Muscular System

Question 1

Compare the three types of muscle tissue

Answer 1

• Skeletal muscle is voluntary, whereas smooth and cardiac muscle is involuntary
• Skeletal and cardiac muscle are striated
• Cardiac muscles have intercalated disks and branchlike networks
• Skeletal muscles have long cells with multiple nuclei

Question 2

What are the three functions of skeletal muscle?

Answer 2

1) Movement of the skeleton
2) Maintenance of posture
3) Generation of heat

Question 3

The ______ is the deepest layer of this connective tissue and surrounds the individual fibers within fascicles.

The ______ is a connective tissue layer around each fascicle.

The ______ is a connective tissue sheath that encases the entire muscle and forms the innermost layer of the deep fascia.

Answer 3

endomysium(endo- “within”)

perimysium (peri- “around)

epimysium (epi- “above”)

Question 4

List compounds stored in muscle cells that are used to generate energy:

_____ stores oxygen

_____ is the storage form of glucose

Answer 4

Myoglobin

Glycogen

Question 5

Explain what happens in muscle cells contracting anaerobically.

1. Breakdown of _____, a compound similar to ATP in that it has a high-energy bond that breaks down to release energy. This energy is used to make ATP for muscle contraction. It generates ATP very rapidly, but its supply is limited.
2. ________ This process breaks glucose down incompletely without using oxygen. A few ATPs are generated in these reactions, as is a byproduct called ____, which is later oxidized for energy when oxygen is available.

Answer 5

creatine (KRE-ah-tin) phosphate

Anaerobic glycolysis

lactate

Question 6

This type of exercise results in hypertrophy, where the muscle cells grow in size, which allows the myofibrils to form more cross bridges. It also increases muscle stores of creatine and glycogen, and therefore more rapid ATP.

Answer 6

Resistance training

Question 7

a steady partial contraction of the muscle that keeps the body in position

Answer 7

muscle tone

Question 8

Individual muscle fibers (cells) are arranged in bundles, or _____, held together by dense connective tissue

Answer 8

fascicles

Question 9

a band of dense regular connective tissue that attaches a muscle to a bone

Answer 9

tendon

Question 10

Muscle Cells

The muscle fiber’s cytoplasm is called the ____, and its plasma membrane is the ____.

Extensions of this membrane tunnel deep in the interior of the muscle fiber as a network of ____, which are important in muscle cell stimulation.

Answer 10

sarcoplasm; sarcolemma

T-tubules

Question 11

Muscle Cells

Muscle fibers contain large amounts of smooth endoplasmic reticulum, known as the _____ _____, where calcium is stored.

The vast majority of the muscle fiber’s volume is taken up by bundles of protein filaments called _____, which work to contract the muscle.

Answer 11

sarcoplasmic reticulum (SR)

myofibrils

Question 12

stem cells that can produce new myoblasts

Answer 12

satellite cells

Question 13

the transmission of electrical and chemical signals between cells or even within a single cell

Answer 13

communication

Question 14

Chemical Communication

Chemical signals alter cell activity by binding to specific proteins called _____. The signal that binds the receptor is known as the ____.

A ____ fits into a ____ like a key in a lock.

Answer 14

receptors

ligand

Question 15

nerve cells that carry signals from the brain and spinal cord to stimulate movement

Answer 15

motor neurons

Question 16

nerve cells that carry signals from the peripheral to central nervous system

Answer 16

sensory neurons

Question 17

a single neuron and all the muscle fibers it stimulates constitute a _____

Answer 17

motor unit

Question 18

In a resting cell, the intracellular fluid contains a small excess of negative ions, and the extracellular fluid contains a small excess of positive ions. As a result of these unpaired charges, the plasma membrane of a living cell carries a difference in electric charge (voltage) on either side that is known as a ____ _____

Answer 18

membrane potential

Question 19

Because the membrane potential can change, muscle cells and neurons show the property of _____

These changes create electric signals, because they spread along the membrane, much like an electric current spreads along a wire. This spreading wave of electric current is called the _____ _____ because it calls the cell into action.

Answer 19

excitability

action potential

Question 20

A nerve fiber contacts a muscle cell at a kind of synapse called the _____ _____

At the synapse, there is a tiny space known as the _____ _____, across which acetylcholine travels to attach to a receptor in the muscle cell’s receiving membrane, known as the ____ ____ _____.

Answer 20

neuromuscular junction (NMJ)

synaptic cleft

motor end plate

Question 21

A contracting subunit of skeletal muscle is called a ______

It consists of a band of protein filaments, _____ and ____ , which give muscles their striated appearance.

Answer 21

sarcomere

myosin

actin

Question 22

This image shows the _____ _____ mechanism of muscle contraction

Answer 22

sliding filament

Question 23

In addition to actin, myosin, and ATP, ____ is needed for muscle contraction. It enables cross-bridges to form between actin and myosin so the sliding filament action can begin.

