1. Tissue and Skin

2. Tissues
Tissues are layers or groups of similar cells with a common function
4 types of tissues include:
Epithelial
Connective
Muscle
Nervous

3. Epithelial Tissue
Epithelial tissue covers all free body surfaces, forms the inner lining of body cavities, lines hollow organs, and is the major tissue of glands.
A basement membrane anchors epithelium to connective tissue. Epithelial tissue lacks blood vessels, has cells that are tightly packed, and is continuously replaced.
It functions in protection, secretion, absorption, and excretion.

4. Epithelial Tissue
Apical Surface
Basal Surface
A free surface or edge exposed to the body’s exterior or to the cavity/lumen of an internal organ.
Basement membrane
Lower surface of epithelium
Structureless material secreted by the cells.

5. Types of Epithelial Tissue
Simple
Squamous
Cuboidal
Columnar
Pseudostratified
Stratified
Squamous
Cuboidal
Columnar
Transitional

6. Simple Squamous Epithelial
This tissue consists of a single layer of thin, flattened cells through which substances pass easily.
It functions in the exchange of gases in the lungs and lines blood vessels, lymph vessels, and membranes within the thorax and abdomen.

7. Simple Cuboidal Epithelium
This tissue consists of a single layer of cube shaped cells.
It carries on secretion and absorption in the kidneys and various glands.

8. Simple Columnar Epithelium
This tissue is composed of elongated cells whose nuclei are near the basement membrane.
It lines the uterus and digestive tract, where it functions in protection, secretion and absorption.

9. Pseudostratified Columnar
This tissue appears stratified because the nuclei are at two or more levels.
Its cells may have cilia that move mucus over the surface of the tissue.
It lines tubes if the respiratory system.

10. Stratified Squamous Epithelium
This tissue is composed of many layers of cells; the top layers are flattened.
It protects underlying cells from harmful environmental effects.
It covers the skin and lines the oral cavity, esophagus, vagina and anal canal.

11. Stratified Cuboidal Epithelium
This tissue is composed of two or three layers of cube-shaped cells.
It lines the larger ducts of the sweat gland, salivary glands and pancreas.
It functions in protection.

12. Stratified Columnar Epithelium
The top layer of cells in this tissue contains elongated columns. Cube-shaped cells make up the bottom layers.
It is in part of the male urethra and parts of the pharynx
Functions in protection and secretion.

13. Transitional Epithelium
Specialized to become distended.
It is in the walls of organs of the urinary tract.
It helps prevent the contents of the urinary passageways from diffusing out.

14. Connective Tissue
Connects, supports, protects, fills spaces, stores fat, produces blood cells, protects against infections, and helps repair damage tissues
Most are well vascularized except tendons, ligaments and cartilage
Fibers—made by CT cells and secreted
Collagen fibers (white)
Elastic fibers (yellow)
Reticular fibers (fine collagen)

15. Types of Connective tissue
From most rigid to softest:
Bone
Cartilage
Dense connective tissue
Loose connective tissue
Blood

16. Major Cell types Fibroblasts produce collagenous and elastic fibers
Macrophages are phagocytes
Mass cells release heparin and histamine and usually are near blood vessels

17. Bone
The extracellular matrix of bone contains mineral salts and collagen
Its cells usually form concentric circles around osteonic canals
Active tissue that heals rapidly
Osseus tissue
Most rigid connective tissue, with deposits of mineral salts and collagen within the matrix.
Bone cells, called osteocytes, lie within lacunae and are arranged in concentric circles
Good blood supply, enabling rapid recovery after an injury.
Rocklike hardness allows protection and support of other body organs

18. Cartilage Provides a supportive framework for various structures.
Cartilage cells (chondrocytes) lie within lacunae in the gel-like fluid matrix.

19. Types of Cartilage
Hyaline cartilage is white with abundant fine collagen fibers, is found at the ends of bones, and supports respiratory passages.
Elastic cartilage, with elastic fibers, provides a framework for the external ears and parts of the larynx.
Fibrocartilage is a tough tissue that provides a shock-absorbing function in intervertebral disks and in the knees and pelvic girdle.

20. Dense Connective Tissue
This tissue consists of densely packed collagenous fibers and is very strong but lacks a good blood supply.
Fibroblasts—cells that make fibers
It is found as part of tendons and ligaments.

21. Loose Connective Tissue
This type of tissue forms delicate, thin membranes throughout the body that bind body parts together.
Fibroblasts are separated by a gel-like ground substance that contains collagenous and elastic fibers.
It binds the skin to underlying organs and fills spaces within muscle.

22. Areolar Tissue Most widely distributed connective tissue in the body
Cusions and protects body organs it wraps
“Glue” that holds internal organs together

23. Adipose Tissue Fat storing connective tissue
Found beneath the skin (insulates the body), around joints, padding the kidneys and other internal organs, and in certain abdominal membranes.

24. Reticular Connective Tissue
Network of interwoven reticular fibers associated with reticular cells
Internal supporting framework

25. Blood
Blood is composed of cells (red and white) suspended in a fluid matrix (plasma).
It is formed in the blood-forming tissues inside red bone marrow and functions to transport substances throughout the body.

26. The Integumentary System
The skin and its accessory structures make up the integumentary system.
Five major functions
Serving as a barrier against infection and disease
Helping to regulate body temperature
Removing waste products from the body
Providing protection against Ultraviolet radiation from the sun
Producing vitamin D

27. Layers of Skin Epidermis Dermis Subcutaneous layer beneath dermis
not part of skin

28. Subcutaneous Layer Hypodermis Loose Connective Tissue Adipose Tissue
Major Blood Vessels

29. Epidermis
Layer of stratified squamos epithelium that lacks blood vessels
Thickest on Palms
Keratonized
Outermost Layer
Its layers are made of Mostly DEAD CELLS.
Most of the cells of the epidermis undergo rapid cell division (MITOSIS).
As new cells are produced, they push older cells to the surface of the skin.  The older cells become flattened, lose their cellular contents and begin  making KERATIN.

30. Dermis
Composed of irregular dense connective tissue that binds the epidermis to underlying layer
Contains blood vessels
Nerve tissue is scattered through the dermis