Human Anatomy Quiz

Skeletal System Functions

• Bones provide structural support and shape to the body.
• Bones protect vital organs like the brain, heart, and lungs.
• Bones and skeletal muscles enable body movement.
• Red and white blood cells are produced in bone marrow.
• Bones store important minerals like calcium and phosphorus.

Bone Classification

• Long bones (e.g., femur, humerus) have a long, cylindrical shaft.
• Short bones (e.g., in wrists and 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, it is dense and solid.
• Spongy bone is porous and honeycomb-structured 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 allows new bone growth for length.
• Osteoblasts on the outer periosteum surface make compact bone, osteoclasts on the inner endosteum surface expand the marrow cavity to support width growth.

Axial Skeleton Bones

• Skull (frontal, parietal, occipital, temporal, sphenoid, ethmoid)
• Orbit, zygomatic, mandible
• Hyoid bone
• Vertebral Column (cervical, thoracic, lumbar, sacrum, coccyx)
• Rib cage (sternum, ribs)

Appendicular Skeleton Bones

• Pectoral Girdles (clavicle, scapula)
• Upper limbs (humerus, radius, ulna, carpals, metacarpals, phalanges)
• Pelvic Girdle (hip bones, sacrum, coccyx)
• Lower limbs (femur, patella, tibia, fibula, tarsals, metatarsals, phalanges)

Joint Types and Movements

• Fibrous (immovable, rigid)
• Cartilaginous ( semi-movable, rigid)
• Synovial (freely movable)
• 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 voluntary movement.
• Cardiac (striated, involuntary) - found in heart walls, controls heartbeat.
• Smooth (visceral, involuntary) - found in internal organs (e.g., 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)
• Sarcomeres (actin and myosin filaments)

Sliding Filament Mechanism

• Calcium enters the muscle fiber
• Calcium binds to troponin, changing the actin shape, exposing myosin binding sites on actin.
• Myosin heads bind to the exposed actin sites.
• Myosin heads pull actin filaments inward.
• The filaments slide past each other, shortening the muscle fiber and creating contraction.

Myosin Cross-Bridge Cycling

• Calcium and Myosin cross-bridge cycling are key elements in the sliding filament mechanism Calcium and ATP are necessary for contraction

Role of Calcium and ATP (in muscle contractions)

• Calcium initiates contraction by binding to troponin, exposing myosin binding sites on actin
• ATP provides the energy for myosin heads to bind to and pull actin filaments, generating the contraction.
• ATP is constantly regenerated.

Muscle Contraction Events (from nerve stimulation)

• Nerve signal triggers calcium release
• Calcium allows myosin to bind to actin
• Myosin pulls actin filaments inward, shortening muscle fibers.
• Shortening causes overall muscle contraction

Muscle Terms

• Origin: Attachment point on stationary bone
• Insertion: Attachment on movable bone.
• Belly: Fleshy, contracting part of the muscle
• Muscle Naming (based on location, shape, size, number of origins, action, or attachments).

Examples of Muscle Actions

• Deltoid - arm abduction/flexion
• Biceps - elbow flexion
• Triceps - elbow extension
• Quadriceps - knee extension
• Hamstrings - knee flexion
• Gastrocnemius - plantar flexion (pointing toes)
• Abdominals - trunk flexion
• Erector spinae - trunk extension

Homeostasis Definition

• Maintaining a relatively stable internal environment within the body, despite external changes.
• Regulates things like temperature, pH, fluid balance and nutrient levels.

Anatomical Position Description

• Upright standing, feet flat and slightly apart, arms at the sides with palms facing forward, head, eyes, and toes pointing straight ahead.

Directional Terms (Relative positions of body parts)

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

Body Planes

• Sagittal: Divides body vertically into left and right sides
• Coronal: Divides body vertically into front and back portions.
• Transverse: Slices the body horizontally, dividing it into upper and lower portions.

Anatomical Regions and Quadrants

• Quadrants (RUQ, LUQ, RLQ, LLQ)
• Regions (umbilical, hypogastric, epigastric, hypochondriac, lumbar, iliac)

Major Body Cavities

• Dorsal cavity (Cranial, spinal)
• Ventral cavity (thoracic, abdominal, pelvic).

Basic Chemistry

• Matter: Anything that occupies space and has mass
• Element: Pure substance cannot be broken down into simpler substances by chemical means
• Atom: The smallest unit of an element that retains its properties
• Four elements comprising 96% of body weight are Oxygen, Carbon, Hydrogen, and Nitrogen.
• Atom components are protons (positively charged particles in the nucleus), neutrons (neutral particles in the nucleus), and electrons (negatively charged particles orbiting the nucleus)

Chemical Bonds (ionic, covalent, hydrogen)

• Ionic bond: transfer of electrons from one atom to another
• Covalent bond: sharing of electrons between atoms
• Hydrogen bond: weak attraction between a hydrogen atom with a partial positive charge and another atom with a partial negative charge.

Electrolytes, Cations, and Anions

• Electrolyte: Substances that form ions when dissolved in water
• Cations: positively charged ions
• Anions: negatively charged ions

Molecules versus Compounds

• Molecules: two or more atoms of the same or different elements chemically bonded together (Eg H2, O2).
• Compounds: two or more different atoms chemically bonded together (eg. H2O)

Six Forms of Energy

• Chemical, radiant, electrical, thermal, mechanical, and nuclear.

Catalysts and Enzymes

• Catalysts: speed up reactions by lowering activation energy
• Enzymes: biological catalysts made of proteins, speed up reactions without being consumed
• Catalysts and enzymes help biological processes occur with lower consumption of energy.