Nervous System (without Brain) Flashcards
Sensory Impulses
- To monitor changes occurring inside and outside the body
- Changes = stimuli
Interpretation
-To process and interpret sensory input and decide if action is needed
Motor Output
- A response to integrated stimuli
- The response activates muscles or glands
Central Nervous System vs. Peripheral Nervous System
- Central nervous system (CNS)
- Brain
- Spinal cord- Peripheral nervous system (PNS)
- Nerves outside the brain and spinal cord
- Spinal nerves (31 pairs)
- Cranial nerves (12 pairs)
- Nerves outside the brain and spinal cord
- Peripheral nervous system (PNS)
Neurons
-also called nerve cells; cells of the nervous system that specialize in transmitting messages throughout the body
Functions of Neurons
- sensory (afferent) neurons
- motor (efferent) neurons
- interneurons
Sensory Afferent Neurons
-carrying two or toward the center nurse that convey impulses to the CNS from sensory receptors
Motor (Efferent)
-carrying away are from, carries impulses from the CNS to effector organs, the muscles, and glands
Interneurons
-also called association neurons, they complete the pathway between afferent and efferent neurons
Neurons (Structural)
- Classified by irritability (ability to respond to stimuli) and conductivity (ability to transmit an impulse)
- Multipolar neuron
- Bipolar neuron
- Unipolar neuron
Multipolar, BiPolar, Unipolar
- multipolar neurons: several processes extending from the neuron
- bipolar neurons: neurons that have two processes, and axon and a dendrite
- unipolar neurons: a single process emerging from the cell body
Factors that Affect Transmission
- Myelinated or unmyelinated
- Lack or excess of sodium and potassium
- amount of nodes of ranvier
- Number of poles
Reflex Arc
- Stimulus at distal end of a neuron
- Receptor
- Sensory Neuron
- Spinal cord, Integration center (Interneuron)
- Motor Neuron
- Effector
- Response
- 2 Neuron Reflex Arc
- Sensory straight to effector
- Ex: Knee-Jerking
- 2 Neuron Reflex Arc
Synapse
- Gap between the two neurons
- Makes sure that the impulse goes in the correct direction
- the region of communication between neurons, or a neuromuscular junction between a neuron and a muscle cell
Salvatore Conduction
- The Impulses Jump
- Fibers that have myelin sheaths conduct impulses much faster because the impulse leaps from node of rancher to node of ranvier along the length of the fiber
- No electrical current can flow across an axon membrane that is insulated by fatty myelin
- Fibers that have myelin sheaths conduct impulses much faster because the impulse leaps from node of rancher to node of ranvier along the length of the fiber