The Tissue Level of Organization

1. A. Types of tissues B. Epithelial tissues 1. General features 2. Covering and lining epithelia a. Arrangement of layers b. Cell shapes c. Classification (1) Simple squamous (2) Simple cuboidal (3) Simple columnar (4) Stratified squamous (5) Stratified cuboidal (columnar) (6) Pseudostratified (7) Transitional 3. Glandular epithelia a. Structural classification b. Functional classification C. Connective tissues 1. General features 2. Classification a. Loose connective tissues (1) Areolar (2) Adipose (3) Reticular b. Dense connective tissues (1) Dense regular (2) Dense irregular (3) Elastic c. Cartilage (1) Hyaline (2) Fibrocartilage (3) Elastic d. Specialized connective tissues (1) Osseous (2) Vascular D. Membranes 1. Mucous membranes 2. Serous membranes 3. Cutaneous membranes 4. Synovial membranes The Tissue Level of Organization

2. What is a tissue? • A similar group of cells working together to serve a particular function

3. Types of Tissue • 1. epithelial • 2. connective • 3. muscle • 4. nervous

4. Epithelial Tissues • 1. covering and lining • 2. glandular

5. General Features of Epithelia • 1. closely packed cells • 2. continuous sheets • 3. apical vs basal surface • 4. basement membrane • 5. avascular • 6. nerve supply • 7. high mitotic rate Apical Surface Basal Lamina Vs. Reticular Lamina

6. Covering and lining epithelia You are responsible for Handout #2 Epithelial Tissues • 1. arrangement of layers a. simple b. stratified c. pseudostratified • 2. shape of apical cells a. squamous b. cuboidal c. columnar d. transitional

7. Simple Squamous External Surface (Serosa) of Small Intestine Location: lining heart (endocardium) and blood vessels (endothelium), lymphatic vessels, alveoli of lungs, glomerular capsule of kidneys, part of serous membranes Function: diffusion, osmosis, and filtration

8. Stratified Squamous Skin: Sole of Foot Mucosa of Vagina nonkeratinized forms line mouth and tongue, pharynx, esophagus, anal canal, and vagina Location: keratinized form forms epidermis Function: protection against wear-and-tear

9. Simple Cuboidal Kidney Tubules Location: lines kidney tubules and small ducts of many glands, covers ovary, forms pigmented epithelium of retina Function: absorption and secretion

10. Stratified Cuboidal Duct of a Sweat Gland Location: relatively rare; lines larger ducts of some glands and part of the male urethra Function: protection

11. Simple Columnar Internal Surface (Mucosa) of Small Intestine Location: lines GI tract from stomach to anal canal, ducts of some glands, gallbladder; ciliated form lines oviducts, uterus, central canal of spinal cord Function: Secretion and absorption

12. Stratified Columnar Location: Limited regions of the Pharynx, larynx, Anal canal, and Male urethra (very rare)

13. Pseudostratified Mucosa of the Trachea Location: lines much of lower respiratory system down to bronchiolar level; nonciliated form may be found in some gland ducts, epididymis, and part of male urethra Function: secretion from goblet cells, movement of mucous across surface by ciliary action

14. Transitional Allantoic Duct of Umbilical Cord Location: urinary bladder!!!, portions of ureters and urethra Function: allows distention of organ without causing an increase in tension in wall of organ

15. Glandular Epithelium • 1. secretory portions of glands • 2. endocrine vs exocrine

16. Structural classification of exocrine glands • 1. unicellular gland (the goblet cell) • 2. multicellular gland

17. Functional Classification of Exocrine Glands • 1. merocrine (eccrine) • 2. holocrine • 3. apocrine

18. Connective Tissues • Three basic elements: 1. cells 2. ground substance 3. fibers a. collagen b. elastin c. reticular fibers • Matrix = ground substance + fiber(s)

19. Classification of Connective Tissues • 1. Loose connective tissues a. areolar (fibroblastic cell type) b. adipose (adipocytic cell type) c. reticular (fibroblastic cell type) 2. Dense connective tissues a. dense regular (fibroblastic cell type) b. dense irregular (fibroblastic cell type) c. elastic (fibroblastic cell type)

20. Classification of Connective Tissues Continued… • 3. Cartilage (chondrocytic cell type) a. hyaline b. fibrocartilage c. elastic • 4. Bone • 5. Blood

21. Know Handout #3 Connective Tissue TypesThree Basic Elements • 1. Cells • Ground substance (ground substance is a more or less homogeneous, amorphous, water-based background substance in which the specific differentiated elements of a connective tissue are suspended. • Fibers (E.g. collagen, elastin, reticular) Matrix= Ground substance + fibers that separates cells

22. Areolar (Loose) Location(s): papillary dermis of skin, hypodermis, mucous membranes, blood vessels, nerves, and around body organs (i.e. everywhere) Description: loosely woven fibers embedded in ground substance; many different cell types wander through; fibroblasts form basic tissue Function: strength, elasticity, and support

23. Adipose (Loose) Location: hypodermis; around heart, kidneys, and eyes; yellow bone marrow; around joints Description: adipocytes that store fats, forming a characteristic “signet ring” appearance Function: provide insulation, energy storage, protection from mechanical injury

24. Reticular (Loose) Location: stroma of liver, spleen, lymph nodes; red bone marrow; basement membranes Description: net work of very short interlacing collagen fibers and fibroblasts Function: form framework of organs, binds together smooth muscle cells

25. Dense Regular Location: tendons, aponeuroses, and most ligaments Description: collagen fibers arranged in parallel bundles, with fibroblasts scattered between Function: provides strong attachments between parts

26. Dense Irregular Location: dense fascia, reticular dermis, perichondrium, periosteum, joint capsules, dura mater, membrane capsules, heart valves Description: collagen fibers randomly arranged and fibroblasts, forming a sheet Function: strength, support, and protection

27. Elastic (Dense) Location: lung, elastic arteries, trachea and bronchial tree, true vocal cords, vertebral ligaments, suspensory ligament of penis Description: elastic fibers that branch freely, forming sheets or ligaments Function: provides extensibility and elasticity to various organs that must be stretched

28. Hyaline Cartilage Location: articular surfaces of bones; anterior ribs; nose, parts or larynx, trachea, and bronchial tree; embryonic skeleton Description: Chondrocytes embedded in cartilage matrix rich in collagen fibers Function: resists compressive forces, provides smooth surfaces for articulation at synovial joints

29. Fibrocartilage Location: pubic symphysis, intervertebral discs, menisci of shoulders and knees Description: consists of scattered Chondrocytes with hyaline cartilage matrix among bundles of collagen fibers Function: support, fusion (between pubic bones and between vertebrae), deepening of shoulder and knee joints

30. Elastic Cartilage Location: epiglottis, external ear, auditory tubes Description: Chondrocytes embedded in cartilage matrix rich in network of elastic fibers Function: allows structure to be semi-rigid and extensible; structure can return to resting shape

31. Bone Location: comprises the bones of the skeleton Description: osteocytes embedded in a mineralized matrix of collagen fibers and ground substance Function: support, protection, storage, provides levers for movement; provides for blood cell formation

32. Blood Location: within blood vessels and heart Description: formed cellular elements suspended in a liquid matrix (plasma) Function: transport of gases, immune function, blood clotting

33. Membranes • 1. mucous membrane (mucosa) • 2. serous membrane (serosa) a. parietal layer vs. visceral layer (serous fluid) b. endothelium (endocardium) c. mesothelium • 3. cutaneous membrane (epidermis) ________________________________________ • 4. synovial membrane (not really a membrane)