3.1.1-5 nervous system Flashcards
nervous system
communication system of neurons between the body’s internal cells and organs and the external world
3 main functions of the nervous system
receive, process and coordinate information
central nervous system (CNS)
brain and spinal cord.
process’ and integrates information received from the body’s internal and external environments and to activate appropriate responses
brain
intricate network of neurons, organised into identifiable areas and structures that have specialised functions
spinal cord
long, thing bundle of nerve tissue that extends from the base of the brain to the lower back.
allows communication between the brain and PNS
peripheral nervous system (PNS)
entire network of nerves located outside the CNS.
carries information to and from the CNS from the body’s muscles, organs and glands and sensory organs
somatic nervous system
connected to our sensory receptors and skeletal muscles.
carries motor messages from CNS on efferent tract and sensory messages to CNS along afferent tract
sensory (afferent) neurons
carry information received by sensory receptors to CNS
motor (efferent) neurons
carry information from CNS to control voluntary movements of the skeletal muscles
autonomic nervous system
connects CNS to the body’s organs, visceral muscles and glands, without conscious effort
sympathetic nervous system
activates internal muscles, organs and glands to prepare the body for vigorous activity or to deal with a stressful or threatening situation
parasympathetic nervous system
helps to maintain the internal body environment in a steady, balanced state of normal functioning
effects of the sympathetic nervous system
dilate pupils. accelerate heartbeat. inhibit flow of saliva. dilate bronchi. inhibit bladder contraction. secretion of adrenaline and noradrenaline.
effects of the parasympathetic nervous system
stimulate flow of saliva.
slows heartbeat.
constricts bronchi.
contracts bladder
conscious response to stimuli
reaction to sensory stimulus that involves awareness.
voluntary and intentional
unconscious response to stimuli
reaction to sensory stimulus that doesn’t involves awareness.
involuntary and unintentional
reflex arc / spinal reflex
unconscious, involuntary and automatically occurring response to certain stimuli without any involvement of the brain
neuron
individual nerve cell that is specialised to receive, process and/or transmit information
synapse
communication junction between two neurons
synaptic transmission
process of neurons communicating with each other
dendrite function
detect and receive info from other neurons
axon function
transmit neural information to other neurons or cells in muscles and glands
myelin function
insulates axon and prevents interference from the activity of other nearby axons
nodes of ranvier
small unmyelinated gaps along axon
myelin
white, fatty substances surrounding axon
axon terminals function
sotres and secretes neurotransmitters and carries its chemical message to other neurons or cells
terminal button
small structure like a sac that stores neurotransmitters
neurotransmitters
chemical substances produced by a neuron that carry a message to other neurons or cells in muscles, organs or other tissue
reuptake
reabsorption of neurotransmitter that don’t bind to a receptor successfully back into the terminal button (axon terminal) by the presynaptic neuron
neurotransmitter excitatory effect
stimulate or activate postsynaptic neurons to perform their functions.
e.g. glutamate
neurotransmitter inhibitory effect
block or prevent postsynaptic neurons from firing.
e.g. GABA
glutamate (Glu)
primary excitatory neurotransmitter in CNS.
enhances information transmission.
involved in perception, thinking, movement and enhances processes of learning and memory
GABA (gama amino butyric acid)
primary inhibitory neurotransmitter in the CNS.
maintain neurotransmission at an optimal level.
without it, activation of postsynaptic neurons might get out of control.
counterbalances glutamate
lock and key process
neurotransmitter fits perfectly into receptor site
abnormal levels of serotonin leads to what
depression
abnormal levels of GABA leads to what
anxiety
abnormal levels of serotonin and dopamine leads to what
ADHD
Parkinson’s disease
progressive CNS neurodegenerative disorder characterised by both motor and non-motor symptoms, such as tremors, muscle rigidity and problems with cognitive function
causes of parkinsons disease
degeneration and loss of neurons in substantia nigra
substantia nigra
located in basil ganglia (midbrain).
role in control of voluntary muscle movements, coordination (balance, walking, talking, writing).
produces dopamine
role of dopamine
carries messages on how to control body movements
4 key motor symptoms of Parkinson’s disease
temor.
muscle rigidity.
slowness of voluntary movement (bradykinesia).
postural instability, balance problems and gait (walking) disturbances
tremor
continuous, involuntary shaking (trembling) of the body
muscle rigidity
muscles unable to relax and are tight even at rest
bradykinesia
difficulty starting new movements or stopping an ongoing movement.
decrease in fine motor coordination
postural instability, balance problems and gait (walking) disturbances
inability to maintain steady, upright posture or take corrective action to prevent a fall
non-motor symptoms of Parkinson’s disease
decrease or loss of sense of smell (anosmia), sweating and increased sensitivity to temperatures, fatigue.
problems with cognitive function
Parkinson’s disease treatment
no cure.
medications can be converted into dopamine by neurons or mimic its role
