Lecture Test 4 Flashcards
List the types of Neurogial cells
Astrocytes Microglial Cells Ependymal Cells Olgiodendrocytes Schwann Cells
What are the 3 cell types fond in the nervous system?
Schwann Cells, Neurons, Neuroglia
Function of Astrocytes?
Most abundant, support and brace neurons and anchor to nutrient supply, form the blood-brain barrier
Function of Microglial Cells?
Defensive cell
Function of Ependymal Cells?
Permeable barrier, circulates CSF
Function of Oligodendrocytes?
Myelin Sheath
Function of Schwann Cells?
Myelin Sheath of PNS, vital to regeneration of damaged peripheral nerve fibers
Function of Neurons?
Responsive to stimuli and transmit electrical signal
Function of Neuroglia?
Support cells, surround and wrap more delicate neurons
Nissl Bodies
Clustered free ribosomes and rough ER
Neurofibrils
Bundles of intermediate filaments, maintain cell shape
Axoplasmic Transport
Movement of stuff to (Retrograde) and from (Anterograde) cell body
Cell Body
Biosynthetic center and receptive region
Axons
Conducting region of neuron
Dendrites
Main receptive and input regions (graded potentials toward cell body)
Myelin Sheath
Protects and insulates fibers
Increases transmission speed of nerve impluses
Neurolemma
Outer layer of myelin sheath
Node of Ranvier
Gaps between schwann cells
Saltatory conduction
propagation of action potentials along myelinated axons
Increases conduction velocity
Fastest neuron speed, slowest neuron speed, what makes it fast?
150 m/s = Fastest
1 m/s = Slowest
Larger diameter of axon and more myelin sheaths make it faster
How does an action potential cross a synapse?
- Action potential reaches presynaptic terminal
- Voltage gated Ca++ channels open
- Influx of Ca++
- Synaptic vesicles fuse with membrane (exocytosis)
- Neurotransmitters released across synaptic cleft and diffuse to postsynaptic terminal
- Causes Na+ channels to open and Na+ flows into postsynaptic membrane
- If threshold is reached, then action potential is initiated
- Neurotransmitter is broken down by specific enzymes in synaptic cleft
Excitatory Neurotransmitter
Causes depolarization of the membrane and promotes action potential generation
Inhibitory Neurotransmitter
Causes hyperpolarization and depresses action potential generation
One way Conduction
Refractory period ensures one way conduction.
Recovery period when Na+ channels hold to ‘recharge’
Temporal summation
2 excitatory stimuli close in time cause EPSP’s that add together
Spatial summation
2 simultaneous stimuli at different locations cause EPSP’s that add together
Facilitation
Post synaptic potentials (EPSP’s) evoked by an impulse are increased when that impulse closely follows a prior impulse
EPSP’s
Allows Na+ and K+ to diffuse simultaneously in opposite directions.
Helps trigger an action potential distally at the axon hillock of the postsynaptic neuron
IPSP’s
Reduces a postsynaptic neuron’s ability to generate an action potential
Hyperpolarized by making membrane more permeable to K+ and Cl-
Convergence
One neuron influenced by many others
Divergence
One neuron sending a signal to many others
Embryological development of the nervous system
Neural tube => Primary brain vesticles (Forebrain, Midbrain, Hindbrain) => Secondary brain vesicles => Adult brain structures => Adult neural canal regions
Nerve
Bundle of fibers that transmits impulses of sensation to the brain or spinal cord and impulses to the muscles and organs
Neuron
Specialized cell transmitting nerve impulses
Tract
Large bundle of nerve fibers
Ganglion
Structure containing a number of nerve cell bodies
Nucleus
Collection of neurons (gray matter) in the brain stem associated with one or more cranial nerves
Gray Matter
Consists of mainly nerve cell bodies and dendrites
White Matter
Consists of mainly nerve fibers and their myelin sheaths
Three layers of protection for the brain
Bones, Meninges, and CSF
5 Major regions of the adult brain
Perietal Temporal Occipital Frontal Prefrontal Cortex
Function associated with Perietal Lobe
Touch
Function associated with Occipital Lobe
Vision, Charactures
Function associated with Temporal Lobe
Auditory/Smell/Taste
Auditory Association
Function associated with Frontal Lobe
Planning, Language
Muscles of Speech
Function associated with Prefrontal Cortex
Concept of Future/Past
Sense of Humor
Primary Motor
Posterior portion of frontal lobe (central sulcus)
Primary Sensory
Parietal Lobe (central sulcus)
Basal Nuclei
Island of gray matter deep in white matter
Intensity of movement
Internal Capsule
Impulses to and from spinal cord
Diencephalon
Thalamus and Hypothalamus
Limbic System
Both sides of thalamus
Emotion, Behavior, Motivation, Long-term memory
Mesencephalon
Corpora Quadrigemina, Tegmentum, Cerebral Aqueduct, and Cerebral Peduncles
Pons
Conduction Tracts; Bridge
Cerebellum
Timing and pattern for skeletal muscles (agility)
Medulla Oblongata
Cardiovascular and Respiratory
Reticular Formation
Filters out repetitive stimuli
Regulates skeletal/visceral muscle
Maintains cortical alertness
5 Basic Organizational Divisions of the Nervous System
- Receptor
- Sensory Neuron
- Interneurons
- Motor Neuron
- Effector
Monosynaptic reflex
Involves one synapse
Polysynaptic Reflex
Involves more than one synapse
Ipsilateral Reflex
Does not cross the spinal cord
Contralateral Reflex
Crosses the spinal cord
Tendon Reflex
Prevents putting more tension on a tendon than it can stand
Crossed Extensor Reflex
Extension of a limb on opposite side of body during withdraw reflex
Autonomic Nervous System Function
Regulate visceral activities
Sympathetic of ANS function?
Fight or Flight
Parasympathetic of ANS function?
Rest and Repose
Fiber that releases Acetylcholine of ANS?
Ganglia, cholinergic
Fiber that releases Norepinephrine of ANS?
Effectors of ANS, adrenergic
Sympathetic and Parasympathetic functions of the following organs/Tissues
- Iris
- Tears
- Salivary Glands
- Blood to Muscles
- Heart Rate
- Blood to Digestive
Organ/Tissue Sympathetic Parasympathetic
Iris Dilation Constriction
Tears None Tears Flow
Salivary Glands Slows Increases
Blood to M Increases None
Heart Rate Increases Decreases
Blood to D Decreases None
3 components of sensory unit
Receptor, Neural Pathway, Interpreting Center
Categories of Receptors?
Mechanoreceptors Thermoreceptors Chemoreceptors Nocireceptors Photoreceptors Osmoreceptors
Adaptation
(Except Pain) If a Stimulus does not change, the impulses sent decreases
Projection
The brain makes us think a sensation is coming from an area that 1st felt the stimulus (Phantom Limb)
Touch
Free Nerve Endings
Root Hair Plexuses
Tactile Discs
Pressure
Light: Tactile/Meissiners corpuscles
Deep: Lamellated/Palinian Corpuscles
Spinothalamic Tract
Sensory Data: PNS => Primary Sensory Cortex
Corticospinal Tract
Motor Data: Frontal Motor Cortex => Muscles
Types of Proprioceptors and Functions
Tendon Receptors: Tension
Muscle Spindles: Tension and Stretch
Joint Receptors: Joint Position
Papillae
Bumps on tongue
5 categories of taste
Sweet, Sour, Salty, Bitter, Umami
