Overview of the Human Skeleton

Learning Goals I CAN… …describe the functions of the skeletal system …describe the types of cartilage and where they are found in the body and what their functions are …Compare and Contrast compact/spongy bone (includeing where located in the body) …Describe the microscopic structure of bone …Describe the 2 major tissue types in the skeleton …Describe the 4 classifications of bones …compare and contrast cartilage and bone …explain how bones get their nutrients …use the terms osteon/Haversian system and central canal/Haversian canal correctly …describe the differences in bone and cartilage matrices …describe the main function of the Haversian system

Functions of the Skeleton I. Functions of the Skeleton supportEssentially all tissues/organs hang off the skeletal system A. The bones of the skeletal system provide support for the body. Essentially all tissues/organs hang off the skeletal system protection Your rib cage surrounds vital organs to keep them safe from damage B. The bones of the skeletal systems provide protection for the body. Your rib cage surrounds vital organs to keep them safe from damage movementMuscles contract and when attached to bones it causes movement. C. The bones of the skeletal system provide movement for the body. Muscles contract and when attached to bones it causes movement.

Functions of the Skeleton storage The calcified matrix stores calcium and other minerals (and it regulates how much of these minerals will be in the blood stream) D. The bones of the skeletal system provide storage for the body. The calcified matrix stores calcium and other minerals (and it regulates how much of these minerals will be in the blood stream) hemopoiesisSpongy bone houses bone marrow that makes blood cells E. The bones of the skeletal system provide hemopoiesis for the body. Spongy bone houses bone marrow that makes blood cells Hemopoiesis – process of making blood cells

Types of Bones II. Types of Bones shapesLong, short, flat, irregular A. The names of the types of bones suggest their shapes. Long, short, flat, irregular “”are classified as long bones B. Many of the “important” bones are classified as long bones *ALL TYPES OF BONES HAVE COMMON CHARACTERISTICS*

Microscopic Structure of Bone and Cartilage I. Microscopic Structure of Bone and Cartilage bonecartilage A. There are two major types of tissue in the skeletal system: bone and cartilage. highly specialized connective tissue whose matrix is hard and calcified Bone – highly specialized connective tissue whose matrix is hard and calcified a specialized fibrous connective tissue that has the consistency of hard plastic or gristle- like gel Cartilage – a specialized fibrous connective tissue that has the consistency of hard plastic or gristle- like gel

Microscopic Structure of Bone and Cartilage spongy bone dense/compact bone B. The two types of bone are: spongy bone and dense/compact bone. porous bone in the end of the long bone which maybe filled with marrow Spongy bone – porous bone in the end of the long bone which maybe filled with marrow bone that has a hard dense outer layer Dense/Compact bone – bone that has a hard dense outer layer in the end of the long bone 1. Spongy bone is found in the end of the long bone small openings that are filled with marrow. The small openings are formed by trabeculae. a. Texture results from small openings that are filled with marrow. The small openings are formed by trabeculae. needle-like threads of spongy bone Trabeculae – needle-like threads of spongy bone

produce red and white blood cells. b. One of the main functions of spongy bone is to produce red and white blood cells. the outer layer of bones. The calcified matrix does not contain any open spaces. 2. Compact bone is found in the outer layer of bones. The calcified matrix does not contain any open spaces. the circular arrangements of calcified matrix and cells that give bone its characteristic appearance Osteons – the circular arrangements of calcified matrix and cells that give bone its characteristic appearance ring of calcified matrix surrounding the Haversian canal Concentric lamella – ring of calcified matrix surrounding the Haversian canal The canal in the Haversian system that contains a blood vessel Central canal – The canal in the Haversian system that contains a blood vessel Microscopic Structure of Bone and Cartilage a.k.a. Haversian System a.k.a. Haversian canal

is hard and contains calcium a. The matrix of this connective tissue is hard and contains calcium Boneosteocytes lacunae canaliculi b. Bone cells called osteocytes live within the dense calcified matrix in small openings called lacunae, each is connected to another by a canaliculi. bone cells Osteocytes – bone cells space or cavity; for example lacunae in bone contain bone cells Lacunae – space or cavity; for example lacunae in bone contain bone cells an extremely narrow tubular passage or channel in compact bone Canaliculi – an extremely narrow tubular passage or channel in compact bone Microscopic Structure of Bone and Cartilage

Cartilage C. Cartilage is similar and different from bone 1. Similarities to bone: Consists more of a matrix than cells Consists more of a matrix than cells Contains living cells housed in lacuna Contains living cells housed in lacuna cartilage cell Chondrocytes – cartilage cell 2. Differences from bone Matrix is flexible and consist of a gel- like substance instead of a hard calcified matrix Matrix is flexible and consist of a gel- like substance instead of a hard calcified matrix No canaliculi-nutrients pass through matrix (which is a long process which is why it takes a long time to heal) No canaliculi-nutrients pass through matrix (which is a long process which is why it takes a long time to heal) Microscopic Structure of Bone and Cartilage