Chapter 4 Tissues PDF

Tissues A&P CONCEPTS 1 FALL 2024 CHAPTER 4 Big Picture Cells are the building blocks of tissues, and tissues are the building blocks of organs. Each different tissue type is suited to the job it has. Being able to verbally and visually identify different tissue types will give you a deeper unde...

Tissues A&P CONCEPTS 1 FALL 2024 CHAPTER 4 Big Picture Cells are the building blocks of tissues, and tissues are the building blocks of organs. Each different tissue type is suited to the job it has. Being able to verbally and visually identify different tissue types will give you a deeper understanding of the physiology of the body as we study it in this class. Learning Outcomes – Part I ❖ Describe the general makeup of a tissue ❖ Define histology ❖ List the four primary tissue types & generally where they are found ❖ Identify the three embryonic germ layers, & the adult structures derived from each.  Tissues & Histology Tissues are groups of specialized cells & the extracellular substances surrounding them. Histology is the study of tissues under the microscope Tissues are classified by the structure of the cells, the composition of the extracellular matrix, & the function of the cells. There are four general tissue types: Epithelial Connective Nervous Muscle Germ Layers During embryonic development, three cell layers form These cell layers give rise to all the different structures & tissues of the body Endoderm Lining of the digestive tract Mesoderm Organs, muscles, bones, & blood vessels Ectoderm Skin & Nervous System Checkpoint #1 The nervous system originates from which germ layer? A. Ectoderm B. Endoderm C. Mesoderm Learning Objectives – Part II ❖ List & explain the characteristics of epithelial tissue ❖ Describe the general functions of epithelial tissue ❖ Describe how epithelial tissue is classified & named ❖ Relate the form & function of epithelial tissue ❖ Identify the type & location of several different types of epithelial tissue ❖ Distinguish between endocrine & exocrine glands ❖ Differentiate between unicellular & multicellular glands. Functions of Epithelial Tissues ❖ Protection of underlying structures ❖ Acting as a barrier ❖ Permitting the passage of substances ❖ Secreting substances Discussion: if you were going to create something ❖ Absorbing substances to accomplish any of these tasks, what would it look like? Characteristics of Epithelial Tissues ❖ Mostly composed of cells ❖ Covers or lines body surfaces ❖ Has an exposed (apical) surface ❖ Attaches at the basal surface ❖ Cellular connections ❖ Avascular ❖ Capable of regeneration Classification of Epithelial Tissues ❖ Number of layers Pro Tip: Look for the nuclei ❖ Simple vs. stratified vs. pseudostratified Layers – ❖ Shape of cells ◦ A single row = simple epithelium ❖ Squamous, columnar or cuboidal ◦ More than one row = likely stratified epithelium ❖ Cell modifications ❖ Keratinization ◦ Pseudostratified will look like more than one row ❖ Cilia but all cells are connected to basement membrane Shape of cells – ** LOOK AT THE APICAL SURFACE** ◦ Flat nucleus = squamous cells ◦ Round nucleus = cuboidal cells ◦ Oval nucleus = columnar cells Examples of the Relationship of Form & Function in Epithelial Tissues A single layer of squamous cells – best for filtration and diffusion, as well as providing a smooth surface for the protection of an organ or a cavity A single layer of cuboidal cells – think secretion A single layer of columnar cells – creates a thick barrier capable of both secretion and absorption Multiple layers of flat cells – a thick barrier that is primarily protective and difficult to penetrate Glands: Endocrine vs. Exocrine ❖ Both endocrine & exocrine glands are primarily made of epithelial tissue. ❖ Endocrine glands are ductless & release their products (hormones) into the