Muscular System

What is the topic of Chapter 6 in the book?; The Muscular System.
What are muscles responsible for in the body?; All types of body movement.
How do muscles function in the body?; They contract or shorten.
What are the three basic muscle types found in the body?; Skeletal muscle, Cardiac muscle, Smooth muscle.
What is the shape of muscle cells?; Elongated (muscle cell = muscle fiber).
What causes the contraction of muscles?; Movement of microfilaments.
What do the prefixes 'myo' and 'mys' refer to?; Muscle.
What does the prefix 'sarco' refer to?; Flesh.
How are most skeletal muscles attached?; Most are attached by tendons to bones.
What is the characteristic of skeletal muscle cells in terms of nuclei?; Cells are multinucleate.
What does it mean for skeletal muscles to be striated?; They have visible banding.
Are skeletal muscles voluntary or involuntary?; Voluntary – subject to conscious control.
How are skeletal muscle cells surrounded and bundled?; By connective tissue, which allows great force but tires easily.
What is the function of endomysium?; To wrap around a single muscle fiber.
What does perimysium wrap around?; A fascicle (bundle) of muscle fibers.
What does the epimysium cover?; The entire skeletal muscle.
What is the fascia?; It is on the outside of the epimysium.
What does the epimysium blend into?; A connective tissue attachment.
What is a tendon?; A cord-like structure.
What is an aponeurosis?; A sheet-like structure.
What are the sites of muscle attachment?; Bones, cartilages, and connective tissue coverings.
What are the characteristics of smooth muscle?; No striations, spindle-shaped cells, single nucleus, involuntary (no conscious control), found mainly in the walls of hollow organs, slow, sustained, and tireless.
What are the characteristics of cardiac muscle?; Striated, usually has a single nucleus, joined to another muscle cell at an intercalated disc, and involuntary.
Where is cardiac muscle found?; Only in the heart.
How is cardiac muscle connected to another muscle cell?; At an intercalated disc.
What is the pace of cardiac muscle?; Steady pace.
What is one function of muscles?; To produce movement.
How do muscles help maintain posture?; By contracting and providing support.
What role do muscles play in stabilizing joints?; They help to support and protect the joints.
In addition to movement, what else do muscles generate?; Heat.
What is the characteristic of the nuclei in skeletal muscle cells?; They are multinucleate and located just beneath the sarcolemma.
What is the sarcolemma?; Specialized plasma membrane.
What is the sarcoplasmic reticulum?; Specialized smooth endoplasmic reticulum.
What is a myofibril?; Bundles of myofilaments.
How are myofibrils aligned to give distinct bands?; I band represents the light band, and A band represents the dark band.
What does the I band represent?; The light band.
What does the A band represent?; The dark band.
What is the sarcomere?; The contractile unit of a muscle fiber.
What is the organization of the sarcomere?; It consists of thick filaments (myosin filaments) and thin filaments (actin filaments).
What are thick filaments in the sarcomere composed of?; The protein myosin.
What enzymes do thick filaments (myosin filaments) have?; ATPase enzymes.
What is the organization of the sarcomere?; The sarcomere is organized with thin filaments (actin filaments) composed of the protein actin.
What are thin filaments composed of in the sarcomere?; Thin filaments are composed of the protein actin.
What are the extensions of myosin filaments called?; Heads or cross bridges.
What is the relationship between myosin and actin?; They overlap somewhat.
What is irritability in the context of skeletal muscle?; The ability to receive and respond to a stimulus.
What is contractility in the context of skeletal muscle?; The ability to shorten when an adequate stimulus is received.
What is required for skeletal muscles to contract?; Stimulation by a nerve (motor neuron).
What is a motor unit?; One neuron and the muscle cells stimulated by that neuron.
What is the association site of nerve and muscle called?; Neuromuscular junctions.
What is the synaptic cleft?; The gap between nerve and muscle.
Do nerves and muscles make direct contact?; No, they do not make contact.
What fills the area between the nerve and muscle?; Interstitial fluid.
What is a neurotransmitter?; A chemical released by a nerve upon arrival of a nerve impulse.
What is the neurotransmitter for skeletal muscle?; Acetylcholine.
Where does the neurotransmitter attach in the muscle?; To receptors on the sarcolemma.
