Musculoskeletal System

  1. Complete the following chart describing the different types of muscle:

Type of muscle

Location

Structure and function

skeletal

 

 

 

 

 

Throughout the body, attached to bones via tendons

  • Consists of flexible muscle fibers that range from less than half an inch to just over three inches in diameter 

  • Contract to produce movement, sustain body posture and position, maintain body temperature, store nutrients, and stabilize joints

smooth

 

 

 

 

 

In walls of hollow visceral organs (such as the liver, pancreas, and intestines), except the heart

  • Contains thick and thin filaments that do not arrange into sarcomeres, resulting in a non-striated pattern

  • Generate slow, sustained contractions and relaxations that aid in the movement of substances such as food and blood through these organs

cardiac

 

 

 

 

 

In the thick middle layer of the heart

  • Made up of sarcomeres that allow for contractility

  • Responsible for the contractility of the heart and, therefore, the pumping action

  1. How does a typical cell generate energy in the mitochondria?  What is the preferable nutrient energy source of body cells?  Identify the by-products of the process.

    • A typical cell generates energy in the mitochondria through a process called cellular respiration, primarily via the Krebs cycle and oxidative phosphorylation

    • The preferable nutrient energy source for body cells is glucose

    • The by-products of this process include carbon dioxide (CO₂) and water (H₂O).

  2. Do somatic or autonomic nerves stimulate skeletal muscle?

    • Somatic nerves stimulate skeletal muscle

      • They are responsible for voluntary muscle movements, while autonomic nerves control involuntary functions such as heart rate and digestion.

  3. One characteristic of muscle tissue is excitability.  What is the usual stimulus that

    activates skeletal muscle contraction?

    • The usual stimulus that activates skeletal muscle contraction is a signal from the nervous system, specifically an action potential from a motor neuron

    • This signal leads to the release of neurotransmitters at the neuromuscular junction, triggering muscle fiber contraction.

  4. Describe the role of the chemical transmitter, acetylcholine, in skeletal muscle

    contraction.

    • Acetylcholine (ACh) is a neurotransmitter that plays a crucial role in skeletal muscle contraction

    • When a nerve impulse reaches the neuromuscular junction, ACh is released from the motor neuron into the synaptic cleft

    • It binds to receptors on the muscle cell membrane, leading to depolarization and the generation of an action potential

    • This action potential triggers the release of calcium ions from the sarcoplasmic reticulum, initiating the contraction process by enabling the interaction between actin and myosin filaments

    • After contraction, ACh is broken down by acetylcholinesterase, terminating the signal.

  5. Name the chemical enzyme that inactivates acetylcholine.  What is the result of this

    action?

    • The chemical enzyme that inactivates acetylcholine is acetylcholinesterase.

    • The result of this action is the termination of the signal transmission at the neuromuscular junction, leading to muscle relaxation and the cessation of nerve impulse activity.

  6. What is the role of ligaments in joint movement?

    Ligaments are strong, fibrous connective tissues that connect bones to other bones at joints. Their primary roles in joint movement include:

    • Stability: They provide support and maintain the alignment of joints.

    • Limiting Movement: Ligaments restrict excessive or abnormal movements, preventing injuries.

    • Proprioception: They contain sensory receptors that help the body sense joint position and movement.

    Overall, ligaments play a crucial role in ensuring safe and functional joint movement.

  7. How are skeletal muscles attached to bone?

    • Skeletal muscles are attached to bones via tendons

      • Tendons are strong, fibrous connective tissues that connect muscle to bone, allowing for the transfer of force when the muscle contracts, resulting in movement of the skeleton.

  8. What is the function of collagen and inorganic salts such as calcium in bone?

    • Collagen provides tensile strength and flexibility to bone, while inorganic salts like calcium contribute to the hardness and rigidity

    • Together, they create a strong and resilient structure essential for supporting the body and protecting organs.

  9. Complete the following chart describing the three types of cartilage: 

    Type of cartilage

    Structure

    Function

    Location

     

    elastic

     

     

    Chondrocytes (healthy cells found only in cartilage) are organized into elastic fibers, which make up a threadlike network or matrix

    Supports parts of your body that need to bend and move to function

    • Nasal tip

    • External ear

    fibrocartilage

     

     

    Large bundles of collagen fibres made up of Type I collagen

    Acts as a cushion within joints, where it helps manage compression forces and reduces stress placed on joints

    • Intervertebral discs

    • Insertions of ligaments and tendons

    hyaline

     

     

    A matrix that contains closely packed collagen fibers

    Helps your bones move smoothly past each other in your joints

    • Ribs

    • Nose

    • Larynx

    • Trachea

  10. Identify two health conditions that are clinically significant related to the degenerative pathophysiology of musculoskeletal cartilage.

