Understanding the Human Body: A Comprehensive Guide to Tissue Types and Functions

1. The Animal Body Tour

2. Levels of structure • Cells • Tissues: Cells combined in distinct ways into layers. Specialization (division of labor) • Organs: Made of more than one kind of tissue. Perform common function. • Organ systems: Several organs combine to perform major body function.

3. Levels of structure • Example, circulatory system

