Week 2 - Skeletal System PDF

Week 2 Human Anatomy & Physiology - 1 (HMG380) SKELETAL SYSTEM Dr. Merin Thomas [email protected] Office hours : Monday& Wednesday, 3.00pm to 5.00pm Tuesday & Thursday,...

Week 2 Human Anatomy & Physiology - 1 (HMG380) SKELETAL SYSTEM Dr. Merin Thomas [email protected] Office hours : Monday& Wednesday, 3.00pm to 5.00pm Tuesday & Thursday, 1.00pm to 3.00pm  Learning Objectives Functions of Bone & Skeletal system Divisions of Skeletal System Types of Bones Bones that make up the skull, Vertebral Column, Thoracic Cage, Pelvis Histology of Bone Tissue Fracture and Repair of Bone Bone’s role in Calcium Homeostasis Joints  Levels of Structural Organization - LEVEL 3 - TISSUE LEVEL Epithelial Tissue Connective Tissue Muscular Tissue Nervous Tissue Covers body surfaces, Connects, supports, and protects Contracts to make body lines hollow organs & body organs while distributing parts move & in the Carries information cavities, and forms blood vessels to other tissues process generates heat from one part of the glands. Loose Connective body to another Smooth Muscle through nerve Based on shape of Tissue impulses the cell 2 types of cells Dense Connective Tissue Skeletal Muscle Based on number Cardiac Muscle of layers of cells Special Connective Tissue Three parts: CNS, PNS, ANS  The types connective tissue that belong to the skeletal system are Specialized connective tissue: bone ,cartilage Dense regular connective tissue: tendons & ligaments They differ from one another based on the composition of the extra cellular matrix. Extracellular matrix is mainly made up of collagen fibers, ground substance, organic molecules, water and minerals The type and quantity of each varies with different type of tissue  Differences between bone & cartilage BONE CARTILAGE Long, short, flat, irregular, sesamoid Hyaline cartilage, elastic TYPES cartilage, fibrocartilage Protection Reduces friction at joints Assist in movement Acts as shock absorbers b/w Framework of body weight bearing bones FUNCTION Stores minerals Maintains shapes AND Produces blood cells flexibility of certain appendages Vascularised Avascular Made up of specialized cells - Made up of specialized cells - STRUCTURE osteoblasts, osteocytes, osteoclasts chondroblasts & chondrocytes Makes up majority of the axial and Found between bones appendicular skeleton Along respiratory tract LOCATION And few other places where flexibility is needed  Bone tissue is a complex and dynamic living tissue Bone tissue is continuously growing, remodeling, and repairing itself. It contributes to homeostasis of the body by providing support and protection, producing blood cells, and storing minerals and triglycerides. The entire framework of bones and their cartilages constitute the skeletal system. The study of bone structure and the treatment of bone disorders is referred to as osteology The process of bone formation is called as ossification  The adult human skeleton consists of 206 named bones, most of which are paired The skeletons of infants and children have more than 206 bones because some of their bones fuse later in life.  Functions of Bone Tissue 1. Supports soft tissue and provides attachment for skeletal muscles. 2. Protects internal organs. 3. Assists in movement, along with skeletal muscles. 4. Stores and releases minerals. 5. Contains red bone marrow, which produces blood cells , and yellow bone marrow, which stores triglycerides (fats).  Divisions of Skeletal System Bones of the adult skeleton are grouped into two Axial skeleton Appendicular skeleton  Divisions of Skeletal System Adapted from Principles of Anatomy and Physiology, by Tortora, Gerard J. And Bryan H Derrickson, Wiley & Sons, 2020,p 203  TYPES OF BONES Almost all bones of the body can be classified into five main types based on shape 1. Long Bones 2. Short Bones 3. Flat Bones 4. Irregular Bones 5. Sesamoid Bones  TYPES OF BONES Greater length than width Afford considerable Slightly curved for protection and strength provide extensive Vary tremendously in areas for muscle size attachment Complex shapes & Cube-shaped and cannot be are nearly equal grouped in length and into any of width. the previous categories. Develop in certain tendons where there is considerable friction, tension, and physical strain Adapted from