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Medical Neurology

Medical Neurology. Dr Sadik AL- Ghazzawi MRCP, FRCP UK Lecture 1. Neurology Principles of clinical neurology Anatomy and physiology. Nerve cells Types of nerve cells 1-Neuron (variety of neuron) 2-Glial cells. a-Astrocyte:

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Medical Neurology

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  1. Medical Neurology Dr Sadik AL-Ghazzawi MRCP, FRCP UK Lecture 1

  2. Neurology Principles of clinical neurology Anatomy and physiology

  3. Nerve cells Types of nerve cells 1-Neuron (variety of neuron) 2-Glial cells

  4. a-Astrocyte: it is the framework which as the following functions : *supporting the neuron *biochemical control of neuron environment *blood brain barrier by Astrocyte foot processes.

  5. b- Oligodendrocyte: The function of these cells is the formation and maintenance of the myelin sheath which is value for transmission of action potential .

  6. Neuron (Nerve cell )is the basic unit of the nerve system ,characterized by: 1-limitless connection. 2-Adaptability and variability of functions. 3-Has several projection. 4-The axon transmits the impulses which are generated in the neuron.

  7. Anatomical organization of the nervous system ONE

  8. 1-Central nervous system (C.N.S.) • A-The brain :- which consist of : • * Cerebral context (CC) :-which consist of: • - Frontal lobe • -Occipital lobe • - Parietal lobe • -Temporal lobe • *Brain stem (mid brain, pones) • *Cerebellum • B- Spinal cord

  9. 2-Peripherals nervous system (P.N.S.) • Cranial nerves(12 pairs • Spinal nerves ( 31 pairs) divided into : • Cervical spinal nerves (8 pairs) • Thoracic S N (12 pairs) • Lumbar SN (5 pairs) • Sacral SN (5 pairs) • Coccygeal SN ( 1 Pair)

  10. 3-Autonomic nervous system (A.N.S.) It is divide into : A-Parasympathetic autonomic nervous system (crainio-sacral) ,this is because it run with cranial nerves (3rd ,7th, 9th & 10th cranial nerves) and the sacral spinal nerves ( 2nd ,3rd & 4th).

  11. B-Sympathetic autonomic nervous system ( Thoraco-Lumbar), this is because it runs with thoracic spinal nerves & lumbar spinal nerves (T1-L3) and also it run with the sympathetic trunk with its ganglia.

  12. Functional organization of the nervous system TWO

  13. Functional organization of the nervous system The nervous system is divided into the following parts according to the function of that part :

  14. 1-Cerebral hemispheres: at that level the highest nervous system functions are carried A-Anterior half of the cerebral hemisphere deals with executive functions of the human brain

  15. B-Posterior half of the cerebral hemispheres deals with the perception of the environment .

  16. The nervous system is divided physiologically into: 1-The motor system: which is responsible for different movement of different parts of the body. Movement definition: is a contraction or controlled relaxation of a group of muscles and never a single muscle

  17. To perform a voluntary movement we need the participation of the following: A-The Motor Area (Precentral area of the frontal lobe: in this area the first spark for starting the action of movement ,i.e. cells of motor cortex = movement.

  18. B-The cerebellum : which complements the function of the motor area by adding : a-coordination b- timing of contraction and relaxation of the muscle fibers . 3- Extrapyramidal motor system, complement the function of the motor area by giving the movement its smooth and nice shape

  19. i.e.Cerebellum control the coordination of movement and Extrapyramidal motor system control the shape and smoothness of the movement ,while the motor area ignite the spark of the voluntary movement .

  20. 4- Anterior horn cells of the spinal cord and motor cranial nuclei .----------- 5- The muscle fiber SO, A group of anterior horn cells = muscle Cells of the motor cortex = movement

  21. Anatomy of the motor system 1-The motor system starts within the PCJ of the cerebral cortex of the frontal lobe . 2- motor signals passes within the corticospinal tract through the internal capsule ,brain stem were motor fibers coming from the motor cranial nuclei to join the CST to decent down to 3-the spinal cord (anterior horn of the spinal cord).

  22. *PCJ initiates movements of different parts of the opposite side of the body. The representations of the movement of different parts of the body are represented from below-upward (upside down) in the precentral jyris cells ( the foot ,legs ,thigh ,arm ,hand ,face and tongue )are represented upside down were the cells of the movement of the foot are uppermost and the cell of the movement of the tongue are the lower most.

  23. NOTE, This wide representation of the body in the precentral jyrus leads to a limited loss of function when part of the PCJ is affected ,example: monoplegia

  24. Upper motor neuron Which include the motor system from the cerebral cortex down to the anterior horn cell of the spinal cord passing through the corticospinal tract which decussates below the brain stem (lateral corticospinal tract).

