Anatomy and Physiology: Muscular System Quiz

Skeletal System Functions

• Bones provide structural support and shape.
• Bones protect vital organs (brain, heart, lungs).
• Bones, with skeletal muscles, allow for body movement.
• Bone marrow produces red and white blood cells.
• Bones store minerals (calcium and phosphorus).

Bone Classification

• Long bones (e.g., femur, humerus) have a long cylindrical shaft.
• Short bones (e.g., wrist, ankles) are roughly cube-shaped.
• Flat bones (e.g., ribs, skull, shoulder blades) are thin and curved.
• Irregular bones (e.g., vertebrae) have complex shapes.

Compact and Spongy Bone

• Compact bone forms the outer layer, dense and solid.
• Spongy bone is porous, honeycomb-like, located inside bones, containing bone marrow.
• Compact bone provides strength and protection.
• Spongy bone contains bone marrow for blood cell production and mineral storage.

Long Bone Structure

• Diaphysis: The long shaft in the middle.
• Epiphysis: The rounded ends.
• Metaphysis: The area connecting the shaft to the ends.
• Epiphyseal plate: The growth plate in children between the epiphysis and metaphysis.

Osteoblasts and Osteoclasts

• Osteoblasts build new bone.
• Osteoclasts break down old bone.
• Epiphyseal plate growth allows for increase in bone length.
• Osteoblasts on outer periosteum thicken the bone, while osteoclasts on the inside expand the marrow cavity for width growth.

Axial Skeleton Bones

• Skull (frontal, parietal, occipital, temporal, sphenoid, ethmoid)
• Orbit, zygomatic, mandible.
• Hyoid bone
• Vertebral Column (cervical (7), thoracic (12), lumbar (5), sacrum, coccyx)

Appendicular Skeleton Bones

• Pectoral Girdles (Clavicle, scapula) - Acromion, spine, glenoid cavity.
• Upper Limbs (Humerus, radius, ulna, carpals, metacarpals, phalanges).
• Head, greater/lesser tubercles.
• Pelvic Girdle - Hipbones (ilium, ischium, pubis), sacrum, coccyx.
• Lower limbs - Femur (head, greater/lesser trochanters), patella, tibia, fibula, tarsals, metatarsals, phalanges.

Types and Functions of Joints

• Fibrous (immovable, rigid).
• Cartilaginous (semi-movable/rigid).
• Synovial (freely movable).
• Movements:
  • Hinge (knee/elbow - bend/straighten)
  • Ball-and-socket (hip/shoulder - rotate)
  • Pivot (neck - turn)
  • Gliding (Wrist/ankle - slide)

Muscle Tissue Types

• Skeletal (striated, voluntary) - Attached to bones for movement.
• Cardiac (striated, involuntary) - Found in heart walls; controls heartbeat.
• Smooth (visceral, involuntary) - Found in internal organs (stomach & blood vessels).

Whole Muscle Structure

• Epimysium (outer covering)
• Fasciculi (bundles of muscle fibers)
• Perimysium (covering fasciculi).

Single Muscle Fiber Structure

• Endomysium (innermost covering).
• Myofibrils (contractile units).

Sliding Filament Mechanism of Muscle Contraction

• Calcium enters the muscle fiber.
• Calcium binds to troponin, changing the actin shape.
• This exposes myosin binding sites on actin.
• Myosin heads bind to the exposed actin sites.
• Myosin heads pull the actin filaments inward.
• This shortens the muscle fiber, creating contraction.
• Calcium is pumped back out to relax the muscle.

Muscle Contraction: Role of Calcium and ATP

• Calcium ions trigger muscle contraction by binding to troponin.
• ATP provides energy for myosin heads to bind to actin and pull.
• ATP is constantly regenerated for sustained contractions.

Muscle Terms

• Origin: Attachment point on stationary bone.
• Insertion: Attachment on movable bone.
• Belly: Fleshy, contracting part.

