Anatomy 2 - The Skeletal System PDF

The skeletal System Human Anatomyand PhysiologyII Summer Semester 2024  The skeletal system functions 1.Support the body. 2.Protection. 3.Assistance in movement. 4.Mineral homeostasis (storage and release). 5.Blood cell production 6.Lipid storage.  STRUCTURE OF BONE 1....

The skeletal System Human Anatomyand PhysiologyII Summer Semester 2024  The skeletal system functions 1.Support the body. 2.Protection. 3.Assistance in movement. 4.Mineral homeostasis (storage and release). 5.Blood cell production 6.Lipid storage.  STRUCTURE OF BONE 1. Diaphysis : the long portion of the bone. 2. Epiphyses : the two ends of the bone. 3. Metaphysis: between the diaphysis and the epiphyses. 4. Epiphyseal (growth) plate: a hyaline cartilage that allows the bone to grow in length. At about ages 18–21, the cartilage in the epiphyseal plate is replaced by bone. 5. The articular cartilage : a hyaline cartilage covering the epiphysis where the bone forms an joint with another bone. It reduces friction and absorbs shock at freely movable joints.  STRUCTURE OF BONE 6. The periosteum : a connective tissue sheath and blood vessels that surrounds the bone surface (any part not covered by articular cartilage). Bone is made of collagen fibers and minerals (mainly calcium). 99% of the body’s calcium is stored in bone. STRUCTURE OF BONE Metaphysis  Bone Bone cells Cells 1. Osteogenic cells: stem cells that undergo cell division to form osteoblasts. 2. Osteoblasts: Bone building cells,produce collagen fibers and organic components. ‫املحافظة على توازن الجسم‬ 3. Osteocytes: mature bone cells, maintaindailymetabolism. ‫هدم‬ 4. Osteoclasts: causes resorption of bone marrow (break down of bone). Bone Cells  Bone Growth *Factors Affecting Bone Growth and Bone Remodeling: 1. Minerals: calcium, phosphorus, magnesium, and fluoride. 2.Vitamins: VitaminA : stimulates osteoblasts. Vitamin C : synthesis of collagen. VitaminD : absorption of calcium from foods in the GIT. VitaminsK and B12: synthesis of bone proteins.  Bone Growth 3. Hormones During childhood: Growth hormone, Thyroid hormones, Insulin. At Puberty: Sex hormones. -Estrogen and Testosterone increase synthesis of bone in the teenage years. ‫يوقف نمو‬ -Sex hormones, especially estrogens, shut down growth at the epiphyseal plates, causing inhibition of bone elongation in adults. ‫تثبيط‬ ‫استطالة العظم‬  The Skeletal System Parts of the skeletal system: Bones Joints Cartilages Ligaments (connect bone to bone) Tendons (connect bone to muscle) Joint Cartilage  The Skeletal System Classification of Bones on the Basis of Shape: Long bone (Ex. humerus) Short bone (talus) Carpalas ,tarsals Flat bone (sternum) Irregular bone (vertebra) The Skeletal System ‫محور‬ ‫اطراف‬ The Axial Skeleton  The Skull Two sets of bones: = Cranium 1. Cranium 2. Facial bones Sutures Bones are joined by sutures. Only the mandible is attached by a freely movable joint. mandible Cranial Bones TMG  Facial Bones Facial bones: 1. Zygomatic bone 2. Maxillary bone 3. Nasal bone 4. Lacrimal bone 5. Mandibular bone  Paranasal Sinuses  Hollow portions of bones surrounding the nasal cavity.  Functions: ‫تخفف من وزن الجمجمة‬ 1. Lighten the skull (less weight). 2. Amplification of voice. (‫تخفف من حدة الصوت )تضخيم الصوت‬ ‫إيقاع الصوت‬ resonances  Vertebral column Functions: 1. Holds the head ‫يدعم‬/ ‫يسند‬ 2. Stiffens and supports the middle portion of the body 3. Provides attachment for the ribs and pelvic bone 4. Protects the spinal cord Vertebrae are separated by intervertebral discs (cartilages).  