Muscular System Flashcards
Types and Functions of Muscles
Skeletal muscle
Smooth muscle
Cardiac muscle
Skeletal muscle description
Overlying skeleton
Striated
Voluntary
Striated
having long, thin lines, marks, or strips of color, especially in voluntary muscles
Voluntary
Done in accordance with the conscious will of the individual.
Smooth muscle description
Organs or viscera (stomach)
Nonstriated
Involuntary
Nonstriated
smooth and devoid of striations
They are also known as involuntary muscles because their activation is not under the control of the human.
-Found in hollowed internal organs
Involuntary
a muscle that contracts without conscious control and found in walls of internal organs such as stomach and intestine and bladder and blood vessels (excluding the heart)
Cardiac muscle description
Heart
Striated
voluntary
Layers of Connective Tissue (fascia)
Epimysium
Perimysium
Endomysium
Epimysium
External
(which surrounds the muscle)
Perimysium
Middle
(surrounds bundles of muscle fibers)
Endomysium
Most internal
(surrounds muscle fibers)
Fascicles
bundle of muscle fibers, (also called myocytes, bound together via the endomysium tissue that provides pathways for the passage of blood vessels and nerves.)
Tendon
a fibrous connective tissue that attaches muscle to bone.
serves to move the bone or structure
Group of myofibrils
a series of sacromeres-form myofibrils, which, arranged in parallel, make up the muscle cell or muscle fiber.
Myofibrils are composed of
long proteins which include actin, myosin, and titin, etc.
Sarcoplasmic reticulum
necessary for muscle contraction and relaxtion
Example of muscle contraction is
when lifting a heavy weight
Sarcolemma
the plasma membrane of the muscle cellis an excitable membrane and shares many properties with the neuronal cell membrane.
Inside the myofibril
From Z line to Z line
Thin filaments
-Actin
Thick filaments
-Myosin
Filament
the structural proteins of the cell.
Actin and myosin
are responsible for many types of cell movements
force generating proteins of the sarcomere
What is calcium stored away from?
Thin and thick filaments in the sarcoplasmic reticulum (SR)
What happesn when stimulated? (the role of calcium and adenosine triphosphate)
The SR releases calcium
What happesn when stimulated? (the role of calcium and adenosine triphosphate)
The SR releases calcium
What does calcium allow?
It allows actin, myosin, and ATP to interact, causing muscle contraction.
Why does muscle relax?
Calcium returns to the SR.
What is RNA
It converts the information stored in DNA into proteiins
What is ATP
A substance present in all living cells that provides energy for many metabolic processes and is involved in making RNA.
When does a skeletal muscle contraction take place?
Only takes place when it is first stimulated by a nerve.
What does somatic nerve supplies?
It supplies skeletal muscle.
(Emerges from the spinal cord and travels to the skeletal muscle)
Somatic motor
voluntary movements and reflex arcs
A single muscle fiber has
an “all or nothing” response, but a whole muscle can vary its force of contraction
What are two characteristics of a whole muscle that allow the single muscle fiber response?
Motor unit-comprises a single nerve cell, or neuron, that supplies nerves to (innervates) a group of skeletal muscles.
Recruitment- the process by which different motor units are activated to produce a given level and type of muscle contraction.
The Neuromuscular Junction
where nerves and muscle fibers meet—is an essential synapse for muscle contraction and movement.
Axon
portion of a nerve cell (neuron) that carries nerve impulses away from the cell body.
The neuromuscular junction has space between..
motor neuron and muscle
What site does the neuromuscular junction have?
Site of ACh action and activation of muscle membrane.
The action of ACh
contracts smooth muscles, dilates blood vessels, increases bodily secretions, and slows heart rate.
Impairment at the NMJ
Myasthenia gravis
Curare
Neurotoxins
-Clostidium tetani (tetanus)
-Clostidium botulinum (botulism and botox)
