Nervous System Notes PDF

TOPIC XXI: NERVOUS SYSTEM “Left Brain, Right Brain” (Dan Stewart) “Spinal Cord” (Greg Dunn) “Brain” (Alex Konahin) “Maki-e Neurons” (Greg Dunn)  Central nervous system (CNS)...

TOPIC XXI: NERVOUS SYSTEM “Left Brain, Right Brain” (Dan Stewart) “Spinal Cord” (Greg Dunn) “Brain” (Alex Konahin) “Maki-e Neurons” (Greg Dunn)  Central nervous system (CNS) Peripheral nervous system (PNS) Brain and spinal cord Cranial nerves and spinal nerves Integrative and control centers Communication lines between the CNS and the rest of the body Sensory (afferent) division Motor (efferent) division Somatic and visceral sensory Motor nerve fibers nerve fibers Conducts impulses from the CNS Conducts impulses from to effectors (muscles and glands) receptors to the CNS Somatic sensory Somatic nervous Autonomic nervous fiber Skin system system (ANS) Somatic motor Visceral motor (voluntary) (involuntary) Conducts impulses Conducts impulses from the CNS to from the CNS to skeletal muscles cardiac muscles, Visceral sensory fiber smooth muscles, Stomach and glands Skeletal muscle Motor fiber of somatic nervous system Sympathetic division Parasympathetic Mobilizes body division systems during activity Conserves energy Promotes house- keeping functions during rest Sympathetic motor fiber of ANS Heart Structure Function Sensory (afferent) division of PNS Parasympathetic motor fiber of ANS Bladder Motor (efferent) division of PNS Fig. 11.3 A) Nervous System (NS): Overview Network of cells and tissues that: communicate information control body functions coordinate thoughts, actions and emotions Fig. 12.1 A) Nervous System (NS): Overview 2 Divisions: 1) Central NS (CNS) “command centre” Fig. 11.2 A) Nervous System (NS): Overview 2 Divisions: 1) Central NS (CNS) “command centre” brain + spinal cord Fig. 11.2 A) Nervous System (NS): Overview 2 Divisions: 1) Central NS (CNS) “command centre” brain + spinal cord Integration processes + integrates info A) Nervous System (NS): Overview 2 Divisions: Cervical nerves C 1 – C8 2) Peripheral NS (PNS) consists of: Thoracic nerves T1 – T12 Lumbar nerves L1 – L5 Sacral nerves S1 – S5 Coccygeal Fig. 13.2 nerve Co1 A) Nervous System (NS): Overview 2 Divisions: 2) Peripheral NS (PNS) consists of: a) cranial nerves → to/from brain Fig. 13.6 A) Nervous System (NS): Overview 2 Divisions: 2) Peripheral NS (PNS) consists of: a) cranial nerves → to/from brain b) spinal nerves → to/from spinal cord Fig. 12.28 A) Nervous System (NS): Overview 2 Divisions: Sensory input 2) Peripheral NS (PNS) 2 divisions of PNS: Integration Motor output Fig. 11.1 A) Nervous System (NS): Overview 2 Divisions: Sensory input 2) Peripheral NS (PNS) 2 divisions of PNS: a) sensory/afferent division Integration Motor output Fig. 11.1 A) Nervous System (NS): Overview 2 Divisions: Sensory input 2) Peripheral NS (PNS) 2 divisions of PNS: a) sensory/afferent division Integration Motor output → has sensory receptors that detect stimuli (change in Fig. 11.1 internal or external environments) A) Nervous System (NS): Overview 2 Divisions: Sensory input 2) Peripheral NS (PNS) 2 divisions of PNS: b) motor/efferent division Integration Motor output Fig. 11.1 A) Nervous System (NS): Overview 2 Divisions: Sensory input 2) Peripheral NS (PNS) 2 divisions of PNS: b) motor/efferent division Integration Motor output → nerves convey impulses away from CNS Fig. 11.1 A) Nervous System (NS): Overview 2 Divisions: Sensory input 2) Peripheral NS (PNS) 2 divisions of PNS: b) motor/efferent division Integration Motor output → nerves convey impulses away from CNS Fig. 11.1 → innervates (supplies nerves to) effectors = muscles + glands (endocrine or exocrine) A) Nervous System (NS): Overview 2 Divisions: Sensory input 2) Peripheral NS (PNS) 2 divisions of PNS: b) motor/efferent division Integration Motor output → 2 divisions: → somatic NS (voluntary) - Fig. 11.1 effectors are skeletal muscle A) Nervous System (NS): Overview 2 Divisions: 2) Peripheral NS (PNS) 2 divisions of PNS: b) motor/efferent division → 2 divisions: → autonomic NS (involuntary) - effectors are sm. muscle, cardiac muscle, and glands Fig. 14.3 A) Nervous System (NS): Overview 2 Divisions: 2) Peripheral NS (PNS) 2 divisions of PNS: b) motor/efferent division → 2 divisions: → autonomic NS – 2 subdivisions: i. sympathetic – fight/flight/freeze, reproduction Fig. 14.3 A) Nervous System (NS): Overview 2 Divisions: 2) Peripheral NS (PNS) 2 divisions of PNS: b) motor/efferent division → 2 divisions: → autonomic NS – 2 subdivisions: i. sympathetic – fight/flight/freeze, reproduction Fig. 14.3 ii. parasympathetic – rest & digest receptors detect stimuli  PNS receptors detect afferent stimuli (sensory neurons)  PNS receptors CNS detect afferent stimuli integrate (sensory neurons)  PNS PNS receptors CNS detect afferent efferent stimuli integrate (sensory neurons) (motor neurons)  PNS PNS receptors CNS Effector detect afferent efferent executes stimuli integrate response (sensory neurons) (motor neurons) (muscles + glands) Fig. 11.18 Example hand touches something hot (stimulus) Example hand touches Sensory something hot receptor (stimulus) Example hand touches Sensory CNS something hot receptor (stimulus) Example hand touches pull hand away Sensory CNS something hot receptor (effector = (stimulus) sk. muscle)  Central Nervous System (brain & spinal cord) Peripheral Sensory Motor Nervous System Somatic Autonomic (skeletal muscle) (smooth muscle, cardiac muscle, and glands) Sympathetic Parasympathetic B) NS Histology Fig. 11.5 Cell Types: B) NS Histology Fig. 11.5 Cell Types: 1) Neurons B) NS Histology Fig. 11.5 Cell Types: 1) Neurons conduct impulses B) NS Histology Fig. 11.5 Cell Types: 1) Neurons conduct impulses make up CNS + PNS B) NS Histology Fig. 11.5 Cell Types: 1) Neurons conduct impulses make up CNS + PNS mostly amitotic (irreplaceable) B) NS Histology Fig. 11.5 Cell Types: 1) Neurons conduct impulses make up CNS + PNS mostly amitotic (irreplaceable) exceptions = taste, olfaction, memory B) NS Histology Fig. 11.5 Cell Types: 1) Neurons structure: a) cell body B) NS Histology Fig. 11.5 Cell Types: 1) Neurons structure: a) cell body → typical organelles B) NS Histology Cell Types: 1) Neurons structure: a) cell body → typical organelles → RER called - Nissl Bodies B) NS Histology Cell Types: 1) Neurons structure: a) cell body → typical organelles → RER called - Nissl Bodies → groups/clusters in CNS = nuclei (gray matter) B) NS Histology Cell Types: 1) Neurons structure: a) cell body → typical organelles → RER called - Nissl Bodies → groups/clusters in CNS = nuclei (gray matter) → groups/clusters in PNS = ganglia B) NS Histology Fig. 11.5 Cell Types: 1) Neurons structure: b) processes from cell body: B) NS Histology Fig. 11.5 Cell Types: 1) Neurons structure: b) processes from cell body: i) dendrites B) NS Histology Fig. 11.5 Cell Types: 1) Neurons structure: b) processes from cell body: i) dendrites → receive incoming messages + relay to cell body B) NS Histology Fig. 11.5 Cell Types: 1) Neurons structure: b) processes from cell body: ii) axon B) NS Histology