Biology 210 Chapter 10 Muscles PowerPoint by John McGill Based on notes by Beth Wyatt & PowerPoint by Jack Bagwell Types of Muscle Cells Skeletal (Voluntary, Striated) Muscle these are muscles you control; the ones you exercise. Smooth (Involuntary, Smooth) Muscle these are muscles you cannot control They work the inner parts of the body (viscera) Cardiac Muscle (Involuntary, striated) myogenic due to interconnections These muscles of the heart do not get tired. Types of Muscle Cells 1
Skeletal Muscle Cells Smooth Muscle Cells Cardiac Muscle Cells 2
Tissues that Compose Skeletal Muscle Skeletal muscle tissue Connective Tissue Components Nervous Tissue Tissues that Compose Skeletal Muscle Skeletal muscle tissue Composed of skeletal muscle fibers, arranged in fasicles. Connective Tissue Components Will discuss on the next slide Nervous Tissue Attached to SMFs Stimulate muscle contraction. Connective Tissue Components Endomysium a delicate membrane composed of connective tissue which covers the individual skeletal muscle fibers Perimysium the tough connective tissue which binds skeletal muscle fibers together, I.e. wraps around fascicles. Fascicles the groups of muscles fibers Epimysium the whole muscle is covered by a coarse sheet of connective tissue Tendon The epimysium, perimysium and endomysium may come together to form a tendon on the muscle end, is extension of periosteum on bone end. 3
Connective Tissue Components Endomysium Perimysium Fascicles Epimysium Tendon Try this to remember these: Every Paranoid Friend Eats Tomatoes Endomysium a delicate membrane composed of connective tissue which covers the individual skeletal muscle fibers Perimysium the tough connective tissue which binds skeletal muscle fibers together, I.e. wraps around fascicles. 4
Fascicles The groups of muscles fibers Formed from perimysium Epimysium the whole muscle is covered by a coarse sheet of connective tissue Tendon The epimysium, perimysium and endomysium may come together to form a tendon on the muscle end, is extension of periosteum on bone end. 5
Tendon Pictures Connective Tissue Components continued Aponeurosis Also may be formed from the three fibrous wrappings; may merge with the wrappings of another muscle. Tendon Sheath a fibrous connective tissue which encloses certain tendons. Have a lining of synovial membrane which allows easy movement of the tendon. Deep Fascia dense fibrous connective tissue; extensions of this tissue form the epimysium, perimysium, and endomysium. Aponeurosis Also may be formed from the three fibrous wrappings may merge with the wrappings of another muscle. 6
Tendon Sheath a fibrous connective tissue which encloses certain tendons. Have a lining of synovial membrane which allows easy movement of the tendon. Deep Fascia dense fibrous connective tissue; extensions of this tissue form the epimysium, perimysium, and endomysium. Tissues that Compose Skeletal Muscle Nervous Tissue Attached to SMFs Stimulate muscle contraction. 7
Size and Shape of Fibers Size: varies from large to small Shape: varies Broad: Latisimus dorsi Narrow: Sartorius Flat: Latisimus dorsi Bulky: Gastrocnemius Long: Sartorius Circular: Orbicularis oris Triangular: Deltoid Shape: Broad Latisimus dorsi Shape: Narrow Sartorius 8
Shape: Flat Latisimus dorsi Shape: Bulky Gastrocnemius Shape: Long Sartorius 9
Shape: Circular Orbicularis oris Shape: Triangular Deltoid Fiber Arrangement Arrangement of SMF within the muscle, varies. Parallel to long axis Converge to narrow attachment Oblique are slanted Pennate think feather pen Bipennate Curved 10
Parallel to long axis Horizontal: Transversus abdominis Vertical Rectus abdominis Converge to narrow attachment Pectoralis major 11
Oblique are slanted External oblique Pennate think feather pen Vastus group Bipennate two feathered Rectus femoris 12
Curved Fibers are circular Orbicularus oris Attachment of Muscles-Joints Most muscles attach articulating bones across a joint. Upon contraction of the muscle, one bone remains in a fixed position and the other moves. Pelvis Femur Attachment of Muscles-Origin Origin The point of attachment that does not move during muscle contraction. Pelvis 13
Attachment of Muscles-Insertion Insertion the points of attachment that does move when the muscles contract. Femur Attachment of Muscles- Contraction Typically, when a muscle contracts, the insertion is moved closer to the origin. Muscle Actions Muscles work together! Some muscles in a group contract while other relax. Prime mover Antagonist Synergists Fixator muscles 14
Muscle Actions-Prime Mover A muscle or group of muscles which directly performs a specific movement. Flexion of forearm Biceps brachii is PM Muscle Actions-Antagonist When actively contracting, they oppose the movement of the prime mover. They are relaxed when the prime mover is contracting. Flexion of forearm T. brachii is anatagonist Muscle Actions-Synergists contract at the same time as the prime movers; they complement the prime movers. Flexion of forearm brachialis is synergist 15
Muscle Actions- Fixator muscles usually serve to stabilize joints. They help to maintain balance and posture during the contractions of the prime movers. ROLE OF MUSCLES, BONES, AND JOINTS IN MOVEMENT MECHANISM Skeletal Muscle Attached to Bones (by Tendons) With Joint in Between POA s Skeletal Muscle Stimulated by Nerve Impulse Skeletal Muscle Contracts, Pulls on Bone(s), Produces Movement at a Joint Lever ROLE OF MUSCLES, BONES, AND JOINTS IN MOVEMENT any rigid bar free to move around a fixed point called a fulcrum Lever system Rigid bar - a bone F = Fulcrum - joint a point around which the rigid bar rotates L = Load: Weight resistance something that is moved P = Pull - Muscle contraction force producing the movement 16
Naming of Muscles Location Function - named for what they do Shape - shape of the muscle Direction of fibers - orientation of fibers Number of divisions or heads - connections Points of attachment - what bones are attached to OR bone markings Size - how big is the muscle relative to other muscles Location brachialis - in the arm Function - named for what they do Adductor group move leg toward the midline 17
Shape - shape of the muscle deltoid - triangular muscle in the shoulder Direction of fibers - orientation of fibers rectus abdominus rectus refers to up and down Oblique slanting transversus Number of divisions or heads connections biceps brachii 18
Points of attachment What bones are attached to OR bone markings Sternocleidomastoid Size how big is the muscle relative to other muscles Gluteus maximus in human beings, bigger than gluteus medius and minimus. 19