Ch. 9&10 - Nerve Tissue & Muscle Tissue Flashcards
Nerve tissue
Made up of neurons and glial cells
Neuron
Very Labile nerve cells
No CT, rely on glial cells
Glial cells
Cells of the nervous tissue that support the neurons
Aka neuroglia
~90% of the cell population
Maintain the nervous system
Support neurons physically and metabolically
Homeostatically maintain the environment around neuron so they aren’t affected by sudden changes
Secrete neurosteroids that act locally
Astrocytes
Glial cells found in the CNS
Regulate movement between the CNS and the blood
Anatomically and physiologically protect the blood-brain barrier
Derived from the ectoderm
Oligodendrocytes
Glial cells found in the CNS that lay down the myelin onto axons
Derived from the ectoderm
Ependymal cells
Glial cells found in the CNS that line the brain ventricles ad the central canal of the spinal cord
Some have cilia that are used for movement of CSF
Derived from the ectoderm
Microglia
Ag-presenting glial cells found in the gray and white matter of the CNS
Highly phagocytic immune cells of the CNS
Only glial cells that are derived from the mesoderm
Schwann cells
Glial cells found in the PNS
Deposit myelin onto axons
Derived from the ectoderm
What are the five types of glial cells?
Astrocytes, oligodendrocytes, ependymal cells, microglia, and Schwann cells
Nervous system
Deciphers, analyzes, and integrates information
Regulates and controls output and therefore behavior
Bp regulation, pH, glucose levels, etc.
Perikaryon
Area surrounding the nucleus
Don’t use interchangeably with the word “cyton”
Cyton
Cell body of a neuron
Nissl bodies/substance
Very basic ribonuclear proteins found in the cytoplasm of the neuron
Myelin
Schwann cells (PNS) or oligodendrocytes (CNS) wrapped around the axon of a neuron at regular intervals Provides insulation and saltatory conduction
Saltatory conduction
Nerve impulses jump form node to node
Neurons can be classified based on _______ and _______.
structure; function
Classification of neurons based on structure is based on what?
The number of processes coming off of the cell
Unipolar/pseudounipolar, bipolar, multipolar
Unipolar/Pseudounipolar neuron
Have only one process
Sensory neurons
Bipolar neuron
Have two processes
Found in the retina of the eye and the olfactory region of the nose
Rarest of the three types of neurons based on structure
Multipolar neuron
Many processes
Motor neuron
Classification of neurons based on function is based on what?
How the impulse is transmitted
Neurons are _______ cells that exhibit a change in membrane _______ upon stimuli.
excitable; potential
Action potential
Quick depolarization and depolarization of a cell
CNS
Central nervous system
Consists of the brain and spinal cord, which are continuous with one another
Consists of white matter and gray matter
White matter
Makes up tracts of the CNS
Also has glial cells
Tracts
Collection/aggregation/bundle of axons in the CNS
Made up of white matter
Ascending and descending tracts
Ascending tract
Afferent, sensory tracts of the CNS
Carry impulses up from the brain to the spinal cord
Descending tract
Efferent, motor tracts of the CNS
Carry impulses down from the spinal cord to the brain
Gray matter
Made up of cell bodies of motor neurons, interneurons, glial cells, and axons of sensory fibers
CNS
Ganglion
Aggregation/collection of cell bodies located in the PNS
Nerve
Bundle of axons in the PNS
Analagous to a tract in the CNS
Mixed nerve
Nerve made up of both sensory and motor fibers
Dorsal root ganglion
True CT structure in the PNS
Fasciculus
Bundle of axons
Perineurium
True CT that separates fascuculi
Nucleus
Cluster of nerve cell bodies
No CT encapsulation
Equivalent CNS structure to ganglion in PNS
Nerves are found in the _______ and tracts are found in the _______.
PNS; CNS
A nucleus is found in the _______ and a ganglion is found in the _______.
CNS; PNS
Meninges
Singular form is menyx
Fibrous CT surrounding and protecting the spinal cord and brain
Dura mata, arachnoid, and pia mata
Pia mata
Innermost menyx
Thinnest layer of CT covered with simple squamous epithelium
there is a very thin layer of glial cells between the pia mata and the spinal cord, so there isn’t direct contact between the two
Subarachnoid space
Space between the pia mata and the arachnoid
Contains CSF
Arachnoid
Thinner layer of fibrous CT encapsulated with simple squamous epithelium
Has anchoring projections called arachnoid trabeculae that are continuous with the pia mata
Subdural space
Space between the arachnoid and the dura mata
Dura mata
Thick external menyx
Consists of dense, fibroelastic CT that is continuous with the periosteum of the skull
Simple squamous epithelium on the outside
Epidural space
Space outside the dura mata, separating it from the vertebrae
The brain has the brain layers of _______ as the spinal cord, only with less _______.
meninges; space
PNS
Peripheral nervous system
Everything except for the brain and spinal cord
Ganglia and nerves
Axolemma
Cell membrane of an axon
Produces neuroregulin that regulates thickness of myelin
P-zero protein
Protein that tightens up myelin around axons
Nerves won’t function if myelin is too _______.
loose
Dentate gyrus
Area of the hippocampus that can generate new neurons daily due to its population of stem cells
Muscle cells are _______; stimulus causes a _______ or contraction of the fiber.
excitable; shortening
There are three types of muscle, _______, _______, and _______.
smooth; skeletal; cardiac
Skeletal muscle
Consciously controlled muscle
Long, cylindrical cells with striations/banding patterns and multiple nuclei
Building blocks are called myofibrils
Myofibrils
Building blocks of muscle cells
Stacked on top of one another, perfectly aligned
Myofibrils consist of what components?
Sarcomeres
The terms muscle cell and _______ are interchangeable.
muscle fiber
How do muscle cells gain their many nuclei? What is it called when a cell has many nuclei?
Several early embryonic muscle cells called myoblasts fuse together to form one large muscle cell. This is called a syncitial cell.
How can you tell the difference between skeletal and cardiac muscle cells?
Both are striated, but skeletal muscle cells have their nuclei pushed all the way up near the cell membrane
Myofilaments have _______ and _______ filaments.
thick; thin
What are the three proteins that are linked together of the thin myofilaments of muscle cells?
Troponin, tropomyosin, and F-actin
F-actin
One of the three proteins of thin myofilaments
Homopolymer of G-actin
Homopolymer
Polymer of one repeating unit
Connectin
Z-line anchoring protein
H band contains _______ filaments, so it shows up as a _______ band.
only thick; light
I band contains _______ filaments, so it shows up as a _______ band.
only thin; light
A band contains _______ filaments, so it shows up as a _______ band.
both thick and thin; dark
Motor unit
One neuron stimulates multiple muscle cells
Each terminal innervates one muscle cell
The neuron of a motor unit has _______ branches.
collateral
NMJ
Neuromuscular junction
A synapse between the neuron and muscle cell
Vesicles with _______ diffuse from the terminal to the _______.
NTM; end plate
The only place to find receptors in the NMJ is the _______.
end plate
Ionotropic
Very quick ion flow; not delayed
Perimysium
Thin CT layer surrounding fasciculus
Contains bv, lv, and nerves
Fasciculi
Bundle of muscle fibers packed together
Epimysium
Thin CT layer surrounding groups of fasciculi
Contains bv, lv, and nerve fibers
Endomysium
Thin CT layer surrounding individual muscle fibers
Smooth muscle
Involuntary, subconscious muscle