Vertebral column ‫التحام‬/‫اندماج‬ The Sacrum is formed by the fusion of five vertebrae. The wing-like Alae articulate laterally with the hip bones, forming the sacroiliac joints. A A  The Bony Thorax Forms a cage to protect major organs. Made-up of three parts: 1. Sternum 2. Ribs 3. Thoracic vertebrae Ribs are classified into: 1. True ribs (1-7) 2. False ribs (8-12) 3. Floating ribs (11-12) The Appendicular Skeleton  The Pectoral Girdle ‫مفصل الكتف‬ Also called the Shoulder Girdle. Sternoclavicular joint Composed of two bones that allow the upper limb to have free movement: 1. Clavicle = collar bone 2. Scapula = shoulder blade. Shoulder girdles attached to the axial skeleton by the sternoclavicular joint.  The Clavicle It attaches to the manubrium of the sternum medially and to the scapula laterally.  The Clavicle Clavicular fracture most often resulting from a direct blow or a fall on an outstretched hand (FOOSH). Most fractures occur in the middle third of the clavicle. The Scapula  The Upper Limb The arm is formed by a single bone, called: Humerus. The forearm has two bones: 1. Ulna (medial) 2. Radius (lateral). The hand consists of: 1. Carpals – at the wrist 2. Metacarpals – at the palm 3. Phalanges – the fingers.  Humerus Rt. Humerus Rt. Humerus Anterior view Posterior view Radius & Ulna The Hand  The Hand Scaphoid fracture is the most common fracture at the wrist joint. We test the fracture by Snuffbox tenderness (pain). The Hand  The Pelvic Girdle Pelvic girdle is composed of: 1. Hip bones 2. Sacrum 3. Coccyx Hip bones are composed of three pair of fused bones: 1. Ilium 2. Ischium 3. Pubic bone Protects several organs: 1. Reproductive organs 2. Urinary bladder 3. Part of the large intestine Coccyx  The Pelvic Girdle Ilium Ischium Pubis Posterior Anterior Lateral view  The Pelvic Girdle The ilium, connects posteriorly with the sacrum at the sacroiliac joint, is a large bone that forms most of the hip bone. ilium and sacrum ‫يربط بني‬ The upper edge of the alae is called the iliac crest (is an anatomical landmark for giving injections). iliac crest  The Pelvic Girdle The ilium, ischium, and pubis fuse at the deep socket called the Acetabulum which receives the head of Femur.  The Pelvic Girdle The pelvis is subdivided into: 1. False pelvis (greater). 2. True pelvis (lesser).  The Pelvic Girdle Differences between male and female pelvis:  The female pelvic inlet is larger. ‫اخف وأرق‬  The female pelvic bones are lighter and thinner.  The female pelvic outlet is larger.  The female pubic angle is greater. pubic angle in female pubic angle in male Anterior view Inferior view  The Lower Limb The thigh has one bone, called Femur. The leg has two bones: 1. Tibia (medial) 2. Fibula (lateral) The foot: 1. Tarsus – ankle 2. Metatarsals – sole of foot 3. Phalanges – toes  The Lower Limb We have 7 tarsal bones. All toes have three phalanges except the hallux (two phalanges). Joints  Joints Have two functions: 1. Hold the bones together. ‫يربط بني العظام‬ 2. Mobility of the skeleton. ‫تسهيل الحركة‬  Joints The functional classification of joints focuses on the amount of movement allowed by the joint: ‫ما بتتحرك‬ 1. Synarthroses: immovable (Ex: skull sutures). ‫حركتها بطيئة‬ 2. Amphiarthroses: slightly movable (Ex: vertebrae). ‫حركتها واسعة‬ 3. Diarthroses: freely movable (Ex: shoulder).  Joints Structural classification of joints: 1. 2. 3. Knee, shoulder, elbow, wrist …  Joints  Synovial joint structure: Articular capsule: Fibroelastic tissue that envelops the joint. Synovial membrane: ‫يفرز‬ Inner lining of capsule that secretes synovial fluid. Synovial fluid: ‫يزيد من لزوجتها‬ ‫يُغذي‬ Lubricates the joint and nourishes the articular cartilage. The End