its point of insertion in the radius.... radial reflex
the red area seen through the pupil as a result of the reflection of light from the retina. It is usually seen on *fundoscopy and sometimes in photographs taken using a flashlight.... red reflex
see complex regional pain syndrome.... reflex sympathetic dystrophy
a primitive reflex present in newborn babies: if the cheek is stroked near the mouth, the infant will turn its head to the same side to suckle.... rooting reflex
reflex contraction of the stapedius muscle in the middle ear, attached to the *stapes bone, in response to loud sounds. This protects the cochlea from noise damage by limiting the amount of sound that is transmitted via the stapes. The reflex can be measured using a *tympanometer.... stapedial reflex
see Moro reflex.... startle reflex
the reflex maintenance of muscular tone for posture.... static reflex
a primitive reflex in newborn babies that should disappear by the age of two months. If the baby is held in a ‘walking’ position with the feet touching the ground, the feet move in a ‘stepping’ manner. Persistence of this reflex beyond two months is suggestive of *cerebral palsy.... stepping reflex
(myotatic reflex) the reflex contraction of a muscle in response to its being stretched.... stretch reflex
the closing of the eyelids when the supraorbital nerve is struck, due to contraction of the muscle surrounding the orbit (orbicularis oculi muscle).... supraorbital reflex
see pharyngeal arch.... visceral arch
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