Integrated Systems Anatomy and Physiology PDF

Integrated Systems Anatomy and Physiology HOW IS THE BODY SUPPORTED M O D U L E T W O - PA R T 1 Andrea Stephenson Andrea....

Integrated Systems Anatomy and Physiology HOW IS THE BODY SUPPORTED M O D U L E T W O - PA R T 1 Andrea Stephenson [email protected] Acknowledgements: slides adapted from material developed by Dr Julianne Crowley and Dr Mauro Vaccarezza 1  COMMONWEALTH OF AUSTRALIA Copyright Regulations 1969 WARNING This material has been reproduced and communicated to you by or on behalf of Curtin College pursuant to Part VB of the Copyright Act 1968 (the Act). The material in this communication may be subject to copyright under the Act. Any further reproduction or communication of this material by you may be the subject of copyright protection under the Act. Do not remove this notice. All diagrams copied from the McGraw Hill publishers have been copied with permission 2  Recording of Online Sessions As per the Curtin College & Navitas Policy, all online classrooms are recorded and uploaded to Moodle for teaching & study purposes. - As part of this unit, you will be asked to participate in live video sessions that will be recorded. These recordings are made for your benefit and for the benefit of your peers; these recordings will be stored in the College’s Learning Management System (Moodle) for study purposes only and are not to be distributed. - By attending scheduled Zoom classes, you are consenting to participation in a recording in which you may be identified. To opt out of participation you can turn off the video and/or audio when attending each session. Please understand that opting out could restrict your ability to participate in class activities and engage with your classmates and teacher. 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Images: Copyright ©2020 Zoom 4  Learning outcomes Describe the major functions of the skeletal system List the four main tissue types of the skeletal system Describe the formation, growth and maintenance of cartilage Describe the formation, growth and maintenance of bone Identify , name and classify bones in the skeleton Use correct anatomical terminology to describe bony features Be familiar with prefixes and suffixes for the skeletal system 5 Reference Vanputte, Regan & Russo (2020) Seeley' s Anatomy and Physiology (12th Ed) McGraw Hill, New York. Chapter 6, 7 and 8 6  The Skeletal System: Functions 1. Support 2. Protection 3. Assistance with movement 4. Mineral homeostasis 5. Blood cell production 6. Triglyceride storage 7  The Skeletal System: tissue types 1. Bones provide rigid support, protect underlying tissues from damage and store minerals 2. Cartilage provides a semirigid support 3. Tendons attach muscles to bones 4. Ligaments hold bones together 8  Key Features of Cartilage  Cartilage has no blood vessels (avascular)  Cartilage has no nerves (aneural)  Cartilage is a flexible connective tissue less rigid than bones but more stable than muscles  Cartilage cells are formed from cells in the perichondrium (connective tissue which surrounds the cartilage of developing bone). Perichondrium contains blood vessels to provide nutrients to the cartilage by diffusion. 9  Cartilage Composition Cartilage is made of a matrix* produced by chondroblasts which form a ‘shapeless’ background substance. Within this matrix are: 1. A dense network of collagen fibers and elastic fibers 2. Chondrocytes (cartilage cells surrounded by matrix) within spaces called lacunae *matrix is a non cellular substance consisting of proteins and other molecules, such as proteoglycans. 10  How does cartilage grow? 1. Appositional growth (cartilage is added by chondroblasts to the outside of the existing cartilage). It leads to increase in width. 2. Interstitial growth (chondrocytes within the matrix undergo mitosis and add more matrix). It leads to increase in length. 