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Chapter 7 – Nervous System
Two message centers: Functions of these systems: 1. * 2. * Overview of the Nervous System Parts: General Functions: Functions Sensory input: Sensation via nerves Integration: interpretation of data by brain and spinal cord Motor Output: Motor response Divisions of the Nervous System The central Nervous System (CNS)
Peripheral Nervous System (PNS)
Consists of Cranial and spinal nerves Two subdivisions
Afferent (sensory) Efferent (motor)
Nervous Tissue:
Neurons Neuroglia
5 types of Neuroglial cells
Structure of a Neuron: Cell Body: Dentrites: Axon: Myelin Sheath: Function: Insulation and conduction of nerve impulse Formed by: Schwann cells in the ____________ Oligodendrocytes in the _________ Nodes of Ranvier:
Structural Classification of Neurons: Unipolar:___________ axon that enters and exits the cell body Bipolar: one dendrite and one axon Found : Multipolar: many dendrites and _____ axon
Motor Neurons Efferent
Sensory Neurons Afferent
Interneurons Association Neurons
Where Found?
Function?
Structural Classification Uni- Bi- polar Multi-
Pathway
Stimulated by
Sensory Neuron: Interneuron:
Neuroglial Cells and Transmission of Action Potential
6 Types of Neuroglial or Glial Cells: • Glia = greek word for glue • Special types of ________________________ that help ___________
and provide _________________ for nerve cells. • ___________________ neurons and
______________________________. • Supply ____________ and _______________ to neurons. • ______________________ one neuron from another. • Destroy ___________________ and remove ______________neurons.
Motor Neuron:
Name of the Cell Found in CNS or PNS Function Astrocytes
Oligodendrocytes
Microglia Cells
Ependymal Cells
Schwann Cells
Satellite Cells
Nerve Impulse • An __________________________ that travels along a nerve fiber.
• Travels about _________________________________________.
• Rapid ____________________ and ________________ of a small portion of the plasma membrane
Nerve Signal Conduction • _____________________ potential followed by an _______________
potential
Resting Potential • Electrical charge across the ______________________
Inside of cell is _______ compared to the outside Sodium ions _________ Potassium ions ________
Depolarization • Neurotransmitters open _____________ channels
• ___________ rushes into the cell
• inside of cell is now ______________________
Repolarization • _________________ channels open
• __________ flows out of the cell
• Inside becomes more _________________
Refractory Period • Time which the neuron is ________________________________
• In mammals, the absolute refractory period is about ______________ and the maximum firing frequency is about ______ impulses per second
Synapses • The ___________ between a nerve cell and another cell. • To cross a synapse _________________are released.
Transmission across a synapse
• Neurotransmitters stored in______________ in the ________ terminal • Impulse reaches terminal • ____________ channels open • Vesicles fuse with ________________ membrane • _______________________ are released • Receptors bind to ______________ membrane
Common Neurotransmitters
• _____________________ (ACh)
• ______________________ (NE)
• Once released must be removed from synapse
____________________ (AChE) breaks down ACh
Brain Structure and Function
CNS: The Brain and Spinal Cord Gray matter- White matter- Overview of the Brain:
• The brain acts as the main ______________ and __________ of the N.S. • The cranial nerves ____________ the brain and go to specific body areas
– Sensory
– Motor
Brain Meninges: The Protective Coverings Dura Mater (Outermost) Arachnoid Mater Pia Mater (Innermost)
Dura mater- • Tough, fibrous, _____________________ tissue • Made of ___________________________________ layers • Separation of layers to form
_______________________________________________ – Collection of _____________________ and extra _________________
Arachnoid Mater- • ________________________________ connective tissue • CSF in the _______________________________ space
– CSF-clear fluid, _______________________________________ Pia Mater- • Very thin layer • Follows ________________________________________________________
CSF • Made by the ____________________________________ lining the ventricles • Fills all ________________________ and the __________________________ • Hydrocephalus-_________________________________________ in an infant
The Spinal Cord
• Is an extension of the brain • Exits the cranial cavity via _________________________________________ • Runs through the _______________________________________________ • Ends between L ____ & L ____
• Cauda equina (horse’s tail) The Vertebral Column • Made of individual vertebrae separated by ________________________
– _____________________
Anatomy of the Spinal Cord
• Inner _______________________ with a central canal • Outer ________________________________________
Spinal Nerves • Posterior (dorsal) root of a spinal nerve:
– _____________________ (__________________________) fibers • Anterior (ventral) root of a spinal nerve:
– _______________________ (_________________________) fibers • Spinal nerve – joining of posterior & anterior roots
