Chapter 2: Tissues & Skin

1. Chapter 2: Tissues & Skin A & P Miss. Tilley

2. Cells- Cells- Structural units of all living things • Human body has 50-100 trillion cells that combine to form an organism. Organization of cells through chemical analysis; Cells are made up of four elements: Hydrogen, oxygen, carbon, and nitrogen. Living cells are 60% water Cells are constantly bathed in a dilute salt water solution called interstitial fluid.

3. Generalized Cells: Demonstrates many typical features where some demonstrate more specialized functions. All cells have 3 main regions… • A nucleus • Cytoplasm • Plasma membrane

4. Nucleus “The Control Center” Gene-Containing = DNA (Deoxyribonucleic Acid) Once a cell has lost or rejected it’s nucleus for whatever reason is programmed only to die. “For example, if a bacterial cell that has the lac operon is removed its nucleus and placed in a solution with no glucose but some lactose, it will rapidly die. This is because the synthesis of enzymes capable of metabolizing lactose cannot be created because of the lack of nucleus.”

5. Cytoplasm Cellular matrix outside of the nucleus and inside the plasma membrane. This is the site for most cellular activities.

6. Plasma Membrane Fragile Transport Barrier that contains the cell contents and separates them from the surrounding environment. Can use the word cell membrane instead.

7. Cell Diversity • Fibroblasts • Erythrocyte • Epithelial Cell • Skeletal Muscle & Smooth Muscle • Fat Cells • Macrophage • Nerve Cell • Oocyte • Sperm

8. Guess The Cell…

9. Cell Physiology Intracellular Fluid- Solution containing small amount of gases (oxygen & carbon dioxide), nutrients, and salts, dissolved in water. Prefix intra-. Intra- means “within” or “inside.” When used as a prefix with words, it means “within a group.”

10. Interstitial Fluid This is the fluid that constantly bathes the exterior of our cells. Contains nutrients such as amino acids, sugars, fatty acids,and vitamins. Also includes hormones, neurotransmitters, salt and waste products.

12. Look at IV infusions and how they work in the bloodstream Intravenous therapy (IV) is a therapy that delivers liquid substances directly into a vein (intra- + ven- + -ous).

13. Tissues: Epithelial Tissue • The lining or covering of the body. • Epithelial Tissue helps to provide protection, absorption, filtration & secretion. • The skin is composed of a layer of epithelial tissue (Epidermis)

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16. Connective Tissue The main function of connective tissue is to connect tissue as the name explains. *Connective tissue is the most abundant tissue type and is widely distributed throughout the human body. Other functions of connective tissue includes protection, support, and binding of tissues.

17. Connective Tissue Continued... Variations in blood supply: Most are well vascularized but some tissue lack a good blood supply. Out of the following connective tissue which do you believe has the most blood supply? Which one has the least blood supply? • Bone • or • Ligament

19. Extracellular Matrix This makes connective tissue different than the other types of tissues. Found outside the cells Produced by connective tissue cells Secreted to the exterior

20. Different items formed in the extracellular matrix • Collagen (White fibers)- high tensile strength. Collagen is a part of the connective tissue that in the skin helps in firmness, suppleness and constant renewal of skin cells. • Elastic (Yellow fibers)- Ability to stretch & recoil up to 1.5 times their original size. Primarily found in the skin. Where could elastic fibers also be found? • Reticular fibers- fine collagen fibers that form the internal skeleton of soft organs such as the spleen (Only found in lymphoid organs). Less strength than collagen fibers.

22. Different Types of Connective Tissue • Bone • Cartilage • Dense Connective Tissue • Loose Connective Tissue • Adipose Tissue • Reticular Tissue • Blood or Vascular Tissue

23. Bone • Sometimes referred to as osseous tissue. Bone is composed of osteocytes (Bone Cells). *Osteo- relating to bones. • Because of the the rocklike hardness, bone has the exceptional ability to protect and support body organs. • Why would bone be classified as connective tissue?

24. Cartilage Less hard and more flexible than bone. Chondrocytes (Cartilage Cells) are only found in a few places in the body. * Chondro- Prefix for anything related to cartilage. Can you list a few places where you would find cartilage?

