2BONES 206 Bones are said to be in the Human Skeleton. Although the human skeleton is initially made up of cartilages and fibrous membranes this is soon replaced by bone.
3Bones Basic Structure, Types, and Locations When discussing the skeleton is it essential to review over the types of cartilages found in the body.Hyaline CartilagesElastic CartilagesFibrocartilages
4CartilageHyaline Cartilage- Provides support with flexibility and resilience. Makes up the following in the human skeleton1. articular cartilage- covers the ends of most bones2. costal cartilage- connect ribs to sternum3. respiratory cartilage – found in make up larynx4. nasal cartilage- which support the external nose.
5CartilageElastic Cartilage- Very much like hyaline cartilage but ALSO contains more stretch elastic fibers and better able to stand repeated bending.Makes up only 2 skeletal locations1. external ear-2. epiglottis- flap that covers the opening to the larynx each time we swallow.
6CartilageFibrocartilages Cartilage- are highly compressible and have great tensile strength. It is in between hyaline and elastic cartilagesFound in sites that are subjected to both heavy pressure and stretch.1. Menisci- padlike cartilages of the knee2. Disk between the vertebrae.
7CartilageAlways remember bone and cartilage are always distinct different tissues.Bone has a hard matrix while cartilage has a flexible matrix that can accommodate mitosis.
8Division of the Skeleton Axial Skeleton- consists of the bony and cartilaginous parts that support and protect the organs of the head, neck and trunk.Appendicular Skeleton- consists of the bones of the upper and lower limbs and bones that anchor the limbs to the axial skeleton.
9Bone StructureBones differ in size and shape but have similar structure, development, and functions.
10Bone Classification Long Bones Long longitudinal axes, and expanded end.Ex: Forearm and thigh bones.
11Bone Classification Short Bones Cube like, with lengths and widths roughly equal .Bones in the wrists and ankles.
12Bone Classification Flat Bones Plate like structure with broad surfacesEx: Ribs, scapulae, and some bones of the skull.
13Bone Classification Irregular Bones Variety of shapes and are usually connected to several other bones.Ex: Vertebra, and some facial bones.
15Bone Function Bones shape, support, and protect body structures. They also act as levers.House tissue that produces bone/blood cellsStores various inorganic salts.
16Bone FunctionSupport- all the softer tissues of the body; they literally hang from the skeletal framework.Protection- hard, bony “boxes” protect the delicate structures within them. Example: skull to brainMovement- Muscles are anchored firmly to bones.
17Bone Function Mineral and Growth Factor Storage- Bone is a reservoir for minerals like calcium and phosphate. It also stores important growth factors.Blood Cell Formation- Most blood formation or hematopoiesis occurs in the marrow cavities of certain bones.
18Bone StructureBecause bones contain tissue they are considered an organThey contain not only bone (osseous) tissue but nervous tissue, connective tissue, muscle tissue, and epithelial tissue.
19Bone MarkingThroughout the next month as you work with this bones you will need to recognize these markings during labBones are rarely smooth..they display projections, depressions, and openings that serve as sites of muscle, ligament, and tendon attachment as joint surfaces or conduits for blood vessels and nerves.
20Bone MarkingProjections (bulges) that grow outward from the bone surface includesHeads, trochanters, spines, and others.These are just a few a complete list is on pg 179
21Bone Marking Bone depressions and opening include Fossae, sinuses, foramina, and groovesThese are just a few a complete list is on pg 179
22Bone TextureWhen discussing bone texture the outward appearance has a smooth solid look to the naked eye and is referred to as Compact BoneThe internal layer is referred to as Spongy Bone and looks like a honeycomb.We will discuss this in more detail later.
25Structure of a Long Bone Diaphysis- Shaft of the bone, located between epiphysis. A hollow tube made of hard compact bone, hence a rigid and strong structure light enough in weight to permit easy movement.It surrounds a central medullary cavity…”Marrow cavity”In adults the medullary cavity contains fat (yellow marrow) and is called yellow bone marrow cavity.
26Structure of a Long Bone Epiphysis-The outer ends (joints) of a long bone.The exterior of epiphysis is compact bone while the interior of epiphysis is spongy bone.Outer portion of the epiphysis is coated with a layer of hyaline cartilage called Articular Cartilage. Functions like a small rubber cushion .Red bone marrow fills in small spaces in the spongy bone composing the epiphyses.
27Structure of a Long Bone EpiphysisBetween the epiphysis and diaphysis of an adult long bone is an epiphyseal line and remnant of the epiphyseal plate.The epiphyseal plate is a disc of hyaline cartilage that grows during childhood to lengthen the bone.
29Structure of a Long Bone Another structure in all long bones are membranesPeristeum- a strong fibrous membrane covering a long bone except at joint surfaces, where it is covered by articular cartilage.A thin membrane containing bone-forming cells called Endosteum lines the internal bone surfaces.
312 Types of BoneCompact Bone- Wall of the diaphysis is mainly composed of this. Hard and dense; continues matrix with no gaps.Spongy Bone- Found on the ends of the epiphysis…consists of many branching bony plates. Contains spaces that may be filled with marrow. The needle-like threads of spongy bone that surround a network of spaces are called trabeculae.
34Microscopic- Anatomy of Bone In Compact Bone the matrix is organized into numerous structural units called osteons or Haversian systems. Each circular and tube like osteon is composed of calcified matrix.The rings are called a concentric lamella.
35Parts of the Long BondDraw and label the long bone on pg. 180 in book.
37Bone DevelopmentOssification and Osteogenesis are synonyms meaning the process of bone formation.In embryos this process leads to the formation of the bony skeletonAnd continues on until early adulthood as the body continues to grow in size.
