BISC-225 TEST 3 Flashcards
Bone includes active, living tissues - bone tissue, cartilage, dense connective tissue, blood, and nervous tissue
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Bone Shapes: Long, Short, Flat, Irregular, and Sesamoid or round bones
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Long bones – forearm, thigh bones - longitudinal axes and expanded ends
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Short bones – wrist, ankle bones - somewhat cubelike
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Flat bones – ribs, scapulae, some skull bones - platelike structures with broad surfaces
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Irregular bones – vertebrae, facial bones - variety of shapes; usually connected to several other bones
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Sesamoid bones or round bones – kneecap - usually small and nodular, embedded within tendons
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Parts of a Long Bone: Diaphysis, Epiphysis, Periosteum, Compact bone, Spongy bone = cancellous bone, and Medullary cavity
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Diaphysis – shaft of a long bone
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Epiphysis – expanded end – covered with hyaline cartilage
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Periosteum – a fibrous connective tissue that encloses all of the bone except the articular cartilage.
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Periosteum – continuous with ligaments and tendons
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Periosteum – functions in the formation and repair of bone tissue
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process – a bony projection for attachment of ligaments and tendons
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grooves and openings – passageways for blood vessels and nerves
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depression – where a bone might articulate with another bone
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Compact bone(cortical bone) - tightly packed tissue making up the diaphysis .
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Spongy bone(cancellous bone) – comprises the epiphyses
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Spongy bone(cancellous bone) - trabeculae - consists of many branching bony plates
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Spongy bone(cancellous bone) - the spaces between the trabeculae plates help reduce the weight of bone
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Spongy bone(cancellous bone) - most highly developed in regions of epiphyses subjected to compressive forces
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Medullary cavity – hollow chamber within diaphysis
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Medullary cavity - filled with marrow: a type of soft connective tissue
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Bone cells called osteocytes are located in lacunae, which form concentric circles around central canals ( Haversian canals ).
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osteocytes - communicate with other cells by cellular processes passing through canaliculi
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Collagen gives bone its strength and resilience, and inorganic salts make it hard and resistant to crushing.
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osteocytes and lamellae around a central canal form an osteon, sometimes called an Haversian system.
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Compact Bone - osteocytes and lamellae around a central canal form an osteon, sometimes called an Haversian system.
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Compact Bone - each central canal contains blood vessels and nerve fibers
1) blood nourishes bones cells
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Compact Bone - central canals are interconnected by transverse perforating canals
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transverse perforating canals - contain larger blood vessels and nerves
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Spongy Bone - osteocytes lie within trabeculae and get nutrients from substances diffusing into the canaliculi that lead to the surface of these thin, bony plates
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Bones form by replacing existing connective tissue in one of two ways: intramembranous bones or endochondral bones
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intramembranous bones - originate within sheetlike layers of connective tissue
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endochondral bones - begin as masses of cartilage that are later replaced by bone
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Intramembranous Bone - broad, flat bones of the skull
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Intramembranous Bone - Mesenchyme - Osteoblasts
- Membranelike layers of unspecialized, or primitive, connective tissues ( mesenchyme) appear at the sites of future bones.
- Dense networks of blood vessels supply the tissues, which may form around the vessels.
- These primitive cells, mesenchyme cells, enlarge and differentiate into bone-forming cells called osteoblasts.
- Osteoblasts deposit bony matrix around themselves forming spongy bone.
a. some of the spongy bone will become compact bone as spaces fill with bone matrix - Osteoblasts becomes surrounded by bone and become secluded in lacunae – matrix surrounding the cellular processes of osteoblasts forms canaliculi.
a. once these cells are isolated in lacunae, they are called osteocytes - Mesenchyme cells on outside of developing bone give rise to the periosteum.
- Osteoblasts on the inside of periosteum form a layer of compact bone over the surface of newly formed spongy bone.
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Intramembranous Bone - mesenchyme - Membranelike layers of unspecialized, or primitive, connective tissues appear at the sites of future bones.
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Intramembranous Bone - primitive cells, mesenchyme cells, enlarge and differentiate into bone-forming cells called osteoblasts.
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Intramembranous Bone - Osteoblasts deposit bony matrix around themselves forming spongy bone.
a. some of the spongy bone will become compact bone as spaces fill with bone matrix
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Intramembranous Bone - Osteoblasts becomes surrounded by bone and become secluded in lacunae – matrix surrounding the cellular processes of osteoblasts forms canaliculi.
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Intramembranous Bone - lacunae – matrix surrounding the cellular processes of osteoblasts forms canaliculi.
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Osteoblasts - once these cells are isolated in lacunae, they are called osteocytes
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Intramembranous Bone - Mesenchyme - cells on outside of developing bone give rise to the periosteum.