11  Types of Cartilage Name Description Hyaline cartilage Gelatinous, glossy cartilage with evenly distributed collagen fibres. Found where ever strong support and some flexibility is needed, e.g. rib cage, bronchi, articulating surface of bones (articular cartilage). Fibrocartilage More collagen bundles than hyaline. Slightly compressible and very tough. Found where there is a lot of pressure such as the knee, in the temporo- mandibular joint and inter-vertebral discs. Elastic cartilage Matrix collagen similar to hyaline but has elastic fibres added. Somewhat flexible but used when rigidity is needed such as the external ear, epiglottis, auditory tubes. 12  Bone cells Name Function Description and origin Osteoblasts Bone forming cells: Produce Originate in the periosteum the chemicals and structures that make up the matrix Osteocytes Matrix maintenance cells Located in specialised structures called lacunae Osteoclasts Bone destroying cells: Break Large, multinucleated cells. down the matrix Originate in red bone marrow 13  Bone Matrix Components Raw materials Raw material sources 35% organic Collagen fibres, Carbon, hydrogen, Carbohydrates, proteoglycans oxygen, nitrogen proteins and lipids 65% inorganic Hydroxyapatite Calcium ions and Absorbed calcium (CaPO4 crystals) phosphate ions and phosphate ions 14  How does the bone matrix form? Formation of bone through ossification or osteogenesis by osteoblasts which depose the matrix (collagen and hydroxyapatite). Collagen (organic) is produced by Endoplasmic Reticulum and Golgi Apparatus. Released by exocytosis. Hydroxyapatite (inorganic) stored in vesicles, then released by exocytosis. 15 The Importance of Bone Matrix Organic: collagen and proteoglycans Inorganic: hydroxyapatite If collagen is removed, bone is too brittle. If mineral is removed, bone is bendable. 16  Woven and Lamellar Bone Type When formed Fibres arrangement Woven Fetal development, Collagen fibres randomly initial repair of a arranged fracture. It is the immature bone (“draft”). Mechanically weak. Lamellar Woven bone is broken Collagen fibres are parallel to down by osteoclasts and each other in each lamella reformed into thin but in different lamellae the sheets called lamellae. collagen fibres have different It is the mature bone orientations (“final version”). Mechanically strong. 17  Types of Ossification Type of Definition/examples Type of bone Final bone ossification formed type formed Intramembranous Bone forms from Woven bone Lamellar bone mesenchymal stem cells (embryological cells) which differentiate into osteoblasts. E.g. skull bones Endochondral Bone forms from Woven bone Lamellar bone mesenchymal cells producing a cartilage template first which is replaced by bone tissue. E.g. long bones, epiphyses of the clavicles, and most of remaining bones 18  Intramembranous Ossification 1. Occurs in mesenchymal cells within connective tissue such as the tissue surrounding the developing brain 2. Mesenchymal cells differentiate into osteoprogenitor cells 3. These differentiate into osteoblasts 4. The osteoblasts form a woven bone matrix, and eventually either trabeculae or the outer layer of lamellar compact bone 19  Endochondral Ossification 1. Mesenchymal cells aggregate and become osteochondral progenitor cells at about 4 weeks of development 2. These cells differentiate to become chondroblasts that form a cartilage framework 3. Blood vessels invade the framework and osteochondral cells in the perichondrium differentiate into osteoblasts 4. The osteoblasts move into the calcified cartilage framework and deposit a new bone matrix (may start at about week 8) 5. The osteoblasts produce woven bone that is then remodeled (may continue till about 18-20 years of age) 20 Endochondral Ossification 21 Endochondral ossification 22  Bone growth of long bones 1. Appositional growth (new bone is added by osteoblasts to the outside of the existing bone). It makes bones wider and thicker. 2. Interstitial growth (osteoblasts produce more matrix from the inside). It makes bones longer. 23  Bone classification Name Alternative names Description/Comments Spongy bone Cancellous bone or Appears porous (less Trabecular bone matrix compare to compact). Contains columns of bone called trabeculae. Generally surrounded by a sleeve of compact bone. Weight bearing. Found in spine and all articulating joints, especially ends of long bones. Compact bone Cortical bone Hard and compact is found in the outer part of all bones and diaphysis of long bones. Functional unit is the osteon or Haversian system. 24 Spongy and compact bone 25 Compact bone structure 26  Compact Bone Structure The functional unit of compact bone is called Osteon or Haversian system 1. Central (or Haversian) canal contains blood vessels and nerves supplying bone tissue. 2. Lamellae are layers of bone: a) Concentric lamellae b) Interstitial lamellae c) Circumferential lamellae 3. Perforating (or Volkmann’s) canal allows blood vessels from periosteum to penetrate the compact bone. 27  Compact Bone Structure 4. Lacunae are the site for osteocytes. 5. Periosteum is the layer of connective tissue surrounding the bone which supports blood/nerve supply. Found where there is no articular cartilage and contains osteoblasts. 6. Endosteum is the layer of connective tissue lining all internal spaces including spaces in spongy bone. Similar to the periosteum, but more cellular. 28  Divisions of the skeletal system Axial (80 bones) Appendicular (126 bones) 29  The Pelvic girdle Ilium Coxal bone Pubis Ischium Anterior view 30 The Shoulder or Pectoral girdle 2 x Clavicle (collar bone) 2 x Scapula (shoulder blade) Anterior view 31  Classification of bones Long - Upper and lower limbs e.g. femur, tibia Short - Carpals (wrist) and tarsals (foot) Flat - Ribs, sternum, skull, scapulae Irregular - Vertebrae, facial 32  Structure of short, flat and irregular bones Sandwich of spongy bone between two layers of compact bone They have no diaphysis. Flat bones have no epiphysis too. 33  Key structures of long bones Structure Description and location Diaphysis Shaft, largely compact bone Epiphysis Enlarged end of the bone, largely spongy bone. Epiphyseal plate Between diaphysis and epiphysis, also known as the growth plate it is made of hyaline cartilage; present until growth stops. Epiphyseal line Location as for epiphyseal plate. Cartilage is replaced by bone and the bone stops growing in length. Medullary cavity In children the medullary cavity contains red marrow, gradually this changes to yellow in limb bones and the skull (except for epiphyses of long bones). Rest of skeleton contains red marrow. 34 Structure of young (long) bone 35 Structure of long bone 36 From Epiphyseal plate to Epiphyseal line 1. The epiphyseal plate is a band of cartilage left between primary and secondary ossification centres. 2. The plate includes rows of young cartilage cells undergoing mitosis and new cartilage cells are being produced. 3. As a bone ages the cartilage cells are progressively converted to bone. 4. When all the cartilage cells become bone an epiphyseal line is formed. Growth in length stops. 37  Bony Features Name Description Head Enlarged end Body Main part of bone Neck Constriction between head and body Margin or border Edge Angle Bend Ramus Branch off body of bone Crest Prominent ridge Foramen Opening Condyle Smooth rounded articular surface Facet Small flattened articular surface Fossa Shallow depression Meatus Passageway Fissure Narrow slit 38  Bone Projections Name Description Process Prominent projection Tubercle Small rounded bump Tuberosity Knob, round projection Trochanter Tuberosities on proximal femur Epicondyle Near or above a condyle Projections are raised areas of bone for attachment of muscles/ligaments 39  Bone terms and projections Right Femur 40  Prefixes for the skeletal system Prefix Meaning Example of use acetabul vinegar cup Acetabulum append to hang something Appendicular skeleton chondro cartilage Chondrocyte endo within Endosteum lacun pool Lacunae os bone Os cox (hip bone) osteo bone Osteoporosis (reduction in the quality of bone) peri around Periosteum 41  Suffixes for the skeletal system Suffix Definition Example of use - blast create, build Osteoblast (bone forming cells) Chondroblast (cartilage forming cells) - clast break down Osteoclast (bone destroying cells) Chondroclast (cartilage destroying cells - cyte cell Osteocyte (bone cells) Chondrocyte (cartilage cells) 42 QUESTIONS? 43