Human Evolution: Bipedalism and Anatomy

• "Toumai" signifies Sahelanthropus tchadensis, an early hominin known for bipedal traits.
• Shoulder and arm structure supports reaching and grasping, important for tool use.
• Lucy's femur angle confirmed bipedalism, showing adaptation for upright walking.
• Dorsiflexion is the upward movement of the foot toward the shin, crucial for walking and running.
• Humans are endurance runners, evolved for persistence hunting with efficient cooling.
• Hands, with opposable thumbs, enable precision gripping, tool use, and fine motor skills.
• Bipedalism is walking on two legs, freeing hands for tool use and improving energy efficiency.
• "Nari" refers to Nariokotome Boy, a Homo erectus skeleton with human-like proportions.
• Erector spinae and quadratus lumborum stabilize the spine and aid posture.
• Humans excel in endurance running due to sweating, breath control, and long legs.
• The nuchal ligament stabilizes the head during running.
• Homo Erectus is an early human species that walked upright and used tools and fire.
• The stapes in the middle ear is the smallest bone.
• The coccyx is a remnant of ancestors’ tails.
• The appendicular skeleton includes limbs, shoulder girdle, and pelvis.
• Carpal Tunnel Syndrome involves compression of the median nerve in the wrist.
• Fontanelles are soft spots in an infant’s skull that allow for brain growth.
• "Arthritis" denotes joint inflammation and degeneration.
• Humans have 12 pairs of ribs, including true, false, and floating ribs.
• The spinal column protects the spinal cord and provides structural support.
• Menisci cushion the knee joint.
• Adduction is movement toward the body’s midline.
• The origin is the fixed attachment, and the insertion moves during muscle contraction.
• The insertion bone moves during muscle contraction.
• Knee joint movements include flexion and extension.
• The synovial joint provides mobility and reduces friction with synovial fluid.
• Osteoarthritis is a degenerative disease affecting cartilage in joints.
• Shivering involves skeletal muscle contractions to generate heat.
• Thumb mobility increased dexterity for tool use.
• Lower back problems often stem from weak core muscles or poor posture.
• The hyoid bone supports the tongue and is not connected to other bones.
• Teeth lack bone marrow and contain enamel, unlike bones.
• The 8th-10th ribs are false ribs that attach indirectly to the sternum via cartilage.

The Origin of Us Video Summary

• This documentary explores human evolution, focusing on bipedalism, endurance running, tool use, and intelligence.
• Fossil evidence (e.g., Lucy, Toumai) shows the transition to walking upright.
• Sweat glands and long tendons enable long-distance running.
• Dexterous hands and larger brains facilitated tool use, giving humans an evolutionary advantage.
• Cooking and high-energy foods supported brain expansion.

Video Questions

• Key takeaways were reviewed.
• The dorsalis pedis pulse checks blood circulation in the foot.
• The Lachman maneuver evaluates ACL tears by stabilizing the femur and pulling the tibia forward.
• Heat worsens swelling and inflammation.
• Sweat evaporation cools the body through heat loss.
• The hypothalamus regulates body temperature.
• Skeletal muscles cause shivering.
• Bone heals faster due to a better blood supply.
• An MRI examines soft tissue injuries, like ligament tears.
• Ice reduces inflammation and pain, while elevation prevents fluid buildup.

Essential Topics to Study for the Bone Unit

• Major Functions of the Skeletal System
  • Support
  • Protection (e.g., skull protects the brain, ribs protect the lungs)
  • Movement (in conjunction with muscles)
  • Mineral storage (especially calcium and phosphorus)
  • Blood cell production (hematopoiesis in red bone marrow)
  • Fat storage (yellow marrow)
• Bone Structure
  • Compact bone is a dense, strong outer layer
  • Spongy bone is lightweight and porous and contains red marrow
  • Periosteum is the outer membrane covering bone
  • Medullary cavity contains yellow marrow
  • Epiphysis is the end of the bone and contains spongy bone
  • Diaphysis is the shaft of the bone containing the medullary cavity
• Types of Bones
  • Long bones include the Femur and humerus
  • Short bones include the Carpals and tarsals
  • Flat bones include the Skull, ribs, and sternum
  • Irregular bones include Vertebrae
  • Sesamoid bones include the Patella
• Bone Cells
  • Osteoblasts build bone
  • Osteoclasts break down bone
  • Osteocytes are mature bone cells
  • Chondrocytes are cartilage cells involved in early bone growth
• Bone Growth and Development
  • Endochondral ossification involves bone replacing cartilage
  • Epiphyseal plate is the site of bone lengthening
  • Wolff’s Law states that bone grows and remodels in response to stress
• Hormones That Affect Bones
  • Parathyroid Hormone (PTH) raises blood calcium by breaking down bone
  • Calcitonin lowers blood calcium by building bone
  • Growth hormone stimulates bone growth
  • Estrogen/Testosterone stimulates growth during puberty
• Bone Disorders
  • Osteoporosis causes weak, brittle bones due to loss of bone density
  • Osteoarthritis is the wear of cartilage
  • Rheumatoid arthritis is the Autoimmune disease targeting joints
  • Gout is the Uric acid crystal buildup in joints
• Types of Joints
  • Fibrous joints are immovable (e.g., skull sutures)
  • Cartilaginous joints are slightly movable (e.g., spine)
  • Synovial joints are Freely movable, which include Hinge, Ball-and-socket, Pivot, Saddle, Gliding, and Condyloid
• Joint Components
  • Ligaments connect bone to bone
  • Tendons connect muscle to bone
  • Menisci is the Cartilage in the knee for shock absorption
  • Synovial fluid lubricates joints
• Common Injuries
  • Sprain is a Ligament injury
  • Strain is a Muscle/tendon injury
  • Fractures can be simple, compound, greenstick, comminuted, or spiral
  • Dislocation is when a bone slips out of joint
• Key Bones to Know
  • Skull bones include Frontal, parietal, temporal, and occipital
  • Vertebrae are Cervical (7), Thoracic (12), Lumbar (5), Sacrum, and Coccyx
  • Upper limb bones include Humerus, radius, ulna, carpals, metacarpals, and phalanges
  • Lower limb bones include Femur, tibia, fibula, patella, tarsals, metatarsals, and phalanges
  • Pelvis includes Ilium, ischium, and pubis
• Anatomical Terms
  • Anterior/Posterior mean Front/Back
  • Medial/Lateral means Toward midline/away from midline
  • Proximal/Distal means Closer to/farther from point of attachment
  • Superior/Inferior means Above/Below