Nervous System Lecture: CNS (1) PDF

CNS (1)  Sensory S 3/1/pinal T~ · - Lord - enating oderve...

CNS (1)  Sensory S 3/1/pinal T~ · - Lord - enating oderve ↑ (Afferent) S 7 motor Nerve (Efferent) - 1 -- term- - > - & axon - den-cellbody - Cleft r S nemarie earyol -- -5 I = S o 000 , ll > &  Brain/spinal cord) ANS) ⑯ =I - 1 ; gls e -  Nucleus ganglia Greymater) ↑ White & - % 19 erve & #[ A - -  (1 ) Nervous System. The Nervous System Along With Endocrine System Regulates The Functions Of All Other Systems Of The Body. (‫)ىرــخألا مسجــال ةزــهجأ عيمـج فـئاـظو ءامصــال ددغــال ماظــنو يبصعــال زاهجــال مظنـي‬ Divisions of Nervous System: Anatomically the nervous system is divided into two parts: (‫)ﯾـﻨﻘﺴﻢا ﻟـﺠﮭﺎا زﻟـﻌﺼﺒﻲ ﺗﺸـﺮﯾـﺤﯿﺎإ ﻟـﻰ ﻗـﺴﻤﯿﻦ‬ 8 1. The Central Nervous System. (‫)اﻟـﺠﮭﺎا زﻟـﻌﺼﺒﻲا ﻟـﻤﺮﻛـﺰي‬ 2. The Peripheral Nervous System. (‫)اﻟـﺠﮭﺎا زﻟـﻌﺼﺒﻲا ﻟـﻄﺮﻓـﻲ‬ O > - ✤ The central nervous system (CN S) consists of: O1. Brain. (‫)اﻟـﺪﻣـﺎغ‬ &2. Spinal Cord. (‫)اﻟـﺤﺒﻞا ﻟـﺸﻮﻛـﻲ‬ - ✤ The peripheral nervous system (PN S) consists of nerves that exit from (CNS): (‫)ﯾـﺘﻜﻮا نﻟـﺠﮭﺎا زﻟـﻌﺼﺒﻲا ﻟـﻤﺤﯿﻄﻲ ﻣـﻦأ ﻋـﺼﺎب ﺗﺨـﺮج ﻣـﻦا ﻟـﺠﮭﺎا زﻟـﻌﺼﺒﻲا ﻟـﻤﺮﻛـﺰي‬ 3 pair b ,Se O 1. Spinal Nerves (exit from the spinal cord) - (‫)اﻷﻋـﺼﺎا بﻟـﺸﻮﻛـﯿﺔ ﺗـﻨﺸﺄ ﻣـﻦا ﻟـﻨﺨﺎا عﻟـﺸﻮﻛـﻲ‬ 2. Cranial Nerves (exit from the brain) 8 , 5 E⑧ 12 - pair (‫)اﻷﻋـﺼﺎا بﻟـﻘﺤﻔﯿﺔ ﺗـﻨﺸﺄ ﻣـﻦا ﻟـﺪﻣـﺎغ‬ -  Nervous System Cerebral cortex (‫)قشرة الدماغ‬ ‫هي اهم جزء بالدماغ وتحوي‬ Gyri and Sulci The C entral Nervous System: - The Brain: & Located within the cranial cavity (skull).((‫)ﺗـﻘﻊاد ﺧـﻞ ﺗـﺠﻮﯾـﻒا ﻟﺠـﻤﺠﻤﺔ )اﻟﺠـﻤﺠﻤﺔ‬ The brain is divided into three major divisions: 1. The Forebrain (‫)اﻟـﺪﻣـﺎا غﻷﻣـﺎﻣـﻲ‬ S O 2. The Midbrain (‫)اﻟـﺪﻣـﺎا غﻟـﻤﺘﻮﺳـﻂ‬ 3. The Hindbrain (‫)اﻟـﺪﻣـﺎا غﻟﺨـﻠﻔﻲ‬ O - The brain is surrounded by three protective membranous layers called Meninges: E (‫)ﯾـﺤﯿﻂ ﺑـﺎﻟـﺪﻣـﺎغ ﺛـﻼـط ثﺒﻘﺎت ﻏـﺸﺎﺋـﯿﺔاو ﻗـﯿﺔ ﺗـﺴﻤﻰا ﻟـﺴﺤﺎﯾـﺎ‬ ‫ﻣﺤﻤﻲ ﻻﻧﮫ أي إﺻﺎﺑﺔ ﺑﺎل‬ ⑤- So central nervous system 8 1. The Dura Mater (‫ﻟـﺠﺎﻓـﯿﺔ‬‫م‬ ‫ا‬‫)اﻷ‬ There is a fluid between them 3 ‫ﺑﺘﻌﻤﻞ ﻋﺎھﺔ داﺋﻤﺔ)إﺻﺎﺑﺔ أي‬ ‫ ﻣﻤﻜﻦ ﺗﺆدي إﻟﻰ‬brain ‫ﻣﻨﻄﻘﺔ ﺑﺎل‬ E 2. The Arachnoid Mater (‫= )اﻷا مﻟـﻌﻨﻜﺒﻮﺗـﯿﮫ‬called cerebrospinal fluid(CSF) ‫اﻟﺬاﻛﺮة أو إذا‬/‫ﻓﻘﺪان ﺣﺎﺳﺔ اﻟﺴﻤﻊ‬ 3. The Pia Mater (‫)اﻷا مﻟـﺤﻨﻮﻧـﺔ‬ it’s function a shock absorber ‫اﻧﻘﻄﻊ اﻟﺤﺒﻞ اﻟﺸﻮﻛّﻲ ﺑﺘﻼﻗﻲ ﻋﻨﺪ‬.