Nervous System-1 PDF

NERVOUS SYSTEM-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-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 1. The Central Nervous System. (‫)اﻟـﺠﮭﺎا زﻟـﻌﺼﺒﻲا ﻟـﻤﺮﻛـﺰي‬ 2. The Peripheral Nervous System. (‫)اﻟـﺠﮭﺎا زﻟـﻌﺼﺒﻲا ﻟـﻄﺮﻓـﻲ‬ ✤ The central nervous system (CN S) consists of: 1. 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 1. Spinal Nerves (exit from the spinal cord) (‫)اﻷﻋـﺼﺎا بﻟـﺸﻮﻛـﯿﺔ ﺗـﻨﺸﺄ ﻣـﻦا ﻟـﻨﺨﺎا عﻟـﺸﻮﻛـﻲ‬ 2. Cranial Nerves (exit from the brain) (‫)اﻷﻋـﺼﺎا بﻟـﻘﺤﻔﯿﺔ ﺗـﻨﺸﺄ ﻣـﻦا ﻟـﺪﻣـﺎغ‬  Nervous System 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 2. The Midbrain (‫)اﻟـﺪﻣـﺎا غﻟـﻤﺘﻮﺳـﻂ‬ 3. The Hindbrain (‫)اﻟـﺪﻣـﺎا غﻟﺨـﻠﻔﻲ‬ The brain is surrounded by three protective membranous layers called Meninges: (‫)ﯾـﺤﯿﻂ ﺑـﺎﻟـﺪﻣـﺎغ ﺛـﻼـط ثﺒﻘﺎت ﻏـﺸﺎﺋـﯿﺔاو ﻗـﯿﺔ ﺗـﺴﻤﻰا ﻟـﺴﺤﺎﯾـﺎ‬ 1. The Dura Mater (‫)اﻷا مﻟـﺠﺎﻓـﯿﺔ‬ 2. The Arachnoid Mater (‫)اﻷا مﻟـﻌﻨﻜﺒﻮﺗـﯿﮫ‬ 3. The Pia Mater (‫)اﻷا مﻟـﺤﻨﻮﻧـﺔ‬  Nervous System The C entral Nervous System: The Spinal C ord: Located within the vertebral canal of the vertebral column. (‫)ﺗـﻘﻊاد ﺧـﻞ ﻗـﻨﺎا ةﻟـﻌﻤﻮا دﻟـﻔﻘﺮي ﻟـﻠﻌﻤﻮا دﻟـﻔﻘﺮي‬ 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  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  Nervous System The Peripheral Nervous System: Nerves can be divided into different types: (‫)ﯾـﻤﻜﻦ ﺗﻘﺴـﯿﻢا ﻷﻋـﺼﺎإ بﻟـﻰأ ﻧـﻮعا ﻣـﺨﺘﻠﻔﺔ‬ A. Motor (Efferent) Nerve ((‫)ﻋـﺼﺐ ﺣـﺮﻛـﻲ )اﻟـﺼﺎةرد‬ - Nerves that transmit signals from the CNS to the rest of the body. (carries motor commands to the muscles and glands) ‫)اﻷﻋـﺼﺎا بﻟـﺘﻲ ﺗـﻨﻘﻞا ﻹﺷـﺎتار ﻣـﻦا ﻟـﺠﮭﺎا زﻟـﻌﺼﺒﻲا ﻟـﻤﺮﻛـﺰإ يﻟـﻰ ﺑـﻘﯿﺔا ﻟـﺠﺴﻢ )ﺗـﻨﻘﻞ‬ ((‫اﻷاوﻣـﺮا ﻟﺤـﺮﻛـﯿﺔإ ﻟـﻰا ﻟـﻌﻀﻼاو تﻟـﻐﺪد‬ B. Sensory (Afferent)Nerve ((‫)ﻋـﺼﺐ ﺣﺴـﻲ)دراو‬ - Nerves that transmit information from the body to the CNS (carries sensation from the