Nervous System Flashcards
Central nervous system
- transmits motor info to PNS
- receives and processes sensory info from internal and external environment
- consists of motor neurons and interneurons
Brain (CNS)
- processes sensory information and coordinates response
- involved in: decision making, learning, feeling, memory
Sensory neurons
- afferent
- receives sensory information
- transmits info to CNS
- receptors
Neural transmission
Motor neurons
- efferent
- effectors
- transmits messages from CNS to organs, muscles, glands
Interneurons
- only in CNS
- links sensory neurons with CNS then to motor neurons
How the neuron receives messages
- dendrite receives info in form of a chemical message (neurochemical)
- soma sends a message in form of electrical signal
- electrical signal travels down axon
- when signal reaches axon terminals, triggers release of neurochemical
- terminal buttons release neurochemical
Spinal cord (CNS)
long thin bundle of nerve fibres from base of brain to lower back
- ascending tracts transmit sensory info to brain
- descending tracts transmit motor info from brain to organs, muscles, glands
Peripheral NS
network of neurons located outside of CNS
- consists of sensory and motor neurons
- carries info from sensory organs and internal organs to CNS
- transmits info from CNS to organs, muscles, glands
Somatic NS (PNS)
- voluntary movement of skeletal muscles
- transmits sensory info from sensory receptors to CNS
- conscious control
SNS detects sensation and coordinates response ie. picking up cat when he rubs against your leg
Autonomic NS (PNS)
- regulates activity of organs, visceral muscles, glands
- no conscious control
ie. heart rate, breathing
Sympathetic NS (ANS)
- activates internal muscles, organs and glands to prepare body for vigorous activity or to deal with stress/ threatened
- fight, flight response
- arouses/ energises body
- enhances survival
Physiological responses of sympathetic NS
- pupils dilate
- increased heart rate and breathing
- slows digestion
- relaxes bladder
- salivary glands inhibit
Parasympathetic NS (ANS)
- counterbalances effect of SNS
- maintains homeostasis
- more dominant
- calms body and conserves energy
- freeze response
Physiological responses of parasympathetic NS
- pupils constrict
- heart rate and breathing slows
- digestion stimulates
- salivary glands stimulate
Conscious responses
- communication between brain and somatic NS
- goal directed
- awareness
- voluntary
- controlled