Lecture 3: Tissues and Membranes, Epithelial Tissue, Connective Tissue, Nervous Tissue, Muscular Tissue

1. Lecture 3 Tissues and Membranes

2. A. 4 types of tissues • Epithelial tissue • Connective tissue • Nervous tissue • Muscular tissue

3. Classification epithelial of tissues Alveoli and capillaries Glandular epithelium Salivary and thyroid glands Skin (keratin) and oral cavity, esophagus in women b. Transitional epithelium Urinary bladder c. Ciliated epithelium Stomach, goblet cells (intestine and trachea

4. I. Epithelial Tissue (p. 33) • Covers the body - “sheets” (except for glands) • Lines organs and body cavities • No blood supply • Apical Surface – free surface • Basement Membrane – acts as a anchor to cells • Function: protects, absorbs, secretes, filters • Examples: skin, glands, lining of the digestive and respiratory tracts

5. Types of Epithelial Tissue

6. Cuboidal Epithelium • Cells are cube-like

7. 3. Columnar Epithelium • Cells are tall and narrow (kidney)

8. Classified also by layers Simple – one layer Stratified – multi layered

9. Ciliated Pseudostratified columnar

10. B-Epithelial Tissue

12. Glands • Unicellular glands (goblet cells in respiratory and digestive tracts) • Multicellular glands • Exocrine glands (duct glands, Salivary, sweat and stomach glands) • Endocrine glands (ductless glands, hormones) • Pancreas- secrete digestive enzyme-duodenum of small intestine • Pancreatic islets or islets of langerhans , secrete hormone insulin and glucagon directly into the blood

13. II. Connective Tissue • Most abundant • Supports and joins various part of the body • Good blood supply except tendons and ligaments • Examples: cartilage, bone, blood, ligaments, tendons

14. Connective Tissues • Intercellular matrix – fills area between cells (non-living) able to bear weight • may be liquid, semi-solid, gel, hard • able to bear weight, stretch, withstand abuse • Blood (plasma) • Bone (salts)

17. Connective Tissue • B. Classification of Connective Tissue • 1. Bone (Osseous tissue) • a. Bone cells are in tiny cavities called lacunae surrounded by layers of calcified matrix • b. Protect and Support

18. Connective Tissue - Cartilage • 1. Hyaline Cartilage: rubbery & smooth; somewhat hard • found in larynx, attaches ribs to sternum, covers ends of bone

19. 2. Fibrocartilage • Discs in the spinal column

20. 3. Elastic Cartilage a. found in external ear and nose

21. Dense Fibrous Tissue • Makes up tendons and ligaments

22. Loose Connective Tissue • Areoler tissue • Anchors body parts • Surround organs

23. Connective – Adipose Tissue • Stores Fat • Protection from extreme temperatures

25. III. Muscle Tissue • Made of specialized cells that can contract. • 3 types of : Skeletal muscle (tendon) • Smooth muscle • Cardiac muscle

26. a. Skeletal Muscle • Voluntary • Striated • Movement • Multi-nucleated

27. 2. Smooth muscle • Not voluntary • Found in various organs • Non- striated • Single nucleus • Stomach and intestine • Arteries • iris

28. 3. Cardiac muscle • Heart • Striated • Involuntary • One nuclei per cell • Intercalated discs

29. Smooth muscle

31. III. Nervous Tissue • Carry an impulse • Two types of cells: • Neurons: • Neuroglia: support the neurons

32. Nervous Tissue • Receive and conduct impulses • Neuron – nerve cells

34. Membranes

35. Membranes: 3 Types: • 1. Epithelial Membranes • Cutaneous membranes • Serous membranes • Mucous membranes 2. Connective tissue Membranes

36. Membranes: 3 Types: • 1. Cutaneous Membranes • Skin • Epidermis: Stratified epithelium tissue • Dermis: connective tissue

37. 2. Mucous Membrane (muscosa) • - Simple epithelium tissue • Line cavities that are open to the external environment • Many produce mucous • Lining of mouth, digestive tract, reproductive tract, urinary tract, respiratory tract

38. 3. Serous Membrane (Serosa) • Named according to location • Line cavities that are not open to the external environment • Visceral layer: the layer against the internal organs (organs=viscera) • Parietal layer: the layer against the inside wall of the cavity

41. Integumentary System Chapter 5

42. Functions • Protection against abrasion and ultraviolet light • Protection from entry of microorganisms and dehydration • Sensation receptors for heat, cold, touch, pressure, and pain • Production of precursors to Vitamin D when exposed to ultraviolet light • Regulation of temperature by controlling blood flow to the skin and activity of sweat glands • Excretion of waste products through the skin and the gland secretions

43. Facts • The integumentary system consists of the skin and the structures derived from it including hair, nails, and glands. • The skin is the largest organ of the body, covering approximately 2 square meters and having a mass of about 5 kilograms. • The study of the integument is called dermatology.

44. Anatomy of Skin • Epidermis - the five outermost thin layers, mitosis in the deepest layer produces new cells as the older cells move towards the most superficial layer where they are sloughed off • Dermis - the thicker layer below the epidermis containing blood vessels, nerve endings, hair follicles, smooth muscles, lymphatic vessels, sweat glands, and sebaceous glands • Hypodermis - the layer of loose connective tissue under the dermis and not considered part of the skin, it contains half of the body’s stored fat which acts as padding and insulation, it attaches to underlying bones and muscles

45. Structure of Skin

46. This is a micrograph of actual skin sliced thinly and stained. Note the epidermis, dermis, and hypodermis. The outer cells of the epidermis are sloughing off. The dermal papillae are projections of the dermis which extend into the epidermis. They contain tiny blood vessels that supply the epidermis and aid in regulation of body temperature. Fingerprints are projections of the dermal papillae into the epidermis of the fingertips. They increase friction and help improve grip.

47. This image shows the five layers of the epidermis. The outermost layer is called the stratum corneum: -25 layers of dead skin cells -Keratinized Keratin is a protein that builds up in cells of the epidermis as they move from the deepest layer, the stratum basale, towards the skin’s surface. This process is called keratinization and takes 2-4 weeks.

48. Epidermal Layers Composed primarily of keratinized stratified squamous epithelial cells -- consisting of 4-5 layers: • stratum corneum: outermost layer, keratinized dead epithelium • stratum lucidum: layer found in thickest areas of skin • stratum granulosum: 3-5 layers of flattened granular cells, developing keratin fibers • stratum spinosum: multiple layers of cells • stratum basale: deepest layer of single cuboidal or columnar cells, also contains melanocytes - Blisters, Calluses &Psoriasis

49. Skin Color - Genetics, Environment & Physiology: • # of melanocytes - difference in kind, amount & size • sunlight, UV light, etc. • blood in dermis, blood vessels, freckles & moles • other pigments - carotinoids • jaundice – liver disorder

50. Skin, hair, and eye color are all due to a molecule called melanin. This provides protection from the sun’s ultraviolet rays. Melanin is made by special cells in the stratum basale called melanocytes which have extensions reaching towards the skin’s surface. Note the pigment granules in these cell extensions.