Biology 2401 A&P I - Notes exam 2 - Skeletal System Ch. 7. Functions of skeletal system : support of body. production of blood cells

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1 Biology 2401 A&P I - Notes exam 2 - Skeletal System Ch. 7 Functions of skeletal system : support of body protection of soft organs production of blood cells movement (as levers) storage of minerals and fat Dynamic system of levers and support elements - active tissues, about 10% blood supply Each bone is an organ made of tissues - bone, cartilage, loose and dense connective, nerve tissues. Some key root terms: osteo- = bone peri- = around epi- = on, over -cyte = cell -blast = produce, precursor -clast = break down - physis = growth Structure of bones:- most have compact, or dense, bone on outer surface - with spongy, cancellous, bone inside (honeycomb) - surfaces covered with periosteum (outer) or endosteum (inner) periosteum and endosteum are dense connective tissue (fibrous) sheet that contain nerves, blood vessels and undeveloped bone cells collagen fibers continuous with collagen fibers in bone matrix and in tendon or ligament osteocytes live in small cavities called lacunae; lacunae are connected by small canals called canaliculi (allow blood vessels to each cell). 7.3 osteocytes produce collagen fibers that attract inorganic salts (calciun phosphate) to form rigid matrix. in compact bone osteocytes form concentric rings around blood vessel in central canal (Haversian canal). central canal and concentric layers of osteocytes form osteon (Haversian system); these tend to run longitudinally along bone. Gives resistance to bending. Spongy bone does not have osteon arrangement; forms as series of thin plates and rods at angles to each other, forms open honeycomb structure This gives light weight, yet good compacting strength Blood vessels in open spaces (bone marrow - also contains blood tissue) In response to stress bones develop characteristic patterns: Long bones, subject to bending or lateral stress, develop as hollow, thick wall tubes of compact bone. *Why? At ends of bones, subject to compacting stress from many directions, bone develops as spongy bone. *What is the advantage of spongy bone over solid compact bone? *Why is the longitudinal arrangement of osteons important?

2 Bone remodeling - Osteoclast are cells derived from white blood cells that digest bone -Undeveloped cells in periosteum and endosteum divide to produce source of bone cells - These cells mature into osteoblast, cells actively producing new collagen fibers, depositing calcium carbonate and calcium phosphate crystals (matrix is composed of fibers and crystals) -Osteoblast become osteocytes when they are enclosed in the matrix, less active cells that help maintain matrix Osteoclast digest bone, osteoblast produce new bone matrix - bone remodeling helps in keeping bone strong, healing and adjusting to changing stress With aging this process slows and bones are weaker and more brittle. Bone development and growth: 7.3 Ossification (osteogenesis) is process of replace other tissue with bone Bones formed from other tissues in two ways - intramembranous and endochondral intramembranous - form from patches of osteoblast in fibrous tissue, no cartilage some bones of skull, clavicle, mandible are examples endochondral - bone tissue replaces cartilage; cartilage forms model 7.3 Ossification begins in center of bone and expands toward each end - this area is called diaphysis Ossification later begins at each end of the bone and forms the ends - these areas are called the distal (far end) and proximal (near end) epiphysis The remaining cartilage between the diaphysis and the distal epiphysis and between the diaphysis and the proximal epiphysis are called the epiphyseal plates The diaphysis grows toward the ends of the bone, replacing the epiphyseal plate Meanwhile the cartilage of the epiphyseal plates grow toward the end of the bone - the race is on The bone grows longer and longer, mostly made of strong bone, but with growth plates of cartilage; this allows growth but provides strength When diaphysis grows faster and destroys all cartilage of epiphyseal plate (usually because of surge of sex hormones) the long growth stops. The contact of the diaphysis and the epiphysis recognized as epiphyseal line *What is the advantage of this pattern of growth? The only cartilage remaining after the epiphyseal plates are broken down is cartilage on the very ends of the bone; this becomes the articular cartilage that forms a joint.

3 The skeleton - know all 206 bones in the body and their position (more on this later) Articulations (joints) - classify the types of joints and know the kinds of movements around these joints 7.13 Joints classified by amount of movement permitted and by the type tissue that binds them: synarthrosis (immovable) / fibrous suture - example flat bones of skull gomphosis - held by ligament, ex. teeth in socket amphiarthrosis (slightly movable) / cartilagenous symphysis - held by fibrocartilage, ex. disc between vertebrae, anterior connection of pubis diarthrosis - (freely movable) / synovial - distinguished by shapes of articulating surfaces and plane of movement - know example of each: gliding - flat surfaces, nonaxial hinge - axial, 1 plane angular pivot - axial, rotation only ellipsoidal (condylar) - axial, 2 plane angular saddle - axial, 2 plane angular ball-and-socket - axial, rotational and 2 plane angular - movements around synovial joints: gliding flexion and extension, hyperextension abduction and adduction circumduction rotation pronation and supination inversion and eversion depression and elevation protraction and retraction Know structures of a typical synovial joint and their function Fig 7.35,.36 articular cartilage synovial membrane, synovial fluid joint capsule formed by ligaments accessory ligaments (in some) menisci (in some) bursae (around some joints) Review a few specific joints:

