Dr. C. NERVOUS SYSTEM Flashcards
Contains 2 KINDS OF CELLS
Neural Tissue
- Neurons: Cells** that **Send & Receive Signals
- NeuroGlia: Cells** that **Support & Protect Neurons
ORGANS OF THE NERVOUS SYSTEM
- Brain** and **Spinal Cord
- Sensory Receptors of sense organs.
- Nervesconnectnervoussystem withother systems.
CENTRAL NERVOUS SYSTEM - CNS
- _Brain_and _Spinal Cord Occupy_ the _Midline_ or _Central Location_ in the body.
PERIPHERAL NERVOUS SYSTEM - PNS
- Designation** for the **Nerves of the body.
AUTONOMIC NERVOUS SYSTEM - ANS
- REGULATES the Body’s__“Automatic or Involuntary”. Functions.
THE STRUCTURE OF NEURONS
- Cell Body - (Soma)-Main Part.
- DENDRITES: - Short**, **Branched** **Projections
- AXON TERMINALS: - A Long, Single Projection.
- DENDRITES: - Processes or Projections that Transmit Impulses to the Neuron Cell Bodies
- AXONS: - Transmit Impulses AWAY from the Neuron Cell Bodies.
SENSORY NEURONS = AFFERENT
- Neurons of PNSTransmit Impulses to the Spinal Cord and Brain from ALL Parts of the Body.
MOTOR NEURONS = EFFERENT
- Neurons of PNS ‘EFFECT’.TransmitImpulsesin theOPPOSITEDIRECTION**—**AWAYfrom theBrainandSpinalCord.
NEURILEMMA
- Outer Cell Membrane** of a **Schwann Cell.
NEUROGLIA
Many types of Neuroglia** in **CNS** and **PNS
4 TYPES OF NEUROGLIA
IN THE CNS
1. OLIGODENDROCYTES
2. ASTROCYTES
3. MICROGLIA
4. EPENDYMAL CELLS
ASTROCYTES
- Most Numerous
- Create Structural Framework for CNS
- Repair DAMAGED Neural Tissue.
- FORM a 2-layer Structure called the BLOOD-BRAIN BARRIER ( BBB )
OLIGODENDROCYTES
- Produce the FATTY MYELIN SHEATH that Envelops Nerve Fberslocated in the Brain and Spinal Cord.
SCHWANN CELLS
- Are GLIAL CELLS that also Form MYELIN SHEATHS** to the **Peripheral Nervous System.
MICROGLIA
- Microbe-Eating__Scavengers.
EPENDYMAL CELLS
- Produce CSF
NEUROGLIA OF THE PNS
- SATELLITE CELLS: RegulateEnvironmentAroundNeuron
- SCHWANN CELLS: FORMMyelinSheatharoundPeripheralAxons.
A NERVE
- NERVE is a Group of Peripheral Nerve Fibers (AXONS) bundled together like the Strands of a Cable.
- Bundles of AXONS in the CNS, called Tracts, also are Myelinated and form the “White Matter” of the Brain & Cord.
GRAY MATTER
- Brain and Cord Tissue “ Composed” of Cell Bodies and UnmyeLinated AXONS and Dendrites is called GRAY MATTER.
REFLEX ARCS
- Nerve Impulses also called ACTION POTENTIALS can Travel Over Trillions of Routes.
REFLEX ARCS: RECEPTORS
- Receptors are the Beginnings of Dendrites of Sensory Neurons.
REFLEX ARCS: GANGLION
- A Ganglion is a group of Nerve-Cell Bodies located in the PNS. This Ganglion is located NEAR the Spinal Cord.
REFLEX ARCS: SYNAPSE
- Space Separates the AXON Ending of ONE NEURON. This space is called a Synapse.
REFLEX ARCS: 3 NEURON ARCS
- Sensory Neurons
- InterNeurons
- Motor Neurons.
NERVE IMPULSE
- Self-Propagating Wave of Electrical Disturbance that Travels Along the Surface of a Neuron’s Plasma Membrane.
POLARIZATION
- Membrane** of **Each Resting Neuron has a Slight Positive Charge on the Outside** and a **Negative Charge on the Inside called POLARIZATION.
SALTATORY CONDUCTION
- MyeLinated Fiber, “JUMPS” around the Insulating Myelin in a Rapid Type of Conduction called SALTATORY conduction
2 METHODS OF:
PROPAGATING ACTION POTENTIALS
- CONTINUOUS PropaGation: Unmyelinated AXONS ( grey matter - CNS ) - Speed of about 2 mph
- SALTATORY PropaGation: Myelinated AXONS (PNS) (“Jumping”….Speed of 40 to 300 mph !)
SNAPSES
- A SYNAPSE is where Impulses are Transmitted** from **One Neuron** the _Presy_Naptic NEURON** to the PostsyNaptic NEURON.
SYNAPTIC KNOB
- Tiny Bulge at the end of a Terminal Branch of a PresyNaptic Neuron’s AXON.
NEUROTRANSMITTER
- Each Vesicle Contains a Very Small Quantity of a Chemical Compound.
- NeuroTransmitters areChemicalsby which Neurons Communicate.
