HISTOLOGY AP 1 TISSUES Tissues collections of similar

HISTOLOGY A&P 1

TISSUES • Tissues - collections of similar cells working together to perform a function • Tissue classification based on structure of cells, composition of noncellular extracellular matrix, and cell function • Major types of adult tissues – Epithelial – Connective – Muscle – Nervous

EPITHELIAL TISSUE • Cellularity - Consists almost entirely of cells • Covers body surfaces, lines hollow organs, and forms glands – – • • • Outside surface of the body Lining of digestive, respiratory and urogenital systems Heart and blood vessels Linings of many body cavities Has apical and basal surfaces Rests on a basement membrane Specialized cell contacts bind adjacent cells together Avascular - no blood vessels Regenerative -Replaces lost cells by cell division

What is this? ? • What is the name of these types of SIMPLE CUBOIDAL cells? KIDNEYS • Where would I find it? • What might be its function? SECRETION and ABSORPTION

Name this tissue type… • What is the name? • Where is it located? • What is its function? Transitional Bladder, ureters, urethra Provides stretch

Name this tissue type… What is this an image of? Glomerulus Bowman’s capsule (glomerulus of kidneys) Simple cuboidal tissue layer Simple squamous tissue layer • What is the name? • Where is it located? • What is its function? Simple squamous Alveoli of lungs, kidney glomeruli, lining of vessels Filtration (kidneys), diffusion (air sacs of lungs)

Name this tissue type… • What is the name? • Where is it located? • What is its function? Simple columnar Intestinal tract Absorption, secretion of mucus, enzymes, and other substances

Name this tissue type… These structures are… cilia This is a goblet _______ Cell? • What is the name? • Where is it located? • What is its function? Pseudostratified Ciliated Columnar Trachea and bronchial tubes Secretion of mucus, propulsion of mucus by cilia

Name this tissue type… • What is the name? • Where is it located? • What is its function? Stratified squamous Lines mouth, vagina, esophagus, skin protection

STRATIFIED SQUAMOUS • Specific types – Keratinized – contain the protective protein keratin • Surface cells are dead and full of keratin – Non-keratinized – forms moist lining of body openings

CONNECTIVE TISSUE • Most diverse and abundant tissue • Main classes – – Connective tissue proper Cartilage Bone tissue Blood • Characteristics – Varying degrees of vascularity – Nonliving extracellular matrix, consisting of ground substance and fibers – Cells are not as abundant nor as tightly packed together as in epithelium

FUNCTIONS OF CONNECTIVE TISSUE • Enclose organs as a capsule and separate organs into layers. Areolar • Connect tissues to one another. Tendons and ligaments. • Support and movement. Bones. • Storage. Fat. • Insulation. Fat. • Transport. Blood. • Protection. Bone, cells of the immune system

CELLS OF CONNECTIVE TISSUE • Fibroblasts - secrete the proteins needed for fiber synthesis and components of the extracellular matrix • Adipose or fat cells (adipocytes). Common in some tissues (dermis of skin); rare in some (cartilage) • Mast cells. Common beneath membranes; along small blood vessels. Can release heparin, histamine, and proteolytic enzymes in response to injury. • Leukocytes (WBC’s). Respond to injury or infection • Macrophages. Derived from monocytes (a WBC). Phagocytic; provide protection • Chondroblasts - form cartilage • Osteoblasts - form bone • Hematopoietic stem cells - form blood cells • Undifferentiated mesenchyme (stem cells). Have potential to differentiate into adult cell types.

Extracellular Matrix • ECM has 3 major components 1. Protein fibers 2. Ground substance 3. Fluid • Protein fibers – Collagen fibers. Composed of the protein collagen. Strong, flexible, inelastic; great tensile strength (i. e. resist stretch). Perfect for tendons, ligaments – Elastic fibers. Contain molecules of protein elastin that resemble coiled springs. Returns to its original shape after stretching or compression. Perfect for lungs, large blood vessels – Reticular fibers. Formed from fine collagenous fibers; form branching networks (stroma). Fill spaces between tissues and organs.

Name this tissue type… Adipose • What is the name? • Where is it located? Under the skin, around the eyes, kidneys, heart. • What is its function? Protection, storage

Name this tissue type… Fibers? Reticular Cells? lymphocytes • What is the name? Reticular (Loose) Connective Tissue • Where is it located? Internal skeleton: lymph nodes, spleen • What is its function? Soft internal skeleton, supports other cell types

Name this tissue type… What are these cells called? chondrocytes • What is the name? Hyaline. • Where is it located? Embryonic skeleton, cover end of bones, • What is its function? trachea, nose, larynx Support, reinforce, resist compressive stress.

Name this tissue type… Fiber? Collagen Fiber? Elastic Cell? • What is the name? Aerolar Loose connective. Fibroblast • Where is it located? Widely distributed under epithelia • What is its function? Wraps and cushions organs; inflammation.

Name this tissue type… ? ? Fibroblasts ? ? Collagen • What is the name? Dense Connective Tissue. • Where is it located? Tendons, ligaments, aponeurosis • What is its function? Attaches muscles to bones, bones to bones.

Name this tissue type… 1. Haversian Canal 2. Canaliculi 3. Lamella • What is the name? Osseous tissue. • Where is it located? Bones • What is its function? Storage, support 4. Osteocytes in the Lacuna

? ? What important process takes place here? hematopoiesis • What tissue is this? • Spongy bone or cancellous bone • Where is it found? • In the center of flat bones and in the ends of long bones • What is its function? • Support

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MUSCLE TISSUE • Characteristics – Cells are referred to as fibers – Contracts or shortens with force when stimulated – Moves entire body and pumps blood • Types – Skeletal: attached to bones – Cardiac: muscle of the heart. – Smooth: muscle associated with tubular structures and with the skin. Nonstriated and involuntary.

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Layers of skin