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161 Cards in this Set
- Front
- Back
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electrical signals from nerves cause muscle ____________
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muscle contraction
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Motor unit
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One motor neuron and all the muscle cells it innervates
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A motor neuron is a kind of __________ ___________
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a kind of nerve cell
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How many muscle fibers can one motor neuron stimulate?
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One or hundreds of muscle fibers
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Precise number of muscle fibers innervated by a motor neuron depends on...
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amount of fine control needed to control that muscle
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Think of two muscles that require fine control
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The eye and finger require fine control
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When a muscle requires fine control, how many muscle fibers does one motor neuron control?
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Just a few fibers are controlled by one motor neuron
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Think of the real life workplace. What would be an illustration of fine motor control in the muscular system?
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Micro-management; one supervisor (motor neuron) over just a few employees (muscle fibers)
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When a muscle requires less fine control, how many muscle fibers does one motor neuron control?
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One motor neuron controls hundreds of muscle fibers
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What kind of muscles require less fine control? Think of one specific example
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Bulky muscles like hip muscles require less fine control
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Think of the real life workplace. What would be an illustration of the less fine motor control that happens in the muscular system?
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One supervisor over many employees.
In less fine motor control, one motor neuron controls hundreds of muscle fibers |
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Why would your eye need fine motor control?
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One reason would be pupil dilation
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Shape of smooth muscle cells?
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Spindle-shaped fibers
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How would you describe the spindle shape of smooth muscle fibers?
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Smooth muscle cells are shaped like a toothpick with two pointy ends
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How many nuclei do smooth muscle cells have?
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Smooth muscle cells only have one nucleus
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What's special about the nucleus in a smooth muscle cell?
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The nucleus in a smooth muscle cell is elongated
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Do smooth muscle cells have striations?
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No striations on smooth muscle cells
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Smooth muscle: voluntary or involuntary?
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Smooth muscle is involuntary
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Where can you find smooth muscle?
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In the walls of hollow visceral organs
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What would be another good name for smooth muscle?
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Smooth muscle could also be called "visceral muscle"
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Give me four examples of places you'd find smooth muscle.
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Smooth muscle:
Stomach Urinary bladder Respiratory passages Blood vessel walls |
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What does smooth muscle have to do with an asthma attack?
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During an asthma attack, the smooth muscles of the respiratory passages constrict.
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Why do inhaler meds help people having an asthma attack?
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The meds in the inhaler bind to the smooth muscle of the respiratory passages, telling the muscle to relax.
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Fancy word that means "has one nucleus"
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Mononucleate = has one nucleus
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What is the gross structure of smooth muscle like?
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Smooth muscle is often arranged in two overlying sheets or layers
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If you looked at the gastrointestinal (GI) tract, what would the smooth muscle look like?
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The smooth muscle in the GI tract would look like it was arranged in two overlying sheets or layers (because it is!)
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Arrangement of the inner layer of smooth muscle
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Inner layer of smooth muscle is circular
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Arrangement of the outer layer of smooth muscle
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Outer layer is longitudinal muscle
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Function of smooth muscle
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To move contents of visceral structures along
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`Peristalsis
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Smooth muscles moving matter through tubes, wake-like
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_____________________ = alternate contraction and relaxation cycles of smooth muscle in walls of tubes producing a wave of movement along a tube where they occur
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Peristalsis
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How does smooth muscle in tubes accomplish peristalsis?
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Smooth muscle alternately contractions and relaxes in a cycle
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What causes peristalsis?
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Smooth muscle in walls of tubes
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What kind of movement is peristalsis?
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Wave of movement along a tube
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Three characteristics of peristaltic contractions:
1. Speed 2. Duration 3. Resistance to fatigue |
Peristaltic contractions:
Slow Sustained More fatigue-resistant |
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Shape of cardiac muscle cells
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Cardiac muscle cells have an elongated, cylindrical shape
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Cardiac muscle cells have an elongated, cylindrical shape similar to what other kind of muscle cells?
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Cardiac muscle cells have a shape similar to skeletal muscle cells
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Cardiac muscle: striated or not?
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Cardiac muscle is striated
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Which kinds of muscle are striated?
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Skeletal and cardiac muscle is striated
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How many nuclei do cardiac muscle cells have?
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Cardiac muscle cells are mononucleate
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Cardiac muscle cells usually have __ nucleus, but occasionally they have _
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usually have one nucleus, but occasionally have 2
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List the three types of muscle cells in order of their size, from biggest to littlest.
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Skeletal muscle cells are biggest, then smooth cells, then cardiac cells
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Cardiac muscle cells are ________ing cells
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these muscle cells are branching cells
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Cardiac muscle cells are branching cells joined by what?
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Branching cells joined by intercalated discs
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Intercalated discs
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Dark bands at ends of cardiac muscle cells
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Function of intercalated discs
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These discs facilitate contraction as a unit
(allow for communication/teamwork) |
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Cardiac muscle: voluntary or involuntary?