25. Cartilage Continued... Different Types: • Hyaline- Abundant collagen fibers hidden by a glassy blue/white appearance. Typically found in the larynx, ribs, and the ends of most bones. • Fibrocartilage- cushion-like disks between the vertebrae of the spinal cord. • Elastic Cartilage- found in elastic tissue, such as the outer ear.

26. Guess the cartilage type... Hyaline, Fibrocartilage, or Elastic Cartilage.

29. Growth Plates- Epiphyseal Plate Found on the ends of bones where you would find hyaline cartilage in adults. They are active construction sites where cells rapidly divide through mitosis. Does not completely become inactive until the age 18 in females & 21 in males.

30. Dense Connective Tissue Uses collagen as its main matrix element. Forms strong, ropelike structures such as tendons & ligaments.

31. Tendons Attach skeletal muscles to bones. **Think about when people get tendonitis it is from excessive use of the muscle/tendon junction.

32. Ligaments • Connects bones to bones at joints. • Ligaments are more stretchy and contain more elastic fibers than tendons. *Side note- Sprain Vs Strain

33. Loose Connective Tissue Loose connective tissue have more cells, and fewer fibers than any other connective tissue other than blood. • Areolar Tissue • Adipose Tissue • Reticular Tissue

34. Areolar Tissue Soft, pliable, “Cobwebby” tissue that cushions and protects the body organs it wraps. Holds internal organs together in their correct positions. • Lamina Propria- Underlies all mucous membranes.

35. Areolar Tissue Continued... Because of its loose and fluid nature, areolar connective tissue provides a reservoir of water and salts. Essentially all body cells obtain their nutrients from and release waste into this tissue. When a body region is inflamed, the areolar tissue in the body soaks up excess fluid like a sponge. The areolar tissue located in the skin binds the outer layers of the skin to the muscles beneath. Areolar tissue is also found in or around mucous membranes, and around blood vessels, nerves, and the organs of the body.

36. Edema A condition characterized by an excess of watery fluid collecting in the cavities or tissues of the body.

37. Adipose Tissue Commonly called fat. Adipose tissue forms the subcutaneous tissue beneath the skin, where it insulates the body and protects it from external variations such as hot & cold. Adipose can also be found surrounding the kidneys & the eye sockets. Primarily adipose tissue is found in the “depots” such as the hips and breasts. The body utilized these depots to use the fat cells as stored energy if needed.

39. Reticular Connective Tissue Delicate network of interwoven reticular fibers associated with reticular cells. (Very similar to fibroblasts) It forms the Stroma (Bed) or internal framework in lymphoid organs such as the spleen, lymph nodes, and also the bone marrow. The fibers provide support and stability to other types of cells. While the lattice itself is fixed in place through the connections between the fibers and the cells, other types of cells along with fluids can move freely across and through the lattice. This allows for free exchanges between cells, while still providing a reinforcing framework that will support an organ or lymph node.

40. Blood Also known as vascular tissue, is considered a connective tissue due to the nature of the blood cells being surrounded by blood plasma. Blood plasma is classified as a extracellular matrix, such as the bone marrow inside a bone. Blood is a transport vehicle for the cardiovascular system. Waste, gases, nutrients, & many other substances.

42. Muscle Tissue Highly specialized to contract, or shorten to produce movement. 3 different types: • Skeletal Muscle • Cardiac Muscle • Smooth Muscle

43. Skeletal Muscle Skeletal muscles can be controlled voluntarily. When skeletal muscles contract they pull on the bones. Skeletal muscle cells are elongated to provide a long axis for contraction.

45. Cardiac Muscle This tissue type is found only in the heart. Unlike skeletal muscle, cardiac muscle is involuntary and are relatively short cells that fit tightly together.

47. Smooth Muscle Smooth muscle can also be called visceral muscle because you cannot visibly see any muscle striations. Involuntary control. Smooth muscle is found in the walls of hollow organs such as the stomach, uterus and blood vessels. *Peristalsis & Digestion *Prostaglandins & Menstruation

49. Nervous Tissue Cells in the nervous system/tissue are referred to as neurons. All neurons receive and conduct electrochemical impulses from one part of the body to another. Brain, Spinal cord & nerves.