7 The Nervous System PPT-B 22 slides 1 ½ hour

PPT-A OUTLINE PPT-B OUTLINE I. Overall Functions II. NS Organization III. Nervous Tissue IV. Physiology A. Sensory A. Structural A. Cells A. N. Properties B. Integration B. Functional B. Terminology B. Action Potentials C. Motor C. Functional Classification N. D. Structural Classification N. V. Central Nervous System VI Peripheral Nervous System A. Brain A. Nerves B. Spinal Cord B. Autonomic NS PPT-B OUTLINE

V. Central Nervous System (CNS) A. Brain Parietal lobe Left cerebral hemisphere Frontal lobe Occipital lobe Temporal lobe Cephalad Cerebellum Caudal Brain stem (b) Figure 7.13b

Central Nervous System (CNS) … Brain Regions 1. Cerebrum 2. Thalamus, 3. Hypothalamus 3. Brain stem 4. Cerebellum

1. Cerebrum a. Location b. Cerebral Hemispheres c. Cerebral Cortex Anterior Association Area Broca’s area Visual area d. Corpus Callosum (c)

Central sulcus Primary motor area Primary somatic sensory area Premotor area Gustatory area (taste) Anterior association area Speech/language (outlined by dashes) • Working memory and judgment • Problem solving Posterior association area • Language comprehension Visual area Broca’s area (motor speech) Olfactory area Auditory area (c) Figure 7.13c

2. Thalamus 3. Hypothalamus Thalamus & Hypothalamus (b) Adult brain

4. Brain Stem a. Midbrain b. Pons c. Medulla oblongata 5. CEREBELLUM

5. Items Associated with the Brain a. Cerebrospinal Fluid b. Meninges Dura Mater Arachnoid Mater & Subarachnoid Space Pia Mater Skin of scalp Periosteum Bone of skull Periosteal Dura mater Meningeal Superior sagittal sinus Arachnoid mater Pia mater Subdural space Arachnoid villus Subarachnoid space Blood vessel Falx cerebri (in longitudinal fissure only) (a)

Skull Scalp Superior sagittal sinus Occipital lobe Dura mater Tentorium cerebelli Transverse sinus Cerebellum Temporal bone Arachnoid mater over medulla oblongata (b) Figure 7.17b

c. Ventricles d. Blood-brain barrier Lateral ventricle Anterior horn Septum pellucidum Interventricular foramen Inferior horn Third ventricle Lateral aperture Cerebral aqueduct Fourth ventricle Central canal (a) Anterior view

Lateral ventricle Anterior horn Posterior horn Interventricular foramen Third ventricle Inferior horn Cerebral aqueduct Median aperture Fourth ventricle Lateral aperture Central canal (b) Left lateral view Figure 7.18b

Central Nervous System … B. Spinal Cord from foramen magnum to 2nd lumbar vertebra then as a collection of spinal nerves

Functions: Relays information between ____ & _____. Sensory Motor Spinal Reflexes

VI. Peripheral Nervous System (PNS) PNS = Nerves and ganglia connective tissue

Axon Myelin sheath Endoneurium Perineurium Epineurium Fascicle Blood vessels Figure 7.23

A. Nerves and their Classification FUNCTIONAL Mixed nerves = Sensory (afferent) nerves = Motor (efferent) nerves = BY LOCATION 1. Cranial Twelve pairs of nerves Most are mixed three are sensory only

Hypoglossal nerve (XII) Figure 13.6a Location and function of cranial nerves. Filaments of olfactory nerve (I) Frontal lobe Olfactory bulb Olfactory tract Optic nerve (II) Temporal lobe Optic chiasma Optic tract Oculomotor nerve (III) Infundibulum Facial nerve (VII) Trochlear nerve (IV) Vestibulocochlear nerve (VIII) Trigeminal nerve (V) Glossopharyngeal nerve (IX) Abducens nerve (VI) Vagus nerve (X) Cerebellum Accessory nerve (XI) Medulla oblongata Hypoglossal nerve (XII) © 2013 Pearson Education, Inc.