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Cardiac muscle is involuntary
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Where does cardiac muscle occur?
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Cardiac muscle occurs only in the <3
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how are cardiac muscle cells arranged?
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Cardiac muscle cells are arranged in spiral bundles
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Why are cardiac muscle cells arranged in spiral bundles?
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To make figure 8-shaped gross muscle bands of heart
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Contractions of cardiac muscle are highly ______________ed
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Contractions are highly coordinated
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The highly coordinated contractions of cardiac muscle are controlled by these three things:
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Controlled by:
Gap junctions Heart pacemaker Nervous control |
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Function of gap junctions
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Direct electrical continuity between cells
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All skeletal muscles cross at least one _____________
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at least one joint
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Typically, the bulk of a skeletal muscle lies ____________ to the joint it crosses
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the bulk of the muscles likes proximal to the joint it crosses
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The biceps move the elbow joint. So where is the fattest part of the biceps muscle?
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Fattest part is near the elbow joint
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How many attachments to all muscles have?
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They all have two attachment points
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Where is the origin of a muscle?
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At the immovable or less movable bone
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Where is the insertion of a muscle?
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The insertion's at the more movable bone
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Muscles __________ but never __________
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they pull but never push
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What happens to a muscle when it pulls?
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The muscle contracts and shortens
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What happens to the length of a muscle when it relaxes?
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The muscle elongate or lengthens during relaxation
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Why would a muscle relax?
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The motor neuron is no longer activating the muscle
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Where does the insertion of muscle go during contraction?
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The muscle insertion moves toward the origin site/bone
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Where is the origin in your biceps?
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There are actually two up by your shoulder
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Where is the biceps insertion
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By the elbow
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Cordlike connective tissue extensions of muscle that attach muscles to the periosteum of bone
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Tendons
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Tendons are _________-like
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tendons are cordlike
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What are tendons? (forget what they do)
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Tendons are connective tissue extensions of muscle
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Tendons attach muscles to the WHAT of bone?
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attach muscles to the periosteum of bone
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What from within and around a muscle emerges to form the tendon?
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Connective tissue merges
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Aponeurosis
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Broad/fat sheet-like tendon
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Function of aponeurosis
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Attach muscles to bones or muscles to each other
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Aponeurosis is not ________-like
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it's NOT cordlike
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Two famous examples of epineuroses
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Epicranial epineurosis and aponeurosis of external oblique
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Musculoskeletal system works a system of what?
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Works as system of levers
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The musculoskeletal system works as a system of levers. What are the levers?
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Bones are the levers
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Remember our lever system diagrams for the musculoskeletal systems? What would the elbow joint be called in one of those diagrams?
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Elbow joint is a fulcrum
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In the musculoskeletal system, what does the muscle provide to move the lever across/against the joint
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the muscle provides the force to move the lever
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In the musculoskeletal system of levers, what is the forearm of arm (and any weight it holds)?
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The forearm or weight it holds is the resistance
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If you're weightlifting with your biceps, where is the force of this lever system exerted?
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The force is exerted on the muscle insertion on the forearm (radius)
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What class of levers are most lever systems in the body?
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Third class lever systems
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Where is the effort (force) exerted in a third class lever system?
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Force is exerted between the resistance and the fulcrum
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Two examples of household objects that illustrate the third class lever system
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Forceps or tweezers illustrate this system
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In forceps or tweezers, where is the effort (force) applied?
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Effort (force) applied to center of the tool between the fulcrum and resistance
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Do muscles typically work alone?
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No, muscles typically work in groups.
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Prime mover
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Muscle primarily responsible for a particular movement
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Synergists
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Other assisting or stabilizing muscles
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Antagonist
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Performs opposite movement of prime mover
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Those muscles that perform the opposite movement of a particular prime mover/synergist group
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Antagonist
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When the prime mover/synergist group contracts, what happens to the antagonist group?
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The antagonist group relaxes
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These two movements are among the most common of movements enabled by muscles working together
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Flexion and extension are these two movements
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Layman's term for flexion
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Bending
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What happens to the angle between two bones during flexion?
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The angle between two bones decreases
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Two easy examples of flexion in the body
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Elbow or knee bending
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Layman's term for extension
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Extension = straightening or stretching
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What happens to the angle between two bones during extension?
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The angle between two bones increases
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Two easy examples of extension in the body
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Knee or elbow extension
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Prime mover in bending (flexing) the arm at the elbow joint?
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Biceps brachii muscle is prime mover
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Synergist with the biceps brachialis?
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Brachialis muscle is synergist
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Antagonist of the biceps brachii/brachialis?
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Triceps brachii muscle is antagonist
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Which two muscles contract during flexion of the arm?
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Biceps brachii and brachialis
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What muscle movement occurs when the triceps relax?
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Extension occurs
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Prime mover during extension of the arm?