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Intramembranous Bone - Osteoblasts on the inside of periosteum form a layer of compact bone over the surface of newly formed spongy bone.
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intramembranous ossification - process of replacing connective tissue to form an intramembranous bone
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Endochondral Bones
- Bones develop from masses of hyaline cartilage shaped like future bony structures.
- Cartilage cells enlarge and lacunae grow, then the surrounding matrix breaks down and cartilage cells die and degenerate.
- A periosteum forms around the developing bone.
- Blood vessels and undifferentiated cells invade the disintegrating tissue.
a. some of the cells differentiate into osteoblasts and begin to form spongy bone in the spaces previously housing the cartilage - Osteoblasts beneath the periosteum deposit compact bone around the spongy bone.
- The process of forming endochondral bone by the replacement of hyaline cartilage is endochondral ossification.
a. bony tissue begins to replace cartilage in the center of the diaphysis – the primary ossification center
1) bones develop from ossification center to the ends of the cartilaginous structure
b. secondary ossification centers appear in the epiphyses and spongy bone forms in all directions from them
c. a band of cartilage, called the epiphyseal plate, or metaphysis, remains between the two ossification centers as the bone lengthens
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Endochondral Bones - develop from masses of hyaline cartilage shaped like future bony structures.
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Endochondral Bones - hyaline Cartilage cells enlarge and lacunae grow, then the surrounding matrix breaks down and cartilage cells die and degenerate.
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Endochondral Bones - A periosteum forms around the developing bone.
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Endochondral Bones - Blood vessels and undifferentiated cells invade the disintegrating tissue.
a. some of the cells differentiate into osteoblasts and begin to form spongy bone in the spaces previously housing the cartilage
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Endochondral Bones - Osteoblasts beneath the periosteum deposit compact bone around the spongy bone.
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endochondral ossification - process of forming endochondral bone by the replacement of hyaline cartilage
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endochondral ossification - primary ossification center - bony tissue begins to replace cartilage in the center of the diaphysis
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endochondral ossification - primary ossification center - bones develop from ossification center to the ends of the cartilaginous structure
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endochondral ossification - secondary ossification center - appear in the epiphyses and spongy bone forms in all directions from them
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Epiphyseal plate, or metaphysis - a band of cartilage that remains between the two ossification centers as the bone lengthens
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Epiphyseal Plate - first layer ( closest to epiphysis ) – resting cells; anchors plate to the epiphysis
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Epiphyseal Plate - second layer - rows of many young cells undergoing mitosis; cartilaginous disc becomes thicker
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Epiphyseal Plate - third layer – rows of older cells, left behind when new ones form; thickens the plate still more
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Epiphyseal Plate - third layer - osteoblasts accumulate in the intercellular matrix adjacent to the oldest cells and secrete calcium salts, calcifying the matrix – the cells begin to die
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Epiphyseal Plate - fourth layer – quite thin; composed of dead cells and calcified intercellular substance
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Osteoclasts - break down the calcified matrix secreting an acid to dissolve the inorganic components and using lysosomal enzymes to digest the organic componenets.
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Bone-building osteoblasts - invade the region and deposit bone tissue in place of the calcified cartilage.
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Epiphyseal Plate - As long as the cartilaginous cells of the epiphyseal plates are active, the bone will lengthen.
a. once the ossification centers of the diaphysis and epiphyses meet and the epiphyseal plates ossify, lengthening is no longer possible
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Epiphyseal Plate - The bone thickens as compact bone is deposited underneath the periosteum.
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Epiphyseal Plate - Osteoclasts erode bone tissue on the inside, creating the medullary cavity of the diaphysis.
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Homeostasis of Bone Tissue - Osteoclasts and osteoblasts continually remodel the bones.
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osteoclasts - resorb bone tissue
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osteoblasts - deposit bone tissue
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Bone Tissue - Osteoclasts and osteoblasts - about 10 - 20% of bone calcium is exchanged each year
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Vitamin D - necessary for proper absorption of calcium in the small intestine.
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Vitamin D - developing bones are softened if to little of this
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Vitamin D - rickets in children; if to little
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Vitamin D - osteomalcia in adults; if to little
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vitamin D - found in milk and other dairy products fortified with it
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Vitamin D - can form from dehydrocholesterol produced by cells of digestive tract
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Dehydrocholesterol - carried to skin and when exposed to ultraviolet from the sun, is converted to a compound that becomes vitamin D
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Vitamin A - necessary for osteoblast and osteoclast activity during normal development.
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Vitamin C - necessary for collagen synthesis.
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Vitamin C - absence of this vitamin causes the osteoblasts to produce less collagen and the resulting bones are abnormally slender and fragile
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Vitamin C - about 90% of the protein that is part of bone is collagen
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pituitary gland - growth hormone - stimulates division of cartilage cells in the epiphyseal plates.
