1. Introduction to the Nervous System Flashcards
The nervous system
a communication and control network that allows an organism to interact with its environment
General functions of nervous system
Sensory detection, information processing, and the expression of behaviour
Central nervous system (CNS)
Brain and spinal cord
Peripheral nervous system (PNS)
Afferent/sensory division and efferent/motor division
Afferent division
The sensory system, generates input to the CNS
Efferent division
Receives output from CNS, to the somatic nervous system and autonomous nervous system.
Somatic motor system
Efferent division of PNS that stimulates skeletal muscle activity
Autonomic nervous system
Efferent division of the PNS that includes the sympathetic division, parasympathetic division, and enteric nervous system.
Enteric nervous system stimulates…
Intestinal muscle wall, mucosa
Sympathetic division stimulates…
Smooth and cardiac muscle, glands
Parasympathetic division stimulates…
Smooth and cardiac muscle, glands
Components of the Nervous System
neurons, neuroglial cells, blood vessels, connective tissues
Soma
Factory of the neuron
Dendrite
Input transmission of neuron
Axon
Output transmission of neuron
Nissl bodies
A Nissl body is a large granular body found in neurons. These granules are of rough endoplasmic reticulum (RER) with rosettes of free ribosomes, and are the site of protein synthesis.
Predominate neuron shape in invertebrates
Unipolar
Predominate neuron shape in vertebrates
Multipolar
Bipolar neuron example
Dorsal root ganglia cells
Pseudounipolar neuron example
Retinal cells, olfactory epithelium cells (unmyelinated, no dendrites)
Multipolar neuron example
Interneurons, motor neurons
Traditional senses
Sight, hearing, smell, taste touch
Non-traditional senses
Nociception (tissue damage), equilibrioception (balance, coordinate movements), proprioception (know the body parts and positioning), and thermoception (temperature changes)
What do sensory receptors do?
Convert a stimulus into neuronal activity
What type of neurons constitute 90% of all neurons?
Interneurons
What type of neurons constitute 9% of all neurons?
Motor neurons
What type of neurons constitute 0.9% of all neurons?
Sensory neurons
Sensory neurons
Afferent neurons
Bipolar
Sense detection by sensory receptors on receptor cell, transmitted down myelinated axon
Motor neurons
Efferent neurons
Multipolar
Initial signal recieved by dendrites
Axon terminals act on muscles at neuromuscular synapse
Interneuron
Association neuron
Multipolar
Cell body, dendrites, axon terminals
Unmyelinated
Why does shingles (caused by herpes zoster) affect the skin after many years latency?
Reactivated herpes zoster is transported along the sensory axons to the skin.
What’s the consequence of interruption? Such as cancer drugs
Neurodegeneration
Fast axonal transport
Membrane-bound organelles and mitochondria
Slow axonal transport
Proteins
Anterograde axonal transport
From the soma toward the axonal terminals, kinesin
Retrograde axonal transport
From the axonal terminals toward the soma, dynein
Axonal transport depends on what? Describe the mechanism of this.
The movement of transport filaments. This requires energy supplied by glucose. Mitochondria controls the level of cations in the axoplasm by supplying ATP to the ion pumps. An important cation for axonal transport is Ca2+. Transport filaments move along the cytoskeleton (microtubules [M] or neurofilaments [NF]) by means of cross-bridges. Transported components attach to the transport filaments. CaBP, Ca2+-binding protein; NF, neurofilaments.
Role of supportive matrix of the CNS
Provides local environment suitable for neurons to function
What are the components of the local environment?
Neuroglia, CNS circulation, the blood-brain barrier (BBB), the cerebrospinal fluid (CSF)
What are the major roles of the supportive matrix in neurotransmission?
Taking up neurotransmitters; providing myeline sheaths
Neuroglia in the CNS
Astrocytes, oligodendroglia, microglia, ependymal cells
Astrocytes
Structural support, metabolic support; neurotransmiitter uptake and release; ion homeostasis; nervous system repair; synaptic plasticity.
Oligodendroglia
Myelination
Microglia
Immune defense