tissue to the CNS) ‫)اﻷﻋـﺼﺎا بﻟـﺘﻲ ﺗـﻨﻘﻞا ﻟـﻤﻌﻠﻮﻣـﺎت ﻣـﻦا ﻟـﺠﺴﻢإ ﻟـﻰ‬ ‫ا ﻟـﺠﮭﺎا زﻟـﻌﺼﺒﻲا ﻟـﻤﺮﻛـﺰي )ﺗﺤـﻤﻞا ﻹﺣـﺴﺎس ﻣـﻦا ﻷﻧـﺴﺠﺔإ ﻟـﻰا ﻟـﺠﮭﺎا زﻟـﻌﺼﺒﻲ‬ ((‫اﻟـﻤﺮﻛـﺰي‬ C. Mixed Nerves (‫)أﻋـﺼﺎب ﻣـﺨﺘﻠﻄﺔ‬ - Carries motor and sensory innervation (‫)ﯾـﺤﺘﻮي ﻋـﻠﻰأ ﻟـﯿﺎف ﺣـﺮﻛـﯿﺔو ﺣﺴـﯿﺔ‬  Nervous System The Peripheral Nervous System: Functionally, The PNS is divided into subsystems: (‫ ﯾـﻘﺴﻢإ ﻟـﻰ‬،‫)ﻣـﻦا ﻟـﻨﺎﺣـﯿﺔا ﻟـﻮـظﯿﻔﯿﺔ‬ 1. Somatic Nervous System: (‫)اﻟـﺠﮭﺎا زﻟـﻌﺼﺒﻲا ﻟﺠﺴـﺪي‬ - provides the voluntary control of the skeletal muscle.(‫)ﯾـﻮﻓـﺮا ﻟﺴـﯿﻄﺮا ةﻟـﻄﻮﻋـﯿﺔ ﻋـﻠﻰا ﻟـﻌﻀﻼا تﻟﮭـﯿﻜﻠﯿﺔ‬ 2. Autonomic Nervous System: (‫)اﻟـﺠﮭﺎا زﻟـﻌﺼﺒﻲا ﻟﻤﺴـﺘﻘﻞ‬ - 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  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 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) ((‫ا ﻟـﻨﻮم‬:‫)ﯾـﺘﻢ ﺗﻨﺸـﯿﻄﮫأ ﺛـﻨﺎا ءﻟـﺮاﺣـﺔا ﻟـﺒﺪﻧـﯿﺔاو ﻟـﻌﻘﻠﯿﺔ )ﻋـﻠﻰ ﺳـﺒﯿﻞا ﻟـﻤﺜﺎل‬ 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  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 ✤ Neurons or Nerve Cells: (‫)اﻟـﻌﺼﺒﻮا وأ نﻟﺨـﻠﯿﺔا ﻟـﻌﺼﺒﯿﺔ‬ - It is the structural and functional unit of the nervous system. - (‫)ـھوﻲا ﻟـﻮﺣـﺪا ةﻟﮭـﯿﻜﻠﯿﺔاو ﻟـﻮـظﯿﻔﯿﺔ ﻟـﻠﺠﮭﺎا زﻟـﻌﺼﺒﻲ‬ - It is specialized to conduct electrical impulses to and from the nervous system. - (.‫)ـھوﻲ ﻣـﺘﺨﺼﺼﺔ ﻓـﻲإ ﺟـﺮا ءاﻟـﻨﺒﻀﺎا تﻟﻜﮭـﺮﺑـﺎﺋـﯿﺔ ﻣـﻦإو ﻟـﻰا ﻟـﺠﮭﺎا زﻟـﻌﺼﺒﻲ‬ ✤ Neuroglia or Glial Cells: (‫)اﻟـﺨﻼﯾـﺎا ﻟـﺪﺑـﻘﯿﺔا ﻟـﻌﺼﺒﯿﺔ‬ - It is supportive cells that support the neurons both structurally and functionally. - (‫)إﻧـﮭﺎا ﻟـﺨﻼﯾـﺎا ﻟـﺪاﻋـﻤﺔا ﻟـﺘﻲ ﺗـﺪﻋـﻢا ﻟـﺨﻼﯾـﺎا ﻟـﻌﺼﺒﯿﺔ ﻣـﻦا ﻟـﻨﺎﺣـﯿﺔا ﻟﮭـﯿﻜﻠﯿﺔاو ﻟـﻮـظﯿﻔﯿﺔ‬ - It is non-conducting cells that are located close to the neurons - (‫)ـھوﻲ ﺧـﻼﯾـﺎ ﻏـﯿﺮ ﻣـﻮﺻـﻠﺔ ﺗـﻘﻊ ﺑـﺎﻟـﻘﺮب ﻣـﻦا ﻟـﺨﻼﯾـﺎا ﻟـﻌﺼﺒﯿﺔ‬  Nervous System Histology Nervous System: Neurons (Nerve C ells): Each neuron consists of