Muscle Tissue & Neural Tissue (quiz 3) Flashcards
Muscle tissue is composed of cells that optimize the universal cell property of…
contractility
Actin microfilaments and associated proteins generate the forces necessary for ____________ contraction. This drives movement within organ systems, or blood, and of the body as a whole.
muscle
Muscle cells are of ____________ origin and differentiate by a gradual process of cell lengthening
mesodermal
The 3 types of muscle tissue can be distinguished on the basis of morphologic and functional characteristics. What are the 3 types?
-skeletal
-smooth
-cardiac
Are skeletal muscles voluntary or involuntary?
voluntary
Skeletal/striated muscle consists of muscle fibers, which are long cylindrical, __________________ cells/fibers
multinucleated
During muscle development, myoblasts fuse forming __________ with many nuclei
myotubes
What is the stem cell of muscle tissue?
satellite cell (helps form new muscle fibers as needed)
Thin layers of _____________ tissue surround and organize the contractile fibers in skeletal muscle
connective
An entire skeletal muscle is enclosed within a thick layer of dense CT called the ___________ that is continuous with fascia and the tendon binding muscle to bone
epimysium
epi- = outside
Large muscles contain several fascicles (bundles of fibers/cells) of muscle tissue, each wrapped in a thin but dense CT layer called the _____________
perimysium
peri- = around
Within fascicles, individual muscle fibers (elongated multinuclear cells) are surrounded by a delicate connective tissue layer, the ________________
endomysium
endo- = inner/inside
The epimysium is an external sheath of dense irregular CT, surrounding the entire muscle. __________ of this tissue extends inward, carrying the larger nerves, blood vessels, and lymphatics of the muscle
Septa
The perimysium is a thin CT layer that immediately surrounds each bundle of muscle fibers termed a…
fascicle
Within fascicles, there is a very thin, delicate layer of reticular fibers and scattered fibroblasts, the _________________ surrounds the external lamina of individual muscle fibers
endomysium
Skeletal muscle fibers (cells) are composed mainly of….
myofibrils
Each myofibril extends the length of the fiber and is surrounded by parts of the sarcoplasmic reticulum (ER). What is stored here?
calcium
The membrane of myofibrils is called the sarcolemma and it extends into the cytoplasm as….
T-tubules
What is the organization of skeletal muscle from largest to smallest?
-epimysium
-perimysium
-fascicle
-endomysium
-fibril = cytoskeleton (also known as myofibril)
Longitudinally sectioned skeletal muscle fibers show ____________ of alternating light and dark bands
striations
The sarcoplasm is highly organized, containing primarily long cylindrical filament bundles called ____________ that run parallel to the long axis of the fiber. Mitochondria and sarcoplasmic reticulum are found between myofibrils
myofibrils
(myofibrils consist of an end-to end repetitive arrangement of sarcomeres)
Each muscle fiber contains several parallel bundles called….
myofibrils
Each myofibril consists of a long series of sarcomeres, separated by…..
Z discs
Thin filaments are __________ filaments. Thick filaments are __________ filaments
actin, myosin
The sarcomere produces staining differences which cause the dark and light staining bands to be seen by light microscopy and is therefore termed…..
striated
What is the sliding filament theory?
during contraction, neither thick or thin filaments change their length. Contraction occurs as the overlapping thin and thick filaments of each sarcomere slide past one another
There are different types of skeletal muscle fibers. The different fibers can be identified on the basis of…
1) their maximal rate of contraction (fast or slow fibers)
2) their major pathway for ATP synthesis (oxidative phosphorylation or glycolysis)
Ex: skeletal muscles such as those that move the eyes and eyelids need to contract rapidly, while those for bodily posture must maintain tension for longer periods while resisting fatigue
Slow oxidative (SO) or _____________ fibers have high levels of acidic ATPase activity and stain the darkest
type 1
Fast glycolytic (FG) or _____________ fibers stain the lightest
type 2b
Fast oxidative-glycolytic (FOG) or __________ fibers are intermediate between type 1/2b
type 2a
________________________ muscle fibers are adapted for slow contractions over long periods without fatigue, having many mitochondria, surrounding capillaries, and myoglobin, all these features that make fresh tissue rich in these fibers dark or red in color
Slow oxidative
________________ fibers are specialized for rapid, short-term contraction, having few mitochondria or capillaries and depending largely on anaerobic metabolism of glucose derived from stored glycogens, features which make such fibers appear white. Rapid contractions lead to rapid fatigue as lactic acid produced by glycolysis accumulates
Fast glycolytic
_____________________ fibers have physiological and histological features intermediate between those of slow oxidative and fast glycolytic fibers
Fast oxidative-glycolytic
What is another name for mature cardiac muscle cells?
