Lab 7: Organization of Nervous Tissue (Images)
myelin
most long nerve fibers are coated with __________, a fatty layer which insulates the axon just like the plastic over the cord of an electrical appliance
the endoneurium is an additional sheath that surrounds the
myelin sheath
oligodendrocytes
myelinate neurons, wrapping them in fatty tissue (CNS)
Schwann cells
myelinate neurons, wrapping them in fatty tissue (PNS)
mixed nerves
nerves that carry both afferent and efferent fibers are called
efferent nerves (motor)
nerves that carry information out of or AWAY from the CNS are
afferent nerves (sensory)
nerves that carry only sensory processes and conduct impulses only TOWARD the CNS are
clusters
neuron cell bodies are often found in
neuroglia greatly outnumber
neurons
microglia
phagocytic cells, remove pathogens, waste, and cellular debris
dendrites
receive incoming information and contain receptors for neurotransmitters
satellite cells
regulate nutrient, gas and neurotransmitter levels
ependymal cells
secrete and monitor cerebrospinal fluid
A- dendrite, C- axon, B- cell body, D- axon terminal, E- Schwann Cells F- myelin sheath, G- Node of Ranvier, H- Nucleus
What is the correct labeling of this diagram?
the axon terminals store neurotransmitters in tiny vesicles and release them into the synaptic cleft when
a nerve impulse reaches the terminal
Nissl bodies are
a type of rough endoplasmic reticulum involed in metabolic actions of the cell and stain very darkly in histological sections
cell body
all neurons have a _______ from which slender processes extend
peripheral nervous system (PNS)
all of the nerves in the rest of the body
epineurium
all the fascicles are bound together by a white, fibrous connective tissue sheath called the _________, which forms the cordlike nerve visible to the eye
rare neurons, typically found in the eye, ear and olfactory mucosa
bipolar
fascicles
bundles of nerve fibers
neuroglia/glial cells
cells that support and protect neurons
astrocytes
form the blood-brain barrier, controlling the chemical environment of the brain
axons (nerve fibers)
generate and conduct nerve impulses
perineurium
groups of fibers are bound by coarser connective tissue called the _______ and form fascicles
multipolar neurons
have many processes attached to the cell body most neurons in the CNS and neurons that carry impulses AWAY from the CNS are multipolar
unipolar neurons
have one short process
bipolar neurons
have two processes, one axon, and one dendrite attached to the cell body
nodes of Ranvier
in some cases (PNS) there are gaps in the myelin sheath referred to as __________
axon terminals (synaptic knobs)
the axon terminates in many small structures called ________ which form synapses or junctions with neurons or effector cells
central nervous system (CNS)
the brain and spinal cord
nerves are classified according to
the direction in which they transmit impulses
neurotransmission
the insulating layer (myelin) increases the speed of the
synaptic cleft
the junction between the axon terminal of the presynaptic cell and the dendrite of the postsynaptic cell is called the __________
multipolar neuron
the most common neuron in the body named for many branches, processes and extensions that come off of their cell bodies
neurons
the nervous system relies on the transmission of electrical impulses through specialized cells called
neuroplasm or perikaryon
the neuron cell body contains a nucleus surrounded by cytoplasm called ________
neurons are classified according to
the number of processes or projections they have coming off of their cell bodies
Nissl bodies
the perikaryon is dense with ____
dendrites axons
there are two types of neuronal processes:
nearly all neurons that conduct impulses TOWARD the CNS are
unipolar
axon hillock
where the axon joins the cell body
endoneurium
within a nerve, each fiber is surrounded by a delicate connective tissue sheath called a(n) ________, which insulates it from the other neuron processes adjacent to it