Fig. 11.5 Cell Types: 1) Neurons structure: b) processes from cell body: ii) axon → carry impulses away from cell body B) NS Histology Fig. 11.5 Cell Types: 1) Neurons structure: b) processes from cell body: ii) axon → axon hillock = where axon meets cell body B) NS Histology Fig. 11.5 Cell Types: 1) Neurons structure: b) processes from cell body: ii) axon → axon hillock = where axon meets cell body → axon terminal = typically branched with synaptic end bulbs (enlarged tips) B) NS Histology Fig. 11.5 Cell Types: 1) Neurons structure: b) processes from cell body: ii) axon → may be: B) NS Histology Cell Types: 1) Neurons structure: b) processes from cell body: ii) axon → may be:  myelinated – wrapped in many layers of cell membrane Fig. 11.6 B) NS Histology Cell Types: 1) Neurons structure: b) processes from cell body: ii) axon → may be:  myelinated – wrapped in many layers of cell membrane from Schwann cells (PNS) or oligodendrocytes (CNS) Fig. 11.6 B) NS Histology Cell Types: 1) Neurons structure: b) processes from cell body: ii) axon → may be:  myelinated  electrical insulation Fig. 11.6 B) NS Histology Cell Types: Myelin sheath gap (node of Ranvier) 1) Neurons Schwann cell structure: b) processes from cell body: ii) axon → may be:  myelinated  electrical insulation  gaps in myelin sheath are called Nodes of Ranvier Fig. 11.5 B) NS Histology Cell Types: 1) Neurons structure: b) processes from cell body: ii) axon → may be:  myelinated  myelinated axon bundles in: Fig. 12.3 B) NS Histology Cell Types: 1) Neurons structure: b) processes from cell body: ii) axon → may be:  myelinated  myelinated axon bundles in:  CNS = tracts (white matter) Fig. 12.3 B) NS Histology Cell Types: 1) Neurons structure: b) processes from cell body: ii) axon → may be:  myelinated  myelinated axon bundles in:  CNS = tracts (white matter)  PNS = nerves B) NS Histology Cell Types: 1) Neurons structure: b) processes from cell body: ii) axon → may be:  unmyelinated – no myelin B) NS Histology Cell Types: 2) Neuroglia (glial cells) B) NS Histology Cell Types: 2) Neuroglia (glial cells) support neuron cells = can undergo mitosis B) NS Histology Cell Types: 2) Neuroglia (glial cells) support neuron cells = can undergo mitosis (prone to cancer – brain tumor) B) NS Histology Cell Types: 2) Neuroglia (glial cells) types: B) NS Histology Cell Types: 2) Neuroglia (glial cells) types: a) CNS neuroglia B) NS Histology Cell Types: 2) Neuroglia (glial cells) types: a) CNS neuroglia Fig. 11.4 i) oligodendrocytes → produce myelin around axon B) NS Histology Cell Types: 2) Neuroglia (glial cells) types: a) CNS neuroglia ii) microglia → protective – become phagocytic Fig. 11.4 if detect infected, dead, or damaged neurons B) NS Histology Cell Types: 2) Neuroglia (glial cells) types: a) CNS neuroglia ii) microglia → protective – become phagocytic Fig. 11.4 if detect infected, dead, or damaged neurons (because immune cells can’t enter CNS) B) NS Histology Cell Types: 2) Neuroglia (glial cells) types: a) CNS neuroglia iii) astrocytes → surround blood capillaries to form Fig. 11.4 part of blood brain barrier (BBB) B) NS Histology Cell Types: 2) Neuroglia (glial cells) types: a) CNS neuroglia iii) astrocytes → surround blood capillaries to form Fig. 11.4 part of blood brain barrier (BBB) → help control capillary permeability B) NS Histology Cell Types: 2) Neuroglia (glial cells) types: a) CNS neuroglia iv) ependymal – neural Fig. 11.4 epithelia B) NS Histology Cell Types: 2) Neuroglia (glial cells) types: a) CNS neuroglia iv) ependymal – neural Fig. 11.4 epithelia → line brain ventricles + central canal of the spinal cord B) NS Histology Cell Types: 2) Neuroglia (glial cells) types: a) CNS neuroglia iv) ependymal – neural Fig. 11.4 epithelia → line brain ventricles + central canal of the spinal cord → secrete cerebrospinal fluid (CSF) + circulate it (cilia) B) NS Histology Cell Types: 2) Neuroglia (glial cells) types: b) PNS neuroglia Fig. 11.6 B) NS Histology Cell Types: 2) Neuroglia (glial cells) types: b) PNS neuroglia i) Schwann cells Fig. 11.6 B) NS Histology Cell Types: 2) Neuroglia (glial cells) types: b) PNS neuroglia i) Schwann cells → form myelin around axons in PNS Fig. 11.6 B) NS Histology Cell Types: 2) Neuroglia (glial cells) types: b) PNS neuroglia i) Schwann cells → form myelin around axons in PNS Fig. 11.4 ii) Satellite cells B) NS Histology Cell Types: 2) Neuroglia (glial cells) types: b) PNS neuroglia i) Schwann cells → form myelin around axons in PNS Fig. 11.4 ii) Satellite cells → surround neuron cell bodies in ganglia – protection + support B) NS Histology Neuron Classification: 1) Structural/Anatomical: B) NS Histology Neuron Classification: 1) Structural/Anatomical: based on # of cell processes off of cell body Table 11.2 B) NS Histology Neuron Classification: 1) Structural/Anatomical: based on # of cell processes off of cell body a) Unipolar Table 11.2 B) NS Histology Neuron Classification: 1) Structural/Anatomical: based on # of cell processes off of cell body a) Unipolar 1 process that divides into two: central + peripheral Table 11.2 B) NS Histology Neuron Classification: 1) Structural/Anatomical: based on # of cell processes off of cell body a) Unipolar 1 process that divides into two: central + peripheral peripheral end has dendrites Table 11.2 B) NS Histology Neuron Classification: 1) Structural/Anatomical: based on # of cell processes off of cell body a) Unipolar 1 process that divides into two: central + peripheral peripheral end has dendrites = sensory receptors (pain, touch etc) - remainder is axon Table 11.2 B) NS Histology Neuron Classification: 1) Structural/Anatomical: based on # of cell processes off of cell body a) Unipolar 1 process that divides into two: central + peripheral peripheral end has dendrites = sensory receptors (pain, touch etc) - remainder is axon always sensory B) NS Histology Neuron Classification: 1) Structural/Anatomical: based on # of cell processes off of cell body b) Bipolar Table 11.2 B) NS Histology Neuron Classification: 1) Structural/Anatomical: based on # of cell processes off of cell body b) Bipolar 2 processes: 1 axon, 1 process with dendrites Table 11.2 B) NS Histology Neuron Classification: Bipolar 1) Structural/Anatomical: cells based on # of cell processes off of cell body b) Bipolar 2 processes: 1 axon, 1 process with dendrites sensory – retina, nose (olfaction) B) NS Histology Neuron Classification: 1) Structural/Anatomical: based on # of cell processes off of cell body c) Multipolar 3 or more processes: 1 axon, many dendrites Table 11.2 B) NS Histology Neuron Classification: 1) Structural/Anatomical: based on # of cell processes off of cell body c) Multipolar 3 or more processes: 1 axon, many dendrites all interneurons + motor neurons B) NS Histology Fig 11.1 Sensory Neuron Classification: 2) Functional types: based on direction of Interneuron impulse conduction Motor  PERIPHERAL NERVOUS SYSTEM CENTRAL NERVOUS SYSTEM Sensory Cell body receptor (dendrites) Axon Nerve impulse Sensory neuron (usually unipolar) Dendrites Cell body Interneuron (usually multipolar) Nerve