Lecture 3- Bone and Skeletal Tissue Flashcards
Cartilages
What are the three types of cartilage in the body, what are their properties and give examples of where they are located.
- Hyaline cartilage: most abundant, provides support, flexibility and resilience. Found on all joints, in nose, between ribs, trachea, sternum
- Elastic: similar to hyaline but contain elastic fibers. Found in structures that are self supporting but flexible E.g external ear
- Fibrocartilage: contains collagen fibres which give it great tensile strength. Eg disks between vertebrae, and the menisci between the femur and tibia at the knee
Classifying bones by shape
What are the 4 types of bones found in the body, what are their properties and give examples of each
- Long bones:
- longer than they are wide
- have a diaphysis and 2 epiphysis (end)
- diaphysis is made up of compact bone, with marrow filling the hollow central portion (medullary cavity)- when baby, it’s filled with red marrow. During adulthood half red marrow is converted to fatty yellow marrow
- each epiphysis is spongy surrounded by thin layer of compact bone
- Eg humerus, radius, ulna, femur, tibia and fibula - Short bones: sesamoid bone
- cube shaped and mainly spongy bone, with thin layer of compact bone surrounding it
- multiple short bones allow fine movements
- Eg carpals and tarsals and patella - Flat bones: thin and flattened, tend to be curved
- consist of a thin layer of spongy bone surrounded by compact bone
- the spongy bone is location for hematopoiesis
- Eg skull, scapula, ribs, ilium and sternum - Irregular bones: unique shape, don’t fit categories above
- Eg vertebrae, and ischium and pubis of the pelvis are considered irregular
What are the 5 functions of bones?
- Support: for body and soft organs
- Protection: for brain, spinal cord, and vital organs
- Movement: levers for muscle action
- Storage: minerals (calcium and phosphorus) and growth factors
- Blood cell formation (hematopoiesis) in marrow cavities
- Triglyceride (energy) storage
Bone characteristics Explain what the following types of bone markings are and give ex 1. Fissure 2. Foramen 3. Fossa 4. Groove 5. Meatus 6. Sinus
- Fissure: deep furrow cleft of slit eg orbital fissure
- Foramen: round opening through bone eg Foramen magnum
- Fossa: long, baseline depression eg glenoid fossa of scapula
- Groove: narrow, elongated depression eg bicipital groove
- Meatus: passage or channel eg external acoustic meatus of temporal bone
- Sinus: cavity or hollow space in a bone eg ethmoid sinus of nasal cavity
Bone characteristics: projections that form joints Describe and give an example for bellow 1. Condyle 2. Facet 3. Head 4. Ramus
- Condyle: rounded articular projection eg condyles of the femur
- Facet: small, smooth area eg costal facet of thoracic vertebrae
- Head: rounded extremity, protruding from a narrow neck eg head of the fibula
- Ramus: arm like bar eg ramis of the mandible
Bone characteristics: projections that are attachment sites Explain and give an example of the bellow 1. Crest 2. Epicondyle 3. Line 4. Process 6. Spine 7. Tubercle 8. Tuberosity 9. Trochanter
- Crest: narrow ridge eg iliac crest
- Epicondyle: prominence on or above a Condyle eg epicondyles of the humerus
- Line: ridge less prominent than a crest. Eg linea aspera of the femur
- Process: any bony prominence eg coracoid process of the scapula
- Spine: sharp slender prominence eg spine of the scapula
- Tubercle: small rounded prominence eg tubercle of the femur
- Tuberosity: large round, roughened prominence e.g tibial tuberosity
- Trochanter: large blunt prominence found only on the femur eg greater trochanter. Refer to pg 38 human anatomy for pictures
What are the two membranes of bone? What purpose do they serve?
- Periosteum (outer fibrous layer)- covered compact bone on outside
-inner osteogenic layer:
Osteoblasts: bone forming cells
Osteoclasts: bone destroying cells
Osteogenic cells: stem cells
-nerve fibres, nutrient blood vessels, and lymphatic vessels enter the bone via nutrient foramina - Endosteum: delicate membrane on internal surfaces of bone, also contains osteoblasts and osteoclasts - covers spongy bone within
What is the location of red blood cell formation and what’s its formal name
Hematopoietic tissue is the red marrow cavities in adults
Found in trabecular cavities of heads of the femur and humerus and trabecular cavities of the diploe of flat bones
In new born infants:
-medullary cavity and all spaces in spongy bone
Microscopic anatomy of bone: spongy bone
What are the properties of spongy bone?
Spongy bone is a 3 dimensional latticework of porous bony tissue filled with red bone marrow. The trabeculae of spongy bone form and reform according to the lines of stress, providing maximum strength
- no osteons
- contain irregularly arranged lamellae, osteocytes, and canaliculi
- capillaries in endosteum supply nutrients
Chemical compounds of bone: Organic
What are the organic compounds making up bone?
Osteogenic cells, osteoblasts, osteoclasts, osteocytes
- osteoid-organic bone matrix secreted by osteoblasts
- collagen fibres (provide tensile strength and flexibility)
Chemical compounds of bone: inorganic
What are the inorganic compound which make up bone?
Hydroxyapatites (mineral salts)
- makes up 65% bone by mass
- mainly calcium phosphate crystals
- responsible for hardness and resistance to compression
How is bone formed?
Osteogenesis (ossification)- bone tissue formation
Stages:
-begins in the 2nd month of development
-postnatal bone growth untill early childhood
-bone remodeling and repair which is lifelong
What is ossification and what are the two types of ossification?
Ossification is the process of laying down new bone material by osteoblasts
- Intramembranous ossification: membrane develops from fibrous membrane
- forms flat bones eg clavicles and cranial bones - Endochondral ossification
- cartilage (endochonrdal) bond forms by replacing hyaline cartilage
- forms most of the skeleton. Refer to slide 39
What is bone deposit and why does it occur?
Occurs when bone is injured or added strength is needed. Requires a diet rich in protein, vitamins c, d and a, calcium, phosphorus, magnesium and manganese
What is Bone reabsorption and how does it occur?
Osteoclasts secrete lysosomal enzymes which digest organic matrix and acids which convert calcium salts into soluble forms