39Bone DevelopmentThe first 8 weeks of development the human embryo is completely fibrous membranes and cartilageBones continue to grow and develop into adulthood.Bones form by replacing existing connective tissue in one of two waysIntramembranous Bones and Endochondral Bones
41INTRAMEMBRANOUS BONES When a bone develops from a fibrous membrane it is called intramembranous ossification and the bone is called a membrane bone.Intramembranous ossification results in the formation of Flat Bones (Mostly of the skull and clavical).During development membrane like layers of connective tissues appear at the area of future bones.Layers supplied with blood vessels and tissue arranged around the vesselsCells enlarge and change into bone-forming tissue called OSTEOBLAST.
42ENDOCHONDRAL BONES Ex: Most all bones They develop as hyaline cartilage that is later replaced by bone tissue.This is more complex than intramembranous ossification because the hyaline cartilage must be broken down as ossification proceedsPrimary ossification centers appears in the diaphysis, whereas secondary ossification centers appear in the epiphysesAn epiphyseal plate remains between the primary and secondary ossification centers. Development proceeds from masses
43Osteo….The different types bone cells. Osteoblasts - make new bone and help repair damage;Osteocytes- mature bone cells.carry nutrients and waste products to and from blood vessels in the bone;Osteoclasts- break down,reabsorb bone and help to sculpt and shape it. Osteoclasts are very active in kids and teens, working on bone as it is remodeled during growth. They also play an important role in the repair of fractures.
44Bone Growth- Epiphyseal Plate The epiphyseal plates are responsible for lengthening.Long bones continue to lengthen until the epiphyseal plates are ossified.An epiphyseal plate consists of layers of cells: resting cells, young cells, older enlarging cells and dying cells.
45Bone Growth- Epiphyseal Plate Growth in thickness is due to intramembranous ossification beneath the periosteum.The action of osteoclasts forms the medullary cavity.
47HOMEOSTASIS OF BONE TISSUE Osteoclast and osteoblast continually remodel bone.The total mass of bone remains nearly constant throughout life. While it may appear to be lifeless it is VERY activeAdult skeleton normally recycles 5-7% of our bone mass a week…spongy bone replaced every 3-4 years, compact bone every 10.
48Factor Affecting Bone Development Sunlight, hormonal secretions, and exercise all affect bone developmentDeficiencies of vitamin A,C, or D result in abnormal development.Physical stressExercise thickens and strengthens bone tissueLack of activity can cause waste and thin tissue.
49BONE- Blood Cell Formation Hemopoiesis- the process of blood formation.Begins in the yolk, which lies outside the embryo. Later in development, blood cells are manufactured in the liver, spleen, and still later they form in the bone marrow.
50BONE- Blood Cell Formation Marrow- soft tissue within the medullary cavity of long bones, in spongy bone, and in canals of compact bone tissue.
51MARROWRED MARROW-Functions in the formation of red blood cells, white b.c’s and blood plateletsOccupies most cavities of infant bones, later replaced by yellow marrow.Yellow MarrowStores fatInactive in blood cell production.By adolescence, most of our marrow is yellowRed blood cells only live about 120 days, they are replaced or recycled.
52Blood cell production in ADULTS routinely occurs in the heads of the _femur_ and humerous_. If you were to obtaining red marrow samples from the body. Some of the best places to go would be the Sternum and hip bones. Hematopoiesis are very active here
53Inorganic Salt Storage The intercellular matrix of bone tissue contains collagen and inorganic mineral salts.The crystals that are formed are a type of CALCIUM phosphate.
54The need for CalciumOur body requires calcium for a number of vital metabolic processes;Blood clot formation.Nerve impulse conduction.Muscles cell contractions.
55The need for CalciumWhen the blood is low in calcium, parathyroid hormone stimulates osteoclasts to break down bone tissue, releasing calcium salts from the intercellular matrix into the blood.
56OsteomalaciaOsteomalacia- includes a number of disorders in which the bones are inadequately mineralized. Two examples of this included..Rickets – is just osteomalcia that is seen in young children
57RicketsRickets is a softening of bones in children due to deficiency or impaired metabolism of vitamin D, phosphorus, or calciumPotentially leading to fractures and deformity.Rickets is among the most frequent childhood diseases in many developing countries.The predominant cause is a Vitamin D deficiency, but lack of adequate calcium in the diet may also lead to rickets (cases of severe diarrhea and vomiting may be the cause of the deficiency).Although it can occur in adults, the majority of cases occur in children suffering from severe malnutrition, usually resulting from famine or starvation during the early stages of childhood.
59OsteoporosisOsteoporosis- refers to a disease in which bone resorption outpaces bone deposits.Bones become fragile and therefore easily fractured. a condition that results from loss of bone minerals.
61BONES 206 Bones are said to be in the Human Skeleton. This numbers varies between people.Structural bones may develop in the area where the flat bones of the skull fuse.
62Bone RepairDespite remarkable strength, bones are susceptible to fractures or break!Resulting from twists or smashing of bones.Excessive intake of vitamin A and elevated blood levels of the protein homocysteine may increase the risk as well as thin and weaken bones that accompany age.
63Bone RepairNon-displaced fractures- the bone will retain their normal positionDisplaced Fractures- the bones are out of their normal position
64Bone RepairComplete Fracture- the bone is broken in two; completely throughIncomplete Fracture -the bone is not.
65Bone Repair Linear Break- the break parallels the long axis Transverse Break- the break is perpendicular to the bone’s long axis.
66Bone Repair Compound Fracture- the bone ends penetrate the skin Simple Fracture- the bone does NOT penetrate the skin.