Nervous System Anatomy PDF

Introduction to Anatomy Nervous system Prof.Dr. Manal Albadawi  Objectives Definition. Divisions of the Nervous Systems (CNS,PNS and ANS).  Central Nervous System: 1- Brain 2- Spinal cord  Peripheral nervous system  Autonomic nervous system Protection of the central nervous syst...

Introduction to Anatomy Nervous system Prof.Dr. Manal Albadawi  Objectives Definition. Divisions of the Nervous Systems (CNS,PNS and ANS).  Central Nervous System: 1- Brain 2- Spinal cord  Peripheral nervous system  Autonomic nervous system Protection of the central nervous system  Definition  It is the system that is responsible for the control of all activities in the body.  It is formed of highly specialized nerve cell (neurone).  The neurone can receive the stimuli and send impulses to the effector (muscle or gland). Divisions of the nervous system Parts of The Nervous System The nervous system is divided into three main parts: 1- Central nervous system. 2- Peripheral nervous system. 3-Autonomic nervous system.  Divisions of the nervous system 1-Central nervous system - encased in bone  Brain within the skull  Spinal cord within the vertebral canal 2-Peripheral nervous system – voluntary control  Somatic nervous system cranial nerves  spinal nerves 3-Autonomic nervous system – no conscious control  Sympathetic nervous system – fight or flight response  Parasympathetic nervous system. 6  Central Nervous System (C.N.S.) The central nervous system consists of brain and spinal cord.  1) The Brain: Parts of the brain: 1. Cerebrum: ❑ Formed of two cerebral hemispheres connected by the corpus callosum. ❑ Each hemisphere has a lateral ventricle 2. Cerebellum: ❑ Formed of two cerebellar hemisphere connected by the vermis. 3. Brain stem: Is formed of: ▪ Midbrain: {above}. ▪ Pons: {middle}. ▪ Medulla oblongata :{ below}. cerebrum cerebellum BS  Brain ❑Cerebrum A. Cerebral hemisphere A B. Diencephalon 1: Thalamus 2: Hypothalamus 1 ❑Cerebellum (C) 23 ❑Brainstem 4 C 3: midbrain 4: pons 5 5: medulla - Forbrain: ✓ Formed of two cerebral hemispheres. ✓ Contain nuclei of the 1st & 2nd cranial nerves. - Midbrain: ✓ Contains nuclei of the 3rd & 4th cranial nerves. - Hindbrain: ✓ Formed of pons, medulla & cerebellum. ✓ Pons: Contains nuclei of the 5th , 6th , 7th & 8th cranial nerves. ✓ Medull: Contains nuclei of the 9th ,10th ,11th & 12th cranial nerves. ✓ Medull: Contains centers of the heart, respiration, swallowing and vomitting.  Brain Cerebral hemisphere (cerebrum) and diencephalon Brain stem (midbrain, pons and medulla oblongata) Cerebellum 13  2) The Spinal cord: Begins: as the continuation of the medulla oblongata at the base of the skull. Ends: It ends at: - In the newborn: at the level of the third lumbar vertebra (L3). - In the adult: at the level of the lower border of (L1). Location: in the upper two-thirds of the vertebral canal. Length: 45 cm in the male and 42 cm in female Segments: 31 segments; which give rise of 31 pairs of spinal nerves. Enlargements: two enlargements: - Cervical enlargement: gives origin to the brachial plexus. - Lumbosacral enlargement: gives origin to the lumbosacral plexus. Beginning -Direct continuation of M.O. -Below foramen magnum. Poposition In upper 2/3 of vertebral canal. Length =45 cm in =42 cm in Termination Segments  Spinal cord Anatomical position. segments Anatomical Cervical C planes.8 Thoracic T 12 Lumbar Anatomical terms.5[terminology] L Sacral S 5 Bone. Coccygeal 1 Anatomical position. Anatomical planes. Anatomical terms. [terminology] Bone.  2) The Spinal cord: Begins: as the continuation of the medulla oblongata at the base of the skull. Ends: It ends at: - In the newborn: at the level of the third lumbar vertebra (L3). - In the adult: at the level of the lower border of (L1). Location: in the upper two-thirds of the vertebral canal. Length: 45 cm in the male and 42 cm in female Segments: 31 segments; which give rise of 31 pairs of spinal nerves. Enlargements: two enlargements: - Cervical enlargement: gives origin to the brachial plexus. - Lumbosacral enlargement: gives origin to the lumbosacral plexus.  