Week #6 - Nervous System Flashcards
Outline the primary functions of the nervous system to include the coordination of movement.
The primary functions of the nervous system is to transmit information from the senses to the central nervous system, process sensory information and transmit messages to the effectors, and to work with the muscular system to coordinate movement.
*Describe a neuron as the basic functional unit of the nervous system at the cellular level.
Neurons are specialized nerve cells that are the basic cellular unit of the nervous system that transmits nerve impulses from the sensory organs to the central nervous system in order to initiate a proper reaction to a given stimuli.
Dendrites
highly branched extensions that receive signals from other neurons or receptors. They conduct and transmit electrical messages to the neuron cell body for the cell to function.
Cell body
the cell body, or soma, houses the organelles of the neuron and performs most of the cells metabolic processes.
Axon
a long, slender projection of a nerve cell, or neuron, that typically conducts electrical impulses away from the neuron’s cell body.
Myelin sheath
a fatty substance that insulates a neurons axon and increases the speed at which electrical impulses propagate along the myelinated fiber.
Compare and contrast the location, structure and function of the three main types of neurons.
Afferent (sensory) neurons
Location: sensory organs
Structure: cell body in the center, axons diverge into two branches and dendrites on both ends.
Function: are associated with the 5 senses and are
part of the PNS. They transmit electrical signals from a sensory receptor to the CNS.
Interneurons
Location: within the grey matter of the central nervous system
Structure: Most complex dendrite branching struture, dendrites and axon converge from the soma.
Function: Integrates sensory and motor output and performs neuronal oscillations and neurogenesis.
Efferent (motor) neurons
Location: effector organs
Structure: Dendrites and axon diverge from the soma
Function: transmit electrical
signals from the CNS to effectors in order to bring about a response to a stimulus.
central nervous system
Processing of information takes place in simple clusters of neurons called ganglia or a more complex organization of neurons called a brain. Consists of the brain and spinal cord containing grey matter and white matter.
peripheral nervous system
Consists of the afferent and efferent neurons and transmits information to and away from the central nervous system. It coordinates responses to stimuli, movement and regulates the internal environment.
sensory (afferent) nervous system
transmit sensory information to the CNS.
motor (efferent) nervous system
transmit information away from the CNS.
somatic nervous system
voluntary movement of the muscles and organs and reflex movements.
sympathetic nervous system
The sympathetic system promotes arousal and energy generation (‘fight-or-flight’ response).
parasympathetic nervous system
The parasympathetic system is antagonistic to the
sympathetic system. It promotes ‘calming’ and a return to ‘rest and digest’ functions.
Describe the sequence of events involved in a reflex response (including synapses). Explain the
significance of such responses to survival.
A stimulus is first detected in the dendrites of a sensory neuron and triggers an electrical response that is transmitted through the axon terminal of the sensory neuron into the interneuron situated in grey matter within the spinal cord. The neurotransmitters are transferred via small encapsulated vesicles to the interneuron for information processing. They then continue through the axon of the interneuron, passing through the synaptic cleft, and entering through the ion channels of the succeeding motor neuron. It continues to a muscle of the body and stimulates a muscular contraction in reaction to the given stimuli.
