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Questions and Answers
What is one of the main functions of the Musculoskeletal System?
Which type of bone serves as a lever for muscle force exertion?
What additional function does bone serve besides providing shape and support?
What type of muscle contraction is primarily studied in relation to the Musculoskeletal System?
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What component connects skeletal muscle to bones?
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Which nutrient is NOT stored in bones?
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How many bones are there in the human body?
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Which type of joint is primarily associated with the movement of bones?
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What is a common symptom of Myasthenia Gravis?
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Which of the following best describes the underlying mechanism of Myasthenia Gravis?
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What is the prevalence of Myasthenia Gravis estimated to be globally?
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Which of the following is NOT a typical symptom of Myasthenia Gravis?
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Which statement about the antibodies found in Myasthenia Gravis patients is accurate?
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What role do ligaments play in the human body?
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Which type of muscle is characterized by involuntary and rhythmic movements?
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Which structure surrounds each muscle fiber in a skeletal muscle?
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What is the primary component of the organic portion of the bone matrix?
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What initiates muscle contraction according to the sliding filament theory?
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Which type of bone cell is primarily responsible for bone resorption?
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Which ion is primarily involved in triggering the muscle contraction process?
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What is the primary function of proprioceptors?
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What is a characteristic feature of osteons?
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What is the primary role of acetylcholine (ACh) at the neuromuscular junction?
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What role do osteoblasts play in bone health?
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What structural feature is characteristic of diarthroses joints?
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Which protein blocks myosin binding sites on actin filaments?
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Which risk factor is associated with a higher likelihood of developing osteoporosis?
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What type of muscle fiber is primarily responsible for voluntary movements?
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What characterizes the structure of cardiac muscle cells?
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How long does it usually take for damaged cartilage to heal?
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What characterizes the periosteum?
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Which type of proprioceptor specifically detects stretch in muscles?
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Which of the following diseases is classified as a lower motor neuron disease?
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What is NOT a type of cartilage?
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What type of joint is characterized by very limited movement?
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What is a primary characteristic of neuromuscular diseases?
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Which part of a muscle fiber is responsible for energy production?
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Which factor contributes to the natural loss of calcium from bones over time?
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What is the primary function of fibroblast-like type B cells in the synovial membrane?
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What is a common characteristic of osteoarthritis?
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What component of bone is primarily responsible for its hardness?
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Study Notes
Dr. Ly Vu
- Assistant Professor at the Faculty of Pharmaceutical Sciences, UBC
- Scientist at the Terry Fox Laboratory, BC Cancer
- Specializes in Cancer Biology, Molecular Pharmacology, and Molecular Biology
- Teaches PHRM-100 and PHRM 333- Pharmacotherapy in Oncology
Why Study The Musculoskeletal System?
- Provides stability and motility
- Supports and protects soft tissues
- Produces blood cells
- Stores calcium, phosphorus, glycogen, and fat
The Skeletal System: Bone
- Bone is a specialized connective tissue composed of collagen, non-collagenous proteins, and calcified extracellular material
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Three major bone cell types:
- Osteocytes: Mature bone cells maintaining bone mass
- Osteoblasts: Growing cells that generate new bone
- Osteoclasts: Multinucleated cells responsible for bone resorption and remodeling
Bone Anatomy
-
Long Bone structure:
- Epiphysis: The end part of a long bone
- Diaphysis: The shaft or central part of a long bone
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Cross-sectional view:
- Periosteum: Fibrous covering containing blood vessels and osteoblasts
- Hyaline cartilage: Smooth, white cartilage at the ends of bones
- Compact bone: Outer layer of calcified bone
- Spongy bone: Contains red bone marrow
- Marrow cavity: Contains yellow bone marrow
- Endosteum: Osteoblast layer in the marrow cavity
Bone Modeling and Remodeling
- Continuous generation and resorption of bone tissue
- Maintains bone shape and mass; adapts to changes, stresses, and repairs
- Releases calcium into systemic circulation
Bone Loss and Osteoporosis
- Occurs when bone resorption exceeds new bone formation
- Increased fragility of bones
-
Risk factors:
- Sex (women at higher risk)
- Age (older people at higher risk)