When muscles are at rest, two additional proteins called ____ and ____ block the sites on actin filaments where cross-bridges can form

Answer 23

calcium

troponin (tro-PO-nin)

tropomyosin (tro-po-MI-o-sin)

Question 24

Muscle Contraction:

1. ____ is released from a neuron ending into the synaptic cleft at the NMJ.
2. Acetylcholine then binds to receptors in the muscle’s motor end plate and stimulates an action potential.
3. The action potential travels down the sarcolemma and T-tubules and activates ____ channels in the SR.
4. The SR releases calcium into the cytoplasm.
5. Calcium shifts troponin and tropomyosin so that binding sites on actin are exposed.
6. Myosin heads bind to actin, forming cross-bridges.
7. Using the chemical energy contained in ____, myosin heads pull actin filaments together within the sarcomeres, and the cell shortens.
8. New ATP is used to detach myosin heads and move them back to position for another “power stroke.”
9. The muscle relaxes when stimulation ends, and the calcium is pumped back into the SR.

Answer 24

acetylcholine

calcium

ATP

Question 25

Which neurotransmitter is involved in the stimulation of skeletal muscle cells?

Answer 25

acetylcholine

Question 26

When do anaerobic processes occur?

Answer 26

Anaerobic processes are always occurring, but they are particularly important at the beginning of exercise or during very strenuous exercise.

Question 27

This type of exercise: * increases oxygen consymption * increases the muscles blood supply and mitochondria * strengthens the heart * reduces LDL and improves blood glucose control

Answer 27

endurance training

Question 28

Which compound is formed in oxidation of nutrients that supplies the energy for muscle contraction?

Answer 28

ATP

Question 29

In this type of contraction, there is no change in muscle length, but there is a great increase in muscle tension (ex: trying to lift a building)

Answer 29

isometric contraction

Question 30

In this type of contraction, the tone or tension remains the same but the muscle length changes and the muscle bulges (ex: lifting an object)

Answer 30

isotonic contraction

Question 31

In this type of istonic contraction, a muscle as a whole shortens to produce movement (ex: flexing the arm at the elbow to do a bicep curl)

Answer 31

concentric contraction

Question 32

In this type of istonic contraction, a muscle lengthens as it exerts force (ex: lowering the arm at the at the end of a curl). This is more likely to cause soreness.

Answer 32

eccentric contractions

Question 33

Most body movements involve a combination of both isotonic and isometric contractions. When walking, for example, some muscles contract _____ to propel the body forward, but at the same time, other muscles are contracting _____ to keep your body in position.

Answer 33

isotonically isometrically

Question 34

a broad sheet that attaches some muscles to bones or to other muscles

Answer 34

aponeurosis (ap-o-nu-RO-sis)

Question 35

In moving the bones, one end of a muscle is attached to a more freely movable part of the skeleton, and the other end is attached to a relatively stable part. The less movable (more fixed) attachment is called the \_\_\_\_\_\_. The attachment to the body part that moves is called the \_\_\_\_\_\_

Answer 35

origin insertion

Question 36

The main muscle that performs a given movement is the _____ \_\_\_\_\_ Because any muscle that performs a given action is technically called an agonist (AG-on-ist), the muscle that produces an opposite action is termed the \_\_\_\_\_ The "helping"muscles that stabilize or assist are called \_\_\_\_\_

Answer 36

prime mover antagonist synergists

Question 37

In a _____ \_\_\_\_\_, the fulcrum is located between the resistance and the effort (ex: a seesaw or a pair of scissors or lifting the head)

Answer 37

first-class lever

Question 38

**Levers** In a _____ lever, the effort is between the resistance and the fulcrum. (ex: tweezers; bicep curl) \*\*Most lever systems in the body are this type\*\*

Answer 38

third-class lever

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Question 70

**orbicalus muscles** around the eyes is the _____ \_\_\_\_\_\_ its antagonist is the levator _____ \_\_\_\_\_ around the lips is the _____ \_\_\_\_\_ around the cheek is the \_\_\_\_\_\_\_

Answer 70

**orbicalus** **occuli** ## Footnote **orbicularis oris** **levator palpebrae superioris** **buccinator**

Question 71

**Facial Muscles** There are four pairs of mastication (chewing) muscles, all of which insert on and move the mandible. The largest are the \_\_\_\_\_, which is superior to the ear, and the _____ at the angle of the jaw.