What happens to the sarcolemma when the neurotransmitter attaches?; It becomes permeable to sodium (Na+).
What generates an action potential for the transmission of nerve impulse to muscle?; Sodium rushing into the cell.
Can muscle contraction be stopped once it has started?; No, once started, muscle contraction cannot be stopped.
What causes myosin heads to attach to binding sites on the thin filament?; Activation by nerve.
What do myosin heads bind to after attaching to the binding sites on the thin filament?; The next site of the thin filament.
What is another name for myosin heads?; Crossbridges.
What is the Sliding Filament Theory related to?; Muscle Contraction.
What causes the sliding of myosin along actin in the Sliding Filament Theory?; Continued action.
What is the result of the sliding of myosin along actin in the Sliding Filament Theory?; Shortening (contraction) of the muscle.
What is the Sliding Filament Theory?; A theory that explains muscle contraction by the sliding of actin and myosin filaments.
What does the Sliding Filament Theory explain?; Muscle contraction.
Is muscle fiber contraction 'all or none'?; Yes, muscle fiber contraction is 'all or none'.
Can all fibers within a skeletal muscle be stimulated during the same interval?; No, not all fibers within a skeletal muscle may be stimulated during the same interval.
What may give differing responses in a skeletal muscle?; Different combinations of muscle fiber contractions.
What are graded responses in skeletal muscles?; Different degrees of skeletal muscle shortening.
What does rapid stimulus result in for skeletal muscles?; Constant contraction or tetanus.
What does muscle force depend upon?; The number of fibers stimulated.
What results in greater muscle tension?; More fibers contracting.
Can muscles continue to contract unless they run out of energy?; Yes.
What do muscles initially use for energy during contraction?; Stored ATP.
How is energy released for muscle contraction from ATP?; The bonds of ATP are broken.
How much ATP is stored by muscles initially?; 4-6 seconds worth.
What must be utilized to produce ATP for muscle contraction after the initial 4-6 seconds?; Other pathways.
What is the process of directly phosphorylating ADP to regenerate ATP?; Direct phosphorylation.
What high-energy molecule do muscle cells contain for energy transfer?; Creatine phosphate (CP).
What happens to ADP after ATP is depleted?; ADP is left.
How does creatine phosphate regenerate ATP?; By transferring energy to ADP.
How long do CP supplies last before being exhausted?; About 20 seconds.
What is anaerobic glycolysis?; A reaction that breaks down glucose without oxygen.
What is the end product of glucose breakdown in anaerobic glycolysis?; Pyruvic acid and some ATP.
What happens to pyruvic acid in anaerobic glycolysis?; It is converted to lactic acid.
What is anaerobic glycolysis?; A process that provides energy for muscle contraction without the use of oxygen.
Why is anaerobic glycolysis not as efficient?; It requires huge amounts of glucose.
What does lactic acid production lead to?; Muscle fatigue.
What is aerobic respiration?; A series of metabolic pathways that occur in the mitochondria.
What happens to glucose during aerobic respiration?; It is broken down to carbon dioxide and water, releasing energy.
What is the speed of the reaction in aerobic respiration?; Slower and requires continuous oxygen.
What happens when a muscle is fatigued?; It is unable to contract.
What is the common reason for muscle fatigue?; Oxygen debt.
What must be 'repaid' to tissue to remove oxygen debt?; Oxygen.
What is required to get rid of accumulated lactic acid?; Oxygen.
What causes the muscle to contract less?; Increasing acidity (from lactic acid) and lack of ATP.
What happens during isotonic contractions?; Myofilaments are able to slide past each other, and the muscle shortens.
What occurs during isometric contractions?; Tension in the muscles increases, and the muscle is unable to shorten.
What is muscle tone?; Some fibers are contracted even in a relaxed muscle.
How does muscle tone work?; Different fibers contract at different times to provide muscle tone.
Is the process of stimulating various fibers under voluntary or involuntary control?; Involuntary control.
How is movement attained in the body?; Movement is attained due to a muscle moving an attached bone.
How many points are muscles attached to?; At least two points.
What is the origin of a muscle?; The attachment to a moveable bone.
What is the insertion of a muscle?; The attachment to an immovable bone.