    1. Osteoarthritis: A degenerative joint disease characterized by the breakdown of cartilage, leading to pain, stiffness, and reduced mobility.

    2. Rheumatoid Arthritis: An autoimmune disorder that causes chronic inflammation of the joints, resulting in cartilage degradation and joint deformity.

  11. Describe the appearance of compact and spongy bones.

    Compact Bone:

    • Dense and solid structure.

    • Forms the outer layer of bones.

    • Contains tightly packed osteons (Haversian systems).

    • Appears smooth and homogeneous.

    Spongy Bone:

    • Lattice-like structure with trabeculae (thin bony plates).

    • Found mainly at the ends of long bones and in the interior of others.

    • Lighter and less dense than compact bone.

    • Contains red bone marrow in the spaces between trabeculae.

  12. Complete the following chart describing the four classifications of bones: 

    Bone

    Description and example

     

    flat

     

    • Made up of a layer of spongy bone between two thin layers of compact bone

    • Sternum and ribs

    irregular

     

    • Often have a fairly complex shape, which helps protect internal organs

    • Vertebrae

    long

     

    • Hard, dense bones that provide strength, structure, and mobility

    • Femur and humerus

    short

     

    • Shaped roughly as a cube and contain mostly spongy bone

    • The carpals in the wrist

        

  13.    Complete the following chart related to the structure and function of the components of a typical long bone:

     

     

    Bone part

     

    Description (structure, function, location)

    articular cartilage

     

    • Composed of a dense extracellular matrix (ECM) with a sparse distribution of highly specialized cells called chondrocytes

    • Provide a smooth, lubricated surface for low friction articulation and to facilitate the transmission of loads to the underlying subchondral bone

    • At the ends of your bones

    diaphysis

     

    • Tubular shaft that runs between the proximal and distal ends of the bone

    • Structural functionality, the transport of oxygen and immune support, and mineral and fat storage

    • The shaft in the middle of the bone

    epiphyseal plate

     

    • A flat bony structure located between the epiphysis and the metaphysis (the neck portion of a long bone between the epiphysis and the diaphysis) of the long bones

    • Holds the growth plate cartilage, providing the weakest area of the growing bone with strength and stability

    • In the metaphysis at each end of a long bone

    epiphysis

     

    • Spongy cancellous bone covered by a thin layer of compact bone

    • Responsible for articulation

    • On the ends of long bones

    medullary cavity

     

    • Hollow part of bone that contains bone marrow

    • Makes blood cells and stores fat

    • Within the shaft (diaphysis) of long bones

    periosteum

     

    • Composed of two layers: The outer firm and a fibrous layer made up of collagen and reticular fibers and an inner proliferative cambial layer

    • Supplies them the blood they need, and helps them grow and heal

    • Almost all your bones are covered in a periosteum

  14. Bone marrow is found in the medullary cavity and in the spaces of spongy bone.  What is the function of red bone marrow?  Yellow bone marrow?

    Red Bone Marrow:

    • Produces red blood cells, white blood cells, and platelets (hematopoiesis).

    • Found mainly in flat bones (e.g., pelvis, sternum) and the ends of long bones.

    Yellow Bone Marrow:

    • Primarily stores fat (adipocytes).

    • Can convert to red marrow in cases of severe blood loss or increased demand for blood cell production.

  15. Define the term hemopoietic.  What is another word for hemopoietic?

    • The process of blood cell formation, primarily occurring in the bone marrow

  16. Distinguish between the axial skeleton and the appendicular skeleton.

    • Axial Skeleton

      • Comprises the skull, vertebral column, and rib cage.

      • Functions to protect the brain, spinal cord, and thoracic organs.

      • Consists of 80 bones.

    • Appendicular Skeleton

      • Includes the limbs and the girdles (shoulder and pelvic).

      • Facilitates movement and interaction with the environment.

      • Comprises 126 bones.

  17. Describe each region of the vertebral column and the number of bones in each region.

    The vertebral column consists of five regions:

    1. Cervical Region: 7 vertebrae (C1-C7)

    2. Thoracic Region: 12 vertebrae (T1-T12)

    3. Lumbar Region: 5 vertebrae (L1-L5)

    4. Sacral Region: 5 fused vertebrae (S1-S5)

    5. Coccygeal Region: 4 fused vertebrae (Co1-Co4)

    Total: 33 vertebrae in a typical adult.