‫اﻟﺸﺨﺺ ﺷﻠﻞ ﻧﺼﻔﻲ‬ S (‫)امتصاص الصدمات‬ erebrospinal => fluid  Nervous System B‫ينتهي الحبل الشوكيّ ب‬ Lumber vertebrae 1 and Lumber vertebrae 2 The C entral Nervous System: ‫عصاب الشوكية تبقى في نزول إلى ما بعد‬E‫بينما ا‬ ‫ذلك‬ The Spinal C ord: Located within the vertebral canal of the vertebral column. (‫)ﺗـﻘﻊاد ﺧـﻞ ﻗـﻨﺎا ةﻟـﻌﻤﻮا دﻟـﻔﻘﺮي ﻟـﻠﻌﻤﻮا دﻟـﻔﻘﺮي‬ sel Metalla oblongata In Begins at the foramen magnum in the skull, as continuation of the brain. - > (‫ ﻛـﺎﺳـﺘﻤﺮرا ﻟـﻠﺪﻣـﺎغ‬،‫)ﯾـﺒﺪأ ﻓـﻲا ﻟـﻔﺘﺤﺔا ﻟـﻌﻈﻤﻰ ﻓـﻲا ﻟﺠـﻤﺠﻤﺔ‬ The spinal cord also surrounded by the meninges similar to those surrounding the brain. (‫)ﯾـﺤﯿﻂ ﺑـﺎﻟـﺤﺒﻞا ﻟـﺸﻮﻛـﻲأ ﯾـ ًﻀﺎا ﻟـﺴﺤﺎﯾـﺎا ﻟـﻤﺸﺎﺑـﮭﺔ ﻟـﺘﻠﻚا ﻟـﻤﺤﯿﻄﺔ ﺑـﺎﻟـﺪﻣـﺎغ‬ skull & S ↑ d& ⑮ column vertebral S  Nervous System The Peripheral Nervous System: Consists of Nerves, that connect the CNS to every other part of the body 1. 12 pairs of cranial nerves exit from the cranium (‫ ﻣـﻦا ﻷﻋـﺼﺎا بﻟـﻘﺤﻔﯿﺔ ﺗﺨـﺮج ﻣـﻦا ﻟﺠـﻤﺠﻤﺔ‬١٢ ‫)جوز‬ 2. 31 pairs of spinal nerves exit from the spinal cord (‫ ﻣـﻦا ﻷﻋـﺼﺎا بﻟـﺸﻮﻛـﯿﺔ ﺗﺨـﺮج ﻣـﻦا ﻟـﺤﺒﻞا ﻟـﺸﻮﻛـﻲ‬٣١ ‫)جوز‬ * Central nerves ID no Regeneration * Peripheral nerves Do Regeneration ‫رقام‬L‫كلهم حفظ مع ا‬ ‫العصب الشمي‬ I ‫العصب البصري‬ II 2‫ت الع‬0‫محرك لعض‬ III (SO4) ,‫لعضلة من عض)ت الع‬ IV (Superior oblique) 3‫توائم‬ U VF (LR6),‫لعضلة من عض)ت الع‬ E Lateral Rectus) ‫عصب الوجه‬ VIF Vestibulochlear nerve(‫)التوازن السمعي‬ VIII IX ‫اللسان البلعومي‬ ‫ا=بهم‬/ ‫ا=حي?ر‬ X ‫ضافي‬B‫ا‬ XI ‫تحت اللسان‬ XII  ‫‪Nervous System‬‬ ‫&‬ ‫‪The Peripheral Nervous System:‬‬ ‫‪-‬‬ ‫ا"عصاب الطرفية‬ ‫‪ Nerves can be divided into different types:‬‬ ‫)ﯾـﻤﻜﻦ ﺗﻘﺴـﯿﻢا ﻷﻋـﺼﺎإ بﻟـﻰأ ﻧـﻮعا ﻣـﺨﺘﻠﻔﺔ(‬ ‫)ﻋـﺼﺐ ﺣـﺮﻛـﻲ )اﻟـﺼﺎةرد(( ‪A. Motor (Efferent) Nerve‬‬ ‫‪-‬‬ ‫‪ E- Nerves that transmit signals from the CNS‬من الدماغ إلى الحبل‬ ‫الشوكي ثم إلى ‪spinal‬‬ ‫‪to the rest of the body. (carries motor‬‬ ‫‪ nerves‬واخيرا ً إلى‬ ‫)‪commands to the muscles and glands‬‬ ‫العض‪:‬ت)‪( voluntary‬‬ ‫)اﻷﻋـﺼﺎا بﻟـﺘﻲ ﺗـﻨﻘﻞا ﻹﺷـﺎتار ﻣـﻦا ﻟـﺠﮭﺎا زﻟـﻌﺼﺒﻲا ﻟـﻤﺮﻛـﺰإ يﻟـﻰ ﺑـﻘﯿﺔا ﻟـﺠﺴﻢ )ﺗـﻨﻘﻞ‬ ‫اﻷاوﻣـﺮا ﻟﺤـﺮﻛـﯿﺔإ ﻟـﻰا ﻟـﻌﻀﻼاو تﻟـﻐﺪد((‬ ‫)ﻋـﺼﺐ ﺣﺴـﻲ)دراو(( ‪B. Sensory (Afferent)Nerve‬‬ ‫‪ E‬من الجلد)مثل شّكة‬ ‫‪-‬‬ ‫الدبوس(ثم عبر ‪spinal‬‬ ‫‪- Nerves that transmit information from the‬‬ ‫‪ nerves‬الى ‪spinal cord‬‬ ‫‪body to the CNS (carries sensation from the‬‬ ‫ثم إلى ‪sensory center‬‬ ‫‪in the brain‬‬ ‫)اﻷﻋـﺼﺎا بﻟـﺘﻲ ﺗـﻨﻘﻞا ﻟـﻤﻌﻠﻮﻣـﺎت ﻣـﻦا ﻟـﺠﺴﻢإ ﻟـﻰ )‪tissue to the CNS‬‬ ‫بعطيك معنى=‬ ‫ا ﻟـﺠﮭﺎا زﻟـﻌﺼﺒﻲا ﻟـﻤﺮﻛـﺰي )ﺗﺤـﻤﻞا ﻹﺣـﺴﺎس ﻣـﻦا ﻷﻧـﺴﺠﺔإ ﻟـﻰا ﻟـﺠﮭﺎا زﻟـﻌﺼﺒﻲ‬ ‫ا‪I‬حساس)دبوس‪/‬حرق(‬ ‫‪-‬‬ ‫اﻟـﻤﺮﻛـﺰي((‬ ‫سي‬ ‫حركي‪+‬ح ّ‬ ‫‪-‬‬ ‫)أﻋـﺼﺎب ﻣـﺨﺘﻠﻄﺔ( ‪C. Mixed Nerves‬‬ ‫‪-‬‬ ‫⑫‬ ‫‪In spinal‬‬ ‫‪- Carries motor and sensory innervation‬‬ ‫‪nerves‬‬ ‫)ﯾـﺤﺘﻮي ﻋـﻠﻰأ ﻟـﯿﺎف ﺣـﺮﻛـﯿﺔو ﺣﺴـﯿﺔ(‬  Nervous System The Peripheral Nervous System: Lonsus) - Functionally, The PNS is divided into subsystems: (‫ ﯾـﻘﺴﻢإ ﻟـﻰ‬،‫)ﻣـﻦا ﻟـﻨﺎﺣـﯿﺔا ﻟـﻮـظﯿﻔﯿﺔ‬ S 81. Somatic Nervous System: (‫)اﻟـﺠﮭﺎا زﻟـﻌﺼﺒﻲا ﻟﺠﺴـﺪي‬ - provides the - voluntary control of the skeletal muscle.