CVM 711 Lecture 5: Organization of the Nervous System

Receive sensory information, Integrate and interpret information, Generate appropriate motor responses, and Maintain homeostasis 

Functions of the nervous system

What is the function unit of the nervous system?

Neurons

What part of the neuron receives information?

Dendrites

What part of the neuron performs metabolic functions?

Soma (cell body)

What part of the neuron conducts action potentials?

Axon

What part of the neuron communicates with target cells?

Axon (synaptic) terminals

What produces myelin, supports neuronal metabolism, maintains extracellular ion balance, removes neurotransmitters, participates in immune defense, and supports synaptic function?

Glial cells

Which nervous type cell generates action potentials?

Neurons

Which nervous type cell supports neuronal function?

Glial cells

What are the two major divisions of the nervous systems?

Central Nervous System and Peripheral Nervous System

What contains sensory, motor, and integrative functions (acts as the processing center)?

CNS

What does the CNS include?

Brain and spinal cord

What protects the brain?

Skull

What protects the spinal cord?

Vertebrae

What part of the nervous system is the communication network?

PNS

What are the parts of the PNS?

Autonomic Nervous System and Somatic Nervous System

What are the parts of the autonomic nervous system?

Sympathetic nervous system and parasympathetic nervous system

What are the parts of the somatic nervous system?

Sensory and motor

What is the peripheral nervous system composed of?

Spinal and cranial nerves

Are afferent axons sensory or motor?

Sensory

Are efferent axons sensory or motor?

Motor

What direction do afferent (sensory) axons run?

Towards CNS

What direction do efferent (motor) axons run?

Away from CNS

What cells are sensory (afferent) and somatic (outer/voluntary)?

Skin and muscles

What cells are sensory (afferent) and visceral (inner/involuntary)?

Thoracic and abdominal organs

What cells are motor (efferent) and somatic (outer/voluntary)?

Skeletal muscle

What cells are motor (efferent) and visceral (inner/involuntary)?

Smooth muscle, cardiac muscle, and glands

Peripheral nerve axons converge to form _____ spinal nerve at each intervertebral foramina

single

How do afferent sensory axons enter the spinal cord?

Dorsal roots

How do efferent motor axons exit the spinal cord?

Ventral roots

What part of the CNS receives sensory info and supplies motor output?

Spinal cord

What are the two sections of the brain?

Brainstem and forebrain

What are the five major brain regions from caudal to rostral?

Medulla, pons, midbrain, diencephalon, and telencephalon

What makes up the brainstem (from caudal to rostral)?

Medulla, pons, midbrain

What makes up the forebrain (from caudal to rostral)?

Diencephalon, telencephalon

Relays sensory information to the brainstem

Spinal cord

Relays sensory information to the forebrain, relays motor commands between forebrain and spinal cord

Brainstem

Sophisticated information processing, can by-pass brainstem and send motor commands directly to spinal cord

Forebrain (cerebrum)

• Sensory dorsal root axons carry action potentials originating in skin, muscles, tendons, joints, and visceral organs to spinal cord

• Contains cell bodies and dendrites of motor neurons whose axons exit ventral roots to travel to smooth or skeletal muscle

• Contains tracts of axons carrying sensory info to brain and motor commands from brain to motor neurons

• Can control muscle stretch reflexes and limb withdrawal from painful stimuli

Spinal cord