Rowe Cells and Connective Tissue PDF Fall 2024

Cells and Tissues Caroline E. Rowe, PhD Assistant Professor Department of Integrative Biology and Physiology  Objectives Tissues Epithelial Tissue Connective Tissue Membranes Learning Objectives Identify the four basic types of...

Cells and Tissues Caroline E. Rowe, PhD Assistant Professor Department of Integrative Biology and Physiology  Objectives Tissues Epithelial Tissue Connective Tissue Membranes Learning Objectives Identify the four basic types of Tissues Define and identify epithelial tissues based on layers and cell type Define and identify connective tissue proper based on the cell type and components of the ECM Identify the five membranes of the body Identify and differentiate between superficial and deep fascia 2  Objectives Tissues Epithelial Tissue Connective Tissue Membranes Organism Histological Hierarchy: Structure = Function Organ System Organ Tissue @Lupita_Thee_Raccoon Identify the histological hierarchy that forms organisms.  Objectives Tissues Epithelial Tissue Connective Tissue Membranes What is a tissue? Epithelial Tissue Connective Tissue 4 types of bodily tissues Each tissue composed of: Cells Extracellular matrix (ECM) Connects and supports structures Think of the lining of a surface Cells are specific to the function of each Nervous Tissue tissue Muscle Tissue ECM composition supports function Ratio of cells:ECM depends on the function STRUCTURE=FUNCTION Produces movement For control and sending messages 4 Objectives Tissues Epithelial Tissue Connective Tissue Membranes Epithelial tissue MANY cells + little extracellular matrix Two types of epithelial tissue: Membranous and Glandular 5 Objectives Tissues Epithelial Tissues Connective Tissues Membranes Membranous epithelial tissues: cover the outer and inner surfaces of body organs and cavities Line body cavities and the Line body surfaces outside of hollow organs Line insides and outside of hollow organs Where would you find epithelial tissues in the body? Objectives Tissues Epithelial Tissue Connective Tissue Membranes Glandular tissue Continuous with membranous epithelium Made of epithelial cells that make and secrete a product Exocrine glands have ducts, secrete locally onto surfaces or in cavities Unicellular or multicellular Endocrine glands Lack ducts, produce hormones that enter bloodstream Target can be far away or nearby ***Endocrine glands covered with the Endocrine System 7 Objectives Tissues Epithelial Tissue Connective Tissue Membranes Exocrine glands- Unicellular Goblet cell – only unicellular exocrine gland Produces mucin that turns into mucus when mixed with water 8 Objectives Tissues Epithelial Tissue Connective Tissue Membranes Exocrine glands- Multicellular Continuation of epithelial sheet that invaginates into connective tissue Examples: sweat glands, mammary glands, salivary glands, etc. Mammary glands Sweat glands 9 Objectives Tissues Epithelial Tissues Connective Tissues Membranes Characteristics of Epithelia: Cells are held together by tight junctions Avascular but innervated Nutrients reach epithelia from capillaries in underlying connective tissue Supported by a Connective tissue via the basement membrane What is the purpose of an intercellular junction? Objectives Tissues Epithelial Tissues Connective Tissues Membranes Polarity Asymmetric distribution of cellular components Made primarily of cells, very little ECM Cells differ in number and shape High cell death and regeneration What is the difference between the apical and basal surface? Objectives Tissues Epithelial Tissue Connective Tissue Membranes How to classify an epithelium: 1. Number of cell layers 2. Shape of cells *** Stratified epithelia classified by shape of cells on the apical surface of the epithelium 12 Objectives Tissues Epithelial Tissues Connective Tissues Membranes Cell Layer Simple One layer of cells Stratified More than one layer of cells Pseudostratified Appear to be more than one layer Pseudostratified columnar epithelium What is the difference between simple, pseudostratified and stratified epithelium? Objectives Tissues Epithelial Tissues Connective Tissues Membranes Describe what squamous, cuboidal and columnar cells look like. Objectives Tissues Epithelial Tissues Connective Tissues Membranes EXCEPTION: Transitional Epithelium Special ability to stretch and change shape, UMBRELLA CELLS Cells transition between cuboidal when relaxed and squamous when stretched Found exclusively in the urinary tract Nucleus is always round in the apical cell layer FUNCTION: Allow stretch in the structures of the urinary tract What features identify the apical cells of transitional epithelium? Objectives Tissues Epithelial Tissues Connective Tissues Membranes Obvious specializations: Goblet cells and Cilia Goblet cells produce mucus Lubricates apical surfaces Protection Cilia Move mucus across apical surface Identify two types of cell specializations  Objectives Tissues Epithelial Tissues Connective Tissues Membranes Squamous Epithelium Simple: Stratified: One layer of cells is present Multiple layers of cells All cells make contact with the basement membrane Not all cells make contact with the basement membrane Squamous: Squamous: Apical surface cells are flattened in cross section Apical surface cells are flattened in cross section Wider than they are tall Wider than they are tall Oval nuclei Oval nuclei Function: Diffusion and filtration Function: Protection Squamous epithelial cell Basement membrane What features identify a simple squamous epithelium?  