(‫)ﯾـﻮﻓـﺮا ﻟﺴـﯿﻄﺮا ةﻟـﻄﻮﻋـﯿﺔ ﻋـﻠﻰا ﻟـﻌﻀﻼا تﻟﮭـﯿﻜﻠﯿﺔ‬ 82. Autonomic Nervous System: (‫)اﻟـﺠﮭﺎا زﻟـﻌﺼﺒﻲا ﻟﻤﺴـﺘﻘﻞ‬ -[ ‫إرادي‬I - provides an involuntary control of the smooth muscle (stomach), cardiac muscle & (heart), and glands.(‫)ﯾـﻮﻓـﺮ ﺗـﺤﻜ ًﻤﺎ ﻻدارإ ﯾـ ًﺎ ﻓـﻲا ﻟـﻌﻀﻼا تﻟـﻤﻠﺴﺎء )اﻟـﻤﻌﺪة(او ﻟـﻌﻀﻠﺔا ﻟـﻘﻠﺒﯿﺔ )اﻟـﻘﻠﺐ(او ﻟـﻐﺪد‬ It could be sympathetic or parasympathetic ‫و إذا اشتغل واحد منهم يحدث‬ ‫خر تثبيط‬V‫ل‬  Nervous System The Peripheral Nervous System: Autonomic Nervous System: (‫)اﻟـﺠﮭﺎا زﻟـﻌﺼﺒﻲا ﻟﻤﺴـﺘﻘﻞ‬ - - The autonomic nervous system is further subdivided into: (‫)وﯾـﻨﻘﺴﻢا ﻟـﺠﮭﺎا زﻟـﻌﺼﺒﻲا ﻟﻤﺴـﺘﻘﻞإ ﻟـﻰ‬ 1. The Sympathetic Nervous System (‫)اﻟـﺠﮭﺎا زﻟـﻌﺼﺒﻲا ﻟـﻮيد‬ i Is & It is activated during stressful stimuli (ex: fear, pain, exercise). ((‫ا ﻟـﺨﻮاو فﻷﻟـﻢو ﻣـﻤﺎرﺳـﺔا ﻟـﺮﯾـﺎﺿـﺔ‬:‫)ﯾـﺘﻢ ﺗﻨﺸـﯿﻄﮫأ ﺛـﻨﺎا ءﻟـﻤﻨﺒﮭﺎا تﻟﻤﺠﮭـﺪة )ﻋـﻠﻰ ﺳـﺒﯿﻞا ﻟـﻤﺜﺎل‬ 2. The Parasympathetic Nervous System (‫)اﻟـﺠﮭﺎا زﻟـﻌﺼﺒﻲا ﻟﻼيدو‬ , - It is activated during physical and mental rest (ex: sleep) ↓ & -, /jiyligs's a ((‫ا ﻟـﻨﻮم‬:‫)ﯾـﺘﻢ ﺗﻨﺸـﯿﻄﮫأ ﺛـﻨﺎا ءﻟـﺮاﺣـﺔا ﻟـﺒﺪﻧـﯿﺔاو ﻟـﻌﻘﻠﯿﺔ )ﻋـﻠﻰ ﺳـﺒﯿﻞا ﻟـﻤﺜﺎل‬ - su - & Enteric Nervous System: (‫)اﻟـﺠﮭﺎا زﻟـﻌﺼﺒﻲا ﻟـﺪاﺧـﻠﻲ‬ - It is a network of nerves-embedded in the lining - of the digestive system. (‫)إﻧـﮭﺎ ﺷـﺒﻜﺔ ﻣـﻦا ﻷﻋـﺼﺎب ﻣـﺘﻀﻤﻨﺔ ﻓـﻲ ﺑـﻄﺎﻧـﺔا ﻟـﺠﮭﺎا زﻟـﮭﻀﻤﻲ‬ - It is subdivision of the autonomic nervous system.(‫)ـھﻮ ﺟـﺰء ﻣـﻦا ﻟـﺠﮭﺎا زﻟـﻌﺼﺒﻲا ﻟﻤﺴـﺘﻘﻞ‬ - It is directly controls the digesive system. (‫)إﻧـﮫ ﯾـﺘﺤﻜﻢ ﺑـﺸﻜﻞ ﻣـﺒﺎﺷـﺮ ﻓـﻲا ﻟـﺠﮭﺎا زﻟـﮭﻀﻤﻲ‬ ‫ في‬sympathetic+parasympathetic ‫فيه تجمع لل‬ enteric nervous ‫(يسّمى‬digestive sys)‫معاء‬I‫جدار ا‬ ‫ اهم‬.. ‫معاء‬a‫ت في جدار ا‬:‫ يقع ما ب` العض‬system ‫ انها‬gland ‫نها بتنبّه ال‬a parasympathetic ‫وظيفة اله‬ smooth muscle‫ وبتنبه ال‬secretion ‫تفرز‬  Nervous System Histology Nervous System: - ↑ The nervous system consists of two type of cells, Neurons and Neuroglia. (.‫ا ﻟـﻌﺼﺒﻮاو نﻟـﺨﻼﯾـﺎا ﻟـﺪﺑـﯿﻘﺔا ﻟـﻌﺼﺒﯿﺔ‬,‫)ﯾـﺘﻜﻮا نﻟـﺠﮭﺎا زﻟـﻌﺼﺒﻲ ﻣـﻦ ﻧـﻮﻋـﯿﻦ ﻣـﻦا ﻟـﺨﻼﯾـﺎ‬ central nucleus o and nucleous. ·S✤ - -Neurons or Nerve Cells: (‫)اﻟـﻌﺼﺒﻮا وأ نﻟﺨـﻠﯿﺔا ﻟـﻌﺼﺒﯿﺔ‬ - - It is the structural and functional unit of · - Aly Hit - - the nervous system. - 161ssig10s & - &i jw - (‫)ـھوﻲا ﻟـﻮﺣـﺪا ةﻟﮭـﯿﻜﻠﯿﺔاو ﻟـﻮـظﯿﻔﯿﺔ ﻟـﻠﺠﮭﺎا زﻟـﻌﺼﺒﻲ‬ - &jese - It is specialized to conduct electrical - impulses to and from the nervous system. - -0 - -/ 4415 - (.