Parts of the skeletal system Bones (skeleton) No bones about it! Joints. Cartilages. Ligaments

Transcription

1 No bones about it! Have to reference book OFTEN for pictures & names of bones for nearly all homework Should immediately be familiar with major bone names Thigh = femur Arm = humerus Lower jaw = mandible Forearm bones = radius (out) & ulna (in) Heel = calcaneous Spine = vertebra Forehead = frontal Hand = metacarpals Wrist = carpals Parts of the skeletal system Bones (skeleton) Joints Cartilages Ligaments 1

2 Separated into two divisions: Axial skeleton skull and bones that support it like vertebral column, ribs, sternum Vertical axis of body Appendicular skeleton Limbs and all bones associated with them (hips, fingers, etc) Support of the body Protection of soft organs Movement due to attached skeletal muscles Storage of minerals and fats Ca 2+ Blood cell formation hematopoiesis 2

3 The adult skeleton has 206 bones Two basic types of bone tissue: Compact bone Homogeneous Spongy bone Small needle-like pieces of bone Many open spaces Where red blood cell formation occurs Four types of bone shapes Long bone Flat bone Short bone Irregular bone Figure 5.1 3

4 Long bones Typically longer than wide Have a shaft with heads at both ends Contain mostly compact bone for strength Examples: Femur, humerus Short bones Generally cube-shape Contain mostly spongy bone Examples: metacarpals, metatarsals Flat bones Thin and flattened Usually curved Thin layers of compact bone around a layer of spongy bone Examples: Skull, ribs, sternum 4

5 Irregular bones Irregular shape Do not fit into other bone classification categories Example: Vertebrae and hip Epiphysis Ends of the bone Composed mostly of spongy bone Contains red marrow for red blood cell formation Diaphysis Shaft Composed of compact bone 5

6 Periosteum Outside covering of the diaphysis Fibrous connective tissue membrane Sharpey s fibers Secure periosteum to underlying bone Arteries Supply bone cells with nutrients Figure 5.2c Articular cartilage Covers the external surface of the epiphyses Made of hyaline cartilage Decreases friction at joint surfaces Figure 5.2a Medullary cavity Cavity of the shaft Contains yellow marrow (mostly fat) in adults Contains red marrow (for blood cell formation) in infants Figure 5.2a 6

7 Bones do not have smooth surfaces Surface features of bones Sites of attachments for muscles, tendons, and ligaments Passages for nerves and blood vessels Categories of bone markings Projections and processes grow out from the bone surface Depressions or cavities indentations Foramen or meatus (huge or small) holes Osteon (Haversian System) A unit of bone Central (Haversian) canal Opening in the center of an osteon Carries blood vessels and nerves Perforating (Volkman s) canal Canal perpendicular to the central canal Carries blood vessels and nerves 7

8 Figure 5.3 Lacunae Cavities containing bone cells (osteocytes) Arranged in concentric rings Lamellae Rings around the central canal Sites of lacunae Canaliculi Tiny canals Radiate from the central canal to lacunae Form a transport system Detail of Figure 5.3 8

9 Osteon = mansion with many rooms Haversian canals = major hallway Volkman canals = smaller hallways Lamella = wings of mansion lacunae = rooms in each wing Osteocytes = live/grow in rooms Canaliculi = doors connecting rooms In embryos, the skeleton is primarily hyaline cartilage During development, much of this cartilage is replaced by bone (starting at week 9 in utero) Cartilage remains in isolated areas Bridge of the nose Ears Parts of ribs Joints Epiphyseal plates allow for growth of long bone during childhood New cartilage is continuously formed Older cartilage becomes ossified 9

10 When blood vessels penetrate cartilage membrane, stimulate it to become osteoblasts (precursors to osteocytes) Cartilage is broken down Bone replaces cartilage + + collagen & Calcium ions osteoblast osteocyte Bones are remodeled and lengthened until growth stops Bones change shape somewhat Bones grow in width Figure 5.4a 10

11 Figure 5.4b Osteocytes Mature bone cells Osteoblasts Bone-forming cells Osteoclasts Bone-destroying cells Break down bone matrix for remodeling and release of calcium Bone remodeling is a process by both osteoblasts and osteoclasts 11

