The Skeletal System Flashcards
What are the functions of the skeleton?
-Provides support, attachment points, protection, assistance in movement, mineral storage and release, blood cell protection
What is the skeletal system made up of?
-Bones, associated connective tissues, cartilage, tendons, ligaments
What can the types of bone be divided into?
-Axial and appendicular
What do axial bones do?
-Protect vital parts of the body eg. Brain and spinal cord
What do appendicular bones do?
-Allow movement
What are the types of bones?
-sesamoid, short bones, flat bones, long bones, irregular bones
What are sesamoid bones?
-Bones that develop from tendons
What are short bones?
-Bones that are wider than they are long. In the hand for example allowing movement of wrist
What are flat bones?
-thin and flat bones that will mostly protect. Skull and ribs
What are long bones?
Bones that are longer than they are wide. Hard and dense such as thigh bone
What are irregular bones?
Complex shape which help protect internal organs for example the vertebrae
What are the types of microstructure of the bone?
-Compact bone and cancellous bone
What is a compact bone?
-Dense and solid in appearance, protective and strong, repeating circular units
What is a cancellous bone?
-Spongy bone that has open space partially filled with needle-like structures called trabecular-more light-weight
What is the structure of short, flat and irregular bones?
-Inner portion is cancellous, outer portion is compact bone
What is the diaphysis?
-The shaft of a long bone that is hollow with compact bone on outside and spongy on inside
What are the epiphyses?
-Ends of long bones, are cancellous
What is the articular cartilage?
-Covered external surface of epiphyses to protect
What is the epiphyseal line?
-Growth plate that becomes mineralised once growth is complete
What is in the composition of the bone matrix?
-Inorganic salts and organic matrix
What are the features of inorganic salts?
-contain hydroxyapatite which are crystals of calcium and phosphate
What are features of organic matrix?
-Made up of collagen fibres and proteoglycans for flexible strength
What are the features of the bone marrow ?
-Specialised type of connective tissue, site of haemotopoesis, found in cavities of long bones and spaces within spongy bone, contain red and yellow marrow
What are the features of red marrow?
-mainly found in children, in virtually all bones in children and is where red blood cell production occurs
What are the features of yellow marrow?
-Has become saturated with fat and are no longer active in blood cell production-found more in adults
What are the major cells in bone?
-Progenitor cells, osteoblasts, osteocytes, osteoclasts
What do progenitor cells do?
-Make osteoblasts
What do osteoblasts do?
-Form bone, osteogenesis, secretes collagen, produce vesicles that release Ca2+ and phosphate ions to contribute to hydroxyapatite formation
What are osteocytes?
-Differentiated mature cells from non-dividing osteoblasts, surrounded by calcified matrix
What are osteoclasts ?
-Giant cells that reabsorb bone through dissolving the minerals and breaking down the collagen, derived from monocytes and macrophages
What is bone remodelling?
-Ongoing replacement of old bone tissue by new bone tissue by osteoblasts
What happens in the raging Skelton?
-Decreased collagen so more brittle, cancerous bone lost first, incomplete remodelling
What is osteoporosis ?
-Bone resorption exceeds bone deposition
-health condition that weakens bones making them fragile
What regulates blood calcium levels?
-Parathyroid hormone (PTH)
-Vitamin D
-Calcitonin
How does parathyroid hormone regulate calcium levels?
-Stimulates osteoclasts to breakdown bone matrix, increase kidney absorption of calcium from urine-increase calcium levels
How does vitamin D regulate calcium levels?
-Increases calcium absorption from the small intestine-increases calcium levels