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pituitary gland - growth hormone - too little results in a child with pituitary dwarfism
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pituitary gland - growth hormone - too much results in pituitary gigantism
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acromegaly - an excess amount of pituitary gland growth hormone in an adult cause this condition
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Thyroid hormone - can halt bone growth by causing premature ossification of the epiphyseal plates.
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Thyroid hormone - too little may stunt growth, because without its stimulation, the pituitary gland does not produce enough growth hormone
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Parathyroid hormone - stimulates an increase in the number and activity of osteoclasts.
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Male and female sex hormones - promote formation of bone tissue.
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Male and female sex hormones - abundant at puberty, causing the long bones to grow considerably – but also
stimulate ossification of epiphyseal plates
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Male and female sex hormones - estrogens have a stronger effect on epiphyseal plates than androgens
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Physical stress - muscles pull on bones stimulating the bone tissue to thicken and strengthen
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Physical stress - atrophy - lack of exercise, bones become thinner and weaker
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Support, Protection, and Movement - Give shape to structures such as the head, face, thorax, and limbs.
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Support, Protection, and Movement - Support the body’s weight.
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Support, Protection, and Movement - Skull bones protect eyes, ears, brain; rib and shoulder girdle protect heart and lungs.
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Support, Protection, and Movement - Whenever limbs move, bones and muscles interact.
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Blood Cell Formation = Hematopoiesis
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Hematopoiesis - This process begins in the yolk sac, which lies outside the embryo. Later, blood cells are manufactured in the liver and spleen, and still later, in bone marrow.
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There are two kinds of marrow: Red Marrow and Yellow Marrow
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red marrow - functions in the formation of red blood cells, white blood cells, and platelets – red because of the oxygen-carrying pigment hemoglobin
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red marrow - hemoglobin - oxygen-carrying pigment
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Red Marrow - primarily found in spongy bone of the skull, ribs, clavicles, sternum, pelvis, and vertebrae – in adults
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yellow marrow - stores fat and is inactive in blood cell production
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yellow marrow - replaces the red marrow that is present in all the cavities of infant bones as we grow older
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calcium phosphate - hydroxyapatite - Ca10( PO4 )6 (OH )2 - 70% of the intercellular matrix of bone
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Calcium - required for blood clot formation, nerve impulse conduction, and muscle cell contraction.
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Blood is low in calcium: parathyroid hormone stimulates osteoclasts to break down bone tissue, releasing calcium salts from the intercellular matrix.
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Blood calcium level is too high: osteoclast activity is inhibited and alcitonin from the thyroid gland stimulates osteoblasts to form bone tissue, storing excess calcium in the matrix.
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Bone stores phosphorus as calcium phosphate, as well as storing magnesium, sodium, potassium, and carbonate ions.
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Harmful metallic elements - may accumulate in bone such as lead, radium, and strontium.
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Bones - Normally it is 206, but some people have more or less.
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Bones of the skull joined to each other by sutures
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sutural bones ( wormian bones ) - extra bones, develop in the sutures.
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sesamoid bones - extra, small, round bones may develop in tendons.
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Axial Skeleton: skull, hyoid bone, vertebral column, thoracic cage, and middle ear bone.
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skull – the cranium and facial bones
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hyoid bone – located in the neck between the lower jaw and the larynx – supports the tongue
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vertebral column – cartilaginous intervertebral discs -consists of many vertebrae separated this.
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vertebral column - Sacrum - several distal vertebrae fuse to form tthis
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vertebral column - coccyx - a small, rudimentary tailbone is attached to the sacrum’s distal portion
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thoracic cage – composed of twelve pairs of ribs and the sternum
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middle ear bones – transfer sound vibrations to the hearing receptors
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Appendicular Skeleton: pectoral girdle, upper limbs, pelvic girdle, and lower limbs
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pectoral girdle – formed by a scapula and clavicle on both sides of body
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upper limbs – humerus, radius, ulna – these articulate with each other at the elbow joint
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upper limb - the wrist is at the distal end – consists of eight carpals
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metacarpals - the five bones of the palm
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phalanges - the fourteen finger bones
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pelvic girdle – formed by two coxae – joined anteriorly to each other and posteriorly to the sacrum
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lower limbs – femur, tibia, and fibula – femur and tibia articulate with each other at the knee joint, where the patella covers the anterior surface
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tarsals - seven at the distal ends of the tibia and fibula a
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metatarsals - the five bones of the instep
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phalanges - the fourteen toe bones
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Skull: cranium, facial skeleton, and infantile skull
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Cranium - Encloses and protects the brain, its surface provides attachments for muscles that make chewing and head movements possible.
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Cranium - sinuses - Air-filled cavities, which are lined with mucous membranes and connected to the nasal cavity, reduce the weight of the skull and serve as
resonant sound chambers for the voice.