impulse Axon Motor neuron (usually multipolar) Nerve impulse Effectors: Dendrites muscles Cell body or glands Axon B) NS Histology Fig 11.1 Sensory Neuron Classification: 2) Functional types: based on direction of Interneuron impulse conduction Motor a) Sensory/Afferent mostly unipolar B) NS Histology Fig 11.1 Sensory Neuron Classification: 2) Functional types: based on direction of Interneuron impulse conduction Motor a) Sensory/Afferent mostly unipolar from sensory receptors to CNS B) NS Histology Sensory Neuron Classification: 2) Functional types: based on direction of Interneuron impulse conduction Motor b) Interneurons within CNS (between sensory + motor) B) NS Histology Fig 11.1 Sensory Neuron Classification: 2) Functional types: based on direction of Interneuron impulse conduction Motor b) Interneurons within CNS (between sensory + motor) 99% of neurons (mostly multipolar) B) NS Histology Fig 11.1 Sensory Neuron Classification: 2) Functional types: based on direction of Interneuron impulse conduction Motor c) Efferent/Motor CNS to effectors (all multipolar) B) NS Histology Neuron Junctions (Synapses): Fig 11.15 B) NS Histology Neuron Junctions (Synapses): 1) Neuronal junction: neuron to neuron B) NS Histology Neuron Junctions (Synapses): 1) Neuronal junction: neuron to neuron can be chemical (use neurotransmitters) or electrical (ions) Focus Fig. 11.3 B) NS Histology Neuron Junctions (Synapses): Focus Fig. 11.3 1) Neuronal junction: neuron to neuron can be chemical (use neurotransmitters) or electrical (ions) 2) Neuromuscular junction: motor neuron to skeletal muscle B) NS Histology Neuron Junctions (Synapses): 1) Neuronal junction: neuron to neuron can be chemical (use neurotransmitters) or electrical (ions) 2) Neuromuscular junction: motor neuron to skeletal muscle 3) Neuroglandular junction: motor neuron to gland B) NS Histology Chemical Neuronal Synapses: Focus Fig. 11.3 B) NS Histology Chemical Neuronal Synapses: most common Focus Fig. 11.3 B) NS Histology Chemical Neuronal Synapses: most common Structure: 1) Presynaptic Neuron: neuron bringing impulse Focus Fig. 11.3 B) NS Histology Chemical Neuronal Synapses: most common Structure: 1) Presynaptic Neuron: neuron bringing impulse 2) Axon Terminal: with synaptic end bulbs Focus Fig. 11.3 B) NS Histology Chemical Neuronal Synapses: most common Structure: 1) Presynaptic Neuron: neuron bringing impulse 2) Axon Terminal: with synaptic end bulbs inside the end bulb (presynaptic membrane) = synaptic vesicles Focus Fig. 11.3 B) NS Histology Chemical Neuronal Synapses: most common Structure: 1) Presynaptic Neuron: neuron bringing impulse 2) Axon Terminal: with synaptic end bulbs inside the end bulb (presynaptic membrane) = synaptic vesicles containing neurotransmitter (nt) Focus Fig. 11.3 B) NS Histology Chemical Neuronal Synapses: most common Structure: 3) Synaptic Cleft: space between neurons Focus Fig. 11.3 B) NS Histology Chemical Neuronal Synapses: most common Structure: 3) Synaptic Cleft: space between neurons 4) Postsynaptic Neuron: receives the impulse Focus Fig. 11.3 B) NS Histology Chemical Neuronal Synapses: most common Structure: 3) Synaptic Cleft: space between neurons 4) Postsynaptic Neuron: receives the impulse has postsynaptic membrane → = cell membrane of dendrites or cell body with receptor sites for nt Focus Fig. 11.3 C) Central NS (CNS): Protective Features C) Central NS (CNS): Protective Features 1) Bone: skull + vertebral column C) Central NS (CNS): Protective Features Fig. 12.22 2) Meninges: CT around brain + spinal cord Fig. 12.31 C) Central NS (CNS): Protective Features Fig. 12.22 2) Meninges: layers: Fig. 12.31 C) Central NS (CNS): Fig. 12.22 Protective Features 2) Meninges: layers: a) dura mater (outer) Fig. 12.31 C) Central NS (CNS): Protective Features Fig. 12.22 2) Meninges: layers: a) dura mater (outer) → brain = 2 fused layers Fig. 12.31 C) Central NS (CNS): Protective Features Fig. 12.22 2) Meninges: layers: a) dura mater (outer) → brain = 2 fused layers → separated in some places to form Fig. 12.31 spaces = venous (dural) sinuses C) Central NS (CNS): Protective Features Fig. 12.22 2) Meninges: layers: a) dura mater (outer) → brain = 2 fused layers → separated in some places to form Fig. 12.31 spaces = venous (dural) sinuses - contain blood C) Central NS (CNS): Protective Features Fig. 12.22 2) Meninges: layers: a) dura mater (outer) → spinal cord = 1 layer Fig. 12.31 C) Central NS (CNS): Protective Features Fig. 12.22 2) Meninges: layers: a) dura mater (outer) → deep to dura mater = subdural space → filled with ISF Fig. 12.31 C) Central NS (CNS): Protective Features Fig. 12.22 2) Meninges: layers: a) dura mater (outer) → superficial to dura mater = epidural space (spinal Fig. 12.31 cord only) C) Central NS (CNS): Protective Features Fig. 12.22 2) Meninges: layers: a) dura mater (outer) → superficial to dura mater = epidural space (spinal Fig. 12.31 cord only) → filled with fat, blood vessels, CT, etc. C) Central NS (CNS): Protective Features Fig. 12.22 2) Meninges: layers: b) arachnoid mater (mid.) → avascular Fig. 12.31 C) Central NS (CNS): Protective Features Fig. 12.22 2) Meninges: layers: b) arachnoid mater (mid.) → avascular → subarachnoid space Fig. 12.31 → contains cerebrospinal fluid C) Central NS (CNS): Protective Features Fig. 12.22 2) Meninges: layers: b) arachnoid mater (mid.) → avascular → subarachnoid space Fig. 12.31 → contains cerebrospinal fluid → web-like strands of CT secure it to pia mater below C) Central NS (CNS): Protective Features Fig. 12.22 2) Meninges: layers: b) arachnoid mater (mid.) → has arachnoid granulations (brain only) Fig. 12.31 C) Central NS (CNS): Protective Features Fig. 12.22 2) Meninges: layers: b) arachnoid mater (mid.) → has arachnoid granulations (brain only) Fig. 12.31 → project into dural sinuses C) Central NS (CNS): Protective Features Fig. 12.22 2) Meninges: layers: b) arachnoid mater (mid.) → has arachnoid granulations (brain only) Fig. 12.31 → project into dural sinuses → CSF enters granulations to return to blood C) Central NS (CNS): Protective Features Fig. 12.22 2) Meninges: layers: c) pia mater (inner) → on surface of CNS (brain + spinal cord) Fig. 12.31 C) Central NS (CNS): Protective Features Fig. 12.22 2) Meninges: layers: c) pia mater (inner) → on surface of CNS (brain + spinal cord) → vascular Fig. 12.31 C) Central NS (CNS): Protective Features 2) Meninges: layers: c) pia mater (inner) → on surface of CNS (brain + spinal cord) → vascular meningitis = inflammation of meninges C) Central NS (CNS): Protective Features 3) Cerebrospinal Fluid (CSF): surrounds brain + spinal cord Fig. 12.24 C) Central NS (CNS): Protective Features 3) Cerebrospinal Fluid (CSF): surrounds brain + spinal cord in brain ventricles + central canal of spinal cord Fig. 12.24 C) Central NS (CNS): Protective Features 3) Cerebrospinal Fluid (CSF): surrounds brain + spinal cord in brain ventricles + central canal of spinal cord → ventricles: → spaces inside brain (filled with CSF) C) Central NS (CNS): Protective Features 3) Cerebrospinal Fluid (CSF): surrounds brain + spinal cord in brain ventricles + central canal of spinal cord → ventricles: → spaces inside brain (filled with CSF) → 2 lateral ventricles (1st + 2nd) – in cerebrum Fig. 12.4 C) Central NS (CNS): Protective Features 3) Cerebrospinal Fluid (CSF): surrounds brain + spinal cord in brain ventricles + central canal of spinal cord → ventricles: → 3rd ventricle = in diencephalon Fig. 12.4 C) Central NS (CNS): Protective Features 3) Cerebrospinal Fluid (CSF): surrounds brain + spinal cord in brain ventricles + central canal of spinal cord → ventricles: → 4th ventricle = surrounded by pons, medulla oblongata, cerebellum Fig. 12.4 C) Central NS (CNS): Protective Features 3) Cerebrospinal Fluid (CSF): surrounds brain + spinal cord in brain ventricles + central canal of spinal cord → central canal: → space in spinal cord Fig. 12.4 C) Central NS (CNS): Protective Features 3) Cerebrospinal Fluid (CSF): surrounds brain + spinal cord in brain ventricles + central canal of spinal cord → central canal: → space in spinal cord cushions CNS – brain buoyant  4 Superior sagittal sinus Arachnoid granulation Choroid plexus Subarachnoid space Arachnoid mater Meningeal dura mater Periosteal dura mater 1 Right lateral ventricle Interventricular (deep to cut) foramen Third ventricle 3 Choroid plexus of fourth ventricle Cerebral aqueduct Lateral aperture Fourth ventricle Median aperture 2 1 The choroid plexus of each ventricle produces CSF. 2 CSF flows through the ventricles and into the subarachnoid space via the Central canal median and lateral apertures. of spinal cord 3 CSF flows through the subarachnoid space. 4 CSF is absorbed into the dural venous CSF circulation sinuses via the arachnoid granulations. Fig. 12.24 C) Central NS (CNS): Protective Features 3) Cerebrospinal Fluid (CSF): formed from blood plasma (similar composition) Fig. 12.24 C) Central NS (CNS): Protective Features 3) Cerebrospinal Fluid (CSF): formed from blood plasma (similar composition) produced by choroid plexuses (blood capillaries) found in each ventricle Fig. 12.24 Fig. 12.24 C) Central NS (CNS): Protective Features 3) Cerebrospinal Fluid (CSF): formed from blood plasma (similar composition) produced by choroid plexuses (blood capillaries) found in each ventricle Fig. 12.24 circulation: CSF Circulation : Fig. 12.24 CSF Circulation : lateral ventricles Fig. 12.4 CSF Circulation : lateral ventricles interventricular foramina 3rd ventricle Fig. 12.4 CSF Circulation : lateral ventricles interventricular foramen 3rd ventricle cerebral aqueduct 4th ventricle Fig. 12.4 CSF Circulation : lateral ventricles interventricular foramen 3rd ventricle cerebral aqueduct 4th ventricle medial (1) + lateral (2) apertures Fig. 12.4 CSF Circulation : lateral ventricles interventricular foramen 3rd ventricle cerebral aqueduct 4th ventricle medial (1) + lateral (2) apertures subarachnoid space (brain + spinal cord)  arachnoid villi dural sinus (venous blood)  arachnoid villi dural sinus (venous blood) internal jugular veins heart  arachnoid granulations  Lateral CSF ventricle's Lateral ventricles choroid plexuses Through interventricular foramina Third CSF Third ventricle ventricle's choroid plexus Through aqueduct of the midbrain (cerebral aqueduct) Fourth CSF ventricle's Fourth ventricle choroid plexus Through lateral and median apertures Subarachnoid space Arachnoid villi of dural venous sinuses Arterial blood Venous blood Heart and lungs Summary of the formation, circulation, and absorption of cerebrospinal fluid (CSF) Hydrocephalus = abnormal drainage of CSF → accumulation in ventricles → ventricles expand → increase pressure in skull C) Central NS (CNS): Protective Features 4) Blood Brain Barrier (BBB): Fig. 19.24 C) Central NS (CNS): Protective Features 4) Blood Brain Barrier (BBB): 2 cell types: Fig. 11.4 C) Central NS (CNS): Fig. 12.26 Protective Features 4) Blood Brain Barrier (BBB): 2 cell types: a) endothelial cells (of capillaries) with tight junctions C) Central NS (CNS): Protective Features 4) Blood Brain Barrier (BBB): 2 cell types: a) endothelial cells (of capillaries) with tight junctions Fig. 11.4 b) astrocytes – foot processes wrap around endothelial cells C) Central NS (CNS): Protective Features 4) Blood Brain Barrier (BBB): selectively permeable C) Central NS (CNS): Protective Features 4) Blood Brain Barrier (BBB): selectively permeable → allows: glucose, fat soluble material C) Central NS (CNS): Protective Features 4) Blood Brain Barrier (BBB): selectively permeable → allows: glucose, fat soluble material → not toxins, antibiotics, etc. C) Central NS (CNS): Protective Features 5) Cerebral Arterial Circle: Fig. 19.24 C) Central NS (CNS): Protective Features 5) Cerebral Arterial Circle: C) Central NS (CNS): Protective Features 5) Cerebral Arterial Circle: cerebral arteries form circle at base of forebrain Fig. 19.24 C) Central NS (CNS): Protective Features 5) Cerebral Arterial Circle: cerebral arteries form circle at base of forebrain → circles pituitary gland + optic chiasma (where optic nerves cross) Fig. 19.24 C) Central NS (CNS): Protective Features 5) Cerebral Arterial Circle: cerebral arteries form circle at base of forebrain → circles pituitary gland + optic chiasma (where optic nerves cross) → unites the two major blood supplies to the brain (anterior + posterior) Fig. 19.24 C) Central NS (CNS): Protective Features 5) Cerebral Arterial Circle: cerebral arteries form circle at base of forebrain → provides an alternate route for blood if vessels blocked Fig. 19.24  Blood Flow to Brain: Posteriorly: Fig. 19.24  Blood Flow to Brain: Posteriorly: vertebral arteries Fig. 19.24  Blood Flow to Brain: Posteriorly: vertebral arteries Fig. 19.24  Blood Flow to Brain: Posteriorly: vertebral arteries basilar artery Fig. 19.24  Blood Flow to Brain: Posteriorly: vertebral arteries basilar artery Fig. 19.24  Blood Flow to Brain: Posteriorly: vertebral arteries basilar artery posterior cerebral arteries Fig. 19.24  Blood Flow to Brain: Posteriorly: vertebral arteries basilar artery posterior cerebral arteries *Cerebral Arterial Circle = red boxes Fig. 19.24  Blood Flow to Brain: Posteriorly: vertebral arteries basilar artery posterior cerebral arteries *Cerebral Arterial Circle = red boxes  Anteriorly: Internal carotids Fig. 7.6 Fig. 19.24 Fig. 19.24  Anteriorly: Internal carotids middle cerebral arteries (not part of circle) Fig. 19.24  Anteriorly: Internal carotids middle cerebral arteries (not part of circle) anterior cerebral arteries Fig. 19.24  Anteriorly: Internal carotids middle cerebral arteries (not part of circle) anterior cerebral arteries anterior communicating artery joins two ant. cerebrals Fig. 19.24  Anteriorly: Internal carotids middle cerebral arteries (not part of circle) anterior cerebral arteries anterior communicating artery joins two ant. cerebrals posterior communicating arteries Fig. 19.24  Blood Return from brain Fig. 19.29  Blood Return from brain cerebral arteries Fig. 19.29  Blood Return from brain cerebral arteries capillaries Fig. 19.29  Blood Return from brain cerebral arteries capillaries cerebral veins  Blood Return