What are the results of increased muscle use?; Increase in muscle size, strength, and efficiency, and becoming more fatigue resistant.
What is flexion?; It decreases the angle of joint and brings two bones closer together.
What is extension?; It is the opposite of flexion.
What is rotation?; It is the movement of a bone in the longitudinal axis, like shaking the head 'no'.
What are abduction and adduction?; Abduction is the movement away from the midline, while adduction is the movement towards the midline.
What is circumduction?; It is the circular movement at the far end of a limb.
What are the three types of muscle tissue?; Skeletal, smooth, and cardiac muscle.
What are the voluntary muscles responsible for body movements?; Skeletal muscles.
What type of muscle tissue is found in the walls of hollow organs?; Smooth muscle tissue.
Which type of muscle tissue is striated and found in the heart?; Cardiac muscle tissue.
What are the characteristics of skeletal muscle?; Voluntary, striated, and attached to bones for movement.
What are the connective tissue wrappings of skeletal muscle?; Epimysium, perimysium, and endomysium.
What are the characteristics of smooth muscle tissue?; Involuntary, non-striated, and found in the walls of hollow organs.
What are the characteristics of cardiac muscle tissue?; Involuntary, striated, and found in the heart.
What is the microscopic structure of skeletal muscle?; It is composed of myofibrils, sarcomeres, and myofilaments.
How do muscles receive nerve stimulus for contraction?; Through motor neurons and neurotransmitters.
What is the primary energy source for muscle contraction?; Adenosine triphosphate (ATP).
What are the two main types of muscle contractions?; Isotonic and isometric contractions.
What are the different types of muscle movements and their functions?; Flexion, extension, abduction, adduction, and more for various body movements.
What is abduction?; Moving the leg away from the midline.
What is adduction?; Moving toward the midline.
What is circumduction?; A cone-shaped movement where the proximal end doesn't move, while the distal end moves in a circle.
What is a prime mover in muscle movement?; A muscle with the major responsibility for a certain movement.
What is an antagonist muscle?; A muscle that opposes or reverses a prime mover.
What is a synergist muscle?; A muscle that aids a prime mover in a movement and helps prevent rotation.
What does the term 'rectus' indicate in the naming of skeletal muscles?; It indicates straight direction of muscle fibers.
How is the term 'maximus' used in the naming of skeletal muscles?; It indicates the relative size of the muscle, specifically the largest size.
How are many muscles named?; Many muscles are named for bones, for example, temporalis.
What does the name 'triceps' indicate about the muscle?; It indicates that the muscle has three heads.
What is considered when naming skeletal muscles?; Location of the muscle and number of origins.
What factors are considered in the naming of skeletal muscles?; Location of the muscles origin and insertion, shape of the muscle, and action of the muscle.
Give an example of a muscle named based on its location.; sterno (on the sternum).
What type of muscles are named based on their shape?; Deltoid (triangular).
Provide an example of muscles named based on their action.; Flexor and extensor (flexes or extends a bone).
What is the topic of slide 6.38?; Head and Neck Muscles.
What is depicted in Figure 6.14?; Head and Neck Muscles.
What is the topic of slide 6.39?; Trunk Muscles.
What is depicted in Figure 6.15?; Trunk Muscles.
What is the topic of the slide?; Deep Trunk and Arm Muscles.
What is depicted in Figure 6.16?; Deep Trunk and Arm Muscles.
What is the topic of the slide?; Muscles of the Pelvis, Hip, and Thigh.
What is depicted in Figure 6.18c?; Muscles of the Pelvis, Hip, and Thigh.
What is the topic of the slide?; Muscles of the Lower Leg.
What is depicted in Figure 6.19?; Muscles of the Lower Leg.
What is the topic of the slide?; Anterior Superficial Muscles.
What is depicted in Figure 6.20?; Superficial Muscles.
What is the topic of the slide?; Posterior Superficial Muscles.
What is Muscular Dystrophy?; An inherited disorder where muscles enlarge due to increased fat and connective tissue, but fibers degenerate and atrophy.
What is Duchenne MD?; A disorder characterized by lacking a protein to maintain the sarcolemma.
What is Myasthemia Gravis?; A disorder causing progressive weakness due to a shortage of acetylcholine receptors.