ZOO

• Skeletal System


  Offers structural support and framework for the body, consists of 206 bones in an adult human, along with cartilage, ligaments, and tendons, connects bones to muscles and bones together, provides body shape and shields internal organs for protection

  
• Infants have approximately 300 bones at birth, fusion in some bones leads to larger bones, resulting in 206 bones in adults

  
• Osteology


  Branch of Biology studying the structure and function of the skeleton and bones
• Functions of Human Skeletal System

  • Structural support and framework
  • Connects bones to muscles and bones together
  • Provides body shape and shields internal organs for protection
• Divisions of the Skeletal System

  • Axial skeleton
  • Appendicular skeleton

  
• Axial skeleton


  • Made up of 80 bones and constitutes the middle axis, includes the skull, hyoid, auditory ossicles, vertebral column, ribs, and sternum

  
• Skull


  • Consists of the cranium (for brain protection) and facial bones, cranium is made of 8 plate-shaped bones connected at sutures, remaining 14 bones form the facial structure, mandible is the only movable bone

  
• Functions of the Skull

  • Provides protection and support for the brain, meninges, eyes, cerebellum, cerebrum, and brainstem
  • Supports facial muscles and scalp attachments
  • Safeguards vessels and nerves for facial muscles, brain, and related parts
  • Hardens and fuses during development for internal content protection
• Hyoid


  • U-shaped bone situated in the front of the neck, serves as a link between the skull and postcranial skeleton, assists in tongue movement and swallowing, not connected or articulated with other bones

  
• Auditory ossicles


  • Malleus, incus, stapes are three bones in the middle ear that are the smallest bones in the human body, function is to transmit sound from the air to the cochlea

  
• Ribs


  • Long curved bones forming the rib cage, totaling 24 bones in 12 pairs, constructs the protective enclosure around the thorax, safeguards the internal organs within the thoracic cavity, posteriorly connects with the vertebral column and ends anteriorly as cartilage

  
• Sternum


  • Long bone situated in the center of the chest, forms the rib cage along with the ribs, connected to the first seven ribs and the clavicle (collarbone)

  
• Vertebral Column


  • Set of approximately 33 bones called vertebrae, separated by intervertebral discs, divided into 5 categories: cervical, thoracic, lumbar, sacrum, coccyx

  
• Functions of the Vertebral Column

  • Protects the spinal cord
  • Provides stiffening to the body
  • Provides structural support by balancing the body weight
  • Provides attachment to pectoral and pelvic girdles and other muscles
• Cervical Vertebrae


  • Delicate and thin bones in the vertebral column, consist of 7 vertebrae aligned along the neck, named from superior C1 (Atlas) to C7, holding up the skull and enabling head rotation, C2 (Axis) facilitates head and atlas rotation

  
• Thoracic Vertebrae


  • Located in the mid-back region, primarily supports the rib cage, safeguarding the heart and lungs, comprised of 12 vertebrae, named T1 to T12, uniquely associated with supporting and articulating with the ribs

  
• Lumbar Vertebrae


  • Largest vertebrae in the vertebral column, consists of 5 bones located between the rib cage and pelvis, named L1 to L5, L1 is closest to the thoracic vertebrae, L5 is adjacent to the pelvis, functions as the primary load-bearing structure in the spine

  
• Sacral Vertebrae


  • Comprise 5 vertebrae bones that fuse to create the Sacrum, Sacrum is a long, wedge-shaped vertebra at the base of the spine, strong bone supporting upper body weight and transferring it across the pelvis to the legs

  
• Coccyx Vertebrae


  • Composed of three to five fused rudimentary bones, forming a small triangular bone, also known as the tailbone, functions as an attachment point for ligaments, tendons, and muscles, susceptible to fracture in cases of sudden falls or impact

  
• Appendicular Skeleton


  • Divided into 6 regions: shoulder girdle, arms and forearms, hands, pelvis, thighs and legs, feet and ankles

  
• Shoulder (Pectoral) Girdle


  • Comprises 4 bones connecting each arm, forms part of the appendicular skeleton, associated with the upper limbs, includes the scapula (shoulder blade) and clavicle (collarbone) in humans
• Arms and Forearms


  • Constituted of 6 bones, the large bones of the arm include humerus, radius, and ulna

  
• Hands


  • Consist of 54 bones which provide support and flexibility to the soft tissues, categorized into carpals, metacarpals, and phalanges

  
• Pelvic Girdle


  • Situated in the lower trunk as a ring-like bony structure, comprised of the sacrum, coccyx, and paired hip bones (ilium, ischium, and pubis)

  
• Functions of Pelvic Girdle


  • Transfers the weight of the body from the axial skeleton to the appendicular components, especially during movement
  • Provides attachment from several muscles and ligaments enabling movement
  • Majority of women have a gynecoid pelvis and males have an android pelvis, differences in structure create a great pelvic outlet enabling the process of childbirth
• Thighs and Legs


  • Integral part of the appendicular skeletal system, supporting lower limb muscles, facilitate walking, running, standing, and jumping, require strength to effectively bear and support the body's weight
• Feet and Ankles


  • The foot is a firm platform which supports the weight of the body, formed of many bones such as the tarsals, metatarsals, and phalanges
• Tendons


  Joint bones to skeletal muscles, made up of connective tissues
• Ligaments


  Join two bones together, also a type of connective tissue
• Cartilage


  Protects bones at the joints from wear and tear, firm yet softer and more flexible than bones, forms a structural framework of many parts of the body, e.g. ear, nose, ribs, bronchial tubes, etc.
• The majority of women have a gynecoid pelvis and males have an android pelvis. The differences in the structure create a great pelvic outlet enabling the process of childbirth.
• The Femur or thigh bone is the largest and heaviest bone in the human body. At the proximal end of Femur, there is a rounded prominence which is called as the Head of the Femur.

  
• The Tibia and Fibula are the two long bones in the lower leg. They are two separate bones but are closely linked at the knee and the ankle. The top of Tibia connects to the knee joint and bottom connects to the ankle joint. Although Tibia carries all the body weight, it needs the support of Fibula.
• Tissues


  Groups of cells sharing similar shape and function, representing an intermediate organizational level between cells and organ systems
• Histology


  The study of tissues, including histopathology which deals with disease-related tissue study, and standard methods like embedding and sectioning via paraffin blocks
• Types of animal tissues

  • Connective tissue
  • Muscle tissue
  • Nervous tissue
  • Epithelial tissue
• Connective tissue


  • Made of cells and a non-living extracellular matrix, gives shape to organs and maintains their positions, examples include blood, bone, tendon, adipose, ligament, and areolar tissues
• Types of connective tissue

  • Fluid connective tissue
  • Fibrous connective tissue
  • Skeletal connective tissue
• Functions of connective tissues

  • Insulating, binding organs together and providing support, protecting against pathogens, providing shape and storing energy, transporting substances within the body
• Muscle tissue


  • Involved in producing force and generating motion, including skeletal, cardiac, and visceral/smooth muscle