from brain cerebral arteries capillaries cerebral veins dural sinuses Fig. 19.29  Blood Return from brain cerebral arteries capillaries cerebral veins dural sinuses superior vena cava Fig. 19.29 D) Central NS (CNS): Brain Fig. Fig.12.3d 14.1 D) Central NS (CNS): Brain 1) Forebrain Fig. Fig.12.3d 12.2 D) Central NS (CNS): Brain 1) Forebrain a) cerebrum (= right + left cerebral hemispheres) Fig. 12.5 D) Central NS (CNS): Brain 1) Forebrain a) cerebrum (= right + left cerebral hemispheres) → lobes (named after overlying bones): Fig. 12.5 D) Central NS (CNS): Brain 1) Forebrain a) cerebrum (= right + left cerebral hemispheres) → lobes (named after overlying bones): i) frontal Fig. 12.5 D) Central NS (CNS): Brain 1) Forebrain a) cerebrum (= right + left cerebral hemispheres) → lobes (named after overlying bones): i) frontal ii) temporal Fig. 12.5 D) Central NS (CNS): Brain 1) Forebrain a) cerebrum (= right + left cerebral hemispheres) → lobes (named after overlying bones): i) frontal ii) temporal iii) parietal Fig. 12.5 D) Central NS (CNS): Brain 1) Forebrain a) cerebrum (= right + left cerebral hemispheres) → lobes (named after overlying bones): i) frontal ii) temporal iii) parietal iv) occipital Fig. 12.5  Fig. 12.5 D) Central NS (CNS): Brain 1) Forebrain a) cerebrum (= right + left cerebral hemispheres) → lobes (named after overlying bones): i) frontal ii) temporal iii) parietal iv) occipital v) insula – deep to temporal lobe D) Central NS (CNS): Brain 1) Forebrain a) cerebrum (= right + left cerebral hemispheres) → surface features: Fig. 12.5 D) Central NS (CNS): Brain 1) Forebrain a) cerebrum (= right + left cerebral hemispheres) → surface features: i) fissures = deep grooves Fig. 12.5 D) Central NS (CNS): Brain 1) Forebrain a) cerebrum (= right + left cerebral hemispheres) → surface features: i) fissures = deep grooves ① longitudinal fissure separates right + left cerebral Fig. 12.5 hemispheres D) Central NS (CNS): Brain 1) Forebrain a) cerebrum (= right + left cerebral hemispheres) → surface features: i) fissures = deep grooves ② transverse fissure separates cerebellum + cerebrum Fig. 12.5 D) Central NS (CNS): Brain 1) Forebrain a) cerebrum (= right + left cerebral hemispheres) → surface features: i) fissures = deep grooves ② transverse fissure separates Fig. 12.5 cerebellum + cerebrum D) Central NS (CNS): Brain 1) Forebrain a) cerebrum (= right + left cerebral hemispheres) → surface features: i) fissures = deep grooves ③ lateral fissure separates temporal lobe from rest of cerebrum Fig. 12.5 D) Central NS (CNS): Brain 1) Forebrain a) cerebrum (= right + left cerebral hemispheres) → surface features: i) fissures = deep grooves ③ lateral fissure separates temporal lobe from rest of Fig. 12.5 cerebrum D) Central NS (CNS): Brain 1) Forebrain a) cerebrum (= right + left cerebral hemispheres) → surface features: ii) gyri = ridges Fig. 12.5 D) Central NS (CNS): Brain 1) Forebrain a) cerebrum (= right + left cerebral hemispheres) → surface features: ii) gyri = ridges e.g.: → postcentral gyrus in parietal lobe Fig. 12.5 D) Central NS (CNS): Brain 1) Forebrain a) cerebrum (= right + left cerebral hemispheres) → surface features: ii) gyri = ridges e.g.: → postcentral gyrus in parietal lobe → precentral gyrus in frontal lobe Fig. 12.5 D) Central NS (CNS): Brain 1) Forebrain a) cerebrum (= right + left cerebral hemispheres) → surface features: iii) sulci = shallow grooves (separate gyri) Fig. 12.5 D) Central NS (CNS): Brain 1) Forebrain a) cerebrum (= right + left cerebral hemispheres) → surface features: iii) sulci = shallow grooves (separate gyri) e.g.: → central sulcus – between frontal + parietal lobes Fig. 12.5 D) Central NS (CNS): Brain 1) Forebrain a) cerebrum (= right + left cerebral hemispheres) → 3 layers: Fig. 12.6 Fig. 12.5 D) Central NS (CNS): Brain 1) Forebrain a) cerebrum (= right + left cerebral hemispheres) → 3 layers: i) cerebral cortex 2 – 4 mm thick, gray matter Fig. 12.6 Fig. 12.5 D) Central NS (CNS): Brain 1) Forebrain a) cerebrum (= right + left cerebral hemispheres) → 3 layers: i) cerebral cortex 2 – 4 mm thick, gray matter Fig. 12.6 D) Central NS (CNS): Brain 1) Forebrain a) cerebrum (= right + left cerebral hemispheres) → 3 layers: i) cerebral cortex has functional areas: Fig. 12.7 D) Central NS (CNS): Brain 1) Forebrain a) cerebrum (= right + left cerebral hemispheres) → 3 layers: i) cerebral cortex has functional areas: ① motor areas Fig. 12.7 All in frontal lobe D) Central NS (CNS): Brain 1) Forebrain a) cerebrum (= right + left cerebral hemispheres) → 3 layers: i) cerebral cortex has functional areas: ① motor areas Fig. 12.7 All in frontal lobe control skeletal muscle movement D) Central NS (CNS): Brain 1) Forebrain a) cerebrum (= right + left cerebral hemispheres) → 3 layers: i) cerebral cortex has functional areas: ① motor areas Fig. 12.7 3 regions: ⓐ primary motor area (precentral gyrus) Fig. 12.8 D) Central NS (CNS): Brain 1) Forebrain a) cerebrum (= right + left cerebral hemispheres) → 3 layers: i) cerebral cortex has functional areas: ① motor areas Fig. 12.7 3 regions: ⓐ primary motor area (precentral gyrus) ⓑ premotor area D) Central NS (CNS): Brain 1) Forebrain a) cerebrum (= right + left cerebral hemispheres) → 3 layers: i) cerebral cortex has functional areas: ① motor areas Fig. 12.7 3 regions: ⓒ Broca’s area (motor speech) D) Central NS (CNS): Brain 1) Forebrain a) cerebrum (= right + left cerebral hemispheres) → 3 layers: i) cerebral cortex has functional areas: ② sensory areas Fig. 12.7 D) Central NS (CNS): Brain 1) Forebrain a) cerebrum (= right + left cerebral hemispheres) → 3 layers: i) cerebral cortex has functional areas: ② sensory areas Fig. 12.7 ⓐ general sensory area (pain, touch, temp, pressure) D) Central NS (CNS): Brain 1) Forebrain a) cerebrum (= right + left cerebral hemispheres) → 3 layers: i) cerebral cortex has functional areas: ② sensory areas Fig. 12.7 ⓐ general sensory area (pain, touch, temp, pressure) → postcentral gyrus in parietal lobe D) Central NS (CNS): Brain 1) Forebrain a) cerebrum (= right + left cerebral hemispheres) → 3 layers: i) cerebral cortex has functional areas: ② sensory areas Fig. 12.7 ⓑ vision → occipital lobe D) Central NS (CNS): Brain 1) Forebrain a) cerebrum (= right + left cerebral hemispheres) → 3 layers: i) cerebral cortex has functional areas: ② sensory areas ⓒ auditory + olfaction → temporal lobe Fig. 12.7 D) Central NS (CNS): Brain 1) Forebrain a) cerebrum (= right + left cerebral hemispheres) → 3 layers: i) cerebral cortex has functional areas: ② sensory areas Fig. 12.7 ⓓ taste + visceral sensation (e.g. full bladder) → insula D) Central NS (CNS): Brain 1) Forebrain a) cerebrum (= right + left cerebral hemispheres) → 3 layers: i) cerebral cortex has functional areas:  association areas Fig. 12.7 recognize info from memories → parietal, occipital, temporal lobes D) Central NS (CNS): Brain 1) Forebrain a) cerebrum (= right + left cerebral hemispheres) → 3 layers: i) cerebral cortex has functional areas:  others: Fig. 12.7 memory → temporal lobes D) Central NS (CNS): Brain 1) Forebrain a) cerebrum (= right + left cerebral hemispheres) → 3 layers: i) cerebral cortex has functional areas:  others: Fig. 12.7 concious intellect (personality, learning, ideas, judgement, etc.) → prefrontal cortex D) Central NS (CNS): Brain 1) Forebrain a) cerebrum (= right + left cerebral hemispheres) → 3 layers: ii) tracts (white matter) Fig. 12.9  Association fibers D) Central NS (CNS): (within hemisphere) Brain 1) Forebrain a) cerebrum (= right + left cerebral hemispheres) → 3 layers: Association ii) tracts (white matter) fibers types:  association tracts from gyrus to gyrus in same hemisphere Fig. 12.9  Commissural fibers D) Central NS (CNS): Brain 1) Forebrain a) cerebrum (= right + left cerebral hemispheres) → 3 layers: Commissural fibers ii) tracts (white matter) types:  commissural tracts from gyrus to gyrus in opposite hemispheres Fig. 12.9  Commissural fibers D) Central NS (CNS): Brain 1) Forebrain a) cerebrum (= right + left cerebral hemispheres) → 3 layers: Commissural fibers ii) tracts (white matter) types:  commissural tracts from gyrus to gyrus in opposite hemispheres e.g. corpus callosum Fig. 12.9  Projection fibers D) Central NS (CNS): Brain 1) Forebrain a) cerebrum (= right + left cerebral hemispheres) → 3 layers: Projection fibers ii) tracts (white matter) types:  projection tracts run vertically (brain to spinal cord / spinal cord to brain) Fig. 12.9 D) Central NS (CNS): Brain Basal nuclei 1) Forebrain a) cerebrum (= right + left cerebral hemispheres) → 3 layers: Basal nuclei iii) basal nuclei Fig. 12.9 and 12.10 D) Central NS (CNS): Brain Basal nuclei 1) Forebrain a) cerebrum (= right + left cerebral hemispheres) → 3 layers: Basal nuclei iii) basal nuclei paired masses of gray matter (within white matter) Fig. 12.9 and 12.10 D) Central NS (CNS): Brain Basal nuclei 1) Forebrain a) cerebrum (= right + left cerebral hemispheres) → 3 layers: Basal nuclei iii) basal nuclei paired masses of gray matter (within white matter) control skeletal muscle movement Fig. 12.9 and 12.10 D) Central NS (CNS): Brain 2) Diencephalon all gray matter Fig. 12.11 D) Central NS (CNS): Fig. 12.11 Brain 2) Diencephalon all gray matter a) thalamus 2 lobes connected by intermediate mass Fig. 12.13 D) Central NS (CNS): Fig. 12.11 Brain 2) Diencephalon all gray matter a) thalamus 2 lobes connected by intermediate mass (bridge through 3rd ventricle) Fig. 12.13 D) Central NS (CNS): Fig. 12.11 Brain 2) Diencephalon all gray matter a) thalamus 2 lobes connected by intermediate mass (bridge through 3rd ventricle) relay station for impulses coming to cortex (from spinal cord) Fig. 12.13 D) Central NS (CNS): Brain 2) Diencephalon all gray matter b) hypothalamus inferior to thalamus, above pituitary Fig. 12.11 D) Central NS (CNS): Brain 2) Diencephalon all gray matter b) hypothalamus inferior to thalamus, above pituitary major regulator of the internal environment (visceral control) Fig. 12.11 Fig. 12.12 D) Central NS (CNS): Brain 2) Diencephalon all gray matter b) hypothalamus inferior to thalamus, above pituitary major regulator of the internal environment (visceral control) Fig. 12.11 → e.g. blood pressure, heart rate Fig. 12.12 D) Central NS (CNS): Brain 3) Midbrain connects pons + diencephalon Fig. 12.11 D) Central NS (CNS): Brain 3) Midbrain connects pons + diencephalon contains cerebral aqueduct Fig. 12.11 D) Central NS (CNS): Brain 3) Midbrain connects pons + diencephalon contains cerebral aqueduct anterior portion = cerebral Fig. 12.11 peduncles (projection tracts) D) Central NS (CNS): Brain 3) Midbrain posterior portion = 4 nuclei = corpora quadrigemina Fig. 12.13 D) Central NS (CNS): Brain 3) Midbrain posterior portion = 4 nuclei = corpora quadrigemina 2 superior colliculi → visual reflexes Fig. 12.13 D) Central NS (CNS): Brain 3) Midbrain posterior portion = 4 nuclei = corpora quadrigemina 2 superior colliculi → visual reflexes 2 inferior colliculi → hearing Fig. 12.13 D) Central NS (CNS): Brain 4) Hindbrain Fig. 12.11 D) Central NS (CNS): Brain 4) Hindbrain a) Pons anterior to cerebellum Fig. 12.11 D) Central NS (CNS): Brain 4) Hindbrain a) Pons anterior to cerebellum tracts between brain + spinal cord, + tracts to/from cerebellum Fig. 12.11 D) Central NS (CNS): Brain 4) Hindbrain a) Pons anterior to cerebellum tracts between brain + spinal cord, + tracts to/from cerebellum pontine respiratory centres Fig. 12.11 D) Central NS (CNS): Brain 4) Hindbrain b) Medulla oblongata inferior to pons Fig. 12.11 D) Central NS (CNS): Brain 4) Hindbrain b) Medulla oblongata inferior to pons ends at foramen magnum Fig. 12.11 D) Central NS (CNS): Brain 4) Hindbrain b) Medulla oblongata inferior to pons ends at foramen magnum 2 bulges (called pyramids) Fig. 12.13 D) Central NS (CNS): Brain 4) Hindbrain b) Medulla oblongata inferior to pons ends at foramen magnum 2 bulges (called pyramids) = large motor tracts (= part of corticospinal tracts) Fig. 12.13 D) Central NS (CNS): Brain 4) Hindbrain b) Medulla oblongata inferior to pons ends at foramen magnum 2 bulges (called pyramids) = large motor tracts (= part of corticospinal tracts) Fig. 12.9 → just above spinal cord = decussation (crossover) of pyramids D) Central NS (CNS): Brain 4) Hindbrain b) Medulla oblongata 3 vital centres in medulla: i) cardiac Fig. 12.9 D) Central NS (CNS): Brain 4) Hindbrain b) Medulla oblongata 3 vital centres in medulla: i) cardiac ii) vasomotor (blood vessels) Fig. 12.9 D) Central NS (CNS): Brain 4) Hindbrain b) Medulla oblongata 3 vital centres in medulla: i) cardiac ii) vasomotor (blood vessels) Fig. 12.9 iii) respiratory D) Central NS (CNS): Brain 4) Hindbrain b) Medulla oblongata 3 vital centres in medulla: i) cardiac ii) vasomotor (blood vessels) Fig. 12.9 iii) respiratory several non-vital centres for swallowing, sneezing, vomiting D) Central NS (CNS): Brain Note: Brain Stem = midbrain, pons, medulla Fig. 12.13 D) Central NS (CNS): Brain 4) Hindbrain c) Cerebellum posterior to pons/medulla Fig. 12.11 D) Central NS (CNS): Brain 4) Hindbrain c) Cerebellum posterior to pons/medulla has folds similar to gyri = folia Fig. 12.16 D) Central NS (CNS): Brain 4) Hindbrain c) Cerebellum posterior to pons/medulla has folds similar to gyri = folia cortex = gray matter Fig. 12.16 D) Central NS (CNS): Brain 4) Hindbrain c) Cerebellum posterior to pons/medulla has folds similar to gyri = folia cortex = gray matter arbor vitae (deep to cortex, ant. cerebellum) = white matter Fig. 12.16 D) Central NS (CNS): Brain 4) Hindbrain c) Cerebellum posterior to pons/medulla has folds similar to gyri = folia cortex = gray matter arbor vitae (deep to cortex, ant. cerebellum) = white matter coordinates skeletal muscle contraction - balance, posture D) Central NS (CNS): Brain 5) Functional Systems: Fig. 12.17 D) Central NS (CNS): Brain 5) Functional Systems: a) Limbic System nuclei in cerebral hemisphere + diencephalon Fig. 12.17 D) Central NS (CNS): Brain 5) Functional Systems: a) Limbic System nuclei in cerebral hemisphere + diencephalon regulates emotions (laughing, crying, etc.) Fig. 12.17 D) Central NS (CNS): Brain 5) Functional Systems: a) Limbic System nuclei in cerebral