the body and send this information to the Neuroglia, also known as glial cells, act as the
CNS. “helper” cells of the nervous system. Each
Efferent nerves in the PNS carry signals neuron in the body is surrounded by anywhere
from the control center to the muscles, from 6 to 60 neuroglia that protect, feed, and
glands, and organs to regulate their insulate the neuron.
The brain, a soft, wrinkled organ that
weighs about 1.36 kg, is located inside the
cranial cavity, where the bones of the skull
The majority of the nervous system is tissue surround and protect it.
made up of two classes of cells: neurons and The approximately 100 billion neurons of
neuroglia. the brain form the main control center of
Neurons, also known as nerve cells, The brain and spinal cord together form
communicate within the body by transmitting the central nervous system (CNS), where
electrochemical signals. Neurons look quite information is processed and responses
different from other cells in the body due to originate.
the many long cellular processes that extend
The brain, the seat of higher mental
from their central cell body. There are 3 basic
functions such as consciousness, memory,
types of neurons,
planning, and voluntary actions, also
Afferent neurons. Also known as sensory controls lower body functions such as the
neurons, afferent neurons transmit sensory maintenance of respiration, heart rate,
signals to the central nervous system from blood pressure, and digestion.
receptors in the body.
Efferent neurons. Also known as motor
It is a long, thin mass of bundled neurons
neurons, efferent neurons transmit signals
that carries information through the
from the central nervous system to effectors in
vertebral cavity of the spine beginning at
the body such as muscles and glands.
the medulla oblongata of the brain on its
Interneurons. Interneurons form complex superior end and continuing inferiorly to
networks within the central nervous system to the lumbar region of the spine.
integrate the information received from It is around 45 cm (18 in) in men and
afferent neurons and to direct the function of around 43 cm (17 in) long in women.
the body through efferent neurons. In the lumbar region, the spinal cord
separates into a bundle of individual
nerves called the cauda equina (due to its