DP#1 The Central and Peripheral Nervous System Flashcards
Central Nervous System
The brain and the spinal cord; processes and coordinates responses to sensory stimuli.
Identify the two components of the central nervous system (CNS)?
The two components of the central nervous system are the brain and the spinal cord.
Use and example to explain the two main functions of the CNS?
Touching a hot stove (sensory input) causes the CNS to signal muscles in the arm to withdraw (motor output).
How does the brain communicate with the body?
The brain communicates with the body through the spinal cord and nerves to the muscles and organs.
Describe the structure of the spinal cord?
The spinal cord is a 45-centimetere long extension of the brain stem. It is composed of nerve fibers and is directly linked to the peripheral nervous system by 31 pairs of spinal nerves.
Explain the difference between the afferent and efferent pathways that the spinal nerves are connected to.
Afferent-ascending caries out sensory information gathered by our five senses to the brain whereas efferent carries motor commands from the CNS to the skeletal muscles.
Use and example to explain the two roles of the spinal cord
Touching a hot stove sends pain signals from the hand up the spinal cord to the brain. The spinal cord initiates quick, involuntary action like pulling the hand away before the pain signal even reaches the brain.
What is a spinal reflex?
An involuntary and unconscious response to a stimulus involving the spinal cord, which occurs without input from the brain.
What is sensory receptors?
Sensory neurons are a sensory nerve ending that produces an afferent or sensory impulse when stimulated.
What is a sensory neuron?
A nerve cell that carries sensory signals throughout the nervous system.
What is the interneuron?
A nerve cell in the spinal cord that connects motor and sensory neurons by relaying information between the two.
What are the motor neurons?
A nerve cell that transmits motor impulses from the spinal cord to the skeletal and smooth muscles.
Why is a spinal reflex considered to be an unconscious response?
A spinal reflex is an involuntary and unconscious response to a stimulus involving the spinal cord and occurs without input from the brain. Therefore, spinal reflexes occur without conscious awareness.
Explain the role of sensory receptors in the spinal reflex
Sensory stimulus is detected by the sensory receptors.
Explain the role of sensory neurons in a spinal reflex
Sensory neurons transmit the sensory information about the stimulus towards the spinal cord.
Explain the role of interneurons in the spinal reflex
In the case of the spinal reflex, an adaptive motor response is initiated by the interneurons without input from the brain to respond more quickly to the threat detected by the sensory receptors.
Explain the role of motor neurons in a spinal reflex
Information about the motor movement is then relayed to the motor neurons, which transmit the motor impulses from the spinal cord to the skeletal and/or visceral muscles.