‫)ـھوﻲ ﻣـﺘﺨﺼﺼﺔ ﻓـﻲإ ﺟـﺮا ءاﻟـﻨﺒﻀﺎا تﻟﻜﮭـﺮﺑـﺎﺋـﯿﺔ ﻣـﻦإو ﻟـﻰا ﻟـﺠﮭﺎا زﻟـﻌﺼﺒﻲ‬ - or macroglia (macrophages -join; ↑ &✤ Neuroglia or Glial Cells: (‫)اﻟـﺨﻼﯾـﺎا ﻟـﺪﺑـﻘﯿﺔا ﻟـﻌﺼﺒﯿﺔ‬ ot - It is supportive cells that support the h neurons both structurally and functionally. - (‫)إﻧـﮭﺎا ﻟـﺨﻼﯾـﺎا ﻟـﺪاﻋـﻤﺔا ﻟـﺘﻲ ﺗـﺪﻋـﻢا ﻟـﺨﻼﯾـﺎا ﻟـﻌﺼﺒﯿﺔ ﻣـﻦا ﻟـﻨﺎﺣـﯿﺔا ﻟﮭـﯿﻜﻠﯿﺔاو ﻟـﻮـظﯿﻔﯿﺔ‬ - It is non-conducting cells that are located in & - close to the neurons His - (‫)ـھوﻲ ﺧـﻼﯾـﺎ ﻏـﯿﺮ ﻣـﻮﺻـﻠﺔ ﺗـﻘﻊ ﺑـﺎﻟـﻘﺮب ﻣـﻦا ﻟـﺨﻼﯾـﺎا ﻟـﻌﺼﺒﯿﺔ‬ Characteristics of neurons:(‫)اﻟﺨﻠﯿﺔ اﻟﻌﺼﺒﯿﺔ‬ 1)it has axon 2)it has dendritic 3)it has central nucleus and nucleolus 4)it’s cytoplasm has organelles(mitochondria &golgi specially) 5)it has neurofilaments and neurotubules 6)if has protein called nissl substance All of the following characteristics of neurons except:  Nervous System Histology Nervous System: Neurons (Nerve C ells): Each neuron consists of three part: (‫)ﯾـﺘﻜﻮن ﻛـﻞ ﻋـﺼﺒﻮن ﻣـﻦ ﺛـﻼﺛـﺔأ ﺟـﺰءا‬ ‫شارة‬i‫بتجيب ا‬ 1. Cell Body (also called soma or perikaryon). (‫)ﺟـﺴﻢا ﻟﺨـﻠﯿﺔ‬ o ‫العصبية‬ -- multidendrites &G 2. Dendrites. > its (‫)اوزﺋـﺪ ﺷﺠـﺮﯾـﺔ‬- carry)‫للخلية‬ impulse toward 3. Axon. (‫)ﻣـﺤﻮر ﻋـﺼﺒﻲ‬ O > - it has one axon b (the cell body ‫شارة العصبية من‬i‫بنقل ا‬ ‫الخلية العصبية للخلية‬ ‫( ممكن تكون‬target)‫الهدف‬ gland/smooth muscle/ another neuron  - Cell body(neurons) Nervous System ‫تجّمعها بالـ‬ PNS(peripheral ‫تجّمعها بالـ‬ CNS(central nervous system) nervous system) Histology Nervous System: - Neurons (Nerve C ells): => Ganglia(‫ مثل‬dorsal root Nucleus(gray ganglia Cell Body : A matter) (spinal cord ‫اللي حوال` ال‬ - contains a nucleus surrounded by cytoplasm that includes typical cellular organelles such as (lysosomes, mitochondria, and a Golgi complex) - ((‫ ﺟـﻮﻟـﺠﻲ‬، ‫ تﻟـﻤﯿﺘﻮﻛـﻮﻧـﺪرﯾـﺎو‬، ‫)ﯾـﺤﺘﻮي ﻋـﻠﻰ ﻧـﻮةا ﻣـﺤﺎـطﺔ ﺑـﺎﻟﺴـﯿﺘﻮﺑـﻼمز ﺗـﺘﻀﻤﻦ ﻋـﻀﯿﺎت ﺧـﻠﻮﯾـﺔ ﻧـﻤﻮذﺟـﯿﺔ ﻣـﺜﻞ )اﻟـﻠﯿﺰوزوﻣـﺎا‬ - The collections of cell bodies within the CNS are called Gray Matter - (‫)ﺗـﺴﻤﻰ ﻣﺠـﻤﻮﻋـﺎأ تﺟـﺴﺎا مﻟـﺨﻼﯾـﺎاد ﺧـﻞا ﻟـﺠﮭﺎا زﻟـﻌﺼﺒﻲا ﻟـﻤﺮﻛـﺰا يﻟـﻤﺎا ةدﻟـﺮﻣـﺎدﯾـﺔ‬ - The collections of cell bodies within the PNS are called Ganglia. - (‫)ﺗـﺴﻤﻰ ﻣﺠـﻤﻮﻋـﺎأ تﺟـﺴﺎا مﻟـﺨﻼﯾـﺎاد ﺧـﻞا ﻟـﺠﮭﺎا زﻟـﻌﺼﺒﻲا ﻟـﻄﺮﻓـﻲا ﻟـﻌﻘﺪ‬  Nervous System Histology Nervous System: Neurons (Nerve C ells): Dendrites: - Its short processes that project from the cell body. - (‫)ﻧـﺘﻮتاء ﻗـﺼﯿﺮا ةﻟـﺘﻲ ﺗـﻨﺒﺜﻖ ﻣـﻦ ﺟـﺴﻢا ﻟﺨـﻠﯿﺔ‬ , 41593 6 & - It receives impulses from other neurons and conducte - & the electrical signal towards the nerve cell body. - ‫)ﯾـﺘﻠﻘﻰ ﻧـﺒﻀﺎت ﻣـﻦا ﻟـﺨﻼﯾـﺎا ﻟـﻌﺼﺒﯿﺔا ﻷﺧـﺮو ىﯾـﻘﻮم ﺑـﺘﻮﺻـﯿﻞا ﻹﺷـﺎا ةرﻟﻜﮭـﺮﺑـﺎﺋـﯿﺔ ﻧـﺤﻮ ﺟـﺴﻢ‬ (.