DIVISIONS OF THE BRAIN
1. BRAINSTEM
- Medulla OblonGata
- Pons
- Midbrain
2. CereBellum
3. DienCephalon
- Hypothalamus
- Thalamus
4. CereBrum
BRAINSTEM Function Has
2-Way Conduction Paths
- CARDIAC RESPIRATORY and VASOMOTOR centers called the VITAL CENTERS are located in the Medulla Oblongata.
BRAIN STEM: B. &. C
B. PONS
- Connects Cerebellum to Brain Stem
- Somatic and Visceral Motor Control.
C. MIDBRAIN
- Processes Sight, Sound, and Associated Reflexes
- Maintains Consciousness.
CEREBELLUM
- 2nd largest Part of Brain
- Coordinates: Repetitive Body Movements
- 2 HemisPheres
- Covered** with_CEREBELLAR CORTEX_**
BRAIN: CEREBELLUM
- PRODUCE… Smooth Coordinated Movements
- Maintain Equilibrium
- Sustain Normal Postures.
DIENCEPHALON
- Links Cerebrum with Brain Stem.
THALAMUS
- Relays and Processes Sensory Information.
HYPOTHALAMUS
- Hormone Production
- Autonomic Function - Control of Temperature - Thirst - Hunger
THALAMUS PERFORMS the Following Functions
- Major Relay Station between CereBrum**, **CereBellum**, **Spinal Cord**, and **Helps Relay Sensory Signals between Spinal Cord.
- It helps Associate Sensations with Emotion.
HYPOTHALAMUS
- Maintains a Waking Stateand gets the Adrenaline Flowing during a TEST or JOB interview.
- EMOTIONAL CENTER: FeelING… Exhilarated - Angry - Unhappy - Sexually Aroused - Pain.
CEREBRAL CORTEX
- _Thin Layer_of _Gray Matter__Made Up_of _Neuron Dendrites_
- Cell Bodies Forms the Surface of the Cerebrum.
FRONTAL LOBES - MOTOR AREA
- Helps Control Voluntary Movement.
PARIETAL LOBES
- TASTE - AROMA AND TEXTURE
- TWO SECTIONS BEHIND THE FRONTAL LOBES.
COVERING FLUID SPACES in the BRAIN
- Dura Mater
- ArachNoid Mater
- PIA MATER
Dura Mater
Is the _Tough Outer Layer_that _Lines The Vertebral Canal_
ArachNoid Mater
- Is the MemBrane Between the DURA and the PIA MATER.
ArachNoid Membrane
- Sub-AraChnoid Space – FILLED with CSF ( cerebral spinal fluid )
PIA MATER
- Is the Innermost Membrane Covering the Spinal Cord.
CSF
- Cerebrospinal Spinal Fluid
CSF - CHOROID PLEXUS
- Fluid Filtering out of the blood in a network of Brain Capillaries known as the CHOROID PLEXUS
- CSF SEEPS from the Lateral Ventricles into the 3rd Ventricle and _flows down through_the _cerebral into the_4th Ventricle.
BRAIN - 3 CSF SPACES
1. Subdural Space
2. SubaraChnoid Space
3. CerebroSpinal Fluid (CSF)
SPINAL CORD FUNCTIONS SIMILARLY
- It contains the Centers for Thousands** and **Thousands of Reflex Arcs.
GROSS ANATOMY: - SPINAL CORD 3 BRANCHES
VENTRAL ROOT
- Contains AXONS of “MOTOR” Neurons
DORSAL ROOT
- Contains AXONS of Sensory Neuron
DORSAL ROOT GANGLIA
- Contain Cell Bodiesof Sensory Neurons
WHITE MATTER
- Myelinated and UnMyelinated Axons ( mostly myelinated )
GRAY MATTER
- Surrounds Central Canalof the Spinal Cord
PNS – PERIPHERAL NERVOUS SYSTEM
INCLUDES
Cranial & Spinal Nerves
- Connects the brain and Spinal Cord to Peripheral StructuresSkin Surface and the Skeletal Muscles.
CRANIAL NERVES have
12 PAIRS Connected to Brain.
- OPTIC Nerve: 2nd Nerve. Impulses from the Eye to the Brain.
- OCULOMOTOR Nerve. 3rd Nerve: Impulses between the Medulla Oblongata and Structures** in the **Neck** and **Thoracic
- VAGUS Nerve. 10th NERVE: Impulses between the Medulla Oblongata and Structures in the Neck** and **Thoracic AND ADOMINAL CAVITIES.
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
Autonomic Nervous System (ANS)
Impulses to Brainstem for the Following
- CARDIAC Muscle Tissue
- SMOOTH Muscle Tissue
- GLANDULAR Epithelial Tissue
Somatic Nervous System
( SNS ) ( Motor Portion )
- Operates Under Conscious Control
Autonomic Nervous System (ANS)
( Motor or Efferent Portion )
- Regulate Involuntary Functions - for example, the Heartbeat.
AUTONOMIC MOTOR Neurons
- Motor Neurons that make up the Motor Portion of the ANS.
PREGANGLIONIC Neurons
- Conduct Impulses between the Spinal Cord and a Ganglion.
SYMPATHETIC Response Symptoms
- Fight to flight
- Heart Beats Faster.
- Blood Vessels Constrict,
- Sweat / Adrenal Glands Secrete More..
- Salivary, Digestive Glands Secrete More Sparingly.
- Become Sluggish, Hampering Digestion.
ParaSympathetic System
Has also been Referred to
- the CranioSacral System
