Một cơ quan được coi là một cấu trúc được làm bằng hai hoặc nhiều mô. Da bao gồm các loại mô rất nhiều, và bởi vì diện tích bề mặt của nó là rất lớn, nó được coi là cơ quan lớn nhất của cơ thể. Da là màng da được làm bằng hai lớp, lớp biểu bì và hạ bì. Hai lớp này được làm bằng nhiều lớp phụ | Chapter 4 Cells and Tissues 107 7. cartilage 8. columnar 9. Smooth muscle cells are under involuntary control. 10. plasma Chapter 5 The Integumentary System The integumentary system which most people think of as just skin actually consists of nails hair glands and skin. The integument is the most visible part of the body but is taken for granted by most people except perhaps a dermatologist . The Skin An organ is considered to be a structure that is made of two or more tissues. The skin consists of numerous tissue types and because its surface area is so large it is considered to be the largest organ of the body. The skin is the cutaneous membrane that is made of two layers the epidermis and dermis. Those two layers are made of several sub layers. Check out the following list for facts about these layers Epidermis The epidermis is the most outer layer of the skin it consists of four major individual layers. Stratum corneum This is the outermost layer of the epidermis it consists of squamous cells. Stratum granulosum This layer of cells produces a protein substance called keratin. Stratum spinosum This layer of cells produces a substance called desmosomes. Desmosomes connect one layer of tissue to another layer. Stratum germinativum basale This is the deepest layer of the epidermis this layer consists of cells that can reproduce and therefore repair wounds. This layer also consists of cells that produce melanin which is a pigment that gives the skin its color. Dermis The dermis consists of two layers of tissue. Papillary This layer consists of hair follicles and sebaceous glands. This layer also creates the ridges making up fingerprints. Reticular This layer consists of sweat glands. Deep to the dermis is a layer called the hypodermis. This layer is not a part of skin but is many times discussed with the topic of skin. This layer consists of adipose cells and major blood vessels. Connecting the hypodermis to the skeletal muscles is a group of cells called areolar. .
