Connexons: hollow connective tubes

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3 1. tight junctions: like a zipper, these junctions hold the cells tightly together making them impermeable to the extracellular fluid that surrounds them. 2. desmosomes: like buttons, these junctions hold cells under stress together. 3. gap junctions: like a cell phone, these junctions allow cells to communicate quickly. Connexons: hollow connective tubes

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5 Membrane transport via fluid Intracellular fluid: fluid within the cell (nuclearplasm, cytostol) Interstitial fluid: fluid with out the cell, bathes the cells Types of transport Passive diffusion, osmosis, facilitated, filtration, moves along the gradient Active solute pumping, exocytosis, endocytosis, phagocytosis, pinocytosis, moves against the gradient

6 Four Tissue Types 1. Epithelial: lining, covering, glandular 2. Connective: attachments (most abundant) 3. Muscle: produce movement 4. Nervous: irritability and conductivity

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8 Functions of epithelia: Protection - skin Absorption intestines Filtration - kidneys and secretion - glands

9 Characteristics of epithelia: form sheets, have apical surface (draw mountain) basement membrane, avascular, rapidly regenerate (when nourished)

10 Classification of epithelia Arrangement of cells (number of layers) Shape of cells

11 Simple epithelia Simple squamous: (look like floor tiles) filtration or rapid diffusion, air sacs, capillaries Simple cuboidal: secretion, salivary glands, pancreatic glands, walls of kidney tubules Simple columnar: secretion and absorption, line digestive tract from stomach to anus, line mucous membranes (mucosae) goblet cells produce mucous within the line of columnar cells.

12 Stratified epithelia Stratified squamous: (most common) protection, skin, mouth and esophageal linings Stratified cuboidal and columnar: (very rare) found in large glands

13 What the? Epithelia Pseudostratified (often cilliated) columnar: (pseudo = false, fake) looks stratified, but really it s just one layer (simple), absorption and secretion, lines respiratory tract.

14 What the? Epithelia Transitional: a mixture of squamous on the apical surface and cuboidal or columnar at the base, stretch, line urinary bladder, ureters, and urethra

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17 Review examples ksulkowski/tissueslides.htm

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19 Function of connective tissue Supporting Protecting Binding body parts together

20 Characteristics of connective tissue Mostly vascularized (except tendons and ligaments and cartilage) Produce an extracellular matrix the varying cells of the connective tissue are housed in; ground substance and fibers Extreme variations among types of tissue

21 Hidden connective fields Types of Connective Tissue 1. bone: (osseous tissue) bone cells lie in a central cavity surrounded by a very hard matrix with collagen fibers 2. cartilage: cells lie in a somewhat flexible matrix with different types of fibers Hyaline cartilage: collagen fibers in a glassy matrix, larynx, ribs, joints Fibrocartilage: vertebral discs Elastic cartilage: external ear (elastic fibers)

22 Types of Connective Tissue Continued 3. Dense connective tissue: tremendous amounts of collagen fibers in a flexible matrix, tendons, ligaments, dermis of skin 4. loose Connective Tissue: softer tissue with less fibers Areolar tissue: cushions and protects organs, holds excess fluid and nutrients, most abundant Adipose tissue: AKA fat, insulate Reticular tissue: mainly in lymph system

23 Types of Connective Tissue Continued Blood: vascular tissue

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25 Function of muscle tissue movement Characteristics of muscle tissue Cells are fibers Contract and expand Types of muscle tissue Skeletal muscle: attach to skeleton, allow body to move, voluntary, long and thin, multinucleated, Smooth muscle: line hollow organs, allow fluids to move through the body, tapered, uninucleated, involuntary Cardiac muscle: heart only, allows the movement of blood, involuntary, branched, uninucleated,

26 Functions of nervous tissue Irritated and conduct Characteristics of nervous tissue Longest cells, very delicate, don t replicate, conduct electrochemical impulses Types of nervous tissue Neurons nerve cells Supporting cells

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29 Hidden connective fields