Unit 3: Skeletal and Muscular System Exam

Objective 1: Identify the major components of the skeletal system and describe their functions

• Major functions of the skeletal system: support and protection (organs); body movement - muscles “pulling” on bones

• Skeletal system consists of 2 majors divisions: axial and appendicular

Objective 2: Identify the organic and inorganic components of the bone matrix

• Bone tissue is also called osseous tissue

Organic components:

• collagen

• osteoblasts (bone forming cells)

• osteoclasts (bone reabsorbing cells)

Inorganic components:

• calcium phosphate, in storage: calcium, magnesium, sodium and potassium (salts)

Objective 3: Differentiate between red and yellow bone marrow

• Red bone marrow: produces blood cells; found in flat bones

• Yellow marrow: fat storage; found in medullary cavity of long bones

Objective 4: Define hematopoiesis

• Hematopoiesis: the formation of blood cells; occurs in the red bone marrow

Objective 5: Identify the parts of the long bone

• Epiphysis: the ends of the bone; has a thing layer of compact bone, while internally the bone is cancellous (spongy bone); capped with articular cartilage

• Epiphyseal Line: also called the growth plate; found at epiphysis’ of long bones

• Diaphysis: shaft of the long bone; made of compact bone with a central cavity

• Articular/Hyaline Cartilage: found at the ends of long bones; smooth, slippery, and bloodless; allows for smooth movement of bones

• Periosteum: vascular, sensitive life support covering; provides nutrient-rich blood for bone cells; source of bone-developing cells during growth or after a fracture; outermost layer of bone

• Cancellous (spongy) Bone: bone with a spongy appearance containing red marrow

• Compact Bone: dense bone found in the diaphysis; repeated pattern arranged in concentric layers of solid bone; layer just beneath the periosteum

• Medullary Cavity: lightens bone weight and provides space for yellow marrow

• Endosteum: tissue that lines the medullary cavity

Objective 6 & 7: Locate and identify the structures that make up the axial and appendicular skeleton

• Axial: skull (occipital bones and mandible), spine, sternum, ribcage, sacrum, coccyx, hyoid, and ossicles

• Appendicular:
  - Pectoral girdle: scapula, clavicle, humerus, radius, ulna, carpals, metacarpals, and phalanges
  - Pelvic girdle: hips, pelvis, femur, patella, tibia, fibula, tarsals, metatarsals, and phalanges

Objective 8: Identify the parts of the synovial joints

• Bone

• Synovial Membrane: produces synovial fluid

• Synovial Fluid: stored in articular cavity; contains nutrients for cells (cartilage); movement of joints pushes fluid into cartilage to deliver nutrients

• Articular/Hyaline Cartilage: lines the epiphyses of the bones of the joints; allows for smooth movement

• Joint/Articular Capsule (CT): membrane that surrounds the joint

Objective 9: Describe the parts of the knee joint (bones and ligaments)

Bone of the knee joint:

• Femur: thigh bone

• Tibia: medial leg bone

• Fibula: lateral leg bone

• Patella: knee bone

• Lateral/Medial Condyle: bony protrusions of the femur

Ligaments of the knee joint:

• Posterior Cruciate Ligament: Posterior ligament connecting the femur to the tibia

• Anterior Cruciate Ligament: Anterior ligament connecting the femur to the tibia

• Fibular (Lateral) Collateral Ligament: strap-like ligament that stabilizes the hinge motion of the knee preventing excessive lateral movement; thinner and rounder, attaches femur to fibula

• Tibial (Medial) Collateral Ligament: strap-like ligament that stabilizes the hinge motion of the knee preventing excessive medial movement; attaches femur to tibia

• Patellar Ligament: continuation of the quadriceps tendon; attaches the patella to the tibia

Other parts of the knee joint:

• Medial/Lateral Meniscus: cartilage between the femur and the tibia; stabilize the joint and act as shock absorption

• Quadriceps Tendon: connects the quadriceps muscle to the patella

Objective 10: Describe the specific movements that occur at the major joints of the body

Diarthroses (Synovial) Joint: Freely-moving joint allowing for extensive flexibility and movement

• Ball and Socket: ball shaped surface that fits into concave surface; allows for complete ROM (widest range of all joints)
  - shoulder and hip joints

• Condyloid (Ellipsoidal): oval shaped surface that fits into elliptical surface; moves in 2 planes at right angles to one another
  - wrist joint (b/t carpals and radius)

• Gliding (Plane): articulating surfaces, usually flat; gliding movement (non-axial)
  - b/t wrist bones

• Hinge: spool-shaped surface that fits into a concave surface; moves in 1 plane about a single axis (like a door hinge)
  - elbow, knee, ankle, and finger joints

• Pivot: arch-shaped surface that that rotates around a rounded pivot; rotational movement
  - b/t axis and atlas vertebrae

• Saddle: saddle-shaped surface that fits into a socket curved in the opposite direction; movement similar to condyloid joint
  - thumb joint

Objective 11: Differentiate among the types of skeletal joints based on structure and function

• Synarthroses (Fibrous): immovable joint; consists of edges of bones connected by dense fibrous connective tissue
  - skull bones, radius to ulna, tooth to jawbone

• Amphiarthroses (Cartilaginous): semi-moveable joint, limited movement and light flexibility; consists of two bones connected by cartilage
  - intervertebral discs between vertebrae, pubic symphysis

• Diarthroses (Synovial): freely-moveable joint, extensive movement and flexibility; consists of bones connected by joint capsule, bones are technically not in contact w/ each other
  - knee, shoulder, and elbow joints

Objective 12: Define osteoporosis

• Osteoporosis: A condition where bones become weak and brittle (bone building can’t keep up w/ bone depletion)

Objective 13: Identify the three types of muscle tissue found in the human body and discuss their structure, function, and location

• Skeletal Muscle: striated, multi-nucleated, non-branched, contains many mitochondria, composed of contractile fibers; allows for voluntary movement; found all over the body

• Cardiac Muscle: branches, striated, single nucleus, contains many mitochondria; allows for involuntary contraction of the heart; found in the heart

• Smooth Muscle: non-striated, single nucleus, tapered, appears “smooth”; responsible for involuntary muscle movement; found in walls of hollow organs (stomach, intestines, liver, etc.)