12 A break in a bone Types of bone fractures Closed (simple) fracture break that does not penetrate the skin Open (compound) fracture broken bone penetrates through the skin Bone fractures are treated by reduction and immobilization Realignment of the bone Table 5.2 Closed fractures Open fracture 12

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14 Hematoma (blood-filled swelling) is formed Break is splinted by fibrocartilage to form a callus Fibrocartilage callus is replaced by a bony callus Bony callus is remodeled to form a permanent patch of new bone 14

15 Figure 5.5 Forms the longitudinal part of the body Divided into three parts i. Skull ii. Vertebral column iii. Bony thorax (ribs and sternum) Figure

16 Two sets of bones Cranium Facial bones Bones are joined by sutures Only the mandible is attached by a freely movable joint Figure 5.7 Figure

17 Figure 5.8 Figure 5.9 Hollow portions of bones surrounding the nasal cavity Lined with mucosal membranes (secrete mucous) Susceptible to infection since connected to nasal passage, therefore exposed to air-borne viruses & bacteria Figure

18 Functions of paranasal sinuses Lighten the skull Give resonance and amplification to voice Figure 5.10 The only bone that does not articulate (connect) with another bone Serves as a moveable base for the tongue Not easily broken due to location; fractured hyoid bone is usually indication of strangulation of an adult Hyoid bone in adolescents is primarily cartilage, therefore flexible Figure 5.12 The fetal skull is large compared to the infants total body length Fontanelles (soft spot) fibrous membranes connecting the cranial bones Allow the brain to grow Convert to bone within 24 months after birth Figure

19 Figure 5.13 Vertebrae separated by intervertebral discs The spine has a normal curvature Each vertebrae is given a name according to its location Cervical (C 1 -C 7 ) Thoracic (ribs) (T 1 -T 12 ) Lumbar (L 1 -L 5 ) Sacral (5 fused) Coccyx (4 fused) Figure 5.14 Figure

20 Figure 5.17a b Figure 5.17c d Scoliosis Lateral curve Kyphosis Outward (hump) Lordosis Inward (sway back) 20

21 Forms a cage to protect major organs (lungs, heart, etc.) Figure 5.19a Made-up of three parts Sternum Manubrium (top) Body (middle) Xiphoid process (bottom) Ribs True (1-7); connected to sternum False (8-12); not connected to sternum Attached (8-10); connected to rib 7 Floating (11-12); not connected Thoracic vertebrae i. Pectoral girdle ii. Limbs (appendages) iii. Pelvic girdle 21

22 Composed of two bones Clavicle collarbone Scapula shoulder blade These bones allow the upper limb to have exceptionally free movement Figure 5.20c d Two types of limbs: Upper (Arms with hands) Lower (Legs with feet) 22

23 The upper arm is formed by a single bone Humerus Figure 5.21a b The forearm has two bones (remember anatomical position!) Radius (outer) Ulna (inner) Figure 5.21c The hand Carpals wrist Metacarpals palm Phalanges fingers Distal (tips) Middle Proximal (base) Figure

24 The thigh has one bone Femur Figure 5.24a b The leg has two bones Tibia (shin) Fibula Figure 5.24c The foot Tarsals ankle Must know: Talus calcaneus Metatarsals sole Phalanges toes Distal (tip) Middle Proximal (base) Figure

25 Bones of the foot are arranged to form three strong arches Two longitudinal One transverse Figure 5.26 Coxal (hip) bone Composed of three pair of fused bones Ilium Ischium Pubic bone The total weight of the upper body rests on the pelvis Protects several organs Reproductive organs Urinary bladder Part of the large intestine Figure 5.23a 25

26 Figure 5.23b female male 1. Female inlet is larger/more circular 2. Female pubic arch is > 90 (rounder) 3. Female ischial spines are shorter Figure 5.23c Articulations (connections) of bones Functions of joints Hold bones together Allow for mobility Ways joints are classified Functionally how they work Structurally what they look like 26

