Cartilage.pdf

1 Sat 08-June-24 Cartilage 7:30 AM  Semester (2) Tissue & Cell Course Lecture (3) CARTILAGE  Presented by: Dr. Taghreed M. Gorafy MBBS – NUSU M. Sc. of Clinical Human Anatomy - NUSU Ca...

1 Sat 08-June-24 Cartilage 7:30 AM  Semester (2) Tissue & Cell Course Lecture (3) CARTILAGE  Presented by: Dr. Taghreed M. Gorafy MBBS – NUSU M. Sc. of Clinical Human Anatomy - NUSU Cartilage 3 Objectives : By the end of this lecture the students are expected to : Define the cartilage Mention importance of the cartilage Explain the structure of cartilage List the types of cartilage and how to differentiate between them. Determine the compositional differences, function Sat 08-June-24 and location of each type 7:30 AM Cartilage 4 Contents  Definition of cartilage  Functions of cartilage  Types of cartilage Sat 08-June-24 7:30 AM 5 What’s cartilage  Is a specialized form of connective tissue characterized by a firm extracellular matrix (ECM) and cells called chondrocytes.  Chondrocytes synthesize and secrete the ECM and the cells themselves are located in matrix cavities called lacunae.  Avascular and is nourished by the diffusion of nutrients from capillaries in adjacent connective tissue (perichondrium) or by synovial fluid from joint cavities.  Contains chondrocytes embedded in the matrix. Sat 08-June-24 Cartilage 7:30 AM 6 Functions 1. Support soft tissues. 2. Shock-absorbing and sliding area for joints and facilitates bone movements. 3. Essential for the development and growth of long bones both before and after birth. Sat 08-June-24 Cartilage 7:30 AM 7 Types of cartilage Cartilage Hyaline Elastic Fibrocart cartilage Cartilage ilage Sat 08-June-24 Cartilage 7:30 AM 8 Types of cartilage 1. Hyaline cartilage  Is the most abundant cartilage and serves as a temporary skeleton in the fetus until it is replaced with bone.  Location: 1. Articular surfaces of the movable joints 2. Walls of larger respiratory passages 3. Ventral ends of ribs 4. Epiphyseal plate, where it is responsible for the longitudinal growth of bone Sat 08-June-24 Cartilage 7:30 AM 9 Types of cartilage 1. Hyaline cartilage Structure: 1. Matrix 2. Perichondrium 3. Chondroblasts 4. Chondrocytes Sat 08-June-24 Cartilage 7:30 AM 10 Types of cartilage 1. Hyaline cartilage 1. Matrix: Is composed of an amorphous ground substance containing proteoglycan and chondronectin, in which type II collagen is embedded Matrix that is adjacent to chondrocytes is called the territorial matrix, which is poor in collagen but rich in proteoglycans Sat 08-June-24 Cartilage 7:30 AM 11 Fig.1. Matrix of hyaline cartilage Sat 08-June-24 Cartilage 7:30 AM 12 Types of cartilage 1. Hyaline cartilage 2. Perichondrium: Is a sheath of dense CT that surrounds cartilage in most places except at articular surfaces, forming an interface between the cartilage and the tissue supported by the cartilage. It gives the vascular supply for the avascular cartilage and also contains nerves and lymphatic vessels. Sat 08-June-24 Cartilage 7:30 AM 13 Types of cartilage 1. Hyaline cartilage 2. Perichondrium: Consists of: I. Outer fibrous layer containing type I collagen, fibroblasts, and blood vessels. II. Inner cellular layer containing chondrogenic cells and chondroblasts. Sat 08-June-24 Cartilage 7:30 AM 14 Fig.2. Perichondrium of hyaline cartilage Sat 08-June-24 Cartilage 7:30 AM 15 Types of cartilage 1. Hyaline cartilage 3. Chondroblasts: Extremely important in chondrogenesis due to their role in forming both the chondrocytes and cartilage matrix which will eventually form cartilage. Contain an extensive Golgi complex, abundant rough endoplasmic reticulum (RER), lipid droplets, and glycogen. Sat 08-June-24 Cartilage 7:30 AM 16 Fig.3. Chondroblasts of hyaline cartilage Cartilage Sat 08-June-24 7:30 AM 17 Types of cartilage 1. Hyaline cartilage 3. Chondrocytes: Mature cartilage cells that are embedded within lacunae in the matrix. They arise by differentiation of mesenchymal chondrogenic cells and from chondrogenic cells located within the inner layer of the perichondrium into chondroblasts, which are the earliest cells to produce cartilage matrix. Once these cells become totally enveloped by matrix, they are referred to as chondrocyte. Sat 08-June-24 Cartilage 7:30 AM 18 Fig.4. Chondrocytes of hyaline cartilage Cartilage Sat 08-June-24 7:30 AM 19 Cartilage Fig.5. Hyaline cartilage Sat 08-June-24 7:30 AM 20 Types of cartilage 2. Elastic cartilage  Contains elastic fiber networks and collagen fibers typeII.  The principal protein is elastin.  Histologically similar to Hyaline cartilage but contains many yellow elastic fibers lying in a solid matrix.  These fibers give elastic cartilage great flexibility so that it is able to withstand repeated bending.  The chondrocytes lie between the fibres.  Presents in the outer ear, Eustachian tube and epiglottis. Sat 08-June-24 Cartilage 7:30 AM 21 Cartilage Fig.6. Elastic cartilage Sat 08-June-24 7:30 AM 22 Types of cartilage 3. Fibrocartilage  Matrix with large amounts of collagen, lacks an identifiable perichondrium.  Characterized by alternating rows of fibroblast  Only type of cartilage that contains type I collagen  Chondrocytes surrounded by scant matrix and thick parallel bundles of type I collagen fibers.  Located in areas where support and tensile strength are required, such as the symphysis pubic, Intervertebral discs, articular discs, and meniscus of knee. Sat 08-June-24 Cartilage 7:30 AM 23 Cartilage Fig.7. Fibrocartilage Sat 08-June-24 7:30 AM Type of Cartilage Identifying Characteristics Perichondrium Location 25 Hyaline Type II collagen, basophilic matrix, chondrocytes usually Perichondrium usually present Articular ends of long bones, nose, larynx, arranged in groups except on trachea, bronchi, (isogenous groups) articular ventral ends of ribs, surfaces template for endochondral bone formation Elastic TypeII collagen, elastic fibers Perichondrium present Pinna of ear, auditory canal and tube, epiglottis, some laryngeal cartilages Type I collagen, acidophilic Perichondrium Intervertebral discs, Fibrocartilage matrix, chondrocytes absent articular discs, pubic arranged in parallel rows symphysis,insertion of between bundles of tendons, meniscus collagen, always associated of knee with dense collagenous connective tissue and/or Sat 08-June-24 Cartilage hyaline cartilage 7:30 AM 26 Sat 08-June-24 Cartilage 7:30 AM  QUIZ 27 Sat 08-June-24 Cartilage 7:30 AM 28 Q1. How many types of cartilage do you see? Sat 08-June-24 Cartilage 7:30 AM 29 Q2. Fibrocartilage has a matrix with large amounts of: a)Collagen fibers b)Elastic fibers c)Lipids d)Ground substance e)Reticular fibers Sat 08-June-24 Cartilage 7:30 AM 30 Q3. All of the following are true about the perichondrium except: a)That it contains blood vessels b)That is present in hyaline cartilage c)That is present in elastic cartilage d)That is essential for interstitial growth e)That is essential for oppositional growth Sat 08-June-24 Cartilage 7:30 AM 31 Sat 08-June-24 Cartilage 7:30 AM