Chapter 3 - Anatomy of the Nervous System Flashcards
(91 cards)
central nervous system (CNS)
division of the nervous system located within the skull and the spine; composed of two divisions –> the brain (skull) and the spinal cord (located in the spine)
peripheral nervous system (PNS)
division located outside the skull and the spine,
composed of two divisions: somatic nervous system (SNS) and automatic nervous system (ANS)
afferent nerves
carry sensory signals from the skin, skeletal muscles, joints, eyes, ear to the CNS
efferent nerves
carry motor signals from the CNS to the skeletal muscles
somatic nervous system (SNS)
part of the PNS that interacts with the external environment, composed of the afferent nerves and the efferent nerves
automatic nervous system (ANS)
part of the PNS that regulates the body’s internal environment
sympathetic nerves
automatic motor nerves that project from the CNS in the lumbar (small back) and the thoracic (chest area) regions of the spinal chord
parasympathetic nerves
automatic motor nerves that project from the brain and sacral (lower back) region of the spinal chord
cranial nerves
12 pairs of nerves extending from the brain (optic nerves, olfactory nerves, and vague nerves)
meninges
three protective membranes that cover the brain and the spinal cord
dura mater
outer meninx, though membrane
arachnoid membrane (spider web membrane)
immediately inside the dura mater
subarachnoid space
beneath the arachnoid membrane, contains many large blood vessels and cerebrospinal fluid
pia mater
innermost meninx, really delicate, adheres o the surface of the CNS
cerebrospinal fluid (CSF)
protects the CNS, fills the subarachnoid space, the central Canal of the spinal cord and the cerebral ventricles of the brain
central canal:
small central channel that runs the length of the spinal cord
cerebral ventricals
four large internal chambers of the brain: two lateral ventricles, the third ventricle and the fourth one
choroid plexuses
network of capillaries or small blood vessels that protrude into the ventricles from the Pia mater; produces CSF, the excess CSF is continuously absorbed from the subarachnoid space into large blood-filled spaces or dural sinuses
blood-brain barrier
a mechanism that impedes the passage of many toxic substances from the blood into the brain
neurons
cells that are specialized for reception, conduction and transmission of electrochemical signals; they come in an incredible variety of shapes and sizes
Neuron cell membrane
composed of a lipid bilayer, or two layers of fat molecules
external features of a neuron
cell body, myelin, cell membrane, dendrites, axon hillock, axon, nodes of ranvier, buttons, synapses
dendrites
the short processes emanating from the cell body, which receive most of the synaptic contacts from other neurons
axon hillock
the cone shaped region at the junction between the axon and the cell body