27 Synarthroses immovable joints Ex: skull Amphiarthroses slightly moveable joints Ex: spinal column/vertebrae Diarthroses freely moveable joints Ex: shoulder i.fibrous joints Generally immovable -synarthroses ii.cartilaginous joints Immovable or slightly moveable - synarthroses or amphiarthroses iii.synovial joints Freely moveable - Diarthroses Bones united by fibrous tissue Examples Sutures of skull Syndesmoses joints held together by ligaments Allows more movement than sutures Ex: distal end of tibia and fibula Figure 5.27a b 27

28 Bones connected by cartilage Examples Pubic symphysis Intervertebral joints Ribcage Figure 5.27d e Articulating bones are separated by a joint cavity Synovial fluid is found in the joint cavity Shoulder Knee Wrist/ankle Figure 5.24f h Articular cartilage (hyaline cartilage) covers the ends of bones Joint surfaces are enclosed by a fibrous articular capsule Have a joint cavity filled with synovial fluid Ligaments reinforce the joint 28

29 Bursae flattened fibrous sacs Lined with synovial membranes Over 150 in human body Filled with synovial fluid Not actually part of the joint Lubrication Cushioning Tendon sheath Elongated bursa that wraps around a tendon Figure 5.28 Six types: Joint Type Plane or gliding Hinge Pivot Condyloid or ellipse Saddle Ball-and-socket Location Carpals, tarsals Knee, elbow Neck, forearm Wrist, ankle Thumb at carpals Shoulder, hip Figure 5.29a c 29

30 Figure 5.29d f 30

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32 Bursitis inflammation of a bursa usually caused by a blow or friction Tendonitis inflammation of tendon sheaths Arthritis inflammatory or degenerative diseases of joints Over 100 different types Three major ones will be discussed The most widespread crippling disease in the United States 32

33 a. Osteoarthritis Most common chronic arthritis Probably related to normal aging processes b. Rheumatoid arthritis An autoimmune disease the immune system attacks the joints Symptoms begin with bilateral inflammation of certain joints Often leads to deformities c. Gouty Arthritis (gout) Inflammation of joints is caused by a deposition of urate crystals from the blood Can usually be controlled with diet 33

34 Osteoporosis Bone-thinning disease afflicting 50% women over 65, 20% men over 70 Bones become fragile so minor accidents have devastating bone fractures Bones of spine & neck of femur (ball) highly vulnerable Spine: Dowager s hump (kyphosis) Femur: broken hip Causes: estrogen deficiency after menopause Estrogen maintains normal density of bones Poor diet deficient in calcium, vitamin D Smoking Lack of weight-bearing exercises Bunion Outward growth between 1 st phalange and metatarsal joint (where big toe meets sole) Caused by tight-fitting shoes (high heels) or injury (ballet dancers) Usually genetically predisposed (runs in families) Only surgery can correct it 34

35 Clubfoot Congenital (at birth) foot deformity affecting 1:1000 Twice as many boys born with it than girls Linked to smoking and Ecstasy drug use while pregnant Bones, joints, muscles, blood vessels all abnormal Corrected either with series of casts forcing foot to grow correctly or surgery Rickets Softening of bones in children leading to fractures and deformity most frequent childhood diseases in many developing countries Cause: vitamin D deficiency (lack of sunlight) and/or lack of adequate calcium in the diet (usually malnutrition) 35

36 Leukemia cancer of blood cells originating in bone marrow & affects lymphatic system Results in malformed white blood cells that are unable to fight infection Cause: unknown but risk factors include smoking, chemical or radiation exposure Treatment: chemotherapy, radiation, stem cell (bone marrow) transplant Youth At birth, the skull bones are incomplete Bones are joined by fibrous membranes fontanelles Fontanelles are completely replaced with bone within two years after birth Puberty Pelvic girdle broadens in girls as result of hormones Entire skeleton gets stronger/robust in boys Shoulder girdle broadens in boys 36

37 Aging Vertebral cartilage thins leads to decrease in overall height (shrinking) Menopause in women decreases estrogen leads to osteoporosis Test Wednesday, October 24 37