Objectives Tissues Epithelial Tissues Connective Tissues Membranes Cuboidal and Columnar Epithelium Simple: Simple: One layer of cells is present One layer of cells is present Columnar: Cuboidal: Apical cells are column shaped in cross section Apical surface cells are cube shaped in cross section Cells are taller than they are wide As wide as they are tall Oval nuclei, located near the basal surface Round nuclei Cells may display apical cilia and/or goblet cells Function: Absorption and secretion Function: Absorption and secretion Arrows are pointing to what type of cell? What features identify a simple cuboidal epithelium?  Objectives Tissues Epithelial Tissues Connective Tissues Membranes Pseudostratified Columnar Epithelium Pseudostratified: Cilia All cells touch the basement membrane, but not all cells reach the apical surface All cells have cilia and goblet cells; AKA respiratory epithelium Columnar: Apical cells are column shaped in cross section Goblet Cells are taller than they are wide cells Oval nuclei, located near the basal surface Function: Protection What features identify a pseudostratified columnar epithelium?  Objectives Tissues Epithelial Tissues Connective Tissues Membranes Cell Type Simple Stratified Specializations Function Simple Stratified Squamous Simple squamous Stratified Diffusion, Protection Filtration squamous Cuboidal Simple cuboidal Transitional Secretion, Stretch (specialized stratified absorption cuboidal allowing stretch in the urinary tract) Columnar Simple columnar Cilia Secretion, Protection absorption Pseudostratified Cilia, Goblet Columnar cells Identify the functions of the different epithelia. Objectives Tissues Epithelial Tissue Connective Tissue Membranes Connective tissue Most diverse, abundant tissue Provide support for other structures Also has other functions! Anchors muscles for movement Carries/stores nutrients Insulation Immunity 21 Objectives Tissues Epithelial Tissues Connective Tissues Membranes Produce Cells Extracellular Matrix (Fibers + Ground Substance) Fibroblasts Collagen I, II Gel-like suspension Adipocytes Reticular Blood cells Elastic Chondrocytes Osteocytes Macrophages Objectives Tissues Epithelial Tissue Connective Tissue Membranes Fibroblasts Spindle or star shaped Found in connective tissue proper Adipocytes Fat cells which store lipid in cytoplasm Chondrocytes Provide cushion, insulation and thermoregulation Fibroblasts Blood cells Defend against infection by launching an immune response when antigens are present Chondrocytes Osteocytes Found in cartilage Reside in spaces called lacunae Adipocytes Osteocytes Found in bone Reside in spaces called lacunae Macrophages Macrophages Immune cells Blood Cells Name the cells that are found in connective tissues.  Objectives Tissues Epithelial Tissue Connective Tissue Membranes Collagen Provide tensile strength Type I (bone, skin, tendons, ligaments) Type II (hyaline cartilage) Reticular Support tissue structure Type III collagen Stain black (silver) Elastic fibers Name three types of fibers that may be Allow stretch and recoil found in connective tissues and their Stain black (verhoeffs) function. Objectives Tissues Epithelial Tissue Connective Tissue Membranes Ground Substance: Complex gel secreted by fibers that is made of huge, water attracting macromolecules that produces a flexible medium through diffusion of nutrients and waste can occur. Major Function: Because it is so flexible it can also resist compression. What is the function of the ground substance? Objectives Tissues Epithelial Tissue Connective Tissue Membranes 4 types of connective tissue 1. Connective tissue proper 2. Cartilage Reticular 3. Bone 4. Blood 26  Objectives Tissues Epithelial Tissue Connective Tissue Membranes Connective Tissue Proper is divided into two main types: Cells Fibers ECM Subdivisions Function Loose +++ + +++ Loose Areolar Cushioning, Connective Adipose (fat) Support Tissue Proper Reticular Dense + +++ + Dense regular Rigidity, motion Connective Dense irregular resistance Tissue Proper Identify the two major types of connective tissue proper. 