The Muscular System
6.1.1 Describe similarities and differences in the structure and function of the three types of muscle tissue and indicate where they are found in the body.
v Muscles are responsible for all types of body movement
v Three basic muscle types are found in the body
Ø ______
Ø ______
Ø ______
v Characteristics of Muscles
Ø Skeletal and smooth muscle cells are ______(muscle cell = muscle fiber)
Ø Contraction of muscles is due to the movement of microfilaments
Ø All muscles share some terminology
o Prefixes _____ and _____ refer to “muscle”
o Prefix _____ refers to “flesh”
v Skeletal Muscle Characteristics
Ø Most are attached by ______to bones
Ø Cells are ______
Ø ______—have visible banding
Ø ______—subject to conscious control
6.1.2_____ Define and explain the role of the following: endomysium, perimysium, epimysium, tendon, and aponeurosis.
v Connective Tissue Wrappings of Skeletal Muscle
Ø Cells are surrounded and bundled by connective tissue
o Endomysium—encloses a ______muscle fiber
o Perimysium—wraps around a ______(bundle) of muscle fibers
o Epimysium—covers the ______skeletal muscle
o Fascia—on the outside of the ______
v Skeletal Muscle Attachments
Ø Epimysium blends into a connective tissue attachment
o ______—cord-like structures
§ Mostly collagen fibers
§ Often cross a joint due to toughness and small size
o ______—sheet-like structures
§ Attach muscles indirectly to bones, cartilages, or connective tissue coverings
§ Skeletal Muscle Attachments
Ø Sites of muscle attachment
o Bones
o Cartilages
o Connective tissue coverings
6.1.1 Describe similarities and differences in the structure and function of the three types of muscle tissue and indicate where they are found in the body.
v Smooth Muscle Characteristics
Ø Lacks ______
Ø Spindle-shaped cells
Ø ______nucleus
Ø ______—no conscious control
Ø Found mainly in the walls of ______organs
Ø Usually ______layers
v Cardiac Muscle Characteristics
Ø ______
Ø Usually has a single nucleus
Ø ______cells
Ø Joined to another muscle cell at an intercalated disc
Ø ______
Ø Found only in the ______
v Skeletal Muscle Functions
Ø Produce ______
Ø Maintain ______
Ø Stabilize joints
Ø Generate ______
6.1.3 Describe the microscopic structure of skeletal muscle and explain the role of actin- and myosin-containing myofilaments.
v Microscopic Anatomy of Skeletal Muscle
Ø Sarcolemma—specialized ______membrane
Ø Myofibrils—long ______inside muscle cell
Ø ______reticulum—specialized smooth endoplasmic reticulum
Ø ______are aligned to give distinct bands
o I band = ______band
§ Contains only thin filaments
o A band = ______band
§ Contains the entire length of the thick filaments
Ø Sarcomere— ______unit of a muscle fiber
Ø Organization of the sarcomere
o Myofilaments
§ Thick filaments = ______filaments
§ Thin filaments = ______filaments
§ Microscopic Anatomy of Skeletal Muscle
Ø Thick filaments = myosin filaments
o Composed of the ______myosin
o Has ATP enzymes
o Myosin filaments have ______(extensions, or cross bridges)
o Myosin and actin ______somewhat
Ø Thin filaments = actin filaments
o Composed of the ______actin
o Anchored to the ______disc
§ Microscopic Anatomy of Skeletal Muscle
Ø At rest, there is a bare zone that lacks actin filaments called the H zone
v Sarcoplasmic reticulum (SR)
Ø Stores and releases calcium
Ø Surrounds the myofibril
Stimulation and Contraction of Single Skeletal Muscle Cells
v Excitability (also called responsiveness or irritability)—ability to receive and respond to a ______