Principles of Anatomy and Physiology, by Tortora, Gerard J. And Bryan H Derrickson, Wiley & Sons, 2020,p 205  PARTS OF A LONG BONE PROXIMAL EPIPHYSIS Epiphysis - Proximal & Distal ends of the bone METAPHYSIS Diaphysis - long, cylindrical, main portion of the bone Metaphysis - the regions between the diaphysis and the epiphyses DIAPHYSIS Articular cartilage - thin layer of hyaline cartilage covering the part of the epiphysis where the bone forms a joint) with another bone. reduces friction and absorbs shock at freely METAPHYSIS movable joints DISTAL EPIPHYSIS From Principles of Anatomy and Physiology, by Tortora, Gerard J. And Bryan H Derrickson, Wiley & Sons, 2020,p 179  PARTS OF A BONE Articular Cartilage Periosteum - tough connective tissue sheath and its associated blood supply that surrounds the bone surface wherever it is not covered by articular cartilage also protects the bone, assists in fracture repair, helps nourish bone tissue, and serves as an attachment point for ligaments and tendons. The medullary cavity or marrow cavity, is a hollow, cylindrical space within the diaphysis that contains fatty yellow bone marrow and numerous blood vessels. The endosteum is a thin membrane that lines the medullary cavity and the internal spaces of spongy bone. It contains a single layer of osteoprogenitor cells and a small amount of connective tissue.  SKULL/CRANIUM The skull is the bony framework of the head. Contains 22 bones (not including the bones of the middle ears) Rests on the superior end of the vertebral column The bones of the skull are grouped into two parts: 1. Cranial cavity formed by 8 bones held together by joints called as sutures; Encloses & protects the brain 2. Facial bones forms the anterior part of the skull and is made up of 14 bones SKULL/CRANIUM PTERION SKULL/CRANIUM  FEATURES OF THE SKULL/CRANIUM Fontanelles are mesenchyme-filled spaces between cranial cavity bones that are present at birth.  FEATURES & FUNCTIONS OF THE SKULL/CRANIUM Other openings or spaces are also seen in the skull Nasal Cavity, Orbits, Paranasal air sinuses etc. Space within temporal bone – 3 ossicles of middle ear Mandible - only moveable bone of the skull Surface markings - foramina, fissures, processes etc. Protects & stabilizes the positions of the brain, blood vessels, lymphatic vessels, and nerves The outer surfaces of the bones provide areas of attachment for muscles that move various parts of the head & for some muscles that produce facial expressions Together, the cranial cavity and facial bones protect and support the delicate special sense organs for vision, taste, smell, hearing, and equilibrium  VERTEBRAL COLUMN Composed of a series of bones called vertebrae (singular is vertebra), enclosing & protecting the spinal cord. The vertebral column, the sternum, and the ribs form the skeleton of the trunk of the body Approx. 71 cm in an avg. adult male & about 61 cm in an avg. adult female It is a strong, flexible rod It supports the head and serves as a point of attachment for the ribs, pelvic girdle, and muscles of the back and upper limbs.  VERTEBRAL COLUMN - VERTEBRAE 7 cervical vertebrae in the neck region. 12 thoracic vertebrae posterior to the thoracic cavity. 5 lumbar vertebrae supporting the lower back. 5 sacral vertebrae - which fuse by adulthood to form 1 sacrum. 4 coccygeal vertebrae - which fuse by adulthood to form 1 coccyx VERTEBRAL COLUMN - CURVATURES SECONDARY CURVATURE PRIMARY CURVATURE SECONDARY CURVATURE PRIMARY CURVATURE From Principles of Anatomy and Physiology, by Tortora, Gerard J. And Bryan H Derrickson, Wiley & Sons, 2020,p 224  VERTEBRAL COLUMN - ABNORMAL CURVATURES Lateral bending of the Increase in the An increase in the vertebral column, thoracic curve of the lumbar curve of the usually in the thoracic vertebral column that vertebral column region. produces a “hunchback” look Adapted from Principles of Anatomy and Physiology, by Tortora, Gerard J. And Bryan H Derrickson, Wiley & Sons, 2020,p 238  THORACIC CAGE Bony enclosure formed by the Sternum, Ribs and their costal cartilages, and Bodies of the thoracic vertebrae. The thoracic cage is narrower at its superior end and broader at its inferior end and is flattened from front to back. Encloses and protects the organs in the thoracic and superior abdominal cavities, provides