The Nervous System A&P Spring 2017

I. Organization of the Nervous System Structural Classification Central Nervous System (CNS) The Brain The Spinal Cord Peripheral Nervous System (PNS) Nerves that extend from the CNS i. Serve as communication lines that link all parts of the body to the CNS

B. Functional Classification (PNS only) 1. Sensory Division a B. Functional Classification (PNS only) 1. Sensory Division a. nerves that send impulses TO the CNS from sensory receptors 2. Motor Division a. Nerves that carry impulses FROM the CNS to organs, muscles and glands

3. Somatic NS (Subdivision of Motor) a. voluntary control of skeletal muscles 4. Autonomic NS (Subdivision of Motor) a. regulates involuntary events b. also has 2 subdivisions i. Sympathetic- Fight or Flight ii. Parasympathetic- Rest and Digest

Central Nervous System Peripheral Nervous System The Nervous System Central Nervous System Peripheral Nervous System Sensory Motor Somatic Autonomic Sympathetic Parasympathetic

Bell Ringer Create a diagram that shows the relationship between the following: Central NS Motor Autonomic Somatic Peripheral NS Sensory

II. Nervous Tissue: Structure and Function Supporting Cells Neuroglia (Glial Cells) Found in the CNS Astocytes Microglia Ependymal Oligodendrocytes

b. Found in the PNS Schwann cells Satellite cells

Neuroglia Flipbook! Materials: 3 Sheets of paper Page of pictures Stapler (will be passed around) Glue stick Scissors Pen/Pencil

Cover Page NEUROGLIA By: Your Name

Page 1 Found in the Central Nervous System

Page 2 Astrocytes star-shaped cells that anchor neurons to blood capillaries. Helps with exchange of oxygen and nutrients (Paste picture to the back of page 1)

Page 3 Microglia spiderlike cells that monitor the health of neurons. Dispose of debris such as dead brain cells and bacteria. (paste picture to the pack of page 2)

Page 4 Ependymal Cells Line the central cavities of the brain & spinal cord. Forms a protective cushion around the CNS. Cilia help circulate cerebrospinal fluid. (paste the picture to the back of page 3)

Page 5 Oligodendrocytes wrap around nerve fibers of the CNS to form an insulating cover called a “myelin sheath”. (paste the picture to the back of page 4)

Page 6 Found in the Peripheral Nervous System

Page 7 Satellite Cells Form a protective cushion around the PNS. (paste picture to the back of page 6)

Page 8 Schwann Cells Wrap around the nerve fibers of the PNS to form an insulating cover called a “myelin sheath” (Paste picture to the back of page 7)

Page 9 Summary CNS: PNS: Astrocytes Satellite Cells Microglia Schwann Cells Oligodendrocytes Ependymal Cells

Bell Ringer What is the main purpose of ALL neuroglia?

B. Neurons 1. Anatomy a. Cell Body i. center of the neuron ii B. Neurons 1. Anatomy a. Cell Body i. center of the neuron ii. Contains the nucleus and the usual cell organelles

b. Dendrites i. detect incoming messages (electrical signals) ii b. Dendrites i. detect incoming messages (electrical signals) ii. “Listeners” c. Axon i. send messages out ii. “Talkers”

d. Axon Terminals i. End of the axon ii d. Axon Terminals i. End of the axon ii. Contains chemicals that carry messages from one neuron to the next iii. Synaptic cleft is a gap between neurons

e. Myelin Sheath i. material that insulates nerve axons ii. Increases the rate of nerve impulses f. Nodes of Ranvier i. Space between myelin sheaths where the axon is exposed ii. Impulses “Jump” to these spaces

2. Classification a. Functional Groups i. Sensory (afferent) neurons ii. Motor (efferent) neurons iii. Interneurons (association)

b. Structural Groups i. Multipolar neurons ii. Bipolar neurons iii b. Structural Groups i. Multipolar neurons ii. Bipolar neurons iii. Unipolar neurons

III. The Central Nervous System Anatomy of the Cerebrum Cerebral Hemispheres Gyrus (gyri; plural)- ridges Sulcus (sulci; plural)- shallow grooves Fissures- deep grooves Transverse Fissure- separates cerebrum from cerebellum Longitudinal Fissure- separates cerebral hemispheres

2. Lobes a. Frontal i. Primary motor area b. Parietal i 2. Lobes a. Frontal i. Primary motor area b. Parietal i. Primary sensory area c. Temporal i. Auditory area d. Occipital i. Visual area