v ______—ability to shorten when an adequate stimulus is received
v Extensibility—ability of muscle cells to be ______
v Elasticity—ability to ______and resume resting length after stretching
6.2.1 Describe how an action potential is initiated in a muscle cell.
The Nerve Stimulus and Action Potential - How a muscle actually contracts
v Skeletal muscles must be stimulated by a ______(nerve cell) to contract
v Motor unit—one motor neuron and all the skeletal muscle cells stimulated by that neuron
v Neuromuscular junction-
Ø Association site of axon terminal of the motor neuron and muscle
v ______cleft
Ø ______between nerve and muscle
Ø Nerve and muscle ______make contact
Ø Area between nerve and muscle is filled with interstitial fluid
v Transmission of Nerve Impulse to Muscle
1) Neurotransmitter—______released by nerve upon arrival of nerve impulse
- The neurotransmitter for skeletal muscle is acetylcholine (______)
2) Acetylcholine attaches to receptors on the ______
3) Sarcolemma becomes permeable to ______
4) Sodium rushes into the cell generating an action potential
6.2.2 _____ Describe the events of muscle cell contraction
v The Sliding Filament Theory of Muscle Contraction
1) Regulatory proteins are in the ______sites
2) Activation by a nerve causes ______to be released from the sarcoplasmic reticulum.
3) Ca+2 binds to ______
4) Regulatory proteins change shape and ______
5) ______(cross bridges) attach to binding sites on the thin filament
6) Myosin heads then bind to the next site of the thin filament and pull them toward the center of the ______
7) This continued action causes a sliding of the myosin along the actin
8) There is always myosin heads attached to the ______
9) The result is that the muscle is shortened (contracted)
6.3.1 Define origin, insertion, prime mover, antagonist, synergist, and fixator as they relate to muscles.
6.3.2 Demonstrate or identify the different types of body movements.
Muscles and Body Movements
v Movement is attained due to a muscle moving an attached bone
v Muscles are attached to at least two points
Ø ______- Attachment to a moveable bone
Ø ______- Attachment to an immovable bone
Types of Ordinary Body Movements
v Flexion
Ø Decreases the angle of the joint
Ø Brings two bones ______
Ø Typical of hinge joints like knee and elbow
v Extension
Ø ______of flexion
Ø Increases angle between two bones
v ______
Ø Movement of a bone around its ______axis
Ø Common in ball-and-socket joints
Ø Example is when you move atlas around the dens of axis (shake your head “no”)
v Abduction
Ø Movement of a limb ______from the midline
v Adduction
Ø Opposite of abduction
Ø Movement of a limb ______the midline
v ______
Ø Combination of flexion, extension, abduction, and adduction
Ø Common in ball-and-socket joints
Ø You make an imaginary cone
Special Movements
v Dorsiflexion
Ø ______the foot so that the superior surface approaches the shin
v Plantar flexion
Ø Depressing the foot ( ______)
v Inversion
Ø Turn sole of foot ______. Toward the inside
v ______
Ø Turn sole of foot laterally. Toward the outside
v Supination
Ø Forearm rotates laterally so palm faces ______
v Pronation
Ø Forearm rotates medially so palm faces ______
v ______
Ø Move thumb to touch the tips of other fingers on the same hand
Types of Muscles
v Prime mover—muscle with the major ______for a certain movement
v Antagonist—muscle that ______or reverses a prime mover
v ______—muscle that aids a prime mover in a movement and helps prevent rotation
v Fixator—______the origin of a prime mover
6.3.3_____ List some criteria used in naming muscles.
Naming Skeletal Muscles
v By ______of muscle fibers
Ø Example: Rectus (straight)
v By relative ______of the muscle
Ø Example: Maximus (largest)
v By ______of the muscle
Ø Example: Temporalis (temporal bone)
v By number of ______
Ø Example: Triceps (three heads)
v By location of the muscle’s origin and insertion
Ø Example: Sterno (on the sternum)
v By ______of the muscle
Ø Example: Deltoid (triangular)
v By ______of the muscle
Ø Example: Flexor and extensor (flexes or extends a bone)