three part: (‫)ﯾـﺘﻜﻮن ﻛـﻞ ﻋـﺼﺒﻮن ﻣـﻦ ﺛـﻼﺛـﺔأ ﺟـﺰءا‬ 1. Cell Body (also called soma or perikaryon). (‫)ﺟـﺴﻢا ﻟﺨـﻠﯿﺔ‬ 2. Dendrites. (‫)اوزﺋـﺪ ﺷﺠـﺮﯾـﺔ‬ 3. Axon. (‫)ﻣـﺤﻮر ﻋـﺼﺒﻲ‬  Nervous System Histology Nervous System: Neurons (Nerve C ells): Cell Body : - 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 - 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 Histology Nervous System: Neurons (Nerve C ells): Axon: - It is a long cable-like projection that can extend away from the cell body - (‫)ـھوﻮ ﻛـﯿﺒﻞـط ﻮﯾـﻞ ﯾـﻤﺘﺪ ﺑـﻌﯿ ًﺪا ﻋـﻦ ﺟـﺴﻢا ﻟﺨـﻠﯿﺔ‬ - It carries nerve signals away from the cell body, and carries some types of information back to it. - (‫ 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  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 of 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: 1. Motor neurons (Efferent): - 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): - Receive stimuli from the receptors throughout the body to the CNS. - (‫)ﯾـﺘﻠﻘﻰا ﻟـﻤﻨﺒﮭﺎت ﻣـﻦا ﻟﻤﺴـﺘﻘﺒﻼت ﻓـﻲ ﺟـﻤﯿﻊأ ﻧـﺤﺎا ءﻟـﺠﺴﻢإ ﻟـﻰا ﻟـﺠﮭﺎا زﻟـﻌﺼﺒﻲا ﻟـﻤﺮﻛـﺰي‬ 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 1. Unipolar neurons (also called pseudounipolar neurons): (‫)ﻋـﺼﺒﻮأ نﺣـﺎدﯾـﺔا ﻟـﻘﻄﺐ‬ - Have a single process emerges from the cell body that divides after a short 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. (‫)وﺟـﺪت ﻓـﻲا ﻟـﻌﻘﺪا ﻟـﺸﻮﻛـﯿﺔ‬ 2. Bipolar neurons: (‫)ﻋـﺼﺒﻮن ﺛـﻨﺎﺋـﯿﺔا ﻟـﻘﻄﺐ‬ - Have one main dendrite and one axon (‫)ﻟـﺪﯾـﮫاز ﺋـﺪة ﺷﺠـﺮﯾـﺔاو ﺣـﺪو ةﻣـﺤﻮاو رﺣـﺪ‬ -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 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 :  Nervous System Histology Nervous System: Neurons (Nerve C ells): Classification of neurons according to the length of axons: (:‫)ﺗـﺼﻨﯿﻒا ﻟـﺨﻼﯾـﺎا ﻟـﻌﺼﺒﯿﺔ ﺣﺴـﺐـط ﻮا لﻟـﻤﺤﺎرو‬ 1. Golgi type I: (١ ‫)ﺟـﻮﻟـﺠﻲ‬ - have long axons, and connect remote regions. - (‫ ﺗـﺮﺑـﻂا ﻟـﻤﻨﺎـطﻖا ﻟـﻨﺎﺋـﯿﺔ‬، ‫)ﻟـﺪﯾـﮭﺎ ﻣـﺤﺎـط روﻮﯾـﻠﺔو‬ - Ex: pyramidal cells of motor cortex in cerebrum - (‫ا ﻟـﺨﻼﯾـﺎا ﻟﮭـﺮﻣـﯿﺔ ﻟﻠﻘﺸـﺮا ةﻟﺤـﺮﻛـﯿﺔ ﻓـﻲا ﻟـﺪﻣـﺎغ‬:‫)ﻣـﺜﺎل‬ 2. 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 Histology Nervous System: Neuroglia (Glial C ells): They are the supporting cells of the nervous system. (‫)ـھﻢا ﻟـﺨﻼﯾـﺎا ﻟـﺪاﻋـﻤﺔ ﻟـﻠﺠﮭﺎا زﻟـﻌﺼﺒﻲ‬ - 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: 1. Astrocytes (‫)اﻟـﺨﻼﯾـﺎا ﻟﻨﺠـﻤﯿﺔ‬ 2. Oligodendrocytes (‫)ﺧـﻼﯾـﺎ ﻗـﻠﯿﻠﺔا ﻟـﺘﻐﺼﻦ‬ 3. Microglia (‫)ﺧـﻼﯾـﺎا ﻟـﺒﻠﻌﻤﺔ‬ 4. Ependymal Cells (‫)ﺧـﻼﯾـﺎا ﻟـﺒﻄﺎﻧـﺔا ﻟـﻌﺼﺒﯿﺔ‬ There are four types of neuroglia in the PNS: 1. Schwann Cells (‫)ﺧـﻼﯾـﺎ ﺷـﻮنا‬ 2. Satellite Cells (‫)ﺧـﻼﯾـﺎ ﺳـﺎﺗـﻠﮫ‬  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: ✤ act as phagocytes (like tissue macrophages) they remove cellular debris formed during normal development of the nervous system and phagocytize microbes and 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: 4. Ependymal Cells - They are single layer of cuboidal cells that possess microvilli and cilia - (‫)ـھﻢـط ﺒﻘﺔاو ﺣـﺪة ﻣـﻦا ﻟـﺨﻼﯾـﺎا ﻟـﻤﻜﻌﺒﺔا ﻟـﺘﻲ ﺗـﻤﺘﻠﻚـھأ ﺪبا‬ - 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 : - These cells encircle PNS axons. (‫)ـھﺬا هﻟـﺨﻼﯾـﺎ ﺗـﺤﯿﻂ ﻣـﺤﺎا روﻟـﺠﮭﺎا زﻟـﻌﺼﺒﻲا ﻟـﻄﺮﻓـﻲ‬ - Function : ✤ 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(( ‪.‬‬  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: - surrounds individual axons (innermost layer) ((‫)ﯾـﺤﯿﻂ ﻛـﻞ ﻣـﺤﻮر ﻋـﻠﻰ ﺣـﺪه )اﻟـﻄﺒﻘﺔا ﻷﻋـﻤﻖ‬ 2. Perineurium: - surrounds bundles of axons (fascicles) (middle layer) ((‫)ﯾـﺤﯿﻂ ﺑﺤـﺰم ﻣـﻦا ﻟـﻤﺤﺎرو )اﻟﺤـﺰم( )اﻟـﻄﺒﻘﺔا ﻟـﻮﺳـﻄﻰ‬ 3. Epineurium: - surrounds an entire nerve (outermost covering) ((‫)ﯾـﺤﯿﻂ ﺑـﻌﺼﺐ ﻛـﺎﻣـﻞ )ﻏـﻼف ﺧـﺎرﺟـﻲ‬