Biol 105 Mammalian Nervous System Notes

Ch 45: The Mammalian Nervous System – Structure and Higher Function

45.1 Functions are Localized in the Nervous System

 Vertebrate nervous systems

o Central nervous system (CNS): brain and spinal cord

o Peripheral nervous system (PNS): nerves that connect the CNS to
all tissues and sensors of the body

o Enteric nervous system: in the gut

 Neuron: a nerve cell

 Nerve: bundle of axons in the PNS that carries information.

o In one nerve, some axons may be carrying information to the CNS
while others are carrying information from the CNS to the body’s
organs.




 Peripheral nervous system:

o Afferent portion carries information from sensory receptor cells to the
CNS.

o Efferent portion carries information from the CNS to muscles and
glands.

o Both have conscious and unconscious divisions

,  The CNS develops from the neural tube of an embryo.

 The anterior part develops into the hindbrain, midbrain, and forebrain.

 The rest becomes the spinal cord.

 Information flow in the adult nervous system will follow paths that emerge
from the linear neural tube

 Midbrain: develops structures that integrate information from the senses and
coordinate motor responses.

 Hindbrain: becomes the medulla, pons, and cerebellum.

o Medulla and pons control physiological functions, such as breathing

 Midbrain, medulla, and pons make up the brainstem.

o All information traveling between the spinal cord and higher brain
areas must pass through the brainstem.

 The cerebellum coordinates muscle activity and maintains balance