‫اﻟﺨـﻠﯿﺔا ﻟـﻌﺼﺒﯿﺔ‬  Nervous System is * axon sorroundel connective Histology Nervous System: by tissue Neurons (Nerve C ells): 11 Jeste Axon: : gl Cellboy)1 - It is a long cable-like projection that can extend away from the cell body Si - (‫)ـھوﻮ ﻛـﯿﺒﻞـط ﻮﯾـﻞ ﯾـﻤﺘﺪ ﺑـﻌﯿ ًﺪا ﻋـﻦ ﺟـﺴﻢا ﻟﺨـﻠﯿﺔ‬ Cneuronansymusle)- target It carries nerve signals away from the cell body, and carries some types of information back to it. [02 - (‫ ﯾﺤـﻤﻞ ﺑـﻌﺾأ ﻧـﻮا عاﻟـﻤﻌﻠﻮﻣـﺎإ تﻟـﯿﮫ‬، ‫)ﯾﺤـﻤﻞا ﻹﺷـﺎا تارﻟـﻌﺼﺒﯿﺔ ﺑـﻌﯿ ًﺪا ﻋـﻦ ﺟـﺴﻢا ﻟﺨـﻠﯿﺔو‬ - The axon end dividing into many fine processes called (axon terminals or axon telodendria) - - (‫)ﯾـﻨﻘﺴﻢ ﻧـﮭﺎﯾـﺔا ﻟـﻤﺤﻮإ رﻟـﻰا ﻟـﻌﺪﯾـﺪ ﻣـﻦا ﻟـﻨﺘﻮا تاءﻟـﺪﻗـﯿﻘﺔ ﺗـﺴﻤﻰ )ـطأﺮا فاﻟـﻤﺤﻮرا‬ ✤ The tips of some axon terminals swell into bulb-shaped structures called synaptic - end bulbs. (‫)ﺗﺘﻀﺨـﻢـطأ ﺮفا ﺑـﻌﺾ ﻧـﮭﺎﯾـﺔا ﻟـﻤﺤﻮإ زﻟـﻰـھ ﯿﺎﻛـﻞ ﻋـﻠﻰ ﺷـﻜﻞ ﺑـﺼﯿﻠﺔ ﺗـﺴﻤﻰا ﻟـﺘﺸﺎﺑـﻚا ﻟـﻌﺼﺒﻲ‬ - = , 2014 - is 65511 5 == S S ↳ C Acetylcholine/ as Adrenaline  Nervous System Histology Nervous System: Neurons (Nerve C ells): Axon: · & - Bundle of& axons within the CNS are called White Matter - - (‫)ﺗـﺴﻤﻰ ﻣﺠـﻤﻮﻋـﺔ ﻣـﻦا ﻟـﻤﺤﺎوﯾـﺮاد ﺧـﻞا ﻟـﺠﮭﺎا زﻟـﻌﺼﺒﻲا ﻟـﻤﺮﻛـﺰا يﻟـﻤﺎا ةدﻟـﺒﯿﻀﺎء‬ - Bundle of6 axons within the PNS are called Nerve. # -. (‫)ﺗـﺴﻤﻰ ﻣﺠـﻤﻮﻋـﺔ ﻣـﻦا ﻟـﻤﺤﺎاد روﺧـﻞا ﻟـﺠﮭﺎا زﻟـﻌﺼﺒﻲا ﻟـﻄﺮﻓـﻲا ﻟـﻌﺼﺐ‬  Nervous System Histology Nervous System: Neurons (Nerve C ells): Classification of neurons according to function: Sy 155 o1. Motor neurons (Efferent): - T , - Sending impulse from the CNS or ganglia to effector cells ( muscle fibers and gland) - ((‫)ﯾـﺮﺳـﻞ ﻧـﺒﻀﺎت ﻣـﻦا ﻟـﺠﮭﺎا زﻟـﻌﺼﺒﻲا ﻟـﻤﺮﻛـﺰا وأ يﻟـﻌﻘﺪإ ﻟـﻰا ﻟـﺨﻼﯾـﺎا ﻟﻤﺴـﺘﺠﯿﺒﺔ )أﻟـﯿﺎا فﻟـﻌﻀﻼاو تﻟـﻐﺪة‬ 2. Sensory neurons (Afferent): % & 0 , 215% - Receive stimuli from the receptors throughout the body to the CNS. - (‫)ﯾـﺘﻠﻘﻰا ﻟـﻤﻨﺒﮭﺎت ﻣـﻦا ﻟﻤﺴـﺘﻘﺒﻼت ﻓـﻲ ﺟـﻤﯿﻊأ ﻧـﺤﺎا ءﻟـﺠﺴﻢإ ﻟـﻰا ﻟـﺠﮭﺎا زﻟـﻌﺼﺒﻲا ﻟـﻤﺮﻛـﺰي‬ O 3. Internerons: (‫)أﻋـﺼﺎب ﺑـﯿﻨﯿﺔ‬ - Form a communicating and integrating network (circuits) between the sensory and motor neurons. (‫)ﺗـﺸﻜﯿﻞ ﺷـﺒﻜﺔ ﺗـﻮاﺻـﻞدو ﻣـﺞ )اودﺋـﺮ( ﺑـﯿﻦا ﻟـﺨﻼﯾـﺎا ﻟـﻌﺼﺒﯿﺔا ﻟﺤﺴـﯿﺔاو ﻟﺤـﺮﻛـﯿﺔ‬  Nervous System Histology Nervous System: Neurons (Nerve C ells): Classification of neurons according to structure : ‫ﺗـﺼﻨﯿﻒا ﻟـﺨﻼﯾـﺎا ﻟـﻌﺼﺒﯿﺔ ﺣﺴـﺐا ﻟـﺒﻨﯿﺔ‬ - ( based on the number of dendrites and axons that originate from the cell body) - (‫ﺑـﻨﺎء ً ﻋـﻠﻰ ﻋـﺪا دﻟـﺘﺸﻌﺒﺎاو تﻟـﻤﺤﺎا روﻟـﺘﻲ ﺗـﻨﺸﺄ ﻣـﻦ ﺟـﺴﻢا ﻟﺨـﻠﯿﺔ‬ - j 1. Unipolar neurons (also called pseudounipolar neurons): (‫)ﻋـﺼﺒﻮأ نﺣـﺎدﯾـﺔا ﻟـﻘﻄﺐ‬ g I - di -- - Have a single process emerges from the cell body that divides after a short l 04m distance into two branches. (‫)ﻟـﺪﯾـﮫ ﻧـﺘﻮاو ءﺣـﺪة ﯾﻨـﺒﺜﻖ ﻣـﻦ ﺟـﺴﻢا