cardiomyocytes
Mature cardiac muscle cells have a striated banding pattern comparable to that of skeletal muscle. Unlike skeletal muscle, each cardiac muscle cell usually only has _______________.
1 nucleus
Cardiac muscle is surrounded in delicate sheath of __________________ with a rich capillary network (densely innervated w/ blood supply)
endomysium
A unique characteristic of cardiac muscle is the presence of transverse lines that cross the fibers where the myocardial cells join. These are called _____________________ and consist of many junctional complexes. The discs are full of ________________ and fascia adherens junctions which together provide strong intercellular adhesion. There are also gap junctions, which provide ionic continuity between the cells (a syncytium)
intercalated discs, desmosomes
Cardiac muscle cells within one fiber often branch and join with cells in ____________ fibers. The tightly knit bundles of cells are interwoven in spiraling layers that give a wave of contraction that squeezes the ventricles
adjacent
The structure and function of the contractile apparatus in cardiac muscle cells are essentially the same as in….
skeletal muscle (sarcomeres)
In cardiac muscle, mitochondria occupies up to ______% of the cell volume, higher than in slow oxidative skeletal muscle fibers. ______________ are the major fuel of the heart and are stored as triglycerides in small lipid droplets
40, Fatty acids
In cardiac muscle, T-tubules in ventricular muscle fibers are well-developed, with large lumens and penetrate the sarcoplasm, while in atrial muscle, T-tubules are….
much smaller
Cardiac muscle fiber contraction is _____________ and ________________
intrinsic, spontaneous
Impulses for contraction/heart beat are initiated, regulated, and coordinated by nodes of myocardial fibers called….
conducting cells
Cells or fibers of smooth muscle are long, __________ structures with elongated nuclei centrally located at the cells widest part
tapering
Which muscle tissue is this?
The cells stain uniformly along their lengths, and close packing is achieved with the narrow ends of each cell adjacent to the broad parts of neighboring cells. The cells are linked by numerous gap junctions
smooth muscle!
uniform= non-striated
Smooth muscle is specialized for what?
slow, steady contraction under the influence of autonomic nerves and hormones
Smooth muscle is a major component of…..
-blood vessels
-digestive tract
-respiratory tract
-urinary tract
-reproductive tract
Fibers of smooth muscle also called visceral muscle are unstriated cells, each of which is enclosed by an external lamina and a network of type I and type III collagen fibers comprising the….
endomysium
In most of the digestive tract and certain similar structures, smooth muscle is organized into 2 layers which contract in a coordinated manner to produce a wave that moves the tracts contents in a process termed…..
peristalsis
Most molecules that allow contraction are similar in the 3 types of muscle, but the contractile filaments of ___________ muscle are oriented at oblique angles to the long axis of the cell, resulting in a twisting of the smooth muscle cells during contractions
smooth
In smooth muscle, where do thin filaments attach to?
dense bodies (located on cell membrane, deep in cytoplasm)
In smooth muscle cells, bundles of thin and thick myofilaments crisscross the sarcoplasm _______________
obliquely
Smooth muscle is not under _______________ control and its fibers typically lack well-defined neuromuscular junctions. Stimulations by the ANS is propagated to more distant fibers via gap junctions that allow all of the smooth muscle cells to contract synchronously
voluntary
Where is neural tissue found?
in the nervous system (PNS/CNS)
Neurons are electrically excitable as they have a _________________ potential
transmembrane
Impulses or information travels through neural tissue as….
action potentials
Only __________ transmit action potentials, but _______ maintain the environment
neurons, glia
Neurons are describe functionally as:
1)
2)
3)
1) sensory
2) motor
3) interneurons
What are the anatomical divisions of the nervous system?