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Triceps brachii is prime mover
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Antagonists during extension of the arm
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Biceps brachii/brachialis are anatagonists
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Muscle tone
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A state of continuous partial contractions
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Name for continuous partial muscle contractions
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Tonic contractions
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Loss of tone (lengthening) leads to total relaxation or THIS
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Leads to flaccidity of muscles
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What happens if all nerves to a muscle are cut and loss of tone leads to total relaxation?
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There will ultimately be paralysis of that muscle and atrophy
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Muscle tone counteracts gravity to maintain THIS
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to maintain posture
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Disuse of muscles leads to a loss of WHAT
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leads to a loss of muscle tone
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"Wasting away" of muscle
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Atrophy
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Explain muscle tone
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Even in a "relaxed" state, some motor units are active to keep some of the muscle fibers in a partially contracted state
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During relaxation, muscles have no visible contraction or movement, but the muscle still has some WHAT in it?
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still has some tension in it
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Back and neck muscles have just enough tone to counteract WHAT?
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to counteract the pull of gravity on our head and trunk
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What would happen to our head and trunk without muscle tone?
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They would be pulled forward and down by gravity
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Thigh and leg muscle tone allow us to counteract gravity's tendency to WHAT?
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gravity's tendency to pull us to the floor
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Two examples of tonus
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Back & neck muscles
Thigh and leg muscle tone |
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Poor posture causes WHAT more quickly?
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causes fatigue more quickly
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Poor posture produces abnormal WHAT on ligaments, joints & bones
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produces abnormal pull
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Poor posture does WHAT to organs
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crowds organs
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What is an example of poor posture crowding organs?
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Crowding the lungs and decreasing breathing capacity
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Regular exercise increases muscle WHAT? (three things)
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Increases muscle size, strength, and endurance
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Scientific term for increase in muscle size
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hypertrophy = increase
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Why do muscles increase in size with regular exercise? (2 reasons)
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It actually increases the size of muscle cells
and also prevents disuse atrophy |
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Endurance
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Resistance to fatigue
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Another name for aerobic exercise
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endurance exercise = aerobic
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Aerobic exercise
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Prolonged activities that get <3 rate & respiration up
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Aerobic exercise increases what ability?
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ability to sustain moderate exercise over a long period
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Aerobic exercise increases WHAT to muscles?
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increases blood supply to muscles
(actually adds more capillaries) |
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Aerobic exercise causes muscle cells to make more of these
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Cells make more mitochondria
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If muscle cells make more mitrochondria from regular aerobic exercise, what production does this increase?
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increases ATP production
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Aerobic exercise causes muscle cells to make more mitrochondria. It also gives cells the ability to do what?
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ability to store more oxygen
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Why do aerobic exercise, aside from what it does for muscles?
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This exercise improves function of other body systems too
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Aerobic exercise improves _________tion
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improves digestion
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Aerobic exercise improves WHAT elimination?
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waste elimination is improved
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Aerobic exercise improves what kind of coordination?
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Improves neuromuscular coordination
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Aerobic exercise strengthens what system?
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Strengthens skeletal system
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Aerobic exercise strengthens and enlarges what?
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strengthens and enlarges heart
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Enlargement of the heart
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Hypertrophy
(because the heart is muscle) |
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If the heart is strengthened and enlarged, what can it to?
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Pump more blood and so get more O2 & nutrients to tissues
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Aerobic exercise increases the number of THESE to muscle
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blood vessels to muscle
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Aerobic exercise clears THESE from blood vessel walls
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clears fat deposits
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Aerobic exercise increases WHAT efficiency
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increases lung efficiency
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Aerobic exercise produces better distribution and use of WHAT?
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better distribution and use of oxygen
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Aerobic exercise improves efficiency of body WHAT generally?
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body metabolism generally
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How do you do strength training?
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Force the muscles to contract with as much force as possible
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Another name for strength training
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strength training = resistance training
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Is strength training isometric exercise?
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Not STRICTLY isometric exercise since there is movement, just somewhat
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Why is strength training somewhat isometric?
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Somewhat isometric because of the tremendous resistance to movement
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Point of strength training
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to build muscle mass (like bodybuilders)
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Why does strength training build muscle mass?
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It enlarges individual muscle cells/fibers
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How do muscle cells/fibers get bigger from strength training?
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Muscle cells get more myofilaments per cell
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Does strength training increase the number of muscle fibers?
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No, but it does increase number of myofilaments in each fiber
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Strength training increases reinforcing WHAT around muscle?
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reinforcing connective tissue
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Which builds endurance better: aerobic exercise or strength training?
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aerobic exercise builds endurance better
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2 benefits of good body mechanics:
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Good body mechanics:
Conserves energy Provides freedom from strain & fatigue |
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What happens because of poor body mechanics? (2)
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strain and fatigue comes from poor body mechanics
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What's an example of a problem caused by poor body mechanics?
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Lower back pain is an example
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_______________ = How to fit a person's job to their anatomical, physiological, and psychological characteristics so as to enhance human efficiency & well-being
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Ergonomics
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Ergonomics literally means what?
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Ergonomics = "work laws"
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