Nervous System Flashcards
What are the 2 major components of the nervous system?
central nervous system (CNS)
peripheral nervous system (PNS)
What makes up the CNS?
the brain and spinal cord
What are the 2 types of components of the PNS?
sensory components
motor components
What is included in the sensory components of the PNS?
sensory ganglia and nerves
sensory receptors
What type of stimuli affect the sensory components of the PNS?
internal and external stimuli
What type of neurons are involved in the sensory component of the PNS?
afferent neurons
What are the 2 categories of motor components of the PNS?
somatic
visceral (aka autonomic)
What is involved in the somatic motor components of the PNS?
motor nerves
What do motor nerves of the PNS effect?
skeletal muscle movement
What is involved in the visceral motor components of the PNS?
autonomic ganglia and nerves
What do the visceral motor components of the PNS effect?
effectors:
smooth muscle, cardiac muscle and glands
What type of neurons are involved in the motor component of the PNS?
efferent neurons
What are the 2 major types of neurons in the PNS? what do they do, broadly?
afferent neurons sense changes to internal and external environment
efferent neurons receive signals to cause effects on the motor components
Describe the organization of the nervous system (direction of signaling and components)
in the PNS, afferent neurons sense a change to the internal/external environment and signal to the sensory components (sensory ganglia and nerves, sensory receptors) which send a signal to the CNS (brain and spinal cord)
the brain and spinal cord send signals to the motor components of the PNS (somatic motor nerves and visceral autonomic ganglia and nerves)
the motor components of the PNS send signals to the effectors (skeletal muscles, smooth muscles, cardiac muscles, and glands) via efferent neurons
What is grouped together to make the PNS?
the afferent and efferent divisions
What is grouped together to make the CNS?
the integrating centers (brain and spinal cord)
What is the overall function of the afferent division of the PNS?
to send signals from the PNS to the CNS
What happens when a signal is received from the afferent division of the PNS by the CNS?
the brain and spinal cord integrate the signal and send messages to the efferent division of the PNS which has different effects on the body
What type of movement does the somatic nervous system component of the efferent division of the PNS cause?
voluntary movement of the skeletal muscle
What type of movement does the visceral/autonomic nervous system component of the efferent division of the PNS cause?
involuntary movement of smooth and cardiac muscles, and has effects on glands
What is the enteric nervous system?
it’s associated with the gut and is regulated separately
This basic organization of the nervous system is based on animals with what type of symmetry?
bilateral
Which animals are an exception to this organization of the nervous system into afferent sensory, integrating, and efferent motor divisions?
cnidarians (ex. sea anemones and jellyfish)
Describe the Cnidarian nervous system
it’s one interconnected nerve net
neurons are distributed throughout the body and are not specialized into different divisions like the afferent sensory, integrating, or efferent motor
neurons can have APs in both directions because they’re not specific
complex behaviours are still observed