- Race (white and Asian individuals at higher risk)
- Family history
- Body frame size (smaller body frames have higher risk)
- Hormone levels
- Dietary factors (low calcium intake)
- Medical conditions
The Skeletal System: Cartilage
- Tough, durable connective tissue providing cushioning and protection
-
Three types of cartilage:
- Hyaline cartilage (most common)
- Elastic cartilage
- Fibrocartilage
- Lacks blood vessels, lymphatics, and nerves, but is surrounded by perichondrium
- Repair and replacement of injured cartilage is slow due to avascularity and low metabolic rate
Joints
- Where bones meet and articulate
- Allow bending and movements
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Functional types:
- Synarthroses (no joint cavity)
- Diarthroses (synovial joints, have joint cavity)
Synovial Joints
- Surrounded by articular capsule (encloses the joint)
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Articular capsule:
- Outer layer: fibrous layer of ligaments
- Inner layer: synovial membrane secreting synovial fluid
- Joint cavity: Area surrounding bone ends containing synovial fluid
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Two types of cells in synovial membrane:
- Type A cells: Macrophage-like, remove debris and regulate inflammation
- Type B cells: Fibroblast-like, produce synovial fluid
Osteoarthritis and Rheumatoid Arthritis
- Both involve inflammation, thinning of cartilage, swelling, pain, stiffness, and immobilization
- Osteoarthritis (OA): Degenerative, progressive, and age-related joint disease
- Rheumatoid Arthritis (RA): Autoimmune and inflammatory disease
Connecting Components: Ligaments and Tendons
- Ligaments: Fibrous tissue connecting bone to bone, stabilize joints, provide rotational stability
- Tendons: Strong collagen fibrous tissue connecting muscles to bones, transmit muscle contraction force
The Muscular System: Muscle
-
Three types of muscle:
- Skeletal muscle: Striated, multinucleated, voluntary movements
- Cardiac muscle: Striated, multinucleated, involuntary, vigorous, rhythmic movements
- Smooth muscle: Non-striated, single nucleus, involuntary, slow movements
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Functions of muscle :
- Movements and posture
- Blood circulation
- Body heat
- Storage of carbohydrates
Skeletal Muscle Anatomy
- Surrounded by connective tissue:
- Epimysium: Covers the entire muscle
- Perimysium: Surrounds fascicles (bundles of muscle fibers)
- Endomysium: Surrounds individual muscle fibers
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Muscle cells/Myofibers:
- Sarcolemma: Plasma membrane
- Sarcoplasm: Cytoplasm
- Multiple nuclei
- Mitochondria: Generate ATP (energy)
- Sarcoplasmic reticulum: Stores calcium
- Microfibrils: Rod-like organelles containing thick and thin myofilaments
- Sarcomeres: Smallest functional unit of striated muscle tissue
- T-tubules: Invaginations of the sarcolemma
Muscle Contraction: Sliding Theory
- Thick filament (Myosin) moves along the thin filament (Actin) using motor heads
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Steps of muscle contraction:
- Depolarization of muscle membrane
- Release of calcium from sarcoplasmic reticulum
- Binding of calcium to actin
- Sliding of myosin along actin
Neuromuscular System
- How nerves and muscles work together
- Neuromuscular junction: Synapse where a motor neuron connects to a muscle fiber
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Action potential in muscle fibers:
- Motor neuron signal transmission
- Release of acetylcholine (ACh) from synaptic vesicles
- Binding of ACh to nicotinic receptors
- Sodium influx
- Depolarization of muscle fiber
- Propagation of signal
- Degradation of ACh by acetylcholinesterase
Nicotinic Receptor
- Ion-channel linked receptor
- Pentameric protein with two binding sites for acetylcholine
- Opens pore allowing sodium influx
Kinesthesis/Proprioception
- Sense of body movements, position, equilibrium, and force
- Proprioceptors: Nerve fibers that coordinate joint position, tendon/ligament tension, and muscle contraction
The Reflex Arch
- Stereotypic reaction to a trigger
- Harmonizes muscle movements
Proprioception: Stretch Reflex
- Sensory neuron: Conveys changes in muscle length to CNS
- Motor neuron: Sends signal from CNS to muscle
Neuromuscular Diseases
- Disorders affecting muscle function due to problems with nerves and muscles
- Common symptom: Muscle weakness
Types of Neuromuscular Diseases
-
Upper motor neuron diseases:
- Cerebral palsy
- Multiple sclerosis
- Acute disseminated encephalomyelitis
- Transverse myelitis
- Cerebro-vascular accident
- Traumatic brain injury
- Spinal cord injury
-
Extrapyramidal diseases:
- Parkinson’s disease
- Friedreich’s ataxia
- Amyotrophic lateral sclerosis
-
Lower motor neuron diseases:
- Spino-muscular atrophy
- Poliomyelitis, acute faccid myelitis
- Peripheral nerve injury
- Guillain-Barre syndrome
- Charcot-Marie-Tooth disease
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Neuromuscular junction diseases:
- Myasthenia Gravis
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Muscle disorders:
- Dystrophies
- Mitochondrial myopathies
- Ion channel disorders
- Glycogen storage disorders
- Fatty acid oxidation disorders
- Inflammation myopathies
- Endocrine myopathies
- Myopathies associated with a toxic agent
Myasthenia Gravis (MG)
- Autoimmune disorder of neuromuscular transmission
-
Symptoms:
- Ptosis (drooping eyelids)
- Diplopia (double vision)
- Facial expression changes
- Difficulty swallowing
- Shortness of breath
- Dysarthria (impaired speech)
- Weakness in limbs and neck
-
Pathogenesis:
- Production of antibodies against acetylcholine receptors
- Decreased receptor activity and number
- Failed nerve transmission
Summary and Key Points
- The musculoskeletal system is complex and multifaceted
- Each component has distinct functions and structural features
- The musculoskeletal system is interconnected with the central nervous system
- The neuromuscular junction is the point of communication between nerves and muscles
- Understanding drug actions and relevant diseases is crucial
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Description
Test your knowledge on the musculoskeletal system and its functions, along with the basics of bone anatomy. This quiz covers key concepts from PHRM-100 and highlights the importance of the skeletal system in pharmacotherapy for oncology. Evaluate your understanding of bone cells and their roles in maintaining bone health.
