Understanding Human Tissues: Types, Functions, and Characteristics

1. Tissues

2. Key words • “Epi”= upon • “Pseudo”= false • “Squam” = scale • “Strat”= layer • Simple- one layer • Stratified- multiple layers • Cuboidal- cube shaped • Columnar- rectangle shape- column • Squamous- flat shape

3. Tissues • * a group of cells with specialized functions • Types: • 1) Epithelial • 2) Connective • 3) Muscle • 4) Nerve

4. Epithelial Tissues • Covers all free body surfaces • Characteristics: • Lacks blood vessels, attached to a basement membrane, replaced continuously • Functions: protects, secretes, absorbs, excretes

5. Types of Epithelial tissues • Simple Squamous- single layer of flat cells • Found: lungs, lines blood vessels, body cavities

6. Types of Epithelial Tissue (cont.) • Simple cuboidal- single layer of cube shaped cells • Found: kidneys and other glands

7. Types of Epithelial Tissue (cont.) • Simple columnar- single layer of elongated cells, nucleus is located near bottom of cell • Contains microvilli- helps with absorption • Contains goblet cells- secretes mucus • Found: uterus, digestive tract

8. Types of Epithelial Tissues • Pseudostratified columnar- single layer of cells that look layered due to nuclei palcement • cilia- to move mucus or sex cells • Found: reproductive system, respiratory system

9. Types of Epithelial Tissues • Stratified Squamous- many flat layers of cells, protects • Found: skin, mouth, throat, vagina, anal canal

10. Types of Epithelial Tissues • Stratified cuboidal- layers of cube shaped cells, protects • Found: mamary glands, sweat glands, slivary glands, pancreas

11. Types of Epithelial Tissues • Stratified columnar- top layer is elongated, bottom layers are cube shaped, protects • Found: male urethra, pharynx

12. Types of Epithelial Tissues • Transitional- specialized to change shape under tension • Found: Bladder

13. Connective Tissue • General Characteristics: • Support • Protection • Fills spaces • Stores fat • Produce blood cells • Protect against infection • Helps repair damaged tissue

14. Connective Tissue • Cells are separated by matrix (intercellular material) • Types of cells: • Fibroblasts- produce collagenous and elastic fibers • Macrophages- are phagocytes (eat other cells and materials) • Mast cells- help with blood clotting and immune response

15. Connective Tissue • Types of fibers in CT: • Collagenous fibers- thick fibers made of collagen, grouped in parallel bundles, holds tissues together, found in tendons • Elastic fibers- thin fibers, stretch easily, build networks, made of elastin • Reticular fibers- very thin fibers, delicate support

16. Connective Tissue- Loose fibrous • Forms delicate, thin membranes • Has many fibroblasts • Has a lot of collagenous and elastic fibers • Function: Binds skin to tissue beneath and provides nourishment to epithelial tissue, fills space between muscle

17. Connective tissue- Adipose • Type of loose connective tissue, Fat • Function- protection, traps heat, and energy stores in the body • Found: beneath skin, around vital organs, around joints. • Note how nucleus is pushed to the side.

18. Connective tissue- Dense fibrous • Made of tightly packed collagenous fibers • Function: Rigid structure, connects tissues • Found: tendons, ligaments, white of eyes, deep layer of skin

19. Connective tissue- Hyaline, Elastic, fibrocartilage • Cartilage- rigid yet partially flexible • Function: provides support, protects, forms structure for developing bones • 3 types of Cartilage • Hyaline: • Fine collagenous fibers, chondrocytes, intercellular matrix- looks like white plastic • Found : ends of bone in joints, soft part of nose, rings of respiratory passage

20. Cartilage continued: • Elastic cartilage • Made of dense network of elastic cartilage- flexible • Found: makes framework for ears, and parts of larynx • Fibrocartilage • Very tough tissue, contains many collagenous fibers • Shock absorbers • Found between disks in vertebral column

21. Connective Tissue: Bone • Osteocytes, Intercellular matrix contains mineral salts and collagen, which makes bone rigid and collagen reinforces the mineral components • Function: structure, protection, provides framework • Found throughout whole body in skelton

22. Connective Tissue: Blood • Cells suspended in fluid matrix (plasma), red blood cells, white blood cells, platelets • Blood forms in red marrow of long bones • Function: Transports, helps maintain stable internal environment • Found: throughout body in blood vessels and heart chambers

23. Muscle Tissue • Characteristics: contract, move structures attatched to them • 3 Types: • Skeletal, Smooth, cardiac

24. Skeletal Muscle Tissue • Structure: Long cells (muscle fibers), striations • Function: attached to bones and helps with movement, can move by voluntary action • Muscle fibers contract when stimulated by nerves, then relax immediately.

25. Smooth Muscle Tissue • Structure: cells lack striations, short, spindle shaped • Function: muscle that works involuntary, constricts/ contracts to move things • Found: digestive system, bladder, blood vessels

26. Cardiac Muscle Tissue • Structure: cells are striated and joined end to end, has an intercalated disk between muscle fibers • Function: involuntary contractions in pumping blood • Found only in heart

27. Nervous Tissue • Structure: neuron (basic cell) has axons and dendrites, neuroglial cells (supports and binds nervous tissue) • Function: Sensitivity and conduction of nerve impulses • Found: Brain, spinal cord, peripheral nerves