chapter 2 Flashcards
central nervous system
brain and spinal cord
the brain
brain receives and processes information from the rest of
the body and generates responses to it.
the spinal cord
cable of nerve fibres stretching from the base of the brain to the lower back.
receives sensory information from the PNS and transmits it up to the brain along the ascending tracts for processing and interpretation. Motor information from the brain is by the descending tracts carried to our muscles, organs and glands so they can react.
divisions of the Peripheral Nervous System (PNS)
consists of all the nerves outside the CNS. Consists of the somatic and autonomic nervous system.
Role of The Peripheral Nervous System
convey sensory information from the body’s internal and external environments to the CNS and transmit motor commands from the CNS to the rest of the body.
ascending tracts
sensory information from the PNS is transmitted up the spinal cord to the brain
descending tracts
carries motor information from the brain back to
the PNS
Somatic Nervous System
the subdivision of the PNS that is responsible for sensing stimuli and controlling voluntary responses.
sensory neurons receive sensory information from receptor cells located around the body. and transmits this information to the CNS. the motor neurons receive commands from the CNS and the information is transferred to the skeletal muscles to enable appropriate responses.
sensory neurons
Specialised afferent neurons located in sense organs that detect and respond to information from the environment and transmit it to the central nervous system
motor neurons
receive commands from the CNS and then the information is transferred to the skeletal muscles located throughout the body
divisions of the autonomic nervous system (ANS)
the sympathetic nervous system, the parasympathetic nervous
system and the enteric nervous system
role of the Autonomic Nervous System
automatically controls our internal organs and glands
Sympathetic Nervous System
dominates when we experience
heightened emotions, during times of vigorous physical activity, or when we perceive a threat.
parasympathetic nervous system
calms and lowers arousal levels, maintains a level of homeostasis. maintains heart rate breathing rate and blood pressure. once high arousal is over the parasympathetic nervous system dominates
SAME
Sensory nerves are Afferent, Motor nerves are Efferent
enteric nervous system (ENS)
controls the activity of the digestive system
conscious response
occur in response to sensory stimuli that involves awareness. eg walking
spinal reflex
occurs automatically and only involve the spinal cord and the somatic nervous system (operate independently from the brain). they are quick responses essential for survival. involve an interneuron making a connection between a sensory neuron and a motor neuron
unconscious response
sensory stimuli is received by the brain and unconscious responses are controlled by the ANS. operate constantly and involuntary eg breathing and perspiration
neurons
individual nerve cells that are specialised to receive, process and transmit electrochemical information
neurotransmitters (key)
chemicals that allow neurons to communicate with each other, they are specific to the receptor site. (glutamate and GABA)
glutamate
excitatory neurotransmitter, responsible for fast transmission of neural messages, involved in cognitive functions
GABA
inhibitory neurotransmitter, calms and slows down neural transmission
Neuromodulators
a type of neurotransmitters that can affect large numbers of neurons at he same time, they have slow and far reaching effects (dopamine and serotonin)
dopamine
responsible for signalling that a reward is available, involved in motivation
serotonin
a neuromodulator that is involved in pain, sleep and mood regulation (low levels are associated with depression)
axon terminal (synaptic buttons)
the end of a pre synaptic neurons axon, containing the synaptic vesicles where neurotransmitters are released from to form a synapse with the dendrite of the postsynaptic neuron
axon
long this fibre of the neuron through which messages are transmitted, coved in myelin sheath
dendrites
the thread like branches that extend from the soma and receive signals form the presynaptic neuron
receptor site (lock)
some neurotransmitters (key) will bind to certain receptor sites (lock) on the posts synaptic neuron
synaptic vesicles
small sacs within the axon terminals of the presynaptic neurons that contain neurotransmitters, they release them into the synaptic cleft
synapse
the junction between the presynaptic and postsynaptic neuron, separated by a gap called the synaptic cleft.
agonists
drugs that are known to increase the release of certain neurotransmitters or imitate them by binding to their receptor sites and causing the postsynaptic neuron to respond the same way as it would to the neurotransmitter eg pain killer
antagonists
drugs known to either inhibit the release of neurotransmitters or block the receptor sites for these neurotransmitters
