Nervous System Flashcards
Nervous System
A communication system that consists of networks of neurons that connects the brain, spinal cord and all other parts of the body to one another via electrochemical signals.
Its role is to receive information from the sensory receptors and send the information through the sensory neurons via the afferent tracks, process the information and respond by sending a message through the motor neurons via the efferent tracks
Central Nervous System
Receives information from the peripheral nervous system, processes the information and then responds. Consists of brain and spinal cord
Brain
An intricate network of cells that plays a vital role in processing information received through neural pathways of the brain
Spinal Cord
A long, thin tube like structure that extends from the base of the brain to the lower back.
Plays a vital role in the spinal reflex
Peripheral Nervous System
Complete network of neurons outside of the central nervous system Consists of glands, organs and muscles. Carries messages to and from the brain.
Somatic Nervous System
Network of neurons within the body that transmit information to the CNS from the muscles, organs and glands (about the internal environment) and from the sensory organs (about the external environment). It also carries information to the body’s muscles, organs and glands
Sensory Neurons
Afferent, carry sensory information from internal and external environments to CNS
Motor Neurons
Efferent, carry motor commands from the CNS to muscles, glands and organs
Interneurons
it connects the motor and sensory neurons and are only found in the CNS
Autonomic Nervous System
Transmits motor messages from the brain to the body’s internal organs, glands and muscles for self regulation as well as involuntary activity.
Operates independently of the brain.
Sympathetic Nervous System
Activates internal muscles, organs and glands to prepare the body for vigorous activity or to deal with stressful or threatening situation
Parasympathetic Nervous System
Helps to maintain the internal body environment in a steady, balanced state of normal functioning in times of minimal stress and in the absence of threat
Fight/Flight/Freeze Response
Involuntary reaction resulting in a state of physiological readiness to deal with an acute stressor or immediate threat
Parasympathetic Examples
- Constricts pupils
- Heart beat at a rate for optimal functioning
- Digestion regulates to allow for eating
- Blood flow is evenly distributed around the body
Sympathetic Examples
- Dilation of pupils to allow more light in
- Heart rate increases to pump blood around the body and oxygen to the head
- Digestion is inhibited to allow more essential bodily functions needed during intense activity
- Blood flow increase to allow for more essential bodily functioning needed during activity
Concious response
Concious response in terms of awareness, voluntary, purposefully or controlled includes: talking, walking, waving your hand.
Concious/ voluntary response usually branch from the somatic section of the peripheral nervous system.
Unconscious Response
Unconscious response in terms of awareness includes breathing and stomach contractions. The unconscious/ involuntary response usually branches from the central nervous system of the peripheral nervous system
Neural Communication
- Neural communication is an electrochemical process. It uses both electrical and chemical energy
- Neurons do not move, they communicate messages
Spinal Reflex (definition)
The spinal reflex is an involuntary, unconscious occuring response to certain stimuli that is perceived as threat, 1that occurs without any involvement of the brain.
The transmission of information from the spinal cord to the brain only takes a fraction of a second. It is important in terms of minimising harm and saving the life of an organism
Spinal Reflex (Steps)
- The sensation of a sensory stimulus is detected by the body’s sensory receptors, which send a signal via sensory neurons to the spinal cord.
- The spinal cord, via interneurons, immediately relays a signal via motor neurons to initiate an automatic/unconscious motor response in the skeletal muscles to the sensory stimulus.
- As the motor neurons send messages to tell the body to respond unconsciously, sensory neurons send their neural impulses to the brain to make it aware of any pain or sensation. The brain’s conscious awareness is not necessary for the reflex response, but the brain will register the sensations independently and after the reflex response has occurred.
Axon
A single tube like structure that transmits neural information from the dendrites to the axon terminals. Usually surrounded by a white fatty substance called myelin
Axon Terminals
Small branches at the end of an axon with terminal buttons which secrete neurotransmitters into the synaptic gap.