1. Histology- Study of Tissues

2. Physiological systems are made up of organs that serve specific functions. Organs are made up of tissues, which are then made up of cells.

3. Four types of tissue: ► Epithelial ► Connective ► Muscle ► Nervous

4. Epithelial tissues are sheets of tightly connected epithelial cells. The tissues form skin and line hollow organs.

5. Some epithelial cells can: ► Secrete substances, like hormones ► Move substances with cilia ► Act as chemical receptors ► Create boundaries ► Control filtration and transport Function of Epithelial cells

6. Cells in Epithelial Tissue ► Squamous Cells- Simple /Stratified ► Columnar Cells- Simple/pseudostratified ► Cuboidal Cells- Simple/stratified ► Transitional Cells

7. Classification of Epithelial Tissue

9. Epithelial Tissue (A)

10. Stratified squamous epithelium, nonkeratinized, from human mouth. LM, H&E stain.

11. Simple Cuboidal Epithelium

12. Simple Columar Epithelium

13. Simple columnar epithelium from human intrahepatic bile duct. LM, trichrome stain.

14. Simple cuboidal epithelium lining follicles of human thyroid gland. LM, H&E stain.

15. Pseudostratified columnar epithelium lining a human bronchus; cilia on many cells. LM.

16. Pseudostratified Columnar Epithelium

17. Transitional epithelium line the urethra of a male infant. LM, H&E stain.

18. Pigmented epithelium from a person of African descent. LM, H&E stain.

19. Keratinized Stratified Squamous Epithelium

20. Non-Keratinized Stratified Squamous Epithelium

21. Transitional Epithelium

22. Skin from human foot; note thick keratin layer. LM, H&E stain.

23. Sweat glands in human skin. LM, H&E stain.

24. Epithelial Tissue (B) ► Simple cuboidal epithelium is found in glandular tissue and in the kidney tubules.

25. Muscle tissues consist of elongated cells that generate force and cause movement. Three types of muscle tissues: ► Skeletal ► Cardiac ► Smooth

26. ► Skeletal: responsible for locomotion and other body movements (e.g., breathing, shivering). ► Cardiac: makes up the heart and is responsible for the heartbeat and blood flow. ► Smooth: involved in movement and generation of forces in internal organs (e.g., gut, blood vessels).

27. Figure 40.4 Filaments in Skeletal Muscle Cells

28. Types of Muscle Tissue

32. Connective tissues are dispersed cells in an extracellular matrix that they secrete. The matrix contains protein fibers: ► Collagen: strong and resistant to stretch, supports skin and connections between muscles and bones ► Elastin: can be stretched and then recoils; found in tissues that stretch (e.g., lungs, arteries)

33. Diagram of Loose CT

36. Connective Tissue

37. Areolar connective tissue; elastic and collagenic fibers in a rat. LM, silver stain.

40. Connective tissues: ► Cartilage provides structural support and is flexible: has chondrocytes; cells that secrete the extracellular matrix. ► Bone: provides support and is hardened by calcium phosphate deposition in the matrix. Bone cells are osteocytes.

41. Hyaline cartilage in cat larynx. LM, H&E stain.

42. Cartilage

43. Fibrocartilage in a mammalian intervertebral disc. LM, H&E stain.

44. Elastic cartilage from a pig's ear.

48. Human compact bone, transverse section. LM, Schmorl's stain.

49. More connective tissues: ► Adipose tissue: includes adipose cells that form and store lipids. Cells are adipocytes. ► Blood: consists of cells in a very liquid extracellular matrix, the blood plasma. There are red blood cells (erythrocytes), white blood cells (leukocytes), and platelets (thrombocytes).

50. Blood cells from domestic chicken (Gallus gallus). LM, Giemsa stain.

52. Normal human adipose cells. LM, H&E stain.

54. Nervous tissues contain two basic cell types: neurons and glia. Neurons encode information as electrical impulses that travel over axons to their targets. Chemical signals from the neuron stimulate a response in the target cell, via receptors. Glia provide support for neurons.

55. Neurons

56. Nervous Tissue Includes Neurons and Glia (A)

57. Organs consist of multiple tissues. An organ system is a group of organs that function together.

58. Different Tissues make up an organ Example: The stomach wall is arranged in layers: ► Epithelial cells ► Connective tissue ► Smooth muscle ► Neurons ► Connective tissue

60. Figure 40.7 Tissues Form Organs Fig 40.7 whole figure except stomach