ﻟﺨـﻠﯿﺔ ﯾﻨـﻘﺴﻢ ﺑـﻌﺪ ﻣـﺴﺎﻓـﺔ ﻗـﺼﯿﺮإ ةﻟـﻰ ﻓـﺮﻋـﯿﻦ‬ - These neurons are more appropriately called pseudounipolar neurons because: (they begin in the embryo as bipolar neurons) -. (‫)ﯾـﺠﺐنا ﺗـﺴﻤﻰـھ ﺬا هﻟـﺨﻼﯾـﺎا ﻟـﻌﺼﺒﻮا نﺣـﺎا يدﻟـﻘﻄﺐا ﻟـﺰاﺋـﻒ ﻷﻧـﮭﺎ ﺗـﺒﺪأ ﻓـﻲا ﻟـﺠﻨﯿﻦ ﻛـﺨﻼﯾـﺎ ﻋـﺼﺒﯿﺔ ﺛـﻨﺎﺋـﯿﺔا ﻟـﻘﻄﺐ‬ - Found in the spinal ganglia. sal root (‫ﻓـﻲا ﻟـﻌﻘﺪا ﻟـﺸﻮﻛـﯿﺔ‬ ‫)وﺟـﺪت‬panglia) - 2. Bipolar neurons: (‫)ﻋـﺼﺒﻮن ﺛـﻨﺎﺋـﯿﺔا ﻟـﻘﻄﺐ‬ O - Have one main dendrite and one axon (‫)ﻟـﺪﯾـﮫاز ﺋـﺪة ﺷﺠـﺮﯾـﺔاو ﺣـﺪو ةﻣـﺤﻮاو رﺣـﺪ‬ meanin & -They are found in the retina of the eye, the inner ear, and the olfactory area of the brain. (‫)ﺗـﻮﺟـﺪ ﻓـﻲ ﺷـﺒﻜﯿﺔا ﻟـﻌﯿﻦاو ﻷا نذﻟـﺪاﺧـﻠﯿﺔاو ﻟـﻤﻨﻄﻘﺔا ﻟـﺸﻤﯿﺔ ﻓـﻲا ﻟـﺪﻣـﺎغ‬ O 3. Multipolar neurons: (‫)ﻋـﺼﺒﻮن ﻣـﺘﻌﺪا ةدﻷﻗـﻄﺎب‬ - Have several dendrites and one axon (‫)ﻟـﺪﯾـﮫاوز ﺋـﺬ ﺷﺠـﺮﯾـﺔ ﻣـﺘﻌﺪو ةدﻣـﺤﻮاو رﺣـﺪ‬ - Most neurons in the brain and spinal cord are of this type, as well as all motor neurons (‫ عﻛـﺬﻟـﻚ ﺟـﻤﯿﻊا ﻟـﺨﻼﯾـﺎا ﻟـﻌﺼﺒﯿﺔا ﻟﺤـﺮﻛـﯿﺔ‬، ‫)ﻣـﻌﻈﻢا ﻟـﺨﻼﯾـﺎا ﻟـﻌﺼﺒﯿﺔ ﻓـﻲا ﻟـﺪﻣـﺎاو غﻟـﺤﺒﻞا ﻟـﺸﻮﻛـﻲ ﻣـﻦـھ ﺬا اﻟـﻨﻮو‬  Nervous System Histology Nervous System: Neurons (Nerve C ells): Classification of neurons according to structure : / - I - ↑ Totes is Pogle O O O Ste ⑤ axon + dendrite  Nervous System Histology Nervous System: Neurons (Nerve C ells): Classification of neurons according to the- length of axons: (:‫)ﺗـﺼﻨﯿﻒا ﻟـﺨﻼﯾـﺎا ﻟـﻌﺼﺒﯿﺔ ﺣﺴـﺐـط ﻮا لﻟـﻤﺤﺎرو‬ ⑧ 1. Golgi type I: (١ ‫)ﺟـﻮﻟـﺠﻲ‬ - have- long axons, and connect remote regions. 00s St [ - (‫ ﺗـﺮﺑـﻂا ﻟـﻤﻨﺎـطﻖا ﻟـﻨﺎﺋـﯿﺔ‬، ‫)ﻟـﺪﯾـﮭﺎ ﻣـﺤﺎـط روﻮﯾـﻠﺔو‬ - Ex: pyramidal cells of motor cortex in cerebrum Cerebral cortex - of the Brain - (‫ا ﻟـﺨﻼﯾـﺎا ﻟﮭـﺮﻣـﯿﺔ ﻟﻠﻘﺸـﺮا ةﻟﺤـﺮﻛـﯿﺔ ﻓـﻲا ﻟـﺪﻣـﺎغ‬:‫)ﻣـﺜﺎل‬ igosion g2. Golgi type II: (٢ ‫)ﺟـﻮﻟـﺠﻲ‬ - & - have short axons which end near the cell body. (‫)ﻟـﺪﯾـﮭﺎ ﻣـﺤﺎرو ﻗـﺼﯿﺮة ﺗﻨﺘﮭـﻲ ﺑـﺎﻟـﻘﺮب ﻣـﻦ ﺟـﺴﻢا ﻟﺨـﻠﯿﺔ‬ - Ex: Cerebral and cerebellar cortex. - - (‫ ﻗﺸـﺮا ةﻟـﻤﺦاو ﻟـﺪﻣـﺎغ‬:‫)ﻣـﺜﺎل‬  Nervous System in CNS Histology Nervous System: macrophages T - cells) Neuroglia D (Glial C ells): < supporative - They are the supporting cells of the nervous system. (‫)ـھﻢا ﻟـﺨﻼﯾـﺎا ﻟـﺪاﻋـﻤﺔ ﻟـﻠﺠﮭﺎا زﻟـﻌﺼﺒﻲ‬ -O - They do not contribute in the electrical impulses but support the neurons both structurally and functionally. (‫)ﻻ ﺗـﺴﺎـھﻢ ﻓـﻲا ﻟـﻨﺒﻀﺎا تﻟﻜﮭـﺮﺑـﺎﺋـﯿﺔو ﻟـﻜﻨﮭﺎ ﺗـﺪﻋـﻢا ﻟـﺨﻼﯾـﺎا ﻟـﻌﺼﺒﯿﺔ ﻣـﻦا ﻟـﻨﺎﺣـﯿﺔا ﻟﮭـﯿﻜﻠﯿﺔاو ﻟـﻮـظﯿﻔﯿﺔ‬ => There are four types of neuroglia in the CNS: - Blood around vessels and capillary O 1. Astrocytes (‫)اﻟـﺨﻼﯾـﺎا ﻟﻨﺠـﻤﯿﺔ‬ - O2. Oligodendrocytes (‫ )ﺧـﻼﯾـﺎ ﻗـﻠﯿﻠﺔا ﻟـﺘﻐﺼﻦ‬around axon, g sheath > - CNSin Myclein 8 3. Microglia (‫ )ﺧـﻼﯾـﺎا ﻟـﺒﻠﻌﻤﺔ‬macrophage Lengulfing - > - cell & cell E 4. Ependymal Cells (‫)ﺧـﻼﯾـﺎا ﻟـﺒﻄﺎﻧـﺔا ﻟـﻌﺼﺒﯿﺔ‬ - There are four types of neuroglia in the PNS: & - around sheath my inon O1. Schwann Cells (‫)ﺧـﻼﯾـﺎ ﺷـﻮنا‬ & around cellog G2. Satellite Cells (‫)ﺧـﻼﯾـﺎ ﺳـﺎﺗـﻠﮫ‬ & (neurons ↑  Nervous System Histology Nervous System: Neuroglia (Glial C ells): Types of neuroglia (glial cells) in the CNS: 1. Astrocytes : - They are star-shaped cells have many processes - (‫)إﻧـﮭﺎ ﺧـﻼﯾـﺎ ﻋـﻠﻰ ﺷـﻜﻞ ﻧﺠـﻤﺔ ﻟـﮭﺎا ﻟـﻌﺪﯾـﺪ ﻣـﻦا ﻟـﻨﺘﻮتاء‬ - They are the largest and most numerous of the neuroglia. (‫)ـھﻢأ ﻛـﺒﺮأو ﻛـﺜﺮ ﻋـﺪد ﻣـﻦا ﻟـﺨﻼﯾـﺎا ﻟـﻌﺼﺒﯿﺔ‬ - Function: - ✤ have a role in support, growth, and nutrition - & of the neurons & - (‫)ﻟـﮭﺎرود ﻓـﻲد ﻋـﻢا ﻟـﺨﻼﯾـﺎا ﻟـﻌﺼﺒﯿﺔو ﻧـﻤﻮـھﺎو ﺗـﻐﺬﯾـﺘﮭﺎ‬ - 3. Oligodendrocytes - Function: ✤ responsible for forming and maintaining the > - myelin sheath around CNS axons. ‫)اﻟـﻤﺴﺆلو ﻋـﻦ‬ (‫ﺗـﺸﻜﯿﻞاو ﻟـﺤﻔﺎظ ﻋـﻠﻰ ﻏـﺸﺎا ءﻟـﻤﺎﯾـﻠﯿﻦ ﺣـﻮل ﻣـﺤﺎا روﻟـﺠﮭﺎا زﻟـﻌﺼﺒﻲا ﻟـﻤﺮﻛـﺰي‬  Nervous System Histology Nervous System: Neuroglia (Glial C ells): Types of neuroglia (glial cells) in the CNS: > - 3. Microglia & - Function: 10 , 3 issue nervous microbe ✤ act as phagocytes (like tissue macrophages) they remove cellular debris formed - during normal development of the nervous system and phagocytize microbes and phagocytes - damaged nervous tissue. ‫)ﺗـﻌﻤﻞ ﻛـﺨﻼﯾـﺎ ﺑـﻠﻌﻤﯿﺔ )ﻣـﺜﻞا ﻟـﺒﻼﻋـﻢا ﻟﻨﺴـﯿﺠﯿﺔ( ﺗـﻘﻮم ﺑـﺈازﻟـﺔا ﻟﺤـﻄﺎا مﻟﺨـﻠﻮا يﻟـﻤﺘﺸﻜﻞأ ﺛـﻨﺎا ءﻟـﺘﻄﻮر‬ - (‫اﻟـﻄﺒﯿﻌﻲ ﻟـﻠﺠﮭﺎا زﻟـﻌﺼﺒﻲو ﺗـﺒﻠﻊا ﻟـﻤﯿﻜﺮوﺑـﺎأ و تﻧـﺴﺠﺔ ﻋـﺼﺒﯿﺔ ﺗـﺎﻟـﻔﺔ‬  Nervous System Histology Nervous System: Neuroglia (Glial C ells): Types of neuroglia (glial cells) in the CNS: ⑨ 4. Ependymal Cells - possess- - They are single layer of cuboidal cells that- microvilli and cilia - - (‫)ـھﻢـط ﺒﻘﺔاو ﺣـﺪة ﻣـﻦا ﻟـﺨﻼﯾـﺎا ﻟـﻤﻜﻌﺒﺔا ﻟـﺘﻲ ﺗـﻤﺘﻠﻚـھأ ﺪبا‬ ga- They line the ventricles of the brain and the central canal of the spinal cord (spaces - - filled with cerebrospinal fluid, which protects and nourishes the brain and spinal cord) - ((‫ ﻟـﺘﻲ ﺗﺤـﻤﻲو ﺗـﻐﺬا يﻟـﺪﻣـﺎاو غﻟـﺤﺒﻞا ﻟـﺸﻮﻛـﻲ‬، ‫)إﻧـﮭﺎ ﺗـﺒﻄﻦا ﻟـﺒﻄﯿﻨﯿﻦ ﻓـﻲا ﻟـﺪﻣـﺎاو غﻟـﻘﻨﺎا ةﻟـﻤﺮﻛـﺰﯾـﺔ ﻟـﻠﺤﺒﻞا ﻟـﺸﻮﻛـﻲ )ﻣـﺴﺎﺣـﺎت ﻣـﻠﯿﺌﺔ ﺑـﺎﻟـﺴﻮاﺋـﻞا ﻟـﺪﻣـﺎﻏـﯿﺔا ﻟـﺸﻮﻛـﻲاو‬ - Function: ✤ produce, and assist in the circulation of cerebrospinal fluid. (‫)إﻧـﺘﺎو جﻣـﺴﺎﻋـﺪة ﻓـﻲا نارود ﻟـﺴﺎﺋـﻞا ﻟـﻨﺨﺎﻋـﻲ‬ & - ✤ They also form the blood–cerebrospinal fluid barrier. (‫)ﻛـﻤﺎأ ﻧـﮭﺎ ﺗـﺸﻜﻞ ﺣـﺎﺟـﺰا ﻟـﺴﺎﺋـﻞا ﻟـﺪﻣـﻮا يﻟـﺸﻮﻛـﻲ‬  Nervous System Histology Nervous System: Neuroglia (Glial C ells): Types of neuroglia in the PNS: 1. Schwann Cells : > 59 - These cells