Question | Answer |
The ability of skeletal muscle to shorten with force | Contractility |
The capacity of skeletal muscle to respond to a stimulus | Excitability |
Ability to be stretched | Extensibility |
Ability to recoil to their resting length | Elasticity |
Connective tissue that surrounds skeletal muscle | Epimysium |
Connective tissue located outside epimysium | Fascia |
Numerous visible bundles found in muscle | Fasciculi |
Loose connective tissue that surrounds fasciculi | Perimysium |
Muscle cells | Muscle fibers |
Connective tissue that surrounds each fiber | Endomysium |
The cytoplasm of each fiber is filled with | Myofibrils |
2 major kinds of protein fibers found in myofibrils | Actin myofilament & Myosin myofilament |
Thin myofilaments | Actin |
Thick myofilaments | Myosin |
Basic structural & functional unity of the muscle | Sarcomere |
Z line to Z line | Sarcomere |
Contains actin & is light | I band |
Extends length of myosin & is darker | A band |
Center of sarcomere that consists of only myosin | H zone |
Dark staining band in center | M line |
Outside the cell membranes is what charge? | Positive |
Inside of cell membranes is what charge? | Negative |
The brief reversal back of the charge is | Action potential |
Nerve cells that carry action potentials to skeletal muscle fibers | Motor neurons |
Neuromusclular junction | Synapse |
Raises the eyebrow | Occipitofrontalis |
Closes the eyelids & causes "crows feet" | Orbicularis oculi |
Flattens the cheeks | Buccinator |
Kissing muscles | Orbicularis oris & buccinator |
Smiling muscle | Zygomaticus |
Sneering | Levator labii superioris |
Frowning | Depressor anguli oris |
Chewing | Mastication |
4 pairs of chewing muscles | 2 pterygoids, temporalis, masseter |
Changes shape of tongue | Intrinsic tongue |
Moves the tongue | Extrinsic tongue |
Lateral neck muscle & prime mover; rotates & abducts the head | Sternocleidomastoid |
The space between the presynaptic terminal & postsynaptic terminal (muscle fiber) is | Synaptic cleft |
Neurotransmitter | Acetylcholine |
Enzyme breaks down | Acetylcholinesterase |
Muscular system produces | Heat |
Attaches muscle to bone | Tendons |
Sliding of actin past myosin during contraction | Sliding filament mechanism |
Sarcomeres shorten causes | Muscles to shorten |
Contraction of an entire muscle in response to a stimulus that causes action potential in one or more muscle fibers | Muscle twitch |
Muscle fiber will contract maximally | All-or-nothing response |
Time between application of stimulus to motor neuron and beginning of contraction is called | Lag phase |
ATP | Adenosine triphosphate |
Needed for energy for muscle contraction | ATP |
ATP is produced in the | Mitochondria |
ATP cannot stock pile, so it stores another | Creatine phosphate |
Without oxygen | Anaerobic respiration |
With oxygen (more efficient) | Aerobic respiration |
When ATP is used during muscle contraction faster than it can be produced | Muscle fatigue |
2 types of muscle contractions | Isometric & Isotonic |
Length doesn't change, tension increases
Ex: holding a ball | Isometric |
Tension is constant, length changes
Ex: throwing a ball | Isotonic |
Contract quickly & fatigue quickly; well for anaerobic | Fast-twitch fibers |
Contract slowly & more resistant to fatigue; aerobic | Slow-twitch fibers |
Points of attachment on each muscle | Origin & insertion |
Most stationary end of muscle (Head) | Origin |
End of muscle undergoing greatest movement | Insertion |
Portion between origin & insertion | Belly |
Bicep attaches at scaplua | Origin |
Bicep attaches at radius | Insertion |
Muscles that work together to accomplish specific movements | Synergists |
Muscles work in opposition to one another | Antagonists |
Plays major role in a group of synergists | Prime mover |
Muscles are named according to | Location & size |
3 types of muscle in the body | Skeletal, cardiac, smooth |
Union between a nerve fiber & a muscle fiber | Neuromuscular junction |
What does the muscular system do | Permits movement of the body, maintains posture, & circulates blood throughout the body |
Group of muscles on each side of back; responsible for keeping the back straight & body erect | Erector spinae |
Accomplishes quiet breathing; dome-shaped muscle; aids in breathing | Diaphragm |
Tendinous area of the abdominal wall; consists of white connective tissue | Linea alba |
On each side of the lines alba | Rectus abdominis |
Cross the rectus abdominis at 3 or more locations, causing a person to look segmented | Tendinous inscriptions |
Abdominis layers of muscle from superficial to deep | External abdominal oblique, internal abdominal oblique, & transverses abdominal muscles |
Rotates scapula | Trapezius |
Elevates the ribs during inspiration | External intercostals |
Adducts & flexes the arm | Pectoralis major |
Medially rotates, adducts, & powerfully extends the arm; "Swimmer muscles" | Latissimus dorsi |
Most involved in breathing | External intercostals & internal intercostals |
Attaches the humerus to the scapula & clavicle & is major abductor of upper limb | Deltoid |
Extends the forearm | Triceps brachii (posterior) |
Flexes the forearm | Biceps brachii (anterior) |
Also flexes the forearm | Brachialis |
Flexes and supinates the forearm | Brachioradialis |
Flexes the wrist | Flexor carpi |
Extends the wrist | Extensor carpi |
Flexes the fingers | Flexor digitorum |
Extends the fingers | Extensor digitorum |
19 hand muscles located within hand | Intrinsic hand muscles |
Contract during forced expiration | Internal intercostals |
Buttocks | Gluteus maximus |
Hip muscle & common injection site | Gluteus medius |
Extends the leg | Quadriceps femoris (anterior) |
Flexes the thigh | Sartorius "Tailors muscle" |
Flexes leg & extends thigh | Hamstrings (posterior) |
Form the calf muscle; flexes foot & toes | Gastrocnemius & soleus (Calcaneal tendon) |
Lateral muscles of leg; turns foot outward & plantar flexion | Peroneus muscles |
20 muscles within foot | Intrinsic foot |