27  Objectives Tissues Epithelial Tissue Connective Tissue Membranes Loose Connective Tissue Proper Loose Areolar Connective Tissue Reticular Connective Tissue Adipose Connective Tissue “Fat” Underlies epithelia, surrounds muscle, nerves Forms a network that creates a support for Lobulated fat cells arranged in a cluster and blood vessels adipose, lymph nodes, bone marrow, Maintains shape, cushions and provides Retains bodily fluid kidney, liver, etc. insulation Cells and fibers which may be present: Cells and fibers present: Cells and fibers present: Fibroblasts Fibroblasts Adipocytes Blood cells Reticular fibers (type III collagen) Reticular fibers (type III collagen) Adipocytes Collagen and elastic fibers  Objectives Tissues Epithelial Tissue Connective Tissue Membranes Dense Connective Tissues Contain the following cells and fibers: Fibroblasts Mostly collagen I (elastic or a combination) Dense Regular Connective Tissue Dense Irregular Connective Tissue Fibers are arranged in parallel Fibers are arranged randomly Location: Uni-directional strength, e.g. ligaments and tendons Location: Multi-directional strength, e.g. dermis of the skin What are the similarities and differences between dense regular and irregular connective tissue?  Objectives Tissues Epithelial Tissue Connective Tissue Membranes Membranes = Epithelium + Connective Tissue Note: All epithelium must maintain a connective tissue. Why? Membranes are formed by which two structures. Objectives Tissues Epithelial Tissue Connective Tissue Membranes Cutaneous Membrane (Skin): True epithelium; exposed to an external environment Epithelium (Epidermis) Stratified Squamous Connective Tissue (Dermis) Dense irregular connective tissue Identify the epithelium and connective tissue of the skin.  Objectives Tissues Epithelial Tissue Connective Tissue Membranes Mucus Membrane: Produce mucus Are true epithelia Simple Have goblet cells Columnar Cilia always present Epithelium Simple Columnar OR Pseudostratified columnar Pseudostratified Columnar Connective Tissue Loose connective tissue “Lamina Propria” specific to mucus producing membranes Identify the epithelium and connective tissue of a mucus membrane. Objectives Tissues Epithelial Tissue Connective Tissue Membranes Serous membranes (Mesothelium) Produce serous fluid within a body cavity Lines a body cavity (mesothelium) Epithelium Simple squamous Connective Tissue Loose connective tissue Identify the epithelium and connective tissue of a serous membrane Objectives Tissues Epithelial Tissue Connective Tissue Membranes Endothelial Membrane Lines blood vessels and the heart Release substances that affect the vessels and the heart Epithelium Simple squamous Connective tissue Loose connective tissue Identify the epithelium and connective tissue of an endothelial membrane Objectives Tissues Epithelial Tissue Connective Tissue Membranes Fascia = Mixed layer of connective tissues 1. Superficial fascia: Loose Areolar Connective Tissue Adipose Connective Tissue 2. Deep fascia Dense Regular Connective Tissue Dense Irregular Connective Tissue Can you predict the function of each of these fascial layers based on the properties of their connective tissues? Objectives Tissues Epithelial Tissue Connective Tissue Membranes Blood Distributes nutrients, oxygen and protection The ground substance of blood is less viscous White blood cells (Leukocytes) have distinctive nuclei and cell size Function in immunity Red blood cells (Erythrocytes) Concave and are anucleate Function in gas transportation (O2 and CO2) Platelets Cell fragments, anucleate Function in blood clotting Describe the components of blood and how they act as a connective tissue. Pseudostratified columnar: Nuclei at different levels, cilia and goblet cells. Simple cuboidal: cells are as tall as they are wide and the nucleus is round Simple squamous: cells are super flat, like pancakes, nucleus projects into the lumen and is a horizontal oval. Simple columnar: Cells are taller than wide, nucleus is a vertical oval at the basal surface of the cell. Transitional: Cells are cuboidal but dome shaped, projecting into the lumen. The nucleus is round. Stratified squamous: Many layers of cells, cells on the apical surface of the epithelium are squamous in shape. Princess of love and joy: perky ears, adorable nose, loving eyes and spritely demeanor Objectives Tissues Epithelial Tissue Connective Tissue Membranes Blood Distributes nutrients, oxygen and protection The ground substance of blood is less viscous White blood cells (Leukocytes) have distinctive nuclei and cell size Function in immunity Red blood cells (Erythrocytes) Concave and are anucleate Function in gas transportation (O2 and CO2) Platelets Cell fragments, anucleate Function in blood clotting Describe the components of blood and how they act as a connective tissue.