Week 4 Muscular System Flashcards
What are the three types of muscles
Smooth
Cardiac
Skeletal
What are the prominent locations of smooth muscle
Wall of GI tract
Walls of arteries and veins
Around glands
What type of control does smooth muscle have
Involuntary
What type of control does cardiac muscle have? Where is it located
Wall of heart
Involuntary control
Where is skeletal muscle located and what type of control does it have
Attached/covers bones
Voluntary control
Endomysium covers?
Covers cardiac muscle fibers
What do gap junction do in cardiac muscle
Let’s kind through from cell to cell
What do intercalated disks do in cardiac muscle
Coordinates impulses
What is a sarcolemma
Membrane of a cardiac muscle cell
What are the 3 primary functions of skeletal muscle
Skeletal movement
Posture maintenance
Heat generation
Structure of a muscle: what is a fascicle
Bundle of muscle fibers (cells)
-many bundles make up a whole muscle
What does connective tissue do? What are the 3 layers of CT
Holds fascicles together
3 layers: endomysium, perimysium, epimysium (deep fascia)
What is a band of dense CT that attaches muscle to bone
Tendon
Nerve impulses are aka?
Hint they cause movement
Motor impulses
Nerve impulses are carried by
Motor neurons
The axon carries impulses to the
Muscles (target area)
What is the motor unit
The stimuli and all stimulated muscle fivers
What is the neuromuscular junction (NMJ)
The point at which a nerve fiber contacts a muscle cell (synapse)
What is the specific neurotransmitter released @NMJ
Acetylcholine (ACh)
ACh crosses the synaptic cleft and attaches to a ACh receptor at the
Motor end plate (receiving muscle membrane)
What is initiated by the ACh/receptor
Action potential
Motor unit is a
Single neuron and all the muscle fibers it stimulates
What uses small motor units and are more controlled, very precise movements
Fine movements
(Ex. Muscles of the hand, eye)
What uses larger motor units
Broad movements
(Ex. Maintaining posture, walking, golfing)
What are the properties of muscle tissue
Excitability
Action potential
Contractility
What is the functional unit of contraction in the skeletal muscle fiber
Sarcomere
Sarcomeres contract via the
Sliding filament mechanism
Do the actin or myosin filaments in the sarcomere change in length as the contraction proceeds
Actin filaments change in length b/c myosin pulls them together
Calcium is needed for
Muscle contraction
Where is calcium stored
In the sarcoplasmic reticulum (SR)
(Stored here until released into the cytoplasm by action potential)
When the SR releases the calcium into cytoplasm, it binds to troponin causing both proteins to shift off of actin and expose binding sites this allows for
Cross bridges to form between actin and myosin so that the sliding action can begin
Muscle contraction requires
Energy (ATP)
What are the 4 storage compounds that ensure an adequate supply of energy
Myoglobin
Glycogen
Creatine phosphate
Fatty acids
What does myoglobin store
Oxygen
(Increasing the oxygen storage capacity of the muscle)
Glycogen stores what
Storage form of glucose
(Can generate both anaerobically and aerobically)
Creatine phosphate can be used as an
Interim energy source
(Generates atp independently of glucose)
Fatty acids are stored as
Triglycerides
(Can be oxidized for energy)
Most ATP is produced via
Aerobic metabolism
(Requires oxygen)
Aerobic metabolism is efficient but has limitations which include (2)
Slow to start generating ATP
Requires a lot of oxygen
What does excess post exercise oxygen consumption (EPOC) represent?
The energy required to establish the resting rate; from rapid breathing
What occurs in anaerobic ATP metabolism
Breakdown of creatine phosphate
Anaerobic glycolysis (lactic acid)
What are the three types of muscle contractions
Muscle tone or tonus
Isotonic contraction
Isometric
A partially contracted state of the muscle that is normal even when it is not in use (ex. posture maintenance) describes what type of muscle contraction
Muscle tone or tonus
What muscle contraction is described as having no change in tension but the muscle length changes (ex. Walking)
Isotonic contraction
What are the 2 types of isotonic contraction? Describe them
-Concentric contractions-muscle shortens
-Eccentric contractions- muscle lengthens
What type of muscle contraction is described by a great increase in tension, muscle length is unchanged and there is no movement
Isometric
(Ex pushing against an immovable object)
Muscles work in
Pairs
What are prime movers (contract)
Muscle that performs the movement
Antagonists (relax) is a muscle that produces the
Opposite movement to that of the prime mover
What are synergists
Muscles that assist the prime movers to accomplish a movement
-stabilize the body during movement
Synergists and prime movers are collectively known as
Agonists
How many classes of levers are there that vary depending on the relative position of the fulcrum, effort and resistance
3 classes of levers
Describe first class fulcrum
Fulcrum is between the resistance and effort
Describe second class fulcrum
Load (R) is between the fulcrum and effort
Describe third class fulcrum
Most body systems; effort is between load and fulcrum
Lever in musculoskeletal lever system refers to
Bone
Fulcrum in musculoskeletal lever system refers to
Joint
Effort in musculoskeletal lever system refers to
Force applied by muscle
Resistance in musculoskeletal lever system refers to
Load/weight of body oart
Effects of aging begin at age
40
What are the effects of aging on muscles
Gradual loss of muscle cells
Loss of power, notably in the extensor muscles
Tendency to flex hips and knees
Decrease in height
What are spasms
Sudden and involuntary muscular contraction
Always painful
Colic is
A spasm of the visceral muscles
(Ex. Belly ache)
What is atrophy
Decrease in the size of the muscle when not being used
What is a stretched or torn muscle, or tears between muscle and its tendon
Strain
Describe sprains
A stretched or torn ligament
(Ligament tissue that connects bones at a joint)
What is delayed onset muscle soreness (DOMS)
Stiffness and pain experienced the day or two after an intense workout
What is rhabdomyolysis
Potentially life threading from overtraining
-overworked muscle cells undergo necrosis
Rhabdomyolysis can cause
Irreversible kidney damage
Muscular dystrophy is deterioration of the muscle tissue (with intact nerves); what can result and what is the life expectancy
Death results from weakened of cardiac muscle or paralysis of respiratory muscles
-life expectancy 25-40 years
What muscle disease often results from an autoimmune disorder and is a result of blocked transmission of nerve impulses across the NMJ
Myasthenia gravis
Myasthenia gravis affects who? What is a common early sign
Affects adults and begins with muscles of the head
-dropping of eyelids (ptosis) early sign
What is myalgia
Muscular pain
What is myositis
Inflammation of muscle tissue
What is fibrositis
Inflammation of CT, specifically tissues associated with muscles and joints
What is fibromyositis
Combination of myositis and fibrositis
-can be acute with severe pain on motion or chronic
Fibromyalgia syndrome (FMS) is
Widespread muscle aches, tenderness and stiffness with fatigue and sleep disorders
-no known cause may be autoimmune, difficult to diagnose
What is plantar fasciitis
A form of tendinitis involving CT in the bottom of the foot
What involves the synovial sheath that encloses tendons
-it is more common in women in their 40’s after injury or surgery
And may have severe swelling & severe pain with activity
Tenosynovitis