hemisphere + diencephalon regulates emotions (laughing, crying, etc.) contains areas involved in memory (memories evoke emotional responses) D) Central NS (CNS): Brain 5) Functional Systems: b) Reticular Formation nuclei in brain stem Reticular formation Fig. 12.18 D) Central NS (CNS): Brain 5) Functional Systems: b) Reticular Formation nuclei in brain stem cortex, thalamus, + hypothalamus involved Reticular formation Fig. 12.18 D) Central NS (CNS): Brain 5) Functional Systems: b) Reticular Formation nuclei in brain stem cortex, thalamus, + hypothalamus involved (together form RAS = Reticular Activating System) Reticular formation Fig. 12.18 D) Central NS (CNS): Brain 5) Functional Systems: b) Reticular Formation regulates alertness + attention Reticular formation Fig. 12.18 D) Central NS (CNS): Brain 5) Functional Systems: b) Reticular Formation regulates alertness + attention → filters stimuli + only sends new/unusual signals to other brain Reticular areas formation Fig. 12.18 D) Central NS (CNS): Brain 5) Functional Systems: b) Reticular Formation regulates alertness + attention → filters stimuli + only sends new/unusual signals to other brain Reticular areas formation sleep results when Fig. 12.18 inhibited D) Central NS (CNS): Brain 5) Functional Systems: b) Reticular Formation regulates alertness + attention → filters stimuli + only sends new/unusual signals to other brain Reticular areas formation sleep results when Fig. 12.18 inhibited if damaged = coma E) Central NS (CNS): Spinal Cord 1) structure: foramen magnum to L1/L2 (conus medullaris) Conus medullaris Cauda equina Filum terminale Fig. 12.28 E) Central NS (CNS): Spinal Cord 1) structure: foramen magnum to L1/L2 (conus medullaris) Conus medullaris Cauda equina nerves continue down from spinal cord Filum terminale through vertebral foramina as cauda equina (horse’s tail) Fig. 12.28 E) Central NS (CNS): Spinal Cord 1) structure: foramen magnum to L1/L2 (conus medullaris) Conus medullaris Cauda equina nerves continue down from spinal cord Filum terminale through vertebral foramina as cauda equina (horse’s tail) → exit at intervertebral Fig. 12.28 E) Central NS (CNS): Spinal Cord 1) structure: filum terminale → = CT extension of pia mater – anchors conus Conus medullaris medullaris of spinal Cauda equina cord to coccyx Filum terminale Fig. 12.28 E) Central NS (CNS): Spinal Cord 1) structure: filum terminale → = CT extension of pia mater – anchors conus medullaris of spinal cord to coccyx → location where CSF samples taken Fig. 12.29 E) Central NS (CNS): Spinal Cord 2) cross-sectional structures: Fig. 12.31 E) Central NS (CNS): Spinal Cord 2) cross-sectional structures: a) anterior median fissure + Fig. 12.31 posterior median sulcus E) Central NS (CNS): Spinal Cord 2) cross-sectional structures: a) anterior median fissure + Fig. 12.31 posterior median sulcus → separate cord into right + left halves E) Central NS (CNS): Spinal Cord 2) cross-sectional structures: a) anterior median fissure + Fig. 12.31 posterior median sulcus → separate cord into right + left halves a) central canal → contains CSF E) Central NS (CNS): Spinal Cord 2) cross-sectional structures: fig. 12.28b c) Gray Matter → cell bodies + dendrites of motor neurons + interneurons E) Central NS (CNS): Spinal Cord 2) cross-sectional structures: c) Gray Matter → cell bodies + dendrites of motor neurons + interneurons SS VS VM SM Fig. 12.32 E) Central NS (CNS): Spinal Cord 2) cross-sectional structures: c) Gray Matter Fig. 12.31 → H-shaped: → cross bar = gray commissure E) Central NS (CNS): Spinal Cord 2) cross-sectional structures: c) Gray Matter Fig. 12.31 → H-shaped: → cross bar = gray commissure → horns: i. dorsal horn = sensory E) Central NS (CNS): Spinal Cord 2) cross-sectional structures: c) Gray Matter Fig. 12.31 → H-shaped: → cross bar = gray commissure → horns: i. dorsal horn = sensory ii. lateral horn = motor E) Central NS (CNS): Spinal Cord 2) cross-sectional structures: c) Gray Matter Fig. 12.31 → H-shaped: → cross bar = gray commissure → horns: i. dorsal horn = sensory ii. lateral horn = motor iii. ventral horn = motor E) Central NS (CNS): Spinal Cord 2) cross-sectional structures: c) Gray Matter Fig. 12.31 → H-shaped: → cross bar = gray commissure → horns: i. dorsal horn = sensory ii. lateral horn = motor iii. ventral horn = motor Fig. 12.32 E) Central NS (CNS): Spinal Cord 2) cross-sectional structures: d) White Matter Fig. 12.31 → myelinated axons containing ascending (sensory) or descending (motor) tracts E) Central NS (CNS): Spinal Cord 2) cross-sectional structures: d) White Matter Fig. 12.31 → myelinated axons containing ascending (sensory) or descending (motor) tracts → forms columns: i. dorsal column E) Central NS (CNS): Spinal Cord 2) cross-sectional structures: d) White Matter Fig. 12.31 → myelinated axons containing ascending (sensory) or descending Dorsal white (motor) tracts column → forms columns: i. dorsal column Fig. 12.33  Fig. 12.31 E) Central NS (CNS): Spinal Cord 2) cross-sectional structures: d) White Matter → myelinated axons containing ascending (sensory) or descending (motor) tracts → forms columns: i. dorsal column ii. lateral column  Fig. 12.31/12.33 E) Central NS (CNS): Spinal Cord 2) cross-sectional structures: d) White Matter → myelinated axons containing ascending (sensory) or descending (motor) tracts → forms columns: i. dorsal column ii. lateral column iii. ventral column E) Central NS (CNS): Spinal Cord 3) functions: → sensory + motor impulses Fig. 12.32 E) Central NS (CNS): Spinal Cord 3) functions: → sensory + motor impulses → produces reflexes → fast, predictable, automatic responses to changes in environment Fig. 12.32 E) Central NS (CNS): Spinal Cord 3) functions: → sensory + motor impulses → produces reflexes → fast, predictable, automatic responses to changes in environment Fig. 12.32 → e.g. withdrawal reflex F) Peripheral NS (PNS): Structures Pyram idal c ells (upper motor neurons) Primary motor cortex Thalam us Cerebr Cer ebru um m Midbra in Midbr ain Cer ebellu m Cerebe ll um Pon s Po ns Medulla Medulla oblongata oblongata Cervic al spinal cord Cer vical spinal cor d Lumbar spinal cor d Lum ba r spinal cord Pyr amida l (latera l and ven tral c ortico spi nal) Spinocerebellar Dorsal column–medial lemniscal pat hways F) Peripheral NS (PNS): Structures 1) Cranial Nerves 12 pairs total Fig. 13.6  NERVOUS SYSTEM – CRANIAL NERVES I. Olfactory Oh SAMPLE MNEUMONIC DEVICES II. Optic Once III. Oculomotor One CRANIAL NERVES IV. Trochlear Takes V. Trigeminal The VI. Abducens Anatomy VII. Facial Final VIII. Vestibulocochlear Very IX. Glossopharyngeal Good X. Vagus Vacations XI. Accessory Are XII. Hypoglossal Had Fig. 13.6 …or whatever else you can come up with!  