support for the bones of the upper limbs  THORACIC CAGE - BONES FORMING RIBS 12 pairs STERNUM Attached to sternum anteriorly and thoracic FLAT BONE vertebrae posteriorly From Principles of Anatomy and Physiology, by Tortora, Gerard J. And Bryan H Derrickson, Wiley & Sons, 2020,p 234 -235  THORACIC CAGE - BONES FORMING Thoracic Vertebrae Adapted from Principles of Anatomy and Physiology, by Tortora, Gerard J. And Bryan H Derrickson, Wiley & Sons, 2020,p 236  PELVIS The pelvic (hip) girdle consists of the two hip bones The hip bones unite anteriorly at a joint called the pubic symphysis. They unite posteriorly with the sacrum at the sacroiliac joints. The complete ring composed of the Hip bones (Pubic symphysis & Sacroiliac joints) Sacrum, and Coccyx forms a deep, basin like structure called the bony pelvis From Principles of Anatomy and Physiology, by Tortora, Gerard J. And Bryan H Derrickson, Wiley & Sons, 2020,p 251  PELVIS Functionally, the bony pelvis provides a strong and stable support for the vertebral column and pelvic and lower abdominal organs. The pelvic girdle of the bony pelvis also connects the bones of the lower limbs to the axial skeleton. There are structural differences between male and female pelvis From Principles of Anatomy and Physiology, by Tortora, Gerard J. And Bryan H Derrickson, Wiley & Sons, 2020,p 251  PELVIS From Principles of Anatomy and Physiology, by Tortora, Gerard J. And Bryan H Derrickson, Wiley & Sons, 2020,p 253 -255  PELVIS - GENDER DIFFERENCE Female Pelvis Male Pelvis From Principles of Anatomy and Physiology, by Tortora, Gerard J. And Bryan H Derrickson, Wiley & Sons, 2020,p 256  HISTOLOGY OF BONE By weight, bone is composed of 60% inorganic component, 30% organic component and 10% water. Approximately 30% of this organic matrix is collagen; the remainder includes various non collagenous proteins, glycoproteins and carbohydrates. The proportions of these components vary with age, location and metabolic status.  HISTOLOGY OF BONE Majority of the inorganic mineral salts are in the form of microcrystalline hydroxyapatite (Ca10 (PO4)6 (OH)2). The microcrystals confer hardness and much of the rigidity of bone and are the main reason why bone is easily seen on radiographs. The major ions in bone mineral include calcium and phosphate among others Less numerous ions are citrate, magnesium, sodium, potassium, fluoride, chloride, iron, zinc, copper, aluminum, lead, strontium, silicon and boron, many of which are present only in trace quantities.  HISTOLOGY OF BONE The process of bone tissue formation is called ossification The deposition of calcium salts (Calcium carbonate or some other insoluble calcium compound) is called as Calcification. Ossification and calcification are NOT the same. Calcification occurs normally during the formation of bone. However, calcium can also be deposited abnormally in soft tissue. This causes soft tissue to become hard – could be pathological.  HISTOLOGY OF BONE A bone’s hardness depends on the crystallized inorganic mineral salts, a bone’s flexibility depends on its collagen fibers.  HISTOLOGY OF BONE BONE tissue contains 4 types of cells 1. Osteoprogenitor cells 2. Osteoblasts 3. Osteocytes 4. Osteoclasts From Principles of Anatomy and Physiology, by Tortora, Gerard J. And Bryan H Derrickson, Wiley & Sons, 2020,p 181  HISTOLOGY OF BONE Unspecialized bone stem cells derived from mesenchyme, the tissue from which almost all connective tissues are formed. The only bone cells to undergo cell division; the resulting cells develop into osteoblasts. Found along the inner osteogenic layer of the periosteum, in the endosteum, OSTEOPROGENITOR CELLS and in the canals within bone that contain blood vessels. Bone-building cells Synthesize & secrete collagen fibers and other organic components needed to build the extracellular matrix of bone tissue, a process called bone deposition OSTEOBLASTS Initiates calcification As osteoblasts surround themselves with extra-cellular matrix, they become trapped in their secretions and become osteocytes. Mature bone cells Main cells in bone tissue and maintain its daily metabolism, such as the exchange of nutrients and wastes with the blood. OSTEOCYTES  HISTOLOGY OF BONE Huge cells derived from the fusion of as many as 50 monocytes (a type of white