Answer 71

temporalis masseter (mas-SE-ter)

Question 72

**Muscles of Upper Extremities** * arm extension and adduction * originates from the vertebral spine in the middle and lower back * covers the inferior half of the thoracic region

Answer 72

**latissimus dorsi**

Question 73

**Muscles of the Upper Extremities** * Raises shoulders and pulls them back * Superior portion extends and turns head

Answer 73

Question 74

**Muscles of Upper Extremities** * Flexes and raises the arm * Medially rotates the arm, pulling it across the chest * Synergizes with the latissimus dorsi to adduct the arm

Answer 74

pectoralis major

Question 75

**Muscles of the Upper Extremities** * Moves the scapula forward and stabilizes it when pushing or pulling something * Aids in flexing and ABducting the arm above the horizontal level

Answer 75

Question 76

**Muscles of the Upper Extremities** * ABducts the arm up to the horizontal level * Synergizes with pects to flex and rotate anteriorly * Synergizes with lats to extend the arm posteriorly

Answer 76

Question 77

**Muscles of the Upper Extremities** * Supports the shoulder joint * Composed of supraspinatus, infraspinatus, teres minor, and subscapularis, known together as SITS, and their tendons * May be torn during activities like swinging a golf club, pitching a baseball, or playing tenns

Answer 77

Question 78

**Muscles of the Arm** * Supinates the hand​ * Acts as a synergist to flex forearm

Answer 78

Question 79

**Muscles of the Arm** * Flexes the forearm * Steadies the forearm's slow extension

Answer 79

Question 80

**Muscles of the Arm** * Prominent forearm muscle that flexes the forearm

Answer 80

Question 81

**Muscles of the Arm** * Extends the forearm (straighten the arm) * "Important in pushing because it converts the arm and forearm into a sturdy rod"

Answer 81

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Question 85

**Muscles of Respiration** * Separates thoracic and abdominal cavitoes * When it contracts, the dome-shaped portion is pulled downwards, enlarging the thoracic cavity and allowing inhalation

Answer 85

Question 86

Muscles of Respiration * Change thoracic volume * Attached to the ribs and fill the spaces between them

Answer 86

intercostal muscles

Question 87

**Muscles of the Abdomen** * The abdominal wall has 3 muscle layers: the ____ \_\_\_\_\_ on the exterior, the _____ \_\_\_\_\_ in the middle, and the _____ \_\_\_\_\_ innermost

Answer 87

**internal oblique** **external oblique** **trasversus abdominis**

Question 88

**Muscles of the Abdomen** * Six pack muscles are also known as _____ \_\_\_\_\_ * The midline meeting of the aponeuroses forms the _____ \_\_\_\_\_, which goes from the sternum to the pubic joint

Answer 88

**rectus abdominis** **linea alba**

Question 89

**Muscles of the Pelvis** * Also known as the pelvic floor, the \_\_\_\_\_, has its own form of diaphragm * One of the main muscles is the _____ \_\_\_\_\_ which acts on the rectum and aids in defecation

Answer 89

**perineum** **levator ani**

Question 90

**Deep Muscles of the Back** * This large muscle group goes from the sacrum to the skull * Extends the spine and maintain erect posture * Can be strained if the spine is flexed while lifting

Answer 90

erector spinae

Question 91

**Muscles that move the thigh and leg** * The _____ \_\_\_\_\_ extends the thigh and is important in walking/running by providing a pushing force at the end of the stride * The ______ \_\_\_\_\_ ABducts the thigh and is often used for intramusclar injections

Answer 91

Question 92

**Adductor Muscles** * The adductor muscles are located on the medial thigh; originate at pelvis; insert on the femur * Press the thighs together, as in grasping a saddle between the knees when riding a horse * They include the adductor _____ and adductor \_\_\_\_\_. * Also located in the medial thigh, the _____ crosses both the hip joint and the knee joint. It too adducts the thigh and also flexes the leg at the knee

Answer 92

longus; magnus gracilis

Question 93

**Muscles of the thigh** * A long, narrow muscle that begins at the iliac sine, winds downward and medially across the anterior thigh, and ends on the tibia’s superior medial surface * Called the tailor’s muscle because it is used in crossing the legs in the manner of tailors, who, in days gone by, sat cross-legged on the floor.

Answer 93

Sartorius

Question 94

**Muscles that move the thigh and leg** * The rectus femoris, vastus medialis, vastus medialis, and vastus intermedius make up the ______ \_\_\_\_\_\_

Answer 94

**quadriceps femoris**

Question 95

Muscles that move the leg and thigh * The ______ muscles are made up of the biceps femoris, the semimembranosus, and the semitendinosus * They flex the leg at the knee (as in kneeling) * Extend and rotate the thigh at the hip

Answer 95

hamstring muscles

Question 96

**Muscles that move the foot** * The chief muscle of the calf of the leg is the \_\_\_\_\_\_, which is sometimes called the "toe dancer's" muscle because it is used when standing on tiptoe * The _____ is a flat muscle deep to the gastrocnemius, which is also involved in plantar flexion

Answer 96

gastrocnemius (gas-trok-NE-me-us) soleus

Question 97

**Muscules that move the leg and foot** * Located on the on anterior region of the leg, the ______ \_\_\_\_\_\_ performs dorsiflexion and inversion * On the lateral leg, the ______ \_\_\_\_\_\_ performs eversion

Answer 97

**tibialis anterior** **fibularis longus**