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Essentials of Human Anatomy & Physiology > Muscular system > Flashcards

Muscular system Flashcards

1
Q

Three basic muscle types are found in the body

A

Skeletal muscle
Cardiac muscle
Smooth muscle

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2
Q

Each muscle is a discrete organ, composed of:

A 
Each muscle is a discrete organ, composed of:
muscle fibers
blood vessels
nerve fibers
connective tissue
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3
Q

Endomysium

A

Endomysium - encloses a single muscle fiber

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4
Q

Perimysium

A

wraps around a fascicle (bundle) of muscle fibers

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5
Q

Epimysium

A

Epimysium - surrounds entire muscle

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6
Q

Sites of muscle attachment

A

Bones (with or without tendons)
Cartilage
Aponeuroses - connective tissue sheet-like covering

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7
Q

Skeletal muscle functions

A

Produce skeletal movement
Maintain body posture and body position
Stabilize joints
Generate heat

Support soft tissue and surrounding visceral organs and internal tissues
Move blood and fluids through body, plus aiding with respiration
Guard entrances and exits – swallowing, digestive, urinary
Provide nutrient reserves - starvation

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8
Q

Muscle cell (myocyte) =

A

Muscle cell (myocyte) = muscle fiber

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9
Q

Cell membrane =

A

Cell membrane = sarcolemma

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10
Q

Cytoplasm =

A

Cytoplasm = sarcoplasm

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11
Q

Endoplasmic reticulum (ER) =

A

Endoplasmic reticulum (ER) = sarcoplasmic reticulum (SR)

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12
Q

Contain hundreds of nuclei
Filled with cylindrical structures called myofibrils
Contain actin and myosin

A

muscle fibers

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13
Q

complex organelle composed of bundles of myofilaments

A

Myofibril or Fibril

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14
Q

Specialized smooth endoplasmic reticulum
Stores and releases calcium
Surrounds the myofibril

A

Sarcoplasmic reticulum (SR)

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15
Q

How do actin and myosin act to contract the muscle and make it move?

A

Actin and myosin slide past each other causing the fibre to shorten
The fibre lengthens when the actin and myosin go back to their original places

Actin & myosin give the muscle it’s striated look under the microscope

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16
Q

When a nerve impulse reaches the axon terminal of the motor neuron,

A

1.Calcium channels open, and calcium ions enter the axon terminal
2.Calcium ion entry causes some synaptic vesicles to release acetylcholine (ACh)
3. ACh diffuses across the synaptic cleft and attaches to receptors on the sarcolemma of the muscle cell
I4.f enough ACh is released, the sarcolemma becomes temporarily more permeable to sodium (Na)
5.Depolarization opens more sodium channels that allow sodium ions to enter the cell
Once started, the action potential cannot be stopped, and contraction occurs
6. Enough depolarization allows for Ca2+ to be released from the sarcoplasmic reticulum (SR)
Surrounds the myofibrils and allows for actin and myosin to link
7. K+ efflux causes repolarization and reuptake of Ca2+ back into the SR
8. Acetylcholinesterase (AChE) breaks down acetylcholine into acetic acid and choline
AChE ends muscle contraction

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17
Q

If neuromuscular junction sites are altered

A

If neuromuscular junction sites are altered
can’t bind with ACh - muscle weakness will occur
Ex: Myasthenia Gravis

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18
Q

Muscle fibers contain a reddish brown pigment called ________
Fibers that are red have high amounts of _______, while those that are white have low amounts
_______ allows for high amounts of oxygen to be available to muscle fibers

A

Myoglobin

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19
Q

Properties of muscle fibers

A

Excitability (also called responsiveness or irritability) - ability to receive and respond to a stimulus
Contractility - ability to shorten when an adequate stimulus is received
Extensibility - ability of muscle cells to be stretched
Elasticity - ability to recoil and resume resting length after stretching

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20
Q

Skeletal muscles must be stimulated by a ________ _______ to contract

A

Skeletal muscles must be stimulated by a motor neuron (nerve cell) to contract

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21
Q

one motor neuron and all the skeletal muscle cells stimulated by that neuron

A

Motor unit

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22
Q

Single, brief contraction

Not a normal muscle function

A

Twitch

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23
Q

One contraction is immediately followed by another
Because stimulations are more frequent, the muscle does not completely return to a resting state
The effects are “summed” (added

A

Summing of contractions

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24
Q

Some relaxation occurs between contractions, but nerve stimuli arrive at an even faster rate than during summing of contractions
Unless the muscle contraction is smooth and sustained, it is said to be in ______ _______

A

Unfused (incomplete) tetanus

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25
No evidence of relaxation before the following contractions Frequency of stimulations does not allow for relaxation between contractions The result is a smooth and sustained muscle contraction
Fused (complete) tetanus
26
If muscle activity is strenuous and prolonged, muscle fatigue occurs because:
If muscle activity is strenuous and prolonged, muscle fatigue occurs because: Ionic imbalances occur Lactic acid accumulates in the muscle Energy (ATP) supply decreases
27
The common reason for muscle fatigue is
The common reason for muscle fatigue is O2 debt
28
Isotonic contractions
Isotonic contractions Muscle shortens and the muscle contraction causes movement Example is bending knee, rotating arms, smiling
29
Isometric contractions
Isometric contractions Tension in the muscles increases – generate force without movement The muscle does not shorten
30
Aerobic exercise – uses high amounts of O2
``` Aerobic exercise – uses high amounts of O2 Increases heart rate Increases blood supply to muscles Increases body metabolism increases digestion and elimination Improves coordination Increased bone density Improved blood flow to whole body Efficient gas exchange at lungs ```
31
atrophy
response when muscles are not used as much and they decrease in size
32
fixator
designed to stabilize a joint during movement. fixators groups in ankle prevent them from wobbling when standing
33
antagonist
muscles that oppose the action of another muscle
34
synergist
synergist also known as "helper muscles", that assist the primer mover. can produce same movement or stabilize joints across where prime mover acts, preventing undesirable movements
35
_____ of the muscle attaches to the more movable bone
Insertion
36
_____ of the muscle attaches to the stationary (unmovable) bone
origin
37
muscle's function to response to stimuli
irritability
38
gap junctions that promote rapid conduction of electrical signals throughout the heart
intercalated discs
39
nonstriated muscle
smooth muscle
40
moves the bones of the face
skeletal muscle
41
Cardiac and Smooth are involuntary while skeletal is _______
voluntary
42
Cardiac and ______ muscles are striated
Skeletal
43
Touching the thumb to other fingers
Opposition
44
Forearm rotation medially so that the palm faces posteriorly and the ulna and radius are crossed
Pronation
45
Forearm rotation laterally so that the palm is facing anteriorly and the radius and ulna are parallel
Supination
46
A combination of all the movements, commonly seen in ball and socket joints where the proximal end of the limb is stationary while the distal end moves in a circle
Circumduction
47
Opposite of abduction; movement of a limb toward the body midline
Adduction
48
moving a limb away in the frontal plane from the median plane of the body, spreading the fingers apart
Abduction
49
Movement of a bone around its longitudinal axis.
Rotation
50
]Opposite of flexion; movement in the saggital plane that increases the angle of the joint or distance between two bones or parts of the body.
Extension .
51
Movement in the saggital plane that decreases the angle of the joint and brings two bones closer together.
Flexion
52
A place where a muscle attaches on a bone that is moved by the muscle.
Insertion
53
Origin
Origin A place where a muscle attaches on a bone that is not moved by that muscle.
54
A metabolic process that doesn't require oxygen. Glucose is broken down to pyruvic acid to produce some ATP. Pyruvic acid is then converted to lactic acid.
Anaerobic Glycolysis
55
A metabolic process requiring oxygen and taking place in the mitochondria. Glucose and fat are broken down to carbon dioxide and water in order to release energy.
Aerobic Respiration
56
The process in which creatine phosphate, a high energy molecule, has its energy released to ADP in order to regenerate it to ATP.
Direct Phosphorylation
57
A unit of stored energy which muscles use initially for contraction. Only 4-6 seconds of ATP energy is stored by muscles. The bonds within ATP are broken in order to release the energy.
ATP
58
The place at which the nervous system is connected to the muscular system through a synapse. It is here in which the muscle cells are simulated by a single neuron
Neuromuscular Junction
59
A structure within a unit of myofibril. It is a membrane which actin is embedded in.
Z Disc
60
The contractile unit of a myofibril consisting of Z-discs, A-bands, and I-bands.
Sarcomere
61
Microfilaments of actin and myosin in repeating subunits.
Myofibrils
62
The special type of smooth endoplasmic reticulum found in smooth and striated muscle fibers whose function is to store and release calcium ions.
Sarcoplasmic reticulum
63
The cell membrane of a striated muscle cell.
Sarcolemma
64
Cardiac Muscle
One of the three types of muscle tissues. These have striations, usually a single nucleus, are joined together by another muscle cell by an intercalated disc, function involuntarily, and are found only in the heart.
65
Smooth Muscle
One of the three different types of muscle tissue. This muscle has no striations and is formed from spindle shaped cells, they possess a single nucleus, move involuntarily, and are found mainly in the walls of hollow organs.
66
A type of connective tissue formed when epimysium blends into particular connective tissue attachments.
Collagen Fibers of the Skin
67
A sheet like structure whose primary function is to join muscles to the body parts (bone or muscle) the muscles act upon.Is formed by epimysium blending into connective tissue attachments.
Aponeurosis
68
Is a cord like structure which connects muscles to bones. It is formed by epimysium blending into connective tissue attachments.
Tendon
69
Epimysium
A connective tissue wrapping which covers the entire skeletal muscle.
70
Perimysium
Perimysium A connective tissue wrapping which wraps itself around a fascicle (bundle) of cells/fibers.
71
Endomysium
A connective tissue wrapping which wraps itself around a single muscle cell/fiber.
72
One of the three types of muscles. Muscles move voluntarily and are attached by tendons to bones. They are long, multinucleate (have multiple nucleus), appear striated (due to arrangement of actin and myacin), and are surrounded and bundled by connective tissue. (which supplies nutrients)
Skeletal Muscle
73
A type of tissue which is responsible for movement in body. This movement produces heat as a byproduct.
Muscles
74
Skeletal muscles named based on:
``` Skeletal muscles named based on: Region of body (femoris = thigh) Position (posterior = back) Nature of origin or insertion (biceps = two heads) Shape (deltoid = triangle) Size (maximus = largest) Action (flexor = bending movement) ```
75
Support and position axial skeleton | Aid in breathing
Axial Muscles
76
Support, move, and brace limbs
Apendicular Muscle
77
Facial muscles
Frontalis - raises eyebrows Orbicularis oculi - closes eyes, squints, blinks, winks Orbicularis oris - closes mouth and protrudes the lips Buccinator - flattens the cheek, chews Zygomaticus - raises corners of the mouth
78
Chewing muscles
Chewing muscles Masseter - closes the jaw and elevates mandible Temporalis - synergist of the masseter, closes jaw
79
Neck muscles
Platysma – pulls the corners of the mouth inferiorly | Sternocleidomastoid – flexes the neck, rotates the head
80
Anterior muscles
Pectoralis major - adducts and flexes the humerus | Intercostal muscles – movement of rib cage for breathing
81
Muscles of the abdominal girdle
Rectus abdominis - flexes vertebral column and compresses abdominal contents (defecation, childbirth, forced breathing) External and internal obliques - flex vertebral column; rotate trunk and bend it laterally Transversus abdominis - compresses abdominal contents
82
Posterior muscles
Trapezius - elevates, depresses, adducts, and stabilizes the scapula Latissimus dorsi - extends and adducts the humerus Erector spinae - back extension Quadratus lumborum - flexes the spine laterally Deltoid - arm abduction because of the size of the deltoid, it is a favorite site for injections of small amounts (less than 5 mL)
83
Muscles of the upper limb
Biceps brachii - flexes elbow Brachialis - elbow flexion Brachioradialis - weak muscle for elbow flexion Triceps brachii - elbow extension (antagonist to biceps brachii) Biceps brachii, brachialis, and brachioradialis are all anterior muscles, while triceps brachii is the only posterior muscle
84
Muscles causing movement at the hip joint and thigh
``` Gluteus maximus - hip extension Gluteus medius - hip abduction Iliopsoas - hip flexion Adductor muscles - adduct the thighs Sartorius - flexes the thigh ```
85
Hamstring group - thigh extension and knee flexion
Biceps femoris Semimembranosus Semitendinosus
86
Quadriceps group - extends the knee
``` Rectus femoris (also flexes hip) Vastus muscles (three) Vastus lateralis Vastus intermedius Vastus medialis ```
87
Muscles causing movement at ankle and foot
Tibialis anterior - dorsiflexion Gastrocnemeus – plantar flexion (and weak knee flexor) Soleus - plantar flexion
88
If muscle activity is strenuous and prolonged, muscle fatigue occurs because:
If muscle activity is strenuous and prolonged, muscle fatigue occurs because: Ionic imbalances occur Lactic acid accumulates in the muscle Energy (ATP) supply decreases
89
Aerobic respiration
Aerobic respiration Glucose is broken down to CO2 and H2O, releasing ATP Slower reaction that requires O2 Series of metabolic steps occurring in the mitochondria Lasts for a very long time
90
Anaerobic glycolysis and lactic acid formation
Breakdown of glucose without O2 Glucose  pyruvic acid  lactic acid This reaction is not efficient, but is fast Only lasts for 30 – 60 seconds
91
Direct phosphorylation of ADP by creatine phosphate (CP)
Direct phosphorylation of ADP by creatine phosphate (CP) Muscle cells store CP CP = high-energy molecule After ATP is depleted, ADP is left CP transfers energy to ADP, to regenerate ATP CP supplies are exhausted in less than 15 seconds
92
Aerobic exercise
``` uses high amounts of O2 Increases heart rate Increases blood supply to muscles Increases body metabolism increases digestion and elimination Improves coordination Increased bone density Improved blood flow to whole body Efficient gas exchange at lungs ```

Essentials of Human Anatomy & Physiology (10 decks)

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