Human Skeletal System

_________________________ of the Human Endoskeleton1. Body framework, support and protection2. Base for muscle attachment (tendons and ligaments

are continuous with the periosteum). Bone and muscles together act as levers.

3. Forms some types of blood cells. (Red marrow produces erythrocytes [RBC], thrombocytes, [platelet] and some leukocytes[White blood cell]) Red marrow is found in most bones in infants. In adults it’s found in the skull, ribs, sternum, vertebrae, clavicle and pelvis.

4. Storage area for:a. inorganic saltsb. yellow marrow (stores fats)

Classification of Bones – have greater length

than width and long longitudinal axes and expanded ends. Ex. Arm and leg bones

Classification of Bones bones – somewhat

cube-shaped and have less prominent ends. Ex. Wrist and ankle bones

Classification of Bones Flat bones – flattened surface; for protection;

plate-like with a broad surface for muscle attachment. Ex. Ribs, cranium, sternum

Classification of Bones bones – connect to

other bones, variety of shapes. Ex. vertebrae

Classification of Bones bones – small,

occur often in tendons due to compression. Ex. Patella (kneecap)

Types of Bone Cells Osteoprogenitor cells – cells that undergo

mitosis to produce osteoblasts Osteoblasts – form bone, deposit bony matrix

around themselves. Osteocytes – bone cells isolated in matrix Osteoclasts – form from monocytes (a type of

white blood cell); function to dissolve/reabsorb matrix.

Long Bone ______________________ Structure Diaphysis – shaft (long

part) of the bone. Made of compact bone with a long hollow center.

Medullary canal – a hollow chamber and contains fatty yellow bone marrow

Epiphysis – forms a joint with another bone. Expanded end. Made mostly of spongy bone with a thin layer of compact bone on the surface.

Long Bone Macroscopic Structure Trabeculae – branching

bony plates. Spaces between trabeculae are filled with red bone marrow

Periosteum – covering of fibrous tissue. Forms and repairs bone tissue

Articular cartilage – hyaline cartilage found at the edge of bones.

Endosteum – thin layer of squamous cells that line spaces of spongy bone and the medullary cavity.

Haversian System- microscopic structure of long bones (_______________________) Matrix – made of

mineral salts of calcium and phosphorus for hardness and collagen fibers for strength

Canalculi – small canals that project from lacunae and are routes for nutrients and wastes of osteocytes

Haversian System- microscopic structure of long bones (compact) Lacuna with

osteocyte – small spaces between lamallae that contain mature bone cells (osteocytes)

Haversian Canal – contains blood vessels and nerves

_________________________________ Ossification – bone

formation Human Embryo

Skeleton – composed of hyaline cartilage and fibrous connective tissue membranes. Ossification is replacement of connective tissue by bone, takes 6-7 weeks.

Ossification Intramembranous –

the formation of bone directly on or within fibrous connective tissue (mesenchyme)

Endochondral – formation of bone within a hyaline cartilage

How long bones grow in length and witdth Length –

_______________ plate Width – occurs by

osteoclasts destroying lining of the medullary cavity to widen the diameter. At the same time, osteoblasts from periosteum lay down new matrix on the outside of the bone.

Factors affecting Growth/Development of Human Bone _______________________– necessary for calcium

absorption, extremem lack causes rickets Vitamin A – necessary for bone reabsorption Vitamin C – needed for collagen synthesis (for

flexibility) ____________ – from

various glands Physical stress –

exercise or lack of it

Types of Joints ___________________ – junction of two or more

bones Immovable joint – bones separated by fibrous

tissue or cartilage

Types of Joints __________________

movable joint – connected by fibrocartilage disk or ligaments

___________________ movable joint – ends of bone covered by articulating cartilage. Joint capsule is made of outer layer of ligaments and an inner layer of synovial membrane.

Possible ways to protect freely movable joints ______________ –

flattened pads of fibrous cartilage.

______________ – closed, fluid-filled sacs reduce friction.

Synovial fluid – contained in a joint capsule.

Types of Freely Movable Joints Ball and socket -

movement in all planes and rotational movement around a central axi.

__________________ – allows sliding and twisting. Opposing surfaces nearly flat or slightly curved.

Types of Freely Movable Joints ______________ –

allows movement in one plane only. Bone surfaces are concave and convex.

______________ – allows movement around a longitudinal axis. Rounded process articulates with or rotates in a bony fossa

Types of Freely Movable Joints __________________ –

allows for movement in different planes, no rotation. Form when an oval shaped condyle fits into an elliptical cavity.

__________________ – allows for a wide variety of movement. Articulating surfaces are complementary concave and convex surfaces.

Types of Joint Movement ______________ –

decreasing the angle between two bones.

______________ – increasing the angle between two bones.

Types of Joint Movements ___________________ –

moving away from midline.

__________________– moving toward a

midline

Types of Joint Movement _________________–

moving around an axis.

Circumduction – describes a circle, includes flexion, extension, abduction and adduction.

Types of Joint Movement __________________ –

turning upward. Pronation – turning

downward