bloodstream (Growth hormone, testosterone, insulin) ❖ Exocrine glands have ducts, & release their products into a body cavity or on the surface of the skin (sweat, digestive enzymes, sebum) ❖ Exocrine glands can be further described by their structure ❖ Unicellular glands – goblet cells ❖ Multicellular glands – sweat glands Checkpoint #2 Identify this epithelial tissue type: A. Simple squamous epithelium B. Simple columnar epithelium C. Simple cuboidal epithelium D. Stratified cuboidal epithelium E. Stratified squamous epithelium Learning Objectives – Part III ❖ List and describe the major functions of connective tissue ❖ Identify the origins of connective tissue ❖ Describe the three main components of connective tissue ❖ Give examples of connective tissue types Functions of Connective Tissue ❖ Support ❖ Enclosing and separating other tissues (fascia) ❖ Connecting tissues to each other (tendons) ❖ Storage (bone) ❖ Cushioning and insulating (adipose) ❖ Transporting (blood) ❖ Protection (blood, bone) Connective Tissue Origins ❖ All connective tissue develops from mesenchyme ❖ Mesenchyme is an embryonic connective tissue derived from mesoderm Connective Tissue Components ❖ Specialized Cells ❖ Extracellular matrix: ❖ Protein fibers ❖ Collagen ❖ Reticular ❖ Elastic ❖ Ground substance ❖ Liquid ❖ Solid Checkpoint #3 From what embryonic germ layer does all connective tissue originate? A. Endoderm B. Mesoderm C. Ectoderm Learning Objectives – Part IV ❖ Briefly describe muscle tissue & identify the three types of muscle tissue ❖ Identify nervous tissue and where it is found Muscle Tissue ❖ Muscle tissue is specialized for contraction ❖ There are three types of muscle tissue: ❖ Skeletal muscle (striated, voluntary) ❖ Cardiac muscle (striated, involuntary) ❖ Smooth muscle (unstriated, involuntary) Nervous Tissue ❖ Nerve tissue is specialized for communication (via electrical signaling) ❖ It is found within the nervous system ❖ Neurons and glial cells Checkpoint #4 In which of the following locations would your find cardiac muscle tissue? A. Skin B. Heart C. Brain D. Stomach Learning Objectives – Part V ❖ Describe the process of inflammation in response to tissue damage ❖ Explain the role that inflammation plays in the protection of the body ❖ Relate and explain the five cardinal signs of inflammation ❖ Explain the difference between regeneration and fibrosis ❖ Explain the major events involved in tissue repair  “Inflammation Sets the Stage” -Elaine Marieb & Katja Hoehn Human Anatomy & Physiology, 8th Edition p. 139 Effects of Inflammation ❖ Release of chemical mediators ❖ Increased blood flow to damaged tissue ❖ Decreased blood flow out of tissue ❖ Increased vascular permeability ❖ Increased presence of immune cells & antibodies Signs of Inflammation ❖ Rubor (Redness) ❖ Calor (Heat) ❖ Tumor (Swelling) ❖ Dolar (Pain) ❖ Loss of function Cell Types & Tissue Repair ❖ Labile cells ❖ Continue to divide throughout life ❖ Ex: bone marrow ❖ Stable cells ❖ Don’t usually divide, but have the ability to do so ❖ Ex: Liver cells ❖ Permanent cells ❖ No ability to replicate and divide ❖ Ex: Cardiac muscle, nerve cells  Regeneration vs. Fibrosis ❖ Regeneration – damaged tissue is replaced by the same tissue type ❖ Fibrosis – damaged tissue is replaced by scar tissue Tissues Classified by Their Ability to Regenerate The Process of Healing Checkpoint #5 Susan was skiing and sustained a knee & leg injury, tearing her medial meniscus, straining her quadriceps muscles, spraining her patellar ligament & breaking her tibia. Given what you now know about tissues and healing, which of these structures will heal the best with regeneration? A. Tibia B. Medial meniscus C. Quadriceps muscle D. Patellar ligament Reference VanPutte, C., Regan, J., & Russo, A. (2023). Seeley’s anatomy & physiology (13th ed.). McGraw Hill.