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Cranium: Frontal, Partial, occipital, temporal, sphenoid, ethmoid bones.
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Frontal bone – forms anterior portion above the eyes
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Frontal bone - supraorbital foramen ( supraorbital notch) – upper margin of orbit through which blood vessels and nerves pass to the tissues of the forehead
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Frontal bone - two frontal sinuses
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Parietal bones – one on each side of the skull just behind the frontal bone
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Parietal bones - fused at the midline along the sagittal suture
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Parietal bones - meet the frontal bone along the coronal suture
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Occipital bone – forms the back of the skull and the base of the cranium
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Occipital bone - joins the parietal bones along the lambdoidal suture
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Occipital bone - foramen magnum - houses nerve fibers from the brain that pass through and enter the vertebral canal to become part of the spinal cord
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Occipital bone - occipital condyles - are rounded processes which articulate with the first vertebra of the vertebral column
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Temporal bones – form parts of the sides and the base of the cranium
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Temporal bones - joins the parietal bone along the squamosal suture
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Temporal bones - external acoustic meatus - leads inward to parts of the ear
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Temporal bones - mandibular fossae - depressions that articulate with condyles of the mandible
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Temporal bones - mastoid process - provides attachment for certain muscles of the neck
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Temporal bones - styloid process - anchors muscles associated with the tongue and pharynx
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Temporal bones - carotid canal - transmits the carotid artery
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Temporal bones - jugular foramen - accommodates the jugular vein
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Temporal bones - zygomatic process - joins the zygomatic bone and helps form the prominence of the cheek
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Sphenoid bone – consists of a central part and two winglike structures that extend laterally toward each side of the skull – helps form the base of the skull, the sides of the skull, and floors and sides of the orbits
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Sphenoid bone - sella turcica - a saddle-shaped depression within which the pituitary gland lies
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Sphenoid bone - two sphenoid sinuses
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Ethmoid bone – consists of two masses, one on each side of the nasal cavity
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Ethmoid bone - two masses are joined horizontally by thin cribiform plates
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Ethmoid bone - cribiform plates - form part of the roof of the nasal cavity and nerves associated with the sense of smell pass through tiny opening ( olfactory foramina )
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Ethmoid bone - perpendicular plate - projects downward in the midline to form most of the nasal septum
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Ethmoid bone - superior and middle conchae - delicate scroll-like plates that project inward from the lateral portions of the ethmoid bone – they support mucous membranes that line the nasal cavity
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Ethmoid bone - superior and middle conchae - moisten, warm, and filter incoming air
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Ethmoid bone - ethmoidal sinuses - many small air spaces
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Ethmoid bone - crista galli - triangular process projecting upward into the cranial cavity and provides attachment for the meninges of the brain
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Facial skeleton - made up of 13 immovable bones and one movable bone
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Facial skeleton has: maxillae, palatine bones, palatine bones, lacrimal bones, nasal bones, vomer bone, inferior nasal conchae, and mandible.
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Maxillae - form the upper jaw
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Maxillae - all the immovable facial bones articulate with these bones
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Maxillae - hard palate – anterior portion of this is formed by palatine processes of the maxillary bones
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Maxillae - contain the sockets for upper teeth
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Maxillae - alveolar arch - teeth are located in cavities
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Maxillae - maxillary sinuses - are the largest of the sinuses
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Palatine bones - L-shaped bones whose horizontal portions form the posterior section of the hard palate and the floor of the nasal cavity; the perpendicular portions help form the lateral walls of the nasal cavity
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Zygomatic bones - responsible for the prominences of the cheeks below and to the sides of the eyes
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Zygomatic bones - temporal processes extend posteriorly to join the zygomatic process of the temporal bone
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Zygomatic bones - temporal process and zygomatic process - these two processes make up the zygomatic arch
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Lacrimal bones – thin, scalelike structure located in the medial wall of each orbit
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Nasal bones - long, thin, and nearly rectangular; fused at midline, where they form the bridge of the nose.
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Vomer bone - located along the midline within the nasal cavity
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Vomer bone - joins the perpendicular plate of the ethmoid to form the nasal septum
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Inferior nasal conchae - fragile, scroll-shaped bones attached to the lateral walls of the nasal cavity
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Inferior nasal conchae - support mucous membranes within the nasal cavity
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Mandible - the lower jawbone – horizontal, horseshoe-shaped body with a flat ramus projecting upward at each end
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Mandible - mandibular condyles - articulate with the mandibular fossae of temporal bones
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Mandible - coronoid processes - provide attachments for muscles used in chewing
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Mandible - alveolar border - contains the hollow sockets for the lower teeth
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Mandible - mandibular foramen - on the medial side of mandible; admits blood vessels and a nerve
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Mandible - mental foramen - opens on the outside near the point of the jaw; branches of blood vessels and the nerve
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