Brain regions associated with cranial nerves I - XII:  Brain regions associated with cranial nerves I - XII: I – olfactory forebrain II – optic  Brain regions associated with cranial nerves I - XII: I – olfactory forebrain II – optic III – oculomotor midbrain IV - trochlear  Brain regions associated with cranial nerves I - XII: I – olfactory forebrain II – optic III – oculomotor midbrain IV - trochlear V - trigeminal VI - abducens pons VII – facial VIII - vestibulocochelar  Brain regions associated with cranial nerves I - XII: I – olfactory forebrain II – optic III – oculomotor midbrain IV - trochlear V - trigeminal VI - abducens pons VII – facial VIII - vestibulocochlear IX – glossopharyngeal medulla oblongata X – vagus XI – accessory XII - hypoglossal F) Peripheral NS (PNS): Structures 1) Cranial Nerves 2 pairs = only sensory → I and II Fig. 13.6 F) Peripheral NS (PNS): Structures 1) Cranial Nerves 2 pairs = only sensory → I and II 1 pair = mainly sensory → VIII Fig. 13.6 F) Peripheral NS (PNS): Structures 1) Cranial Nerves 9 pairs = mixed nerves → carry both sensory + motor neurons Fig. 13.6 F) Peripheral NS (PNS): Structures 1) Cranial Nerves 9 pairs = mixed nerves → carry both sensory + motor neurons ▪ motor neurons have cell bodies in brainstem nuclei Fig. 13.6 F) Peripheral NS (PNS): Structures 1) Cranial Nerves 9 pairs = mixed nerves → carry both sensory + motor neurons ▪ motor neurons have cell bodies in brainstem nuclei ▪ sensory neurons have cell bodies in ganglia of PNS F) Peripheral NS (PNS): Structures 1) Cranial Nerves 9 pairs = mixed nerves → carry both sensory + motor neurons → e.g. trigemminal n. (V) → motor fxn = chewing Fig. 13.6 F) Peripheral NS (PNS): Structures 1) Cranial Nerves 9 pairs = mixed nerves → carry both sensory + motor neurons → e.g. trigemminal n. (V) → motor fxn = chewing → sensory fxn = conveys general sensations (touch, pressure, pain, temp.) from face to CNS Fig. 13.6 F) Peripheral NS (PNS): Cervical Structures nerves C1 – C 8 2) Spinal Nerves 31 pairs = all mixed nerves Thoracic nerves T1 – T12 Lumbar nerves L1 – L5 Sacral nerves S1 – S5 Coccygeal nerve Co1 Fig. 13.7 F) Peripheral NS (PNS): Cervical Structures nerves C1 – C 8 2) Spinal Nerves 31 pairs = all mixed nerves Thoracic nerves → 8 cervical T1 – T12 Lumbar nerves L1 – L5 Sacral nerves S1 – S5 Coccygeal nerve Co1 Fig. 13.7 F) Peripheral NS (PNS): Cervical Structures nerves C1 – C 8 2) Spinal Nerves 31 pairs = all mixed nerves Thoracic nerves → 8 cervical T1 – T12 Lumbar nerves L1 – L5 Sacral nerves S1 – S5 Coccygeal nerve Co1 Fig. 13.7 F) Peripheral NS (PNS): Cervical Structures nerves C1 – C 8 2) Spinal Nerves 31 pairs = all mixed nerves Thoracic nerves → 8 cervical T1 – T12 → 12 thoracic Lumbar nerves L1 – L5 Sacral nerves S1 – S5 Coccygeal nerve Co1 Fig. 13.7 F) Peripheral NS (PNS): Cervical Structures nerves C1 – C 8 2) Spinal Nerves 31 pairs = all mixed nerves Thoracic nerves → 8 cervical T1 – T12 → 12 thoracic → 5 lumbar Lumbar nerves L1 – L5 Sacral nerves S1 – S5 Coccygeal nerve Co1 Fig. 13.7 F) Peripheral NS (PNS): Cervical Structures nerves C1 – C 8 2) Spinal Nerves 31 pairs = all mixed nerves Thoracic nerves → 8 cervical T1 – T12 → 12 thoracic → 5 lumbar → 5 sacral Lumbar nerves L1 – L5 Sacral nerves S1 – S5 Coccygeal nerve Co1 Fig. 13.7 F) Peripheral NS (PNS): Cervical Structures nerves C1 – C 8 2) Spinal Nerves 31 pairs = all mixed nerves Thoracic nerves → 8 cervical T1 – T12 → 12 thoracic → 5 lumbar → 5 sacral Lumbar nerves → 1 coccygeal L1 – L5 Sacral nerves S1 – S5 Coccygeal nerve Co1 Fig. 13.7 F) Peripheral NS (PNS): Structures 2) Spinal Nerves 31 pairs = all mixed nerves → 8 cervical → 12 thoracic → 5 lumbar → 5 sacral → 1 coccygeal Exit via intervertebral foramina (except 1st – between atlas + occipital) F) Peripheral NS (PNS): Structures 2) Spinal Nerves each has 2 points of attachment to spinal cord: SS VS VM SM Fig. 12.32 F) Peripheral NS (PNS): Structures 2) Spinal Nerves each has 2 points of attachment to spinal cord: a) Dorsal Root → sensory neurons; SS VS VM SM Fig. 12.32 F) Peripheral NS (PNS): Structures 2) Spinal Nerves each has 2 points of attachment to spinal cord: a) Dorsal Root → sensory neurons; cell bodies in dorsal root ganglion SS VS VM SM Fig. 12.32 F) Peripheral NS (PNS): Structures 2) Spinal Nerves each has 2 points of attachment to spinal cord: b) Ventral Root → autonomic and somatic motor neurons; cell bodies in ventral or lateral horn SS VS VM SM Fig. 12.32 F) Peripheral NS (PNS): Structures 2) Spinal Nerves spinal nerve = joining of dorsal + ventral roots SS VS VM SM Fig. 12.32 F) Peripheral NS (PNS): Structures Dorsal ramus 2) Spinal Nerves Ventral spinal nerve = joining of ramus dorsal + ventral roots Spinal immediately divide into nerve branches = rami: Rami communicantes Fig. 13.8 F) Peripheral NS (PNS): Structures Dorsal ramus 2) Spinal Nerves spinal nerve = joining of dorsal + ventral roots Spinal immediately divide into nerve branches = rami: a) dorsal ramus → innervate skin + muscles of the back Fig. 13.8 F) Peripheral NS (PNS): Structures 2) Spinal Nerves Ventral spinal nerve = joining of ramus dorsal + ventral roots Spinal immediately divide into nerve branches = rami: b) ventral ramus → forms thoracic nerves (T2 – T12) Fig. 13.8 F) Peripheral NS (PNS): Structures A. structures: Dorsal ramus 2) Spinal Nerves Ventral ramus spinal nerve = joining of dorsal + ventral roots Spinal nerve immediately divide into branches = rami: Rami communicantes Fig. 13.8 F) Peripheral NS (PNS): Structures 2) Spinal Nerves Ventral spinal nerve = joining of ramus dorsal + ventral roots Spinal immediately divide into nerve branches = rami: b) ventral ramus → forms thoracic nerves (T2 – T12) OR further branch + join up forming nerve plexuses Fig. 13.8 F) Peripheral NS (PNS): Cervical plexus Structures Brachial plexus 2) Spinal Nerves spinal nerve = joining of dorsal + ventral roots immediately divide into branches = rami: Lumbar b) ventral ramus plexus → forms thoracic nerves (T2 – T12) OR further Sacral branch + join up plexus forming nerve plexuses (= nerve network) Fig. 13.7 Spinal Nerve Plexuses: Plexus Formed by Important Nerves Spinal Nerves: Arising From: Spinal Nerve Plexuses: Plexus Formed by Important Nerves Spinal Nerves: Arising From: a) Cervical C1 – C5 Phrenic (innervates diaphragm) Cervical Ventral rami Plexus Phrenic nerve Fig. 13.9 Spinal Nerve Plexuses: Plexus Formed by Important Nerves Spinal Nerves: Arising From: a) Cervical C1 – C5 Phrenic (innervates diaphragm) b) Brachial C5 – C8, T1 Axillary, Radial, Ulnar, Median, Musculocutaneous  Brachial Plexus Axillary Musculo- cutaneous Radial Median Ulnar Fig. 13.10 Spinal Nerve Plexuses: Plexus Formed by Important Nerves Spinal Nerves: Arising From: a) Cervical C1 – C5 Phrenic (innervates diaphragm) b) Brachial C5 – C8, T1 Axillary, Radial, Ulnar, Median, Musculocutaneous c) Lumbar L1 – L4 Femoral Lumbar Plexus Femoral Femoral Fig. 13.11 Spinal Nerve Plexuses: Plexus Formed by Important Nerves Spinal Nerves: Arising From: a) Cervical C1 – C5 Phrenic (innervates diaphragm) b) Brachial C5 – C8, T1 Axillary, Radial, Ulnar, Median, Musculocutaneous c) Lumbar L1 – L4 Femoral d) Sacral L4 – S4 Sciatic – divides into: Tibial + Common Fibular Sacral Plexus Sciatic Common fibular Tibial Common fibular Sciatic Fig. 13.12 F) Peripheral NS (PNS): Structures 2) Spinal Nerves spinal nerve = joining of dorsal + ventral roots Spinal immediately divide into nerve branches = rami: