Muscular System Flashcards
Compare the three types of muscle tissue
- 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
What are the three functions of skeletal muscle?
1) Movement of the skeleton
2) Maintenance of posture
3) Generation of heat
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.
endomysium(endo- “within”)
perimysium (peri- “around)
epimysium (epi- “above”)
List compounds stored in muscle cells that are used to generate energy:
_____ stores oxygen
_____ is the storage form of glucose
Myoglobin
Glycogen
Explain what happens in muscle cells contracting anaerobically.
- 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.
- ________ 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.
creatine (KRE-ah-tin) phosphate
Anaerobic glycolysis
lactate
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.
Resistance training
a steady partial contraction of the muscle that keeps the body in position
muscle tone
Individual muscle fibers (cells) are arranged in bundles, or _____, held together by dense connective tissue
fascicles
a band of dense regular connective tissue that attaches a muscle to a bone
tendon
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.
sarcoplasm; sarcolemma
T-tubules
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.
sarcoplasmic reticulum (SR)
myofibrils
stem cells that can produce new myoblasts
satellite cells
the transmission of electrical and chemical signals between cells or even within a single cell
communication
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.
receptors
ligand
nerve cells that carry signals from the brain and spinal cord to stimulate movement
motor neurons
nerve cells that carry signals from the peripheral to central nervous system
sensory neurons
a single neuron and all the muscle fibers it stimulates constitute a _____
motor unit
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 ____ _____
membrane potential
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.
excitability
action potential
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 ____ ____ _____.
neuromuscular junction (NMJ)
synaptic cleft
motor end plate
A contracting subunit of skeletal muscle is called a ______
It consists of a band of protein filaments, _____ and ____ , which give muscles their striated appearance.
sarcomere
myosin
actin
This image shows the _____ _____ mechanism of muscle contraction
sliding filament
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
calcium
troponin (tro-PO-nin)
tropomyosin (tro-po-MI-o-sin)
Muscle Contraction:
- ____ is released from a neuron ending into the synaptic cleft at the NMJ.
- Acetylcholine then binds to receptors in the muscle’s motor end plate and stimulates an action potential.
- The action potential travels down the sarcolemma and T-tubules and activates ____ channels in the SR.
- The SR releases calcium into the cytoplasm.
- Calcium shifts troponin and tropomyosin so that binding sites on actin are exposed.
- Myosin heads bind to actin, forming cross-bridges.
- Using the chemical energy contained in ____, myosin heads pull actin filaments together within the sarcomeres, and the cell shortens.
- New ATP is used to detach myosin heads and move them back to position for another “power stroke.”
- The muscle relaxes when stimulation ends, and the calcium is pumped back into the SR.
acetylcholine
calcium
ATP
Which neurotransmitter is involved in the stimulation of skeletal muscle cells?
acetylcholine
When do anaerobic processes occur?
Anaerobic processes are always occurring, but they are particularly important at the beginning of exercise or during very strenuous exercise.
This type of exercise:
- increases oxygen consymption
- increases the muscles blood supply and mitochondria
- strengthens the heart
- reduces LDL and improves blood glucose control
endurance training
Which compound is formed in oxidation of nutrients that supplies the energy for muscle contraction?
ATP
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)
isometric contraction
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)
isotonic contraction
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)
concentric contraction
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.
eccentric contractions
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.
isotonically
isometrically
a broad sheet that attaches some muscles to bones or to other muscles
aponeurosis (ap-o-nu-RO-sis)
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 ______
origin
insertion
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 _____
prime mover
antagonist
synergists
In a _____ _____, the fulcrum is located between the resistance and the effort (ex: a seesaw or a pair of scissors or lifting the head)
first-class lever
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**
third-class lever
orbicalus muscles
around the eyes is the _____ ______
its antagonist is the levator _____ _____
around the lips is the _____ _____
around the cheek is the _______
orbicalus occuli
orbicularis oris
levator palpebrae superioris
buccinator
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.
temporalis
masseter (mas-SE-ter)
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
latissimus dorsi
Muscles of the Upper Extremities
- Raises shoulders and pulls them back
- Superior portion extends and turns head
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
pectoralis major
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
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
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
Muscles of the Arm
- Supinates the hand
- Acts as a synergist to flex forearm
Muscles of the Arm
- Flexes the forearm
- Steadies the forearm’s slow extension
Muscles of the Arm
- Prominent forearm muscle that flexes the forearm
Muscles of the Arm
- Extends the forearm (straighten the arm)
- “Important in pushing because it converts the arm and forearm into a sturdy rod”
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
Muscles of Respiration
- Change thoracic volume
- Attached to the ribs and fill the spaces between them
intercostal muscles
Muscles of the Abdomen
- The abdominal wall has 3 muscle layers: the ____ _____ on the exterior, the _____ _____ in the middle, and the _____ _____ innermost
internal oblique
external oblique
trasversus abdominis
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
rectus abdominis
linea alba
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
perineum
levator ani
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
erector spinae
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
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.
Sartorius
Muscles that move the thigh and leg
- The rectus femoris, vastus medialis, vastus medialis, and vastus intermedius make up the ______ ______
quadriceps femoris
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
hamstring muscles
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
gastrocnemius (gas-trok-NE-me-us)
soleus
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
tibialis anterior
fibularis longus
