ANP 1105A L2B - Anatomy & Physiology I - 2024 Lecture Notes PDF

ANP 1105A - Anatomy & Physiology I Basic Cellular Physiology & the Anatomy and Physiology of the Cardiovascular, Lymphatic & Respiratory Systems Lecture 2B – Connective Tissue Presented by: Dr. Stephen Gee Faculté de médecine | Faculty...

ANP 1105A - Anatomy & Physiology I Basic Cellular Physiology & the Anatomy and Physiology of the Cardiovascular, Lymphatic & Respiratory Systems Lecture 2B – Connective Tissue Presented by: Dr. Stephen Gee Faculté de médecine | Faculty of Medicine uOttawa.ca Readings Learning Objectives Indicate common characteristics of connective tissue, and list and describe its structural elements. Describe the types of connective tissue found in the body and indicate their characteristic functions. 4.3 Connective Tissue Connective tissue is the most abundant and widely distributed of primary tissues Four main classes – Connective tissue proper – Cartilage – Bone – Blood Major functions: binding and support, protecting, insulating, storing reserve fuel, and transporting substances (blood) Common Characteristics of Connective Tissue Two characteristics make connective tissues different from other primary tissues: Common origin: derived from mesoderm Sparse cells embedded in extracellular matrix (ECM) – The ECM allows connectives to bear weight, withstand tension, and endure abuse BUT connective tissues have varying degrees of vascularization (cartilage is avascular, bone is highly vascularized) Structural Elements of Connective Tissue Collagen triple helix Overview of types of connective tissue. Areolar Loose Adipose Reticular Four main types: 1 Connective tissue proper Regular Dense Irregular Elastic Connective Tissue Hyaline 2 Cartilage Elastic Fibrocartilage 3 Bone 4 Blood Areolar Connective Tissue (a) Connective tissue Proper Loose Areolar Description: Gel-like matrix with all three fiber types; cells: fibroblasts, macrophages, mast cells, and some white blood cells. Elastic fibers Ground Function: Wraps and cushions organs; its substance macrophages phagocytize bacteria; plays important role in inflammation; holds and Fibroblast conveys tissue fluid. nuclei Location: Widely distributed under epithelia of body, e.g., forms lamina propria of mucous membranes; packages organs; surrounds Collagen capillaries. fibers Epithelium Photomicrograph: Areolar connective tissue, a soft packaging tissue of the body (3403). Lamina propria Adipose Tissue (b) Connective tissue Proper Loose Adipose Description: Matrix as in areolar, but very sparse; closely packed adipocytes, or fat cells, have nucleus pushed to the side by large fat droplet. Nucleus of adipose (fat) cell Function: Provides reserve food fuel; insulates against heat loss; supports and protects organs. Location: Under skin in subcutaneous tissue; Fat droplet around kidneys and eyeballs; within abdomen; in breasts. Adipose tissue Photomicrograph: Adipose tissue from the subcutaneous Mammary layer under the skin (350×). glands Reticular Connective Tissue (c) Connective tissue Proper Loose Reticular Description: Loose network of reticular fibers in a gel-like ground substance; reticular cells lie on the fibers. White blood cell Function: Fibers form a soft internal skeleton (lymphocyte) (stroma) that supports other cell types including white blood cells, mast cells, and macrophages. Location: Lymphoid organs (lymph nodes, Reticular bone marrow, and spleen). fibers Spleen Photomicrograph: Dark-staining network of reticular connective tissue fibers forming the internal skeleton of the spleen (350×). Overview of types of connective tissue. Areolar Loose Adipose Reticular 1 Connective tissue proper Regular Dense Irregular Elastic Connective Tissue Hyaline 2 Cartilage Elastic Fibrocartilage 3 Bone 4 Blood Dense-regular (d) Connective tissue Proper Dense Regular Crimped structure of artificial collagen fibers Dense-irregular (e) Connective tissue Proper Dense Irregular Description: Primarily irregularly arranged collagen fibers; some elastic fibers; fibroblast is the major cell type. Nuclei of fibroblasts Function: Withstands tension exerted in many directions; provides structural strength. Location: Fibrous capsules of organs and of joints; dermis of the skin; submucosa of Collagen digestive tract. fibers Shoulder joint Fibrous joint capsule Photomicrograph: Dense irregular connective tissue from the fibrous capsule of a joint (430×). Elastic Connective Tissue Overview of types of connective tissue. Areolar Loose Adipose Reticular 1 Connective tissue proper Regular Dense Irregular Elastic Connective Tissue Hyaline 2 Cartilage Elastic Fibrocartilage 3 Bone 4 Blood Cartilage Matrix secreted from chondroblasts (during growth) and chondrocytes (adults) – Chondrocytes found in cavities called lacunae – 80% water, with packed collagen fibers and sugar proteins (proteoglycans) e.g. chondroitin and hyaluronic Myllokunmingia (524 Ma) acid) Tough, but flexible material Lacks nerve fibers Literally, everyone has one! Legit! Avascular: receives nutrients and structural support from layer of dense irregular CT that surrounds it (perichondrium – provides nutrients to chondroblasts and chondrocytes Hyaline cartilage Elastic Cartilage Fibrocartilage Clinical Relevance Aging chondrocytes lose ability to divide so injuries heal slowly (e.g. sports injuries) Later in life, cartilage can calcify or ossify (become bony), causing chondrocytes to be poorly nourished and die. Overview of types of connective tissue. Areolar Loose Adipose Reticular 1 Connective tissue proper Regular Dense Irregular Elastic Connective Tissue Hyaline 2 Cartilage Elastic Fibrocartilage 3 Bone 4 Blood Bone Blood Derived from mesoderm Overview of Classes of Connective Tissues Overview of Classes of Connective Tissues