Objective 14: Explain the role of agonist and antagonist muscles

• Agonist Muscle: the muscle that’s contracting during movement

• Antagonist Muscle: the muscle that’s relaxing/lengthening during movement

Objective 15: Describe the microscopic structure of the skeletal muscle tissue

From superficial to deep:

• Tendon connects muscle to bone

• Epimysium: membrane covering the entire muscle

• Perimysium: membrane covering fascicle

• Fascicle: bundle of muscle fiber; makes up the entire muscle

• Endomysium: connective tissue outer-membrane covering muscle fiber/cell

• Muscle fiber/cell (myoCYTES): composed of myoFIBRILS

• Sarcolemma: name of a muscle cell’s membrane, NOT the outer CT membrane that covers the cell; helps transduce electrical neural signals

• MyoFIBRIL: make up muscle cells; contains myoFILAMENTS that make up contractile unit of the cell

• MyoFILAMENT: protein fiber that makes up the myoFIBRIL; two major types are actin (thin filament) and myosin (thick filament)

• Sarcomere: contractile unit of the muscle cell; made up of thick and thin myofilaments (myosin and actin respectively)

• I-Band: portion of the muscle made of thin filaments as seen vertically

• A-Band: portion of the muscle made of thick filaments as seen vertically

• Z-Line: boundary line between sarcomeres

• Sarcoplasmic Reticulum: network of tubes that run parallel to the myofilaments (actin & myosin); storage site of Ca+

• T-Tubules: tubules that run perpendicular to myofilaments; allows electrical impulse to travel across cell

• Troponin: protein that covers the binding site on actin (troponIN = on actIN)

• Tropomyosin: protein that is attached to troponin; responsible for moving troponin off actin (tropoMyosin = Move)

• Muscle (covered by epimysium) → fascicles (covered by perimysium) → muscle fiber/cell (covered by endomysium) → myofibrils → myofilaments (actin & myosin)

Objective 16 & 17: Explain how muscle contraction occurs at the level of the sarcomere & explain how an impulse generated by the CNS results in the contraction of a skeletal muscle

Sliding Filament Theory:

1. Signal travels down motor neuron

2. Motor neuron released ACh into synaptic cleft b/t neuron and muscle cell

3. ACh binds to receptors in sarcolemma (muscle cell membrane)

4. Signal is transduced; electrical impulse travels in sarcolemma

5. Signal travels into the cell via t-tubules

6. Impulse stimulates sarcoplasmic reticulum (network) to release Ca+

7. Ca+ binds to troponin on actin, which causes:

8. Tropomyosin moves off of myosin’s binding site on actin

9. Myosin head binds to binding site on actin (requires ATP)

10. Myosin pulls actin toward the center of the sarcomere

11. Myosin head detaches from actin to release the actin (requires ATP)

Objective 18: Discuss the impact of botulinum toxin at the neuromuscular junction

• Botulism toxin is produced by bacteria. Can be consumed or injected via Botox. Botulism toxin prevents the release of ACh, inhibiting signals from motor neurons to muscle cells, causing paralysis

Objective 19: Name the major muscles of the human body, general location, and describe their movements

Movements

• Flexion: bending a limb; decreasing angle of a joint

• Extension: straightening a limb; increasing angle of a joint

• Rotation (Medial/Lateral)

• Pronation: rotation of an arm/leg so palm is down or sole out

• Supination: rotation of an arm/leg so palm is up or sole in

• Abduction: movement away from the midline of the body (raising arms = alien ABDUCTION)

• Adduction: movement toward the midline of the body

• Inversion: movement of sole towards the midline of the body

• Eversion: movement of sole away from the midline of the body

• Protraction: movement forward

• Retraction: movement backward

• Elevation: raise up

• Depression: push down

Major Muscles

• Pectoralis Major: anterior chest; flexes shoulder, adducts shoulder, medially rotates shoulder

• Rectus Abdominus: anterior trunk, from mid-rib to pelvis; flexes spine

• External/Internal Oblique: anterior trunk, lateral to rectus abdominus, internal is deep to external; sagittal flexion of spine, laterally flexes and rotates spine to one side (transversal)

• Trapezius: posterior neck/trunk, runs almost the length of the spine; elevation of scapula (upper fibers), adduct scapula, depression of scapula (lower fibers)

• Deltoid: superior shoulder; abducts shoulder, anterior fibers flex and medially rotate shoulder, posterior fibers extend and laterally rotate shoulder

• Biceps Brachii: anterior proximal arm; flexes elbow, supinates forearm, flexes arm (long head of biceps)

• Triceps Brachii: posterior proximal arm; extends elbow, extends shoulder

• Gluteus Maximus: posterior proximal leg; extends hip, laterally rotates hip, abducts hip

• Psoas: anterior deep pelvis; flexes hip, flexes trunk

• Rectus Femoris (Quadriceps): anterior proximal leg; extends knee, flexes hip

• Biceps Femoris (Hamstrings): posterior proximal leg, deep to gluteus maximus; flexes knee, extends hip

• Gastrocnemius: posterior distal leg; plantar flexes ankle

Objective 20: Explain the meaning of the terms insertion and origin and describe how skeletal muscles attach to the bony skeleton

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