2nd L Flashcards
Df of reflex
an involuntary or automatic, action that the body does in response to something from internal or external environment
draw simple reflex arc
stimuli > sensory ganglion > synapsing with ant horn > post horn > effector
Df Conditioned reflex and Ex
- Conditioned reflex: conditioned reflex is the stimulus which is associated with another stimulus and response is generated. For example: Salivation in a hungry dog in response to ringing a bell.
Df unconditioned reflex and Ex
- The unconditioned reflex : is the innate reaction of the organism Unconditioned reflexes are characterized by a permanent and clear connection between action on the receptor and a certain response,
- Ex : blinking of eyes with strong light, withdrawl of hand when pricked, breast feeding, swallowing, knee jerk, sneezing, coughing
explain the pathological reflexes
Pathologic reflexes (eg, Babinski, Chaddock, Oppenheim, snout, rooting, grasp) are reversions to primitive responses and indicate loss of cortical inhibition. Babinski, Chaddock, and Oppenheim reflexes all evaluate the plantar response. The normal reflex response is flexion of the great toe.
explain the corticospinal tract pathway
1-This tract originates in the motor cortex and travels through the cerebral white matter (corona radiata), the posterior limb of the internal capsule (where the fibers lie very close together), the central portion of the cerebral peduncle (crus cerebri), the pons, and the base (i.e., the anterior portion) of the medulla, where the tract is externally evident as a slight protrusion called the pyramid
2-The medullary pyramids (there is one on either side) give the tract its name. At the lower end of the medulla, 80-85 % of the pyramidal fibers cross to the other side in the so-called decussation of the pyramids. The fibers that do not cross here descend the spinal cord in the ipsilateral anterior funiculus as the anterior corticospinal tract.
3-The majority of pyramidal tract fibers cross in the decussation of the pyramids, then descend the spinal cord in the contralateral lateral funiculus as the lateral corticospinal tract.
explain the Corticonuclear tract pathway
1- Some of the fibers of the pyramidal tract ( corticospinal tract ) branch off from the main mass of the tract as it passes through the midbrain and then take a more dorsal course toward the motor cranial nerve nuclei
2-these fibers supplying the brainstem nuclei and they are partly crossed and partly uncrossed
explain the df of , Paresis , paralysis , differences between disturbance
central ( spastic ) and peripheral ( flacid )
-Paresis : refers to a condition in which muscle movement has become weakened or impaired.
-Paralysis: is the loss of the ability to move and feel in all or part of your body.
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1-central ( spastic ) :
-this syndrome consists of:
Diminished muscular strength and impaired fine motor control
Spastic increased tone
Abnormally brisk stretch reflexes, possibly with clonus
Hypoactivity or absence of exteroceptive reflexes (abdominal, plantar, and cremasteric reflexes)
Pathological reflexes (Babinski, Oppenheim, Gordon, and MendelBekhterev reflexes, as well as disinhibition of the flight response), and (initially) Preserved muscle bulk
-Localization of Lesions in the Central Motor System :
1.1 cerebral cortex : Сauses: a tumor, an infarct or a traumatic injury
Сlinical finding weakness of part of the body on the opposite side.
Hemiparesis is seen in the face and hand
1.2 The cerebral peduncle : clinical signs
А contralateral spastic hemiparesis
an ipsilateral oculomotor nerve palsy (cf. Weber syndrome).
2-peripheral ( flacid ) : The peripheral portion of the motor system comprises the motor cranial nerve nuclei of the brainstem, the motor anterior horn cells of the spinal cord, the anterior roots, the cervical and lumbosacral nerve plexuses, the peripheral nerves, and the motor end plates in skeletal muscle.
-The syndrome of flaccid paralysis consists of the following:
Diminution of raw strength
Hypotonia or atonia of the musculature
Hyporeflexia or areflexia
Muscle atrophy
Fasciculation : Damaged alpha motor neurons can produce spontaneous action potentials.
Fibrillation : With further degeneration of the alpha motor neuron,
explain the lesion of , Ant horn , post horn , lateral column , post column , lateral column in the in the cervical pare
1-Ant horn syndrome: Segmental paralysis(peripheral paralysis and atrophy of muscles innervated by the motor neurons of the corresponding segmented side as that of the lesion.
2-post horn : A longitudinal tear of the posterior horn of the medial meniscus is common in older people as degeneration may be present in the meniscal tissue. With this type of tear, the meniscus has been sliced in the middle - as if it were a bagel bun cut into to pieces
3-lateral column : ipsilateral paralysis (inability to move), paresis (decreased motor strength), and hypertonia (increased tone) for muscles innervated caudal to the level of injury
4-post column :Damage to the dorsal columns (fasciculus gracilis and cuneatus), bilaterally, causes the absence of light touch, vibration, and position sense, bilaterally, from the neck down (below the lesion level)
5- lateral column in the in the cervical pare :Brown-Séquard syndrome is a neurologic syndrome resulting from hemisection of the spinal cord. It manifests with weakness or paralysis and proprioceptive deficits on the side of the body ipsilateral to the lesion and loss of pain and temperature sensation on the contralateral side.
explain the lesion of spinal cord at the levels of , Cervical , thoracic , lumber
1-cervical :
- from c1-c4 : spastic , qudrapelagia , loss of all sensation below the level of lesion
-from c5-c8 : peripheral pepralagia of upper limbs , central papralagia of lower limbs , loss of all sensation , pelvic organ disorder , bernard horner syndrom
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2-Thoracis : T1-T12
lower spastic paraplegia , loss of all sensation below the lvl , pelvic organ disorder , vegetative trophic disorder in the lower half of the trunk and lower limbs limbs
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3- lumber : L1 -s1
lower flacid , lower paraanthsia , pelvic organ disorder
explain the CSF , DF , formation , function , diseases
-DF :Cerebrospinal fluid (CSF) is a clear, colorless body fluid found within the tissue that surrounds the brain and spinal cord
-Formation :CSF is produced by specialised ependymal cells in the choroid plexus of the ventricles of the brain, and absorbed in the arachnoid granulations
-Function :
1-Protection
2-Prevention of brain ischemia
3-Regulation: CSF allows for the homeostatic regulation of the distribution of substances between cells of the brain
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-diseases :
1- meningitis bacterial and fungal
2-viral asceptoc mingitis
3- TB minigitis
4-subarchnoid hemorrhage
5- gulilian barre syndrome
