Bio10004 Anatomy and Physiology 2024 Past Paper

Bio10004 – Anatomy and Physiology 2024 The Skeletal system 1 Dr. Greg Davis (Designed by Dr. ALI AL-RUBAIE) Department of Health Sciences and Biostatistics  Learning objectives and reading At the end of this lecture you should be able...

Bio10004 – Anatomy and Physiology 2024 The Skeletal system 1 Dr. Greg Davis (Designed by Dr. ALI AL-RUBAIE) Department of Health Sciences and Biostatistics  Learning objectives and reading At the end of this lecture you should be able to: 1. List the major functions for the skeletal system. 2. Explain how bones are categorised by their shape and how long bones are categorised by their structure. 3. Compare the basic structures and functions of compact bone and spongy bone. 4. Identify the four cell types in bone and list their major functions.  Skeletal system primary functions Support – Body, soft tissues, organs Storage of minerals and lipids – Calcium, phosphate – Yellow bone marrow stores lipids Blood cell production – Long bones produce red, white cells and more Protection – Heart, lungs, brain, spinal cord  Classification of Bones Bone are identified by: – Shape Long, flat, irregular, short, sesamoid – bone markings Depressions, projections, tunnels – internal tissues Compact, spongy  Bone types long and thin found in arms, legs, hands, feet, fingers, and toes Small, irregular bones Thin with parallel surfaces found between the flat found in the skull, bones of the skull sternum, ribs, and scapula Have complex shapes spinal vertebrae pelvic bones Small and thick Small and flat ankle, wrist bones Develop inside tendons near Fig 6.1 joints of knees, hands, and feet  Classify that bone Proximal phalange (middle segment of finger) Scapular (shoulder) Coxal (hip) Femur Radius  Classify that bone Proximal phalange (middle segment of finger) – Long bone Scapular (shoulder) – Irregular bone Coxal (hip) – Irregular bone Femur - Long bone Radius - Long bone  Bone Markings Depressions or grooves: – along bone surface Projections: – where tendons and ligaments attach – at articulations with other bones Tunnels: – where blood and nerves enter bone Bone parts Diaphysis: – the shaft – compact bone wall – marrow cavity Epiphysis: – wide part at each end – articulation with other bones – Spongy bone Metaphysis: – where diaphysis and epiphysis meet Figure 6–3  Bone (osseous) tissue Dense matrix, containing: – deposits of calcium salts – bone cells within lacunae organized around blood vessels Canaliculi: – form pathways for blood vessels – exchange nutrients and wastes 2/3 of bone matrix is calcium phosphate, Ca3(PO4)2: – which incorporates other calcium salts and ions 1/3 of bone matrix is protein fibers (collagen)  Bone Cells Make up only 2% of bone mass: – Osteocytes – Osteoblasts – Osteo-progenitor cells (immature) – Osteoclasts Osteocytes Mature bone cells that maintain the bone matrix To maintain protein and mineral content of matrix To help repair damaged bone These cells do not divide Figure 6–4  Builders and renovators Osteoblasts Osteoclasts – Immature bone cells that Secrete acids and protein- secrete matrix compounds digesting enzymes (osteogenesis) Osteoporosis?? Figure 6–5  Bone types Compact bone – Contains parallel osteons – Concentric layers of osteocytes – Around central canal Spongy bone – Contains trabeculae – Meshwork of supporting fibre bundles  Compact bone Osteon – The basic unit of mature compact bone Osteocytes are arranged in concentric lamellae Around a central canal containing blood vessels  Bone cells 4 separate types (but really 2 with life cycles) osteoprogenitor → osteoblast → osteocyte Progenitor cells are dividing cells that differentiate into osteoblasts. Osteoblasts build bone and when they have constructed matrix around them, mature into osteocytes. Osteocytes maintain mineral and protein content of surrounding matrix, and are involved in repair of fractures osteoclast These are very different and largely dissolve and remove matrix via enzymes. This allows body to make use of minerals as required. Actions of Osteoblasts and Osteoclasts are usually balanced  Spongy Bone Does not have osteons. The matrix forms an open network of trabeculae Trabeculae have no blood vessels  Periosteum and Endosteum Compact bone is covered with membrane: – periosteum on the outside – endosteum on the inside  Periosteum Functions – Isolate bone from surrounding tissues – Provide a route for circulatory and nervous supply – Participate in bone growth and repair Endosteum An incomplete cellular layer: – lines the marrow cavity – covers trabeculae of spongy bone – lines central canals Contains osteoblasts, osteoprogenitor cells, and osteoclasts Is active in bone growth and repair  Bone growth Continuous remodeling Can change the matric and leave the shape the same – Can change the shape or internal structure of the bone Remodeling – Involves osteocytes, osteoblasts and osteoclasts – Osteocytes continuously removing/replacing calcium salts – Osteoclasts (remove) and osteoblasts (build) and work in balance  Effects of Exercise on Bone Mineral recycling allows bones to adapt to stress Heavily stressed bones become thicker and stronger – Markings on bone also can indicate type of stress – e.g. fractures, weightlifting Bone degenerates quickly – Up to 1/3 of bone mass can be lost in a few weeks of inactivity Osteoblasts are attracted to electrical fields – When bone is stressed creates electrical fields from mineral crystals  Summary Bones – Bone types, markings, classification Bone tissue – Form – Bone cells: osteocytes, osteoblasts, osteoclasts, progenitor cells – Periosteum, endosteum Effects of exercise on bones