PNS: Cranial Nerves I Olfactory nerve—sensory for smell II Optic nerve—sensory for vision I II

PNS: Cranial Nerves V Trigeminal nerve—sensory for the face; motor fibers to chewing muscles X Vagus nerves—sensory and motor fibers for pharynx, larynx, and viscera V X

2. Spinal Nerves: 31 Paired Spinal Nerves C1 2 3 Ventral rami form cervical plexus (C1 – C5) Cervical nerves 4 5 6 7 Ventral rami form brachial plexus (C5 – C8; T1) 8 T1 2 3 4 5 Thoracic nerves 6 7 No plexus formed (intercostal nerves) (T1 – T12) 8 9 10 Lumbar nerves 11 12 Sacral nerves L1 2 3 Ventral rami form lumbar plexus (L1 – L4) 4 5 S1 Ventral rami form sacral plexus (L4 – L5; S1 – S4) 2 3 4 (a)

Sciatic Nerve Phrenic Nerve Superior gluteal Inferior gluteal Pudendal Sciatic Posterior femoral cutaneous Common fibular Tibial Sural (cut) Deep fibular Superficial fibular Plantar branches

© 2013 Pearson Education, Inc. Figure 13.12c The sacral plexus. Gluteus maximus Piriformis Inferior gluteal nerve Common fibular nerve Tibial nerve Pudendal nerve Posterior femoral cutaneous nerve Sciatic nerve Cadaver photo © 2013 Pearson Education, Inc.

Peripheral NS … B. PNS: Autonomic Nervous System Motor subdivision of the PNS,  Organs Involuntary Two subdivisions Sympathetic NS = Stress Parasympatheitic NS = Peace

END OF PPT

Figure 7.2

The Reflex Arc– Simplest Function Five elements: Sensory receptor: Sensory neuron: Integration center (CNS)--interneuron: Motor neuron: Effector organ:

CNS Functioning– Simplest Somatic reflexes Reflexes that stimulate the ____________ Examples: Autonomic reflexes Regulate the activity of ___________

Three-Neuron Reflex Arc Three-neuron reflex arcs Have all 5 elements Example: Flexor (withdrawal) reflex 1 2 Stimulus 3 4 STIMULUS Receptor Sensory Neuron Integration Center-- CNS Motor Neuron Effector 5

Sensory (afferent) neuron Motor (efferent) neuron 1 Sensory receptor 2 Sensory (afferent) neuron 3 Interneuron 4 Motor (efferent) neuron 5 Effector organ Figure 7.11c

1 Sensory (stretch) receptor 2 Sensory (afferent) neuron 3 4 Motor (efferent) neuron 5 Effector organ Figure 7.11b, step 5

Longitudinal fissure Association fibers Superior Commissural fibers (corpus callosum) Lateral ventricle Corona radiata Basal nuclei (basal ganglia) Fornix Internal capsule Thalamus Third ventricle Pons Projection fibers Medulla oblongata Figure 7.15

Cerebrum … Superior corpus callosum Basal nuclei Pons Medulla oblongata

CSF Circulation 4 Superior sagittal sinus Arachnoid villus Choroid plexus Subarachnoid space Arachnoid mater Corpus callosum Meningeal dura mater Periosteal dura mater Interventricular foramen 1 Right lateral ventricle (deep to cut) Third ventricle 3 Choroid plexus of fourth ventricle Cerebral aqueduct Lateral aperture CSF is produced by the choroid plexus of each ventricle. 1 Fourth ventricle 2 Median aperture CSF flows through the ventricles and into the subarachnoid space via the median and lateral apertures. Some CSF flows through the central canal of the spinal cord. 2 Central canal of spinal cord (c) CSF circulation CSF flows through the subarachnoid space. 3 CSF is absorbed into the dural venous sinuses via the arachnoid villi. 4 Figure 7.18c

Figure 7.24 III Oculomotor IV Trochlear VI Abducens I Olfactory II Optic V Trigeminal V Trigeminal VII Facial Vestibular branch Cochlear branch VIII Vestibulocochlear X Vagus IX Glossopharyngeal XII Hypoglossal XI Accessory Figure 7.24

Figure 7.28 Parasympathetic Sympathetic Eye Eye Brain stem Salivary glands Skin Cranial nerves Salivary glands Sympathetic ganglia Heart Cervical Lungs Lungs T1 Heart Stomach Thoracic Stomach Pancreas Liver and gall- bladder Pancreas L1 Liver and gall- bladder Adrenal gland Lumbar Bladder Bladder Pelvic splanchnic nerves Genitals Genitals Sacral nerves (S2 – S4) Figure 7.28

PNS: Autonomic Functioning … Sympathetic—STRESS “fight or flight” Exercise, excitement, emergency, embarrassment unusual stimulus Increases:

PNS: Autonomic Functioning Parasympathetic—PEACE “housekeeping” necessary body functions Increases activities of: Decreases activities of Stress Organ Systems

Figure 7.2