blood cell) and are concentrated in the endosteum. On the side of the cell that faces the bone surface, the osteoclast’s plasma membrane is deeply folded into a ruffled border. Here the cell releases powerful lysosomal enzymes and acids that digest the protein and mineral components of the underlying extracellular bone matrix. OSTEOCLASTS This breakdown of bone extracellular matrix, termed bone resorption is part of the normal development, maintenance, and repair of bone. In response to certain hormones, osteoclasts help regulate blood calcium level They are also target cells for drug therapy used to treat osteoporosis  HISTOLOGY OF BONE Bone is not completely solid but has many small spaces between its cells and extracellular matrix components. Some spaces serve as channels for blood vessels that supply bone cells with nutrients. Other spaces act as storage areas for red bone marrow. Depending on the size and distribution of the spaces, the regions of a bone may be categorized as compact or spongy Overall, about 80% of the skeleton is compact bone and 20% is spongy bone.  FRACTURE AND REPAIR OF BONE From Principles of Anatomy and Physiology, by Tortora, Gerard J. And Bryan H Derrickson, Wiley & Sons, 2020,p 193 BONE’S ROLE IN CALCIUM HOMEOSTASIS BONE’S ROLE IN CALCIUM HOMEOSTASIS From Principles of Anatomy and Physiology, by Tortora, Gerard J. And Bryan H Derrickson, Wiley & Sons, 2020,p 196  JOINTS A joint, also called an articulation or arthrosis, is a point of contact between two bones, between bone and cartilage, or between bone and teeth. Long bones articulate by their ends, flat bones by margins & in irregular bones their surfaces are articular The scientific study of joints is termed arthrology. The study of motion of the human body is called kinesiology. Joints are classified into three principal types based upon the structure of the joint: 1. Fibrous Joints 2. Cartilaginous Joints 3. Synovial Joints Intervertebral Joints - B/w articular surfaces of adjacent 1st Carpometacarpal Joint - B/w articular surfaces of trapezium & vertebrae- slight movement 1st Metacarpal bone- movement around two axes Elbow Joint- B/w articular surfaces of Humerus and Ulna and radius- movement around one axis Proximal Radioulnar Joint- B/w articular surfaces of proximal end of Radius & Ulna- Rotation Shoulder Joint- B/w articular surfaces of Scapula & Atlantoccipital Joint- B/w articular surfaces of Atlas & Occipital Humerus- Movement around multiple axes bone- Movement around two axes  SYNOVIAL JOINTS - INSIDE JOINT CAVITY ARTICULAR SURFACES are covered with articular cartilage Joint cavity enveloped completely by an articular capsule Joint presents a CAVITY which is filled with viscous synovial fluid JOINTS - TYPES OF MOVEMENTS  OSTEOPOROSIS Bone resorption (breakdown) outpaces bone deposition (formation) In large part this is due to depletion of calcium from the body— more calcium is lost in urine, feces, and sweat than is absorbed from the diet. Older women suffer from osteoporosis more often than men for two reasons: (1) Women’s bones are less massive than men’s bones, and (2) Production of estrogens in women decline dramatically at menopause, whereas production of the main androgen, testosterone, in older men wanes gradually and only slightly. Estrogens and testosterone stimulate osteoblast activity and synthesis of bone matrix  Rickets and osteomalacia are two forms of the same disease that result from inadequate calcification of the extracellular bone matrix, usually caused by a vitamin D deficiency.  TOPICS FOR ILLUSTRATION DRAW A NEAT LABELLED DIAGRAM OF THE GIVEN TOPICS ON PLAIN A4 SIZE PAPER – FOLLOW RUBRICS COMPLETED DIAGRAMS TO BE SUBMITTED FOR CORRECTION ON 30.09.2024 – sections 22/66 & 33/77 (Mon/Wed) 08.10.2024 – sections 44/88 (Tue/Thurs) Parts of a long bone  Date Draw Margin for very image PARTS OF A LONG BONE Your Name  REFERENCES Tortora, Gerard J. And Bryan H Derrickson. Principles of Anatomy and Physiology. John Wiley & Sons, 2020 Standring, Susan. Gray’s Anatomy E-Book. Elsevier Health Sciences, 2015. Parker, Steve. The Concise Human Body Book. 2019. Feng X. (2009). Chemical and Biochemical Basis of Cell-Bone Matrix Interaction in Health and Disease. Current chemical biology, 3(2), 189–196. https://doi.org/10.2174/187231309788166398