3. Cerebral White Matter a. inner most part of the brain b 3. Cerebral White Matter a. inner most part of the brain b. contains the “Corpus Callosum” i. a large nerve fiber ii. Connects the cerebral hemispheres

4. Diencephalon a. located on the bottom i 4. Diencephalon a. located on the bottom i. sits on top of the brain stem b. 2 major structures i. Thalamus- relay station for sensory impulses ii. Hypothalamus- regulates body temperature, water balance and metabolism

B. Anatomy of the Brain Stem 1. Midbrain a B. Anatomy of the Brain Stem 1. Midbrain a. Contains two large nerve fibers b. fibers serve as reflex centers i. vision reflex center ii. Hearing reflex center

2. Pons a. means “bridge” b. involved with control of breathing

3. Medulla Oblongata a. merges with the spinal cord b. contains several control centers i. heart rate ii. Blood pressure iii. Breathing iv. Swallowing v. vomiting

C. Anatomy of the Cerebellum 1. “Little Brain” a C. Anatomy of the Cerebellum 1. “Little Brain” a. divided into two hemispheres b. contains gray cortex on the outside c. white cortex in the center d. located on the bottom of occipital lobe

2. Involved with balance & movement a. ensures that skeletal muscle movements are smooth and precise b. controls balance and equilibrium

D. Protection of the Central Nervous System 1 D. Protection of the Central Nervous System 1. Meninges- cover the brain and spinal cord a. Dura Mater i. Outermost layer ii. Very tough

b. Arachnoid Mater i. middle layer ii. Web-like c. Pia Mater i. Inner layer ii. Thinnest iii. Clings to the brain and spinal cord

2. Cerebrospinal Fluid (CSF) a. Watery “broth” i 2. Cerebrospinal Fluid (CSF) a. Watery “broth” i. made from blood plasma b. surrounds brain and spinal cord i. acts as a protective cushion from some forms of trauma c. Continually moving i. forms and drains at a constant rate ii. Specific pressure is maintained

d. Lumbar (Spinal) Tap i. used when testing for diseases that affect the CSF ii. Patients have CSF withdrawn from their lower spine iii. The change in pressure requires patients to remain laying down for 6- 12 hours after the procedure iv. Failure to do so can result in an extremely painful “spinal headache”

E. Anatomy of the Spinal Cord 1. Enclosed in the vertebral column a E. Anatomy of the Spinal Cord 1. Enclosed in the vertebral column a. actually ends just below the ribs i. 1st or 2nd Lumbar Vertebra

b. has 31 pairs of spinal nerves i. nerves branch out from the vertebrae to serve nearby body areas c. spinal nerves that serve the lower body bunch together i. they must extend through the bottom of the vertebral column ii. This grouping is called the “Cauda Equina” which means horse tail

2. Spinal Nerve Roots a. Every spinal nerve connects to the spinal cord in two places i. connections are called “roots” ii. Connect to the front and back side b. Dorsal Roots i. “Back” roots ii. Beginning of Sensory Neurons c. Ventral Roots i. “Front” roots ii. Beginning of Motor Neurons

IV. Peripheral Nervous System Cranial Nerves We will make flash cards for each of the nerves and their functions. There are 12 nerves, so you will need 12 flash cards!

I. Olfactory Sense of smell

II. Optic Sense of vision

III. Oculomotor Movement of eyelids

IV. Trochlear Movement of eyes up and down

V. Trigeminal Sense of touch on the face; movement of jaw for chewing

VI. Abducens Movement of eyes side to side

VII. Facial Movement of facial muscles (facial expression)

VIII. Vestibulocochlear Sense of balance and hearing

IX. Glossopharyngeal Movement of pharynx for swallowing; sense of taste

X. Vagus Movement of digestive organs

XI. Accessory Movement of neck and shoulders

XII. Hypoglossal Movement of the tongue

B. Structure of a Nerve 1. Parts of a nerve a B. Structure of a Nerve 1. Parts of a nerve a. Nerve- bundle of fascicles b. Fascicle- bundle of nerve fibers (processes) c. Nerve fiber (Process)- axon of individual neuron cells

2. Protective Coverings a. Endoneurium- covers the nerve b 2. Protective Coverings a. Endoneurium- covers the nerve b. Perineurium- covers the fascicles c. Epineurium- covers the nerve fibers (processes)

3. Types of nerves a. Sensory i. sends impulses TOWARD the CNS b 3. Types of nerves a. Sensory i. sends impulses TOWARD the CNS b. Motor i. sends impulses AWAY from the CNS c. Mixed i. sends impulses in both directions ii. made of BOTH sensory and motor neurons