The Human Brain: Gyri- Sulci- Left and Right Side of Brain
• The brain senses and controls most of the body in a __________________
• Connection by a collection of white matter = _______________________
Major Sections of the Human Brain
The cerebrum The diencephalon:
– Hypothalamus – Thalamus – Pineal gland
The cerebellum The brainstem
Lobes of Cerebrum • Named for the skull bones that
cover them • Occur in pairs (usually)
General Functions of each Lobe ___________________motor function, behavior, emotions, memory, thinking and smell ___________________body sense, perception, speech ___________________Vision ________________________hearing, taste, language, comprehension, integration of emotions Diencephalon
Contains: • ___________________relays info going to cerebrum
• ___________________regulates temp, water balance, thirst, appetite,
some emotions, regulates pituitary gland
• ___________________secretes melatonin
• ___________________secretes hormones for various functions
Grey Matter in the brain
• Basal nuclei:
• Limbic system:
Cerebellum:
______________gray matter, ___________is white
Responsible for:
Brain Stem
Divided into three sections:
General functions:
Contains reticular system responsible for:
(anasthesia inhibits this causing unconsciousness)
Medulla oblongata-
Pons-
Midbrain-
Peripheral Nervous System (PNS)
• All the rest of the nerves of your body • Two branches
o _______________ Nervous System
o _______________ Nervous System Nerve Anatomy
• ____________________ = covers nerve itself • ____________________ = covers bundles of axons • ____________________ = covers individual axons
Somatic NS
• _______ pairs of Cranial Nerves • _______ pairs of Spinal Nerves
Types of Nerves
• Mixed = ____________________________ • Sensory = ___________________________
• Motor = ____________________________
Cranial Nerves Spinal Nerves
Nerve Plexus: ______________________________________
Name of Plexus Nerves found in plexus
Services what part of the body
Cranial
Nerve # Name of Cranial
Nerve Function Type of Nerve
I Sense of Smell
II Sense of sight
III Movement of eyelid and eyeball
IV Muscles of the eyes
V Muscles for chewing (motor) & pain and touch for face and mouth (sensory)
VI Muscles for eye movement
VII Sense of taste (sensory) & facial expressions (motor)
VIII Sense of Hearing
IX Sense of taste (sensory), blood pressure, tongue movement (motor)
X Innervates smooth muscle of the gut(motor) & feelings of distension/bloating (sensory)
XI Movement of neck muscles
XII Movement of the tongue
The Autonomic Nervous System Two divisions:
– Sympathetic (__________________________________)
– Parasympathetic (__________________________________)
General Characteristics of Sympathetic and Parasympathetic • Both divisions are ________________________ (involuntary)
• Both innervate all ___________________
• Both have 2 ______________________ and 1 ___________________
– Ganglion:
– place where __________________ of the 2nd ANS neurons exit outside the CNS
Some Important functions of the ANS • Regulation of _________________________________________
• Regulation of _________________________________________
• Control of secretions from ______________________
Setup of 2 ANS Neurons Neuron 1 (pre-ganglionic neuron): • Cell body ___________________(spinal cord) and the axon
______________ of the CNS
• Synapses with neuron 2 in the __________________________
Neuron 2 (post-ganglionic neuron): • Cell body in the ________________ and the axon continues to the
______________
• Dendrites synapse with neuron 1 in the __________ and the axon terminals synapse with the _______________
Neuron Setup in the Parasympathetic Nervous System Neuron 1 Neuron 2
The ganglion lies far from the spinal cord
Neuron Setup in the Sympathetic Nervous System Neuron 1 Neuron 2
The ganglion lies close to the Spinal cord Origin of Sympathetic Nerves
Origin of Sympathetic Nerves __Origin of Parasympathetic Nerves Functions of the Sympathetic Division
• prepares the body for emergencies (Fight or flight)
• increases heart rate
• raises blood pressure (vasoconstriction)
• dilates the pupils
• dilates the trachea and bronchi
• Converts liver glycogen into glucose
• shunts blood away from the skin and organs (vasoconstriction)
• pushes blood toward the skeletal muscles, brain, and heart
• inhibits peristalsis in the gastrointestinal (GI) tract
• inhibits contraction of the bladder and rectum
Functions of the Parasympathetic Division
• The “housekeeper” division
• “Rest and Digest”
• Manages functions associated with a relaxed state
• Contraction of the pupils
• Promotes digestion of food
• Slows down the heart rate and decreased heart contraction
• Increased blood flow to the visceral organs (GI tract), normal peristalsis
Sympathetic Neurotransmitters Parasympathetic Neurotransmitters Reflexes
• ________________________________responses
• Occur quickly
• ____________________________ mechanisms
• Cranial Reflexes:
– Blinking of eyes with sudden clapping near eyes
• Spinal Reflexes:
– Quick movement of hand away from the hot pan
Reflex Arc 1. Sensory transducer (hitting of patellar tendon)
2. ______________________________
3. ______________________________
4. Motor neuron
5. ____________________________ (muscle contraction)