Nervous System Flashcards
Parts of the nervous system
Sensory (afferent)
Central
Motor (efferent)
Component of the CNS
Brain
Spinal cord
Components of the peripheral nervous system
Sensory
Motor
Components of the sensory nervous system
Visceral
Somatic
Components of the motor nervous system
Visceral
- sympathetic
- parasympathetic
Somatic
Somatic motor nervous system
Carries info to the skeletal muscles
Visceral motor nervous system
(Autonomic)
Carries info to smooth and cardiac muscles and glands
- sympathetic
- parasympathetic
Sympathetic nervous system
Fight or flight
Parasympathetic nervous system
Rest and digest
Spinal cord functions
Conduction
Locomotion
Reflexes
Conduction
The spinal cord contains bundles of nerve fibers called tracts that carry info up and down the spinal cord
Locomotion
The spinal cord contains groups of neurons that control output to flexor and extensor muscles
Reflexes
The spinal cord regulates autonomic involuntary response for posture, movement, and protection
Spinal cord regions
Cervical
Thoracic
Lumbar
Sacral
Spinal cord enlargements
Cervical (c5-7)- start of the upper limb nerve branches
Lumbar (l1-2)- start of lower limb nerve branches
Causa equina
Bundle of spinal nerves that arise from the medullary cone and innervate lower limbs
Contains lumbar nerves 2-5, all the sacral nerves, and coccygeal nerves
How many pairs of spinal nerves does the spinal cord have?
31
Meninges
Protective fibrous covering around the brain and spinal cord
Meninges layers
Dura mater- physical protection
Arachnoid mater- space w/cervical fluid
Pia mater- innermost layer
Nervous tissue
White matter
Grey matter
Grey matter
Central tissue
Un-myelinated
Contains synapses
Surrounds central canal
White matter
Outer tissue
Myelinated bundles of neurons (tracts)
Spinal nerves
Mixed nerves (sensory & motor)
Each nerve is connected to the spinal cord by two roots
- anterior root contains motor axons
-posterior root contains sensory axons
31 pairs of spinal nerves breakdown
8 cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal
Brain ventricles
4 chambers filled with CSF
CSF
Cerebral spinal fluid is a clear fluid derived from plasma
CSF functions
Buoyancy
Prevents collision
Provides chemical stability
Brain regions
Brain stem
Cerebellum
Diencephalon
Cerebrum
Brain stem
Attaches to the spinal cord
Three regions
1. Mid-brain
2. Pons
3. Medulla
Mid-brain
Relay station btw higher brain regions and the brainstem
Pons
Respiration
Sleep
Posture
Medulla oblongata
Heart rate
Blood pressure
Breathing rate
Diencephalon
Thalamus
Hypothalamus
Thalamus
Directs sensory impulses to the cerebrum
Hypothalamus
Link btw nervous and endocrine systems
Thermoregulation
Hunger/thirst
Sleep
Cerebrum
Largest and most complex
Contains
-landmarks
- hemispheres
- cerebrum cortex
Landmarks
Gyri- ridges and folds
Sulci- valleys and narrow grooves
Fissures- deep grooves
Hemispheres
Connected by corpus callosum
Cerebral cortex
Densely packed grey matter in the surface of the cerebral lobes
Lobes
Frontal
Parietal
Occipital
Temporal
Insula
Frontal
Voluntary movements
Parietal lobe
Receiving and interpreting signals from general senses
Occipital
Vision
Temporal lobe
Hearing and smell
Insula
Understanding spoken language and taste
Cell classes
Neurons
Neuroglia
Neuron properties
Excitability
Conductivity
Secretion
Neuron classes
Sensory neurons
Interneurons
Motor neurons
Motor neuron structure
Dendrites
Soma
Axon
Axon components
Axon hillock
Terminal arborization
Synaptic knob
Axon associated structures
Schwann cell
- Myelin sheath
- Neurolemma
Node of Ranvier
Schwann cell
Type of neuroglia cell that supports electrical transmission down the axon
Myelin sheath
Inner layer of the Schwann cell
- insulates and speed electrical signal
Neurolemma
Outer layer of the Schwann cell
- helps damaged axons heal
Nodes of ranvier
Gaps between myelin
Types of Neuroglia
Oligodendrocytes
Ependymal
Microglia
Astrocytes
Schwann cell
Satellite cell
Oligodendrocytes
CNS
Provide myelin sheath
Ependymal cell
CNS
Produce CSF
Microglia
Macrophages that move throughout CNS
Astrocytes
CNS
Most abundant
Support neuron framework
Monitor neuron health
Stimulate brain capillaries
Schwann cells
In PNS
Satellite cells
Around somas in CNS
Supportive role
Electrical potential
Difference btw the concentration of charged particles btw one point and another
Electrical current
Movement of charged particles from one point to another
Sodium potassium pump
Create electrical potential
Sodium out/potassium in
ECF+/ICF-
Resting membrane potential
Actual value of electrical potential of the plasma membrane when at rest
ICF resting membrane potential
-70 mV (Polarized)
Depolarization
State of the plasma membrane when there is a positive shift in voltage
Local potential
A short range change in voltage along the plasma membrane
Graded, decremental, reversible
Synapses
Region where a neuron carries info to a target cell
Components of the a synapse
Pre-synaptic structure
Synaptic cleft
Post-synaptic structure
Action potential
Dramatic change in the state of plasma membrane
Can occur at axon hillock and along the axon length
Full strength or not at all
Nondecremental
Irreversible
Unmyelinated neurons
Starting in axon hillock and ending in the synaptic knob an action potential triggers a neighboring region of the plasma membrane
Myelinated neurons
(Saltatory conduction)
Sodium ions diffuse through the ICF to the next node bringing the electrical signal with them internally
- signal gets weaker as it goes
- new action potential occurs at nodes of ranvier
