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• Muscle is a metabolically active issue that burns calories
• Muscle


  • Responsible for movement
  • Enables activities of daily living
  • Enables leisure time physical activity
  • Enables occupational performance
  • Enables sport and recreation
• Unhealthy muscle


  • Reduced quality of life
  • Reduced independence
  • Reduced productivity
  • Limited career options
  • Increased rate of morbidity/mortality
• Muscle is woven into the anatomy, blood vessels, and nerves of the body

  
• Types of muscle in the human body

  • Cardiac
  • Smooth
  • Skeletal

  
• Skeletal muscle


  • Majority of muscle in humans
  • Striated appearance
  • Cylindrical and long (from mm to nearly 30 cm)
  • Voluntary
  • Multinucleated
  • Responsible for movement

  
• Cardiac muscle


  • Lattice/branched like network
  • A single nucleus per cell
  • Myogenic
  • Generates its own signals to contract (involuntary)
  • Intercalated disks
  • Part of sarcolemma
  • Portal for cell-to-cell communication
  • Allows for coordinated muscle contraction

  
• Smooth muscle


  • Fusiform shape
  • Spindle arrangement
  • Single nucleus
  • Found in internal organs (bladder, colon, stomach, uterus, esophagus)
  • Non-striated
  • Involuntary muscle
  • Contractions are described as weak, slow, sustained

  
• Muscles contract to move our bodies and enable the function of organs
• Muscle attachment


  • Attachment to our skeleton
  • Location of muscle will dictate function/movement

  
• Types of muscle contraction

  • Isometric (generating force, no change in length)
  • Isotonic (change in length, body moves through range of motion)
  • Eccentric (muscle lengthens)
  • Concentric (muscle shortens)

  
• The arrangement of actin and myosin filaments in the sarcomere is the reason why muscle is "striated"

  
• Muscle fiber components


  • Nucleus/Nuclei
  • Sarcolemma (muscle cell membrane)
  • Sarcoplasm (muscle cytoplasm)
  • Sarcoplasmic reticulum (key for calcium storage and release)
  • Myofibrils (contain filaments where muscle contraction takes place)

  
• Organelles within muscle fiber

  • T-tubule (extensions of sarcolemma that allow signals from nervous system to penetrate deep into muscle fiber)
  • Sarcoplasmic reticulum (release and absorb calcium ions for muscle contraction)

  
• The sarcomere is the smallest contractile unit of muscle fibers
• Sarcomere


  • Actin (thin filament)
  • Myosin (thick filament)
  • Z-line (dividing line between sarcomeres, anchor point for actin filament)
  • H-zone (area within sarcomere that expands/shrinks with contraction/relaxation)
  • A-band (dark band with myosin and some actin)
  • I-band (light band with actin only)
• Alzheimer's Disease


  A brain disorder that gets worse over time, characterized by changes in the brain that lead to deposit of certain proteins. No cure.
• Dementia


  A general term used to describe a person with a loss of memory, language problems, poor problem-solving capabilities that are severe enough to interfere with daily life. Alzheimer's leads to dementia, but dementia is not always caused by Alzheimer's.
• Parkinson's Disease


  A neurodegenerative disorder that affects predominately the dopamine-producing neurons in the substantia nigra area of the brain. Symptoms include tremor, slowness of movement, limb stiffness, and gait/balance problems.
• Alzheimer's disease is named after the person who discovered it, Dr. Alzheimer
• Symptoms of Alzheimer's disease


  • Forgetting husband's name
  • Forgetting own age
  • Forgetting current location
• Alzheimer's disease brain changes

  • Brain shrinkage
  • Abnormal deposits (plaques and tangles)
• Amyloid plaques


  Deposits made of amyloid and other proteins
• Neurofibrillary tangles


  Tau proteins that form tangles inside neurons
• Entorhinal region of the brain

  • Memory centre
  • Main input to the hippocampus
• Progression of Alzheimer's disease symptoms

  1. Slight memory loss

  2. Change in personality

  3. Memory loss progresses, impaired ability to perform tasks

  4. Worsening memory loss, physical decline

  5. Death
• APOE e4 allele is associated with increased risk of Alzheimer's disease
• Alzheimer's disease is often misdiagnosed in early stages
• Positron Emission Tomography (PET)


  Allows visualization of brain activity during cognitive operations, can help identify persons at risk before symptoms appear
• There is currently no effective treatment that can reverse the damage done by Alzheimer's disease by the time of diagnosis
• Anti-acetylcholinesterases (Anti-AChE) drugs are used to try to slow Alzheimer's progression, but are not very effective in late stages
• Early detection methods like MCI assessment, regular exercise, and control of blood pressure/glucose/cholesterol may help delay Alzheimer's progression
• Parkinson's Disease


  A neurodegenerative disorder affecting dopamine-producing neurons in the substantia nigra, leading to symptoms like tremor, slowness of movement, stiffness, and balance problems
• Parkinson's disease progresses even with levodopa treatment, leading to side effects like the "on-off" effect and uncontrollable muscle movements
• Engaging in daily physical activity and exercise has been shown to promote brain health
• Alzheimer's Disease


  A brain disorder that gets worse over time, characterized by changes in the brain that lead to deposit of certain proteins
• Alzheimer's Disease


  • No cure
  • Type of dementia that affects memory, thinking, and behaviour
  • Symptoms eventually grow severe enough to interfere with daily tasks
• Dementia


  A general (umbrella) term used to describe a person with a loss of memory, language problems, poor problem-solving capabilities that are severe enough to interfere with daily life
• Alzheimer's Disease


  Leads to dementia
• Dementia is not always caused by Alzheimer's