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31 Cards in this Set

  • Front
  • Back

What are muscles made of?

composed of muscle cells, myofibres, or muscle fibers that specialize in contraction

What are the 2 classification of muscles based on appearance of contractile cells?

- striated muscle


- smooth muscle

What are the 2 groups striated muscles divide into?

1. Cardiac muscle: involuntary muscle in walls of heart


2. Skeletal muscle: voluntary muscle

What are the 3 bundles of tissue sheath of the skeletal muscle?

1. Epimysium: dense connective tissue covering entire muscle


2. Perimysium: surrounds bundles of fascicles of muscle cells


3. Endomysium: delicate layer of reticular fibers and ECM surrounding each muscle cell

Describe the muscle cell in skeletal muscle

- post mitotic multinucleated synctium


- nuclei lie below sarcolemma


- sarcolemma contains satellite cells (help muscle regeneration)


- where you find site of a triad (2 lateral sacs of sarcoplasmic reticulum and central T tubule)

Describe the myofibrils of the skeletal muscle fiber (hint: sarcomeres)

- myofibrils contain sarcosomes (type of mitochondria)


- 2 filaments: thin and thick filaments


- Thin filament: contains actin, form I band (light)


- Thick filament: contains myosin, form A band (dark)


- I band bisected by Z line, A band bisected by H band

What is a sarcomere?

the basic contractile unit of skeletal muscle and is portion of myofibril between 2 adjacent Z lines

What are the 3 parts of muscle contraction?

1. length of thick&thin filament does NOT change during contraction


2. length of sarcomere decreases / size of H band and I band decreases


3. force of contraction generated by process that moves one filament past the adjacent filament

What are satellite cells?

- cells that are significant in muscle maintenance, repair, and regeneration


- basis of stem cell therapy in muscle injuries and degenerative diseases


- mitotically quiet in adults, but can come back in response to stress/trauma

Describe the cardiac muscle cells

- branched cylinders with centrally located nucleus


- organization of contractile proteins (same as ones found in skeletal muscle)


- have T tubules @ level of Z disc, sarcoplasmic reticulum not extensive, have Diads, and mitochondria are abundant

How are cardiocytes joined?

- cardiocytes are cardiac muscle cells


- joined end to end by intercalated discs

What does cardiac muscle exhibit that is unique to it?

- a spontaneous rhythmic contraction (heart beat)


- initiated, regulated, and coordinated by cardiac conduction cells


- cells organized into Purkinje fibers

What is a myocardial infarction?

- loss of blood supply (ischemia) to the myocardium


- caused by obstruction of atherosclerotic coronary artery


- damages cardiocytes if ischemia occurs for more than 20 minutes



What is reperfusion?

- it is the process of cardiac cell viability being restored


- occurs after myocardial infarction (ischemia) occurs for less than 20 minutes

Where is smooth muscle found?

located in walls of gut, bile duct, ureters, urinary bladder, respiratory tract, uterus, and blood vessels

How is smooth muscle different from cardiac muscle?

- spindle shaped with tapering cells with a central nucleus


- perinuclear cytoplasm contains a lattice work of thick myosin filament, thin actin filaments, and desmin&vimentin filaments (attached to dense bodies)


- invaginations of plasma membrane called caveolae act as T tubule system


- basal lamina surrounds each muscle cell - transmits forces produced by cells

What is the specialization of smooth muscle?

it is specialized for slow and prolonged contraction

What are dense bodies?

It is where actin and myosin filaments attach to. The attachment to the dense body is what determines cell shortening.

How does smooth muscle renew itself?

- smooth muscles divide to maintain or increase their number


- smooth muscle in uterus proliferates during pregnancy

What is included in the central nervous system?

brain and spinal cord



What is included in the peripheral nervous system?

peripheral ganglia, nerves, and nerve endings



What does the nervous system control?

It controls and integrates the functional activities of organs and organ systems. It also enables the body to respond to continuous changes.

Describe the composition of nerve tissue

- consists of neurons and supportingg cells (neuroglial cells)


- neurons are basic unit of structure&function


- 3 main categories: sensory neurons, motor neurons, and interneurons

What are the 3 types of neurons?

1. multipolar neurons


2. bipolar neurons


3. pseudounipolar neurons

What are synapses?

- specialized junctions between neurons that help in transmission of impulses


- how neurons communicated with each other and effector cells



What are examples of peripheral neuroglia?

- schwann cells


- satellite cells


- cells in motor end place


- retina


- certain ganglia located in alimentary canal

What are the 4 types of central neuroglia?

1. astrocytes


2. oligodendrocytes


3. microglia


4. ependymal cells

What is a peripheral nerve?

a bundle of nerve fibers held together by connective tissue



What is each nerve composed of? (peripheral nerve)

- fascicles which are nerve fiber bundles


- enclosed by epineurium, perineurium, and endoneurium


- endoneurium composed of callagenous&reticular fibers with fibroblasts¯ophages

Why can't nerve fibers regenerate from injury in the CNS?

Because the glial cells in the CNS are unable to phagocytose quickly enough, so it leaves a scar.

What is reactive gliosis?

- it is scar formation in the CNS


- astrocytes near lesion are activated and form a scar (reactive gliosis) and becomes a permanent scar (plaque)


- leads to no recovery or very minimal recovery