CNS and PNS
What are the structural classifications for neurons?
test q (be able to identify each one with picture)
-multipolar (generic neuron)
-bipolar
-pseudounipolar
-anaxonic
What part of the neuron decides if an impulse will be sent or not?
axon hillock
what are teledondria?
extensions on axon terminal
What is another name for axon terminal?
synaptic terminal
Where are synaptic vesicles found?
at the synapse
The cell body (also called the ________) contains the nucleus and most of the cell’s organelles and serves as the synthetic or trophic center for the entire neuron
soma
Dendrites are the numerous elongated processes extending from the perikaryon and specialized to __________ stimuli from other neurons at unique sites called synapses
receive
The axon is a single long process ending at a terminal and forming….
synapses
What are axons specialized for?
to generate and conduct nerve impulses to other cells (nerves, muscles, gland cells, etc.)
What increases speed on an axon?
myelin sheath!
CNS axons are myelinated by…..
oligodendrocytes
PNS axons are myelinated by….
schwann cells
What are the exposed gaps between myelin sheaths called?
Nodes or node of ranvier
(an internode is covered in myelin sheath and then the gap between the next internode, is the node)
At the end of the axon is an expansion where the axon terminal forms a…..
synapse
T/F: synapses are multidirectional
FALSE- synapses are unidirectional
What do you need to form neural tissue?
neurons and neuroglia/glial cells
How many types of glia are there?
6 (4 in CNS, 2 in PNS)
What is thought of a substitute for CT within neural tissue?
glial cells
The fibrous intercellular network of CNS tissue superficially resembles collagen by light microscopy, but is actually the network of fine cellular processes emerging from neurons and glial cells. Such processes are collectively called the….
neuropil
What are the neuroglia cells of the CNS?
test q!
1) astrocytes
2) oligodendrocytes
3) ependymal cells
4) microglia
What are the neuroglia cells of the PNS?
1) Schwann cells
2) satellite cells
What are the functions of oligodendrocytes?
-myelinate and insulate CNS axons
-allow faster AP propagation along axons in CNS
What are the functions of astrocytes?
-hold synapses together
-forms part of the BBB
-regulates interstitial fluid composition
What are the functions of the ependymal cell?
-lines ventricles of brain and central canal of spinal cord
-assists in production and circulation of CSF
What are the functions of a microglia?
-phagocytosis in CNS
-protects CNS by engulfing infectious agents and other potential harmful substances
What are the functions of the satellite cell in the NS?
protect/insulate cell bodies of PNS
What are the functions of the schwann cell?
-surround and insulate PNS axons and myelinate those having large diameters
-allows for faster action potential propagation along an axon in the PNS
Are nerves large or small?
large!
Peripheral nerves are bundles of _______ with CT and blood vessels. They carry sensory information into the CNS and motor commands out of CNS.
axons
in or out?
sensory= ?
motor= ?
sensory= in
motor= out
How many cranial nerves are there?
12 pairs of nerves
How many spinal nerves are there?
31 pairs of nerves, and 4 plexuses
A nerve is a structure only found in the….
PNS
Like skeletal muscle, each nerve is organized into ___________ and wrapped
fascicles
What fibers carry information from internal body regions and the environment to the CNS?
afferent (sensory/in) fibers
What fibers carry impulses from the CNS to effector organs?
efferent (motor/out) fibers
Nerves possessing only sensory fibers are called sensory nerves, those composed of only fibers carrying impulses to the effectors are called…..
motor nerves
Most nerves have both sensory and motor fibers and are called __________ nerves, usually also with both myelinated and unmyelinated axons
mixed
