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.
Soma
The body of the neuron, contains the nucleus and the genetic material
Dendrites
An extension of a neuron that detects and receives information from other neurons
Myelin sheath
The white, fatty tissues that encase the axons and aids in the speed of transmission
Excitory Neurotransmitters
A neurotransmitter which increase the likelihood of the post synaptic neuron firing neural messages
- Glutamate (essential for memory and learning)
Inhibitory Neurotransmitters
A neurotransmitter function which decreases the likelihood of the post synaptic neuron from neural messages firing
- GABA
Neurotransmitters
are chemicals produced by the body, which had a role in the communication between post and pre synaptic neurons
- have a chemically distinct shape which binds perfectly to the chemically distinct receptor sites
Post synaptic neuron
- dendrite
- receives neurotransmitter from the axon terminals
Pre synaptic neuron
- Axon terminals
- transmits neurotransmitters to the following dendrites of the following cell
Lock and Key Process
When released into the synaptic gap, the chemically distinct neurotransmitter will bind to the perfect - shaped receptors site
Neurotransmitter = key
Receptor Site = lock
Dopamine
- A type of neurotransmitter
- Allows us to be alert, motivated and aware
- People with Parkinsons disease, the dopamine neurotransmitter levels drop in the neurons
Chronic Stress
Long lived
Increased arousal
Affects our H&W
Acute Stress
- Short lived
- High arousal
- Recovers quickly
Neurodegenerate Disease
A disease involving the lose of function of neurons in the brain over time
Parkinsons Disease
Parkinsons disease is a CNS neurodegenerate disorder characterised by motor and non motor symptoms.
It is the neurodegeneration of the production of dopamine produced by neurons in the substantia nigra (in the mid brain)
Daily Pressure
The numerous, small stressor that comes up as part of day to day life
Life Events
Stressors that force a person to change something about there lifestyle in order to cope with new curcumstances
Acculturative Stress
A source of stress caused by the challenges that arise with moving to a new or foreign culture
Major Stress
A form of stress that causes trauma and distress. They are often preventing the psychological and physiological wellbeing
Catastrope
Large scale, major upheavals that affect an interconnected population
Three main functions of the Spinal Cord
- Recieve sensory information from the body (via the peripheral NS) and send these messages to the brain for processing
- Receives motor information from the brain and sends it to relevant parts of the body like the skeletal muscle so that appropriate actions can be taken.
- Spinal reflex
Pathway of neural travel
- Information always travels in one direction through a neuron
- It is recieved by dendrites, passes through the soma and exits from the axon
- When it reaches the axon terminals, it stimulates the release of neurotransmitter from terminal buttons
- Neurotransmitter will carry messages to the next neuron in chemical form
Cortisol
Cortisol energises the body, increasing energy supplies (blood sugar, enhancing metabolism)
High levels or cortisol over a prolonged period of time leads to impaired immune system function and increased vulnerability to disease
Adrenaline
Circulates through the bloodstreambtobactivate the various body organs
Reuptake
Neurotransmitters that do not bind to the receptor sites in the post synaptic neuron which are then absorbed back into terminal buttons on the presynaptic neuron
Parkinsons Disease
A CNS neurodegenerate disorder characterised by both motor and non motor symptoms.
It is caused by the degeneration of dopamine producing neurons in the substantia nigra
GAS
Stage 1 - Alarm reaction
Stage 2 - Resistance
Stage 3 - Exhaustion
Parkinsons Disease example
Motor:
- tremors (uncontrollable shaking)
- difficulty balancing
- stooped posture
- slowed voluntary movements
Non motor
- Fatigue
- Decrease sense of smell and taste
- Constipation
- Increased sensitivity to temperature
Dopamine
Carries messages that allow for smooth, coordinated function of bodys muscles, organs and movement
Alarm Reaction
When the individual first becomes aware of the stressor
The body goes into temporary state of shock and the ability to deal with the stressor is decrease. The body acts as if it was injured with blood pressure and body temp dropping
The body then goes into countershock in which the sympathetic NS is activated and the resistance to the stressor increases and the F/F/F response is activated (adrenaline is released)
Resistance
If the stressor isn’t dealt with and the state of stress continues, the body’s ability to deal with the stressor rises above normal and cortisol is release to help the body deal with the stressor.
Exhaustion
If the stressor isn’t removed, the body becomes exhausted and the ability to deal with the stressor decreases. Since the individual is dealing with the stressor for a prolonged period of time, its resources have been depleted and its resistance to serious illness is weak
Psychological factors that influence how we respond to a stressor
- attitudes
- motivation
- personality characteristics
- coping strategies
Transaction Model
- it is subjective
- involves the encounter between an individual and the environment
- depends on a person’s interpretation of the stressor as well as there ability to cope with it
Primary Appraisal
Assess the situation and judge its significance
Stressful
- harm/loss
- threat
- challenge
Not stressful
- beign
- irrelevant
- positive
Secondary Appraisal
Assess the resources available to deal with the demands
Internal resources- personality, character, strength and determination
External recourses - money and support from family and friends