  18. Describe the distinguishing characteristics for vertebrae in each vertebral region and features of the sacrum and the coccyx.

  1. Cervical Vertebrae (C1-C7):

    • Small and light

    • Transverse foramina for blood vessels

    • Bifid spinous processes (C2-C6)

  2. Thoracic Vertebrae (T1-T12):

    • Larger than cervical

    • Long, downward-sloping spinous processes

    • Facets for rib articulation

  3. Lumbar Vertebrae (L1-L5):

    • Largest and strongest

    • Short, thick spinous processes

    • No rib facets

  4. Sacrum

    • Five fused vertebrae (S1-S5)

    • Triangular shape

    • Articulates with the pelvis

  5. Coccyx

    • Composed of 3-5 fused vertebrae

    • Small, triangular structure

    • Serves as an attachment site for ligaments and muscles

  1. Describe the structure of an intervertebral disc.

    An intervertebral disc consists of two main components:

    1. Nucleus Pulposus:

      • A gel-like center that provides cushioning and flexibility.

      • Composed of water, collagen fibers, and proteoglycans.

    2. Annulus Fibrosus:

      • A tough outer layer made of concentric rings of collagen fibers.

      • Provides strength and stability, helping to contain the nucleus pulposus.

    These discs act as shock absorbers between vertebrae in the spine.

  2. Define the term ossification.

    Ossification is the process by which bone is formed, renewed, and repaired. It involves the transformation of cartilage or other tissues into bone through the deposition of calcium phosphate and other minerals. There are two main types of ossification:

    1. Intramembranous ossification - Directly forms bone from mesenchymal tissue.

    2. Endochondral ossification - Involves the replacement of cartilage with bone, common in long bones.

    This process is crucial for skeletal development and growth.

  3. Identify the hormones that control long bone growth.

    1. Growth Hormone (GH) - Stimulates overall growth and development.

    2. Thyroid Hormones (T3 and T4) - Regulate metabolism and bone growth.

    3. Sex Hormones (Estrogen and Testosterone) - Promote growth spurts and closure of growth plates.

    4. Insulin-like Growth Factor 1 (IGF-1) - Mediates the effects of growth hormone on bone growth.

  4. How does each type of osteocyte contribute to bone growth?

    Osteocytes are mature bone cells that play a crucial role in bone maintenance and homeostasis. They do not directly contribute to bone growth but are involved in the following ways:

    1. Mechanosensation: Osteocytes sense mechanical stress and strain, signaling osteoblasts to increase bone formation.

    2. Regulation of Mineralization: They help regulate the mineral content of bone by controlling the activity of osteoblasts and osteoclasts.

    3. Communication: Osteocytes communicate with other bone cells through dendritic processes, coordinating bone remodeling.

  5. As bones grow or have stress placed upon them from movement, they need to be remodelled or reshaped.  Describe the role of osteoblasts and osteoclasts in the remodelling process.

    Osteoblasts and osteoclasts play crucial roles in bone remodeling:

    • Osteoblasts: These cells are responsible for bone formation. They synthesize and secrete the bone matrix and facilitate the mineralization process, leading to new bone tissue development.

    • Osteoclasts: These are large cells that break down bone tissue. They resorb bone by dissolving the mineral matrix and degrading the organic components, which is essential for the maintenance and repair of bones.

  6. Identify the hormone responsible for promoting the formation of bone.

    The hormone responsible for promoting the formation of bone is calcitonin. It is produced by the thyroid gland and helps regulate calcium levels in the body, promoting bone formation and inhibiting bone resorption

  7. Identify the hormone responsible for the breakdown of bone.

    The hormone responsible for promoting the formation of bone is calcitonin. It is produced by the thyroid gland and helps regulate calcium levels in the body, promoting the deposition of calcium into the bones. Additionally, growth hormone and estrogen also play significant roles in bone formation.