Protection of the CNS The brain and the spinal cord are protected by 3 barriers ❑ The skull and the vertebral column ❑ The meninges. ❑ The cerebrospinal fluid  The Meninges Definition: are three membranes surround The brain and the spinal cord. ❑The meninges consists of: 1. Dura mater (outer layer). 2. Arachnoid mater (middle layer). 3. Pia mater (inner layer). The dura and arachnoid maters are separated by a space called subdural space. The arachnoid and pia maters are separated by a space called subarachnoid space which contains cerebrospinal fluid. SCALP Skull Dura matter cap  Dura matter Arachnoid matter Arachnoid matter Pia matter Meninges & meningeal Meninges - Three fibrous coats surround CNS. spaces - Layers: 1- Dura matter: Outer, thickest and strongest layer. 2- Arachnoid matter: Middle layer. 3- Pia matter: Thinnest inner layer that lies in direct contact with brain and spinal cord. Meningeal spaces Epidural space : between dura and bone. Subdural space: between dura and arachnoid. Subarachnoid space : ✓ Between arachnoid and pia. ✓ The widest space. ✓ Contains CSF.  The cerebrospinal fluid Definition: The fluid that fills the ventricles and subarachnoid space Volume: 130 ml Function: Reduces the brain weight. Drains the waste products. Protects the central nervous system. Regulates intracranial pressure. Peripheral Nervous System Peripheral nervous system is formed of: a. cranial nerves b. spinal nerves c. ganglia.  Cranial Nerves  12 pairs connected to the brain Cranial Nerves  12 pairs connected to brain  Four Classifications of Cranial Nerves  Sensory nerves: carry somatic sensory information, including touch, pressure, vibration, temperature, and pain  Special sensory nerves: carry sensations such as smell, sight, hearing, balance  Motor nerves: axons of somatic motor neurons  Mixed nerves: mixture of motor and sensory fibers Name  1st 2nd 5th 7th 8th 9th 12th 11th 10th Cranial Nerves - Type and Function  Olfactory Nerves (I)  Special sensory (smell)  Optic Nerves (II)  Special sensory (vision)  Oculomotor Nerves (III)  Mixed (motor and parasympathetic) (eye movements)  The Trochlear Nerves (IV)  Motor (eye movements)  The Trigeminal Nerves (V)  Mixed (sensory and motor) to face Cranial Nerves - Type and Function  The Abducens Nerves (VI)  Motor (eye movements)  The Facial Nerves (VII)  Mixed (sensory, motor and parasympathetic) to face  The Vestibulocochlear Nerves (VIII) special sensory:  Vestibular branch:  balance and equilibrium  Cochlear branch:  Hearing Cranial Nerves - Type and Function  The Glossopharyngeal Nerves (IX)  Mixed (sensory, motor and parasympathetic) to head and neck  The Vagus Nerves (X)  Mixed (sensory, motor and parasympathetic)  Widely distributed in thorax and abdomen  The Accessory Nerves (XI)  Motor to muscles of neck and upper back  The Hypoglossal Nerves (XII)  Motor (tongue movements)  Spinal Nerves  31 pairs originate from the spinal cord  Spinalposition. Anatomical cord nerves Anatomical Cervical C 8planes. Thoracic T 12 Lumbar Anatomical terms. [terminology] L 5 Sacral S Bone. 5 Coccygeal 1  Autonomic nervous system It is the Part of nervous system concerned with innervation of involuntary structures as heart, smooth muscles & glands. It is distributed through central & peripheral nervous system. It is divided into 2 parts: a) Sympathetic system: thoracolumbar outflow Prepare the body for an emergency. It increases the heart rate, raises the blood pressure, inhibits peristalsis and closes the sphincters. b) Parasympathetic system: craniosacral outflow Responsible for restoring energy. It decreases the heart rate, increases the peristalsis and glandular activity and open sphincters.  Thank you Any questions????