encircle PNS axons. (‫)ـھﺬا هﻟـﺨﻼﯾـﺎ ﺗـﺤﯿﻂ ﻣـﺤﺎا روﻟـﺠﮭﺎا زﻟـﻌﺼﺒﻲا ﻟـﻄﺮﻓـﻲ‬ & electrical o - Function : axilleration impulses , ✤ Like oligodendrocytes,--- ↑ they form the myelin sheath around axons. - (‫ ﻓـﺈﻧـﮭﺎ ﺗـﺸﻜﻞ ﻏـﺸﺎا ءﻟـﻤﺎﯾـﻠﯿﻦ ﺣـﻮل ﻣـﺤﺎرو ﻋـﺼﺒﯿﺔ‬،‫)ﻣـﺜﻞا ﻟـﺨﻼﯾـﺎا ﻟـﺪﺑـﻘﯿﺔ ﻗـﻠﯿﻠﺔا ﻟـﺘﻐﺼﻦ‬ ✤ participate in axon regeneration, which is more easily accomplished in the PNS than in the CNS. (‫ يرﻟـﺬي ﯾـﻤﻜﻦ ﺗـﺤﻘﯿﻘﮫ ﺑـﺴﮭﻮﻟـﺔأ ﻛـﺒﺮ ﻓـﻲا ﻟـﺠﮭﺎا زﻟـﻌﺼﺒﻲا ﻟـﻄﺮﻓـﻲ ﻋـﻨﮫ ﻓـﻲا ﻟـﺠﮭﺎا زﻟـﻌﺼﺒﻲا ﻟـﻤﺮﻛـﺰي‬، ‫)اﻟـﻤﺸﺎرﻛـﺔ ﻓـﻲا ﻟﺘﺠـﺪﯾـﺪا ﻟـﻤﺤﻮاو‬  Nervous System Histology Nervous System: Neuroglia (Glial C ells): Types of neuroglia in the PNS: 2. Satellite Cells - - They are flat cells surround the cell bodies of neuron of PNS ganglia. -- - (‫)ـھوﻲ ﺧـﻼﯾـﺎ ﻣﺴـﻄﺤﺔ ﺗـﺤﯿﻂ ﺑـﺄﺟـﺴﺎا مﻟـﻌﺼﺒﻮن ﻟـﻌﻘﺪا ﻟـﺠﺎا زﻟـﻌﺼﺒﻲا ﻟـﻄﺮﻓـﻲ‬ - Function: ✤ providing structural support (‫)ﺗـﻘﺪﯾـﻢا ﻟـﺪﻋـﻢا ﻟﮭـﯿﻜﻠﻲ‬ - ✤ regulate the exchanges of materials between neuronal cell bodies and interstitial fluid. - (‫)ﺗـﻨﻈﯿﻢ ﺗـﺒﺎا لدﻟـﻤﻮدا ﺑـﯿﻦأ ﺟـﺴﺎا مﻟـﺨﻼﯾـﺎا ﻟـﻌﺼﺒﯿﺔاو ﻟـﺴﺎﺋـﻞا ﻟـﺨﻼﻟـﻲ‬  ‫‪Nervous System‬‬ ‫‪Histology Nervous System:‬‬ ‫‪Myelin Sheath:‬‬ ‫ﻏـﻤﺪ ﯾـﺘﺸﻜﻞ ﺣـﻮا لﻟـﻤﺤﻮرا( ‪ It is an insulating layer, or sheath that forms around the axon.‬‬ ‫)إﻧـﮭﺎـط ﺒﻘﺔ ﻋـﺎزﻟـﺔوأ ‪،‬‬ ‫)ﯾـﺘﻜﻮن ﻣـﻦا ﻟـﺒﺮوﺗـﯿﻦاو ﻟـﻤﻮا داﻟـﺪـھﻨﯿﺔ( ‪ It is made up of protein and fatty substances.‬‬ ‫‪ In the CNS it is formed by oligodendrocytes and in the PNS by Schwann cells‬‬ ‫ ‬ ‫)ﻓـﻲا ﻟـﺠﮭﺎا زﻟـﻌﺼﺒﻲا ﻟـﻤﺮﻛـﺰي ﯾـﺘﻢ ﺗـﻜﻮﯾـﻨﮫ ﺑـﻮاﺳـﻄﺔ ﺧـﻼﯾـﺎ ﻗـﻠﯿﻠﺔا ﻟـﺘﻐﺼﻦو ﻓـﻲا ﻟـﺨﻼﯾـﺎا ﻟـﻌﺼﺒﯿﺔا ﻟـﻌﺼﺒﯿﺔ ﺑـﻮاﺳـﻄﺔ ﺧـﻼﯾـﺎ ﺷـﻮنا(‬ ‫‪ Function:‬‬ ‫‪- -‬‬ ‫)ﯾﺤـﻤﻲا ﻟـﻤﺤﻮرا( ‪protects the axon‬‬ ‫>‬ ‫‪- -‬‬‫‪allows electrical impulses to transmit quickly and efficiently along the nerve cells‬‬ ‫)ﯾـﺴﻤﺢ ﻟـﻠﻨﺒﻀﺎا تﻟﻜﮭـﺮﺑـﺎﺋـﯿﺔ ﺑـﺎﻹرﺳـﺎل ﺑﺴـﺮﻋـﺔو ﻛـﻔﺎةء ﻋـﻠﻰـط ﻮا لﻟـﺨﻼﯾـﺎا ﻟـﻌﺼﺒﯿﺔ( ‪-‬‬ ‫)‪ Neurons can be myelinated or unmyelinated (no myelin sheath‬‬ ‫)ﯾـﻤﻜﻦنأ ﺗـﻜﻮا نﻟـﺨﻼﯾـﺎا ﻟـﻌﺼﺒﯿﺔ ﻣـﺤﺎـطﺔ ﺑـﺎﻟـﻤﺎﯾـﻠﯿﻦوأ ﻏـﯿﺮﻣـﺤﺎـطﺔ ﺑـﺎﻟﻤـﯿﺎﻟـﯿﻦ )ﻻ ﻏـﻤﺪا ﻟـﻤﯿﻠﯿﻦ(( ‪.‬‬ ‫‪E‬‬ ‫↓‬ ‫‪disha‬‬  Nervous System Histology Nervous System: Connective Tissue Sheaths Of Peripheral Nerves: There are three layers of connective tissue surrounding each nerve - - (‫)ـھﻨﺎك ﺛـﻼـط ثﺒﻘﺎت ﻣـﻦا ﻷﻧـﺴﺠﺔا ﻟـﻀﺎﻣـﺔا ﻟـﻤﺤﯿﻄﺔ ﺑـﻜﻞ ﻋـﺼﺐ‬ 1. Endoneurium: G - surrounds individual axons (innermost layer) ((‫)ﯾـﺤﯿﻂ ﻛـﻞ ﻣـﺤﻮر ﻋـﻠﻰ ﺣـﺪه )اﻟـﻄﺒﻘﺔا ﻷﻋـﻤﻖ‬ O 2. Perineurium: - surrounds bundles of axons (fascicles) (middle layer) ((‫)ﯾـﺤﯿﻂ ﺑﺤـﺰم ﻣـﻦا ﻟـﻤﺤﺎرو )اﻟﺤـﺰم( )اﻟـﻄﺒﻘﺔا ﻟـﻮﺳـﻄﻰ‬ g 3. Epineurium: - surrounds an entire nerve (outermost covering) ((‫)ﯾـﺤﯿﻂ ﺑـﻌﺼﺐ ﻛـﺎﻣـﻞ )ﻏـﻼف ﺧـﺎرﺟـﻲ‬