  8. Complete the following chart describing the components of a typical synovial joint:

    Joint component

     

    Location

    Structure and function

    articular cartilage

     

     

    Composed of a dense extracellular matrix (ECM) with a sparse distribution of highly specialized cells called chondrocytes

    • Provide a smooth, lubricated surface for low friction articulation and to facilitate the transmission of loads to the underlying subchondral bone

    • At the ends of your bones

    joint capsule

     

     

    Fibrous connective tissue

    • Stabilize the joint, distribute the biomechanical load on the joint and protect the joint by limiting its normal range of motion

    • Attached to the bones via specialized attachment zones at the end of each involved bone

    ligament

     

     

    Made out of connective tissue that has a lot of strong collagen fibers in it

    • Stabilize the joint or hold the ends of two bones together

    • Primarily in the joints

    synovial cavity

     

     

    Two bony surfaces that are encompassed by a fibrous capsule with a synovial lining

    • To prevent friction between the articulating bones involved in body movements

    • Between the segments of the bones and the articular cartilage

    synovial fluid

     

     

    Produced as an ultrafiltrate of blood plasma and is primarily composed of hyaluronan, lubricin, proteinase, collagenases, and prostaglandins

    • Lubricates the joint and allows the ends of the bones to move without friction

    • Between your joints

    synovial membrane

     

     

    Made up of two layers: intimal and subintima

    • Makes synovial fluid, which has a lubricating function

    • Lines the cavities of joints, tendon sheaths, and bursae

  9. Complete the following chart describing hinge and ball and socket joints:

    Type of joint

     

    Movement permitted

    Example of joint

    ball and socket

     

     

    Backward, forward, sideways, and rotating movements

    • The shoulder

    • The joints

    hinge

     

     

    Bending and straightening movements

    • Fingers

    • Knees

    • Elbows

  10. Describe the following musculoskeletal movements and provide an example:

    a) Abduction: Movement away from the midline (Example: Raising arms sideways)

    b) Adduction: Movement toward the midline (Example: Lowering arms to the sides)

    c) Circumduction: Circular movement of a limb (Example: Arm moving in a circular motion)

    d) Dorsiflexion: Raising the foot upwards (Example: Pulling toes towards the shin)

    e) Eversion: Turning the sole of the foot outward (Example: Rolling the foot outward)

    f) Extension: Straightening a joint (Example: Straightening the elbow)

    g) Flexion: Bending a joint (Example: Bending the elbow)

    h) Hyperextension: Extending a joint beyond its normal range (Example: Bending the neck backward)

    i) Inversion: Turning the sole of the foot inward (Example: Rolling the foot inward)

    j) Plantar Flexion: Pointing the toes downward (Example: Standing on tiptoes)

    k) Pronation: Rotating the forearm so the palm faces down (Example: Turning the palm downwards)

    l) Rotation: Turning around an axis (Example: Turning the head side to side)

    m) Supination: Rotating the forearm so the palm faces up (Example: Turning the palm upwards)

  11. Identify the type of movement made by each of the following musculoskeletal

    articulations:

    Joint

     

    Type of movement

    ankle

     

     

    • Dorsiflexion

    • Plantarflexion

    • Inversion

    • Eversion

    • Medial and lateral rotation

    elbow

     

     

    • Extension

    • Flexion

    • Supination

    hip

     

     

    • Flexion

    • Extension

    • Abduction

    • Adduction

    • External rotation

    • Internal rotation

    • Circumduction

    knee

     

     

    • Flexion

    • Extension

    neck

     

     

    • Cervical flexion

    • Cervical extension

    • Cervical rotation

    phalanges

     

     

    • Adduct

    • Abduct

    • Oppose

    shoulder

     

     

    • Abduction

    • Adduction

    • Flexion

    • Extension

    • Internal

    • External rotation

    wrist

    • Flexion

    • Extension

    • Abduction

    • Adduction

  12.  Describe the age-related changes of the musculoskeletal system.

    1. Bone Density: Decreases, leading to osteoporosis and increased fracture risk.

    2. Muscle Mass: Sarcopenia occurs, resulting in loss of muscle mass and strength.

    3. Joint Health: Cartilage thins, increasing the risk of osteoarthritis and joint pain.

    4. Flexibility: Decreases due to changes in connective tissues, leading to stiffer joints.

    5. Posture: Changes in spinal alignment can lead to a stooped posture.

  13. What musculoskeletal disorder are elderly women at risk of developing?  Why?

    Elderly women are at risk of developing osteoporosis.

    • Hormonal Changes: Decreased estrogen levels after menopause contribute to bone density loss.

    • Age: Bone mass naturally decreases with age.

    • Nutritional Factors: Inadequate calcium and vitamin D intake can weaken bones.

    • Physical Inactivity: Sedentary lifestyle can lead to further bone loss.