Muscle Naming

• Based on location, shape, size, number of origins, action, or attachments.
  • Examples: Biceps, Rectus, Deltoid

Major Muscle Actions & Actions

• Deltoid (Arm abduction/flexion)
• Biceps (Elbow flexion)
• Triceps (Elbow extension)
• Quadriceps (Knee extension)
• Hamstrings (Knee flexion)
• Gastrocnemius (Plantar flexion)
• Abdominals (Trunk flexion)
• Erector spinae (Trunk extension).

Homeostasis Definition

• Homeostasis is maintaining a stable internal environment despite external changes. It involves keeping physiological conditions like temperature, pH, fluid balance, and nutrient levels within a normal range.

Anatomical Position

• The anatomical position is a standard reference position for describing locations of body structures, with the person standing upright, feet flat, arms at sides with palms forward, head, eyes and toes pointed straight ahead.

Relative Positional Terms

• Superior (above)
• Inferior (below)
• Anterior (front)
• Posterior (back)
• Medial (toward midline)
• Lateral (away from midline)
• Proximal (closer to)
• Distal (further from)
• Superficial (closer to surface)
• Deep (further from surface)

Body Planes

• Sagittal: Vertical slice dividing body into left and right sides.
• Coronal: Vertical slice dividing body into front and back portions.
• Transverse: Horizontal slice dividing body into upper and lower portions.

Body Quadrants & Regions

• RUQ, LUQ, RLQ, LLQ (quadrants)
• Umbilical, Hypogastric, Epigastric, Hypochondriac, Lumbar, Ilium (regions)

Body Cavities

• Dorsal Cavity (Cranial, spinal)
• Ventral Cavity (thoracic, abdominal, pelvic)

Basic Chemistry (Matter, Elements, Atoms)

• Matter: Anything that occupies space and has mass.
• Element: A pure substance that cannot be broken down into simpler substances.
• Atom: The smallest unit of an element that retains its properties.

Elements Comprising 96% of Body Weight

• Oxygen
• Carbon
• Hydrogen
• Nitrogen

Atomic Components

• Protons (positive charge, in the nucleus)
• Neutrons (neutral charge, in the nucleus)
• Electrons (negative charge, orbiting the nucleus)

Role of Electrons in Chemical Bonding

• Electrons (valence electrons) are involved in bonding.
• Sharing or transferring electrons results in ionic or covalent bonds, making atoms stable and forming molecules.

Types of Chemical Bonds

• Ionic bonds: Occur when one atom transfers electrons to another, creating oppositely charged ions.
• Covalent bonds: Occur when atoms share electrons to achieve a stable electron configuration.
• Hydrogen bonds: Weaker, intermolecular attractions involving hydrogen atoms.

Ions, Electrolytes, Cations & Anions

• Ions: Atoms with a net electrical charge.
• Electrolytes: Form ions when dissolved in water.
• Cations: Positively charged ions.
• Anions: Negatively charged ions.

Water (Molecule & Compound)

• Water (H₂O) is a compound.
• Water is essential for life due to its properties (medium for reactions, nutrient and waste transport, lubrication, regulating temperature, maintaining blood volume)

Catalysts & Enzymes

• Catalysts and enzymes speed up chemical reactions, lowering the activation energy needed.
• Enzymes are biological catalysts (proteins). They are not consumed in the reaction, and they only affect the speed of the reaction.

pH

• pH measures the acidity or basicity of a solution.
• pH scale ranges from 0 to 14, with 7 being neutral.
• Acids release hydrogen ions, bases release hydroxide ions.

Adenosine Triphosphate (ATP)

• ATP is the energy currency of cells.
• ATP stores and transfers energy from food molecules for cellular processes (muscle contraction, active transport, biosynthesis).

Differentiating Mixtures & Solutions

• Mixtures combine various substances without chemical bonding; they can be easily separated. Ex. Salad, Trail mix
• Solutions are formed when one substance dissolves completely in another; they have a uniform appearance. Ex. Sugar dissolving in water
• Suspensions are mixtures where particles are large and don't dissolve, so they float and can settle over time. Ex. Muddy water
• Colloidal suspensions are mixtures where particles are small and they don't settle easily, but the mixture appears uniform but the particles can be seen under a microscope. Ex. Milk, Fog
• Precipitates are solids that form from liquid solutions when two substances react together. Ex. Mixing liquids & Solids forming at the bottom.