Histology

Histology The study of different types of tissues Tissue: Cells working together in functionally related groups

Histology Separated into four major categories based on their function and the embryonic tissue of origin TissueFunction EpithelialCover & Protection ConnectiveSupport MuscleMovement & contraction NervousSignaling & communication

Tissue Engineering: How to Build a Heart ANSWER THESE QUESTIONS IN COMPELTE SENTENCES INTO YOUR NOTEBOOK! TITLE THE SECTION: HOW TO BUILD A HEART 1.Explain why blood supplies pose such a challenge to tissue engineers? 2.Describe what a scaffold is. Does it have to be human? 3.What is decellurization? 4.What is recellurization? 5.What are iPS cells? 6.What are some organs that have been transplanted successfully?

Epithelial Tissue Location: ◦ Lines nearly every cavity and surface of the human body ◦ Form glands Function: ◦ Protect the tissues they cover ◦ Regulate gas and nutrient exchange ◦ Secrete substances such as sweat, hormones, mucus, and enzymes ◦ Provide sensation with the environment

Epithelial Classification ◦ Last name of tissue describes the SHAPE of cells ◦ Squamous: cells wider than tall ◦ Cubodial: cells are as wide as tall, as in “cubes” ◦ Columnar: cells are taller than they are wide, like columns

Epithelial Classification: ◦ First name of tissue indicates the number of layers ◦ Simple: One layer of cells ◦ Stratified: More than one layer of cells

Epithelial Special characteristics: ◦ Cells are packed tightly together, forming a protective layer around organs ◦ High capacity for regeneration ◦ Produce fluids for lubricating tissues and organs ◦ Avascular: No capillaries that directly nourish the cells  Cells get what they need through diffusion of nutrients through the basement membrane

Simple Squamous Epithelium Single layer of flat cells with disc-shaped nuclei Function: ◦ Passage of materials by passive diffusion and filtration ◦ Secrete lubricating substances in serosae

Simple Squamous Epithelium Location ◦ Renal corpuscles ◦ Alveoli of lungs ◦ Lining of heart, blood, and lymphatic vessels ◦ Lining of ventral body cavity

Simple Cuboidal Epithelium Single layer of cube-like cells with large, spherical nuclei Function: ◦ Secretion and absorption

Simple Cuboidal Epithelium Location: ◦ Kidney tubules ◦ Secretory portions of small glands ◦ Ovary and Thyroid follicles

Simple Columnar Epithelium Single layer of column-shaped cells with oval nuclei ◦ Some may have cilia Function: ◦ Absorption ◦ Secretion of mucus, enzymes, and other substances ◦ Ciliated type propels mucus or reproductive cells by ciliary action

Simple Columnar Location: ◦ Non-ciliated: lines digestive tract, gallbladder, ducts of some glands ◦ Ciliated form: lines small bronchi, uterine tubes, uterus

Connective Tissues Most abundant tissue type in the body ◦ Ex: blood, bone, cartilage, tendons, ligaments… Made up of fibers and extracellular components in the embedded in fluid Types of Connective Tissues ◦ Loose Connective Tissue ◦ Dense Connective Tissue ◦ Cartilage ◦ Other Tissues

Connective Tissue Function: ◦ Protect ◦ Store energy ◦ Transport ◦ Insulate ◦ Connect all body tissues

Cartilage Hyaline: ◦ Provides support while still being pliable, most abundant form ◦ Found in the ends of long bones, nose, trachea, and larnyx Elastic ◦ Provides support while still able to stretch ◦ Supports external ear, epiglottis

Cartilage Fibrocartilage: ◦ Provides strong support and handles heavy pressure ◦ Found in intervertebral discs, pubic symphysis, discs of knee joints

Muscle Tissue Cells are extremely long and contain protein fibers capable of contracting Separated into 3 main types: ◦ Skeletal muscle tissue ◦ Smooth muscle tissue ◦ Cardiac muscle tissue TedEd Types of Muscle Tissue

Skeletal Muscle Tissue Voluntary muscle ◦ Can be contracted voluntarily ◦ Function in movement and maintenance of posture ◦ Visible striations Makes up the muscles that are attached to our skeleton

Smooth Muscle Tissue Involuntary muscle ◦ Muscle does not contract voluntarily ◦ Lines most of the organs of the body ◦ No visible striations Found in: ◦ GI Tract ◦ Respiratory Tract ◦ Blood vessels ◦ Bladder ◦ Uterus

Cardiac Muscle Heart, extremely dense, strong tissue Involuntary Large number of mitochondria to provide energy for the continuous contracting of the heart Striated like muscle tissue

Nervous Tissue Found in the brain, spinal cord, and nerves Consists of 2 main cells ◦ Neurons ◦ Neuroglia cells Responsible for communication