4 The Skeleton Know the bone names and the relative position of all bones in the body. I. Axial skeletal system (80 bones) Table 7.1 A. skull (cranium and facial bones) 1. cranium ( box that contains brain; cranial cavity) a. frontal (1) - frontal sinuses b. parietal (2) c. occipital (1) - foramen magnum, occipital condyles d. temporal (2) - external auditory canal, mandibular fossa mastoid process, zygomatic process e. sphenoid (1) - sella turcica, sphenoid sinuses f. ethmoid (1) - cribriform plate, ethmoidal sinuses, perpendicular plate, superior and middle nasal conchae 2. facial bones (support facial muscles, special senses) a. maxillae (2) - alveolar process (teeth socket), maxillary sinuses, palatine process (hard palate) b. palatine (2) - hard palate c. vomer (1) - nasal septum d. zygomatic (2) - zygomatic arch e. nasal (2) f. lacrimal (2) - nasolacrimal canal g. inferior nasal conchae (2) h. mandible (1) - alveolar process (teeth sockets), condylar process, coronoid process, body, ramus i. hyoid (1) j. auditory ossicles (6) - malleus, incus and stapes (pg 271) Be able to identify the bones that form the orbits, the nasal cavity, the hard palate, the bones that have sinuses connected to the nasal cavity. B. neck and trunk 1. vertebral column - know the following structures for each vertebra: body, transverse process, spinous process, articular facet, vertebral arch, vertebral foramen, intervertebral foramen, intervertebral disc Fig Also, know how each region is distinct) - intervertebral discs carry weight, articular facets limit twisting ` a. cervical vertebrae (7, C1 - C7) - all have transverse process with transverse foramen - atlas (C1) - lacks body - axis (C2) - odontoid process (dens) - vertebra prominens (C7) b. thoracic vertebrae (12, T1-T12) - articular surface for ribs

5 c. lumbar vertebrae (5, L1-L5) - heavily built body d. sacrum (5 fused sacral vertebrae from embryo) - articulates with pelvic girdle e. coccyx (3-5 fused coccygeal vertebrae) Spinal curves - at birth single curve, concave from anterior view Fig distinct curves develop to place face forward and to balance body: cervical curve (convex), thoracic (concave), lumbar (convex), sacral (concave) 2. thoracic cage Fig a. ribs - 12 pairs, pair 1-7 true ribs - individual costal cartilage pair 8-12 false ribs fused costal cartilage pair floating ribs- do not connect to sternum - costal cartilage connects ribs to sternum - synovial joints to ribs b. sternum - 3 parts fuse - manubrium, body and xiphoid process II. Appendicular skeleton - bones of the arms and legs and the girdles that attach to axis. A. upper limb pectoral girdle a. clavicle (2) b. scapula (2) - spine, glenoid fossa, coracoid process, acromion The pectoral girdle is specialized to be very flexible to give arms wide range of motion - describe specific features that allows flexibility. 2. arms a. humerus (2) - head, capitulum, trochlea, olecranon fossa b. ulna (2) - medial Pivot joint between radius and ulna allow c. radius (2) - lateral pronation and supination 3. wrist and hand a. carpals (16, 8/hand) - gliding joints between carpals b. metacarpals 10, 5/hand) - The proximal metacarpal of the thumb and the trapezium (one of the carpals) form a saddle joint. This allows the thumb to be opposable to the fingers, allowing power grip and precision grip. Why is this important? c. phalanges (1 is phalanx) - (28, 14/hand, 3/finger and 2/thumb) Muscles that flex and extend fingers located in lower arm, with tendons passing through the carpal tunnel.* What is the advantage and disadvantage of this arrangement? *The upper limb is very flexible and adapted to allow manipulation. Describe four anatomical features that allow this.

6 B. lower limb - more heavily built, and less flexible, to carry weight pelvic girdle - coxae (2), each composed of ischium, ilium and pubis. - acetabulum, iliac crest, obturator foramen, pubic symphysis - "pelvis" is sacrum, coccyx and coxal bones *What is the difference between the false and true pelvis? *How does the male pelvis differ from the female pelvis? Fig leg a. femur (2) - greater and lesser trochanter, capitate ligament, medial and lateral epicondyles and condyles b. patella (2) c. tibia (2) - medial and lateral condyle, medial malleolus d. fibula (2) - lateral malleolus *Tibia is the weight bearing bone in the lower leg, forming the knee and ankle joint. How does this compare to the double bone in the lower arm? 3. ankle and foot Fig 7.32, 7.33 a. tarsals (14, 7/foot) - calcaneus attaches to calcaneus (Achilles) tendon - talus forms joint with tibia b. metatarsals (10, 5/foot) c. phalanges (28, 14/foot) *Describe the arches of the foot (transverse and longitudinal). What is the function of the arches of the foot? *The lower limbs are adapted to carry the weight of the body and withstand the stress of moving. Describe four anatomical features of the lower limbs that allow them to be strong.