  25. Lesion of UMN above the decussating results in : • Loss of some voluntary movement on the opposite side of the body . • Preservation of the reflex activity (difference between UMN and LMN ). • Heightened (increase the reflex activity because of the loss of the inhibitory action of the UMN on the LMN .

  26. Upper motor neuron lesion results in : • A-Positive phenomenon (increase reflex activity ) • b- Negative phenomenon (loss of voluntary movement). • Signs of UMN dysfunction • Muscle paralysis on the opposite side of the body for the voluntary movement

  27. Hypertonia: increase in the muscle tone ,which is of clasp knife type or spastic type , which has pyramidal distributioni.e: involve the flexor muscles of the upper limb and the extensor muscles of the lower limb.

  28. Hyperreflexia. • Extensor planter • All on the opposite side. • Loss of abdominal reflexes • No muscle atrophy but long term disuse atrophy. • Normal electrical activity in the muscle fibers.

  29. Anatomy of lower motor neuron Include, 1-Anterior horn cells 2- Anterior nerve roots 3- Peripheral motor nerves 4- Muscles i.e .Motor unit=AHC +Axon +Group of muscle fibers Note: the nutrition of the muscles depend on the LMN integrity.

  30. Signs of LMN dysfunction 1-Paralysis of all movements (voluntary and involuntary), the difference between UMN and LMN. 2- Hypotonia (flaccidity): loss of muscle tone. 3-Hporeflexia or areflexia. 4-Preservation of the abdominal reflexes 5-Flexor planter reflex

  31. 6- Wasting of the muscles supplied by the LMN in 2-3 weeks time, this is because the nutrition of the muscles depends on the integrity of the LMN. 7- Fibrillation (spontaneous single fiber contraction), which is invisible and it is electromyographic feature. 8- Fasciculation: Spontaneous contraction of a group of a muscle fibers (visible).

  32. 2-Basal ganglia----- (EPS) which are collection of ganglions in the depth of the cerebral hemisphere to complement the function of the motor system(PS) for optimum motor control.

  33. 3-Thalamus, This part of the brain deals with the appreciation and attention to the sensory perception .

  34. 4-Limbic system , deals with the emotions and memory . 5-Hypothalam the part of the brain which deals with theinternal body functions (internal environment).

  35. 6-Brain stem, That part of the central nervous system which has the following functions: A-harboring the sensory and the motor pathways entering and leaving the cerebral hemisphere .

  36. B-Housing nuclei of the cranial nerves (3rd &4th) which control the conjugate eye movements (internuclear mechanism of the conjugate eye movements) .

  37. C-containing the central nuclei for the cardio-respiratory control. D-Maintenance of the arousal of the human brain . (RAS) E-Complement the cerebellum for the balance control .

  38. 7-Spinal cord, it has the following functions: A-Containing the afferent and efferent fibers to the central nervous system. B-It contains and control the lower order motor reflexes.

  39. C-Primary processing of the sensory information coming through the sensory system, including the pain sensation analysis.

  40. 8-Peripheral nervous system which compose of: A-Afferent and efferent connection. B-Sensory cells in the dorsal root ganglia . C-Motor cells in the anterior horn of the spinal cord .

  41. These 3 divisions of the peripheral nervous system compose the essential parts of the (lower motor neuron unit) .

  42. . 9-The autonomic nervous system, ( sympathetic and parasympathetic ) has the following function: A-Unconscious neural control of the body physiology.

  43. B-Cardiovascular and respiratory system control. C-Smooth muscles and the glands of gastrointestinal

  44. Note:- The ANS is controlled centrally by diffuse modulatory system in the brain stem , limbic system and frontal lobe (the arousal and background behavioral responses to threat.

  45. Clinical skills in Solving Neurological Problem ONE

  46. 1-fundamental clinical skills of history –taking & physical examination. Neurological diagnosis . divided, to, 1-Functional diagnosis. 2-Etiological diagnosis 3-anatomical diagnosis,(what is the site of the lesion in the N.S.) 4-pathological diagnosis,(what disease process has occurred at the site).

  47. The history. Rule ONE important in determining both the anatomical & pathological diagnosis. Rule TOW- many neurological patients have no abnormal signs, or simply have physical features that confirm clinical suspicions base on the history.

  48. Rule THREE In complex problems, the history can only yield a , short list, of potential site of the lesion(s) & final localization must wait the formal examination. Rule FOUR - this is because disease at one site in the N.S may produce symptoms mimicking a lesion at another site.

  49. presenting complain; 1-allow the patient sufficient uninterrupted time to speak. age. occupation. handedness. hemisphere dominance. History 1-probe the history in specific areas. 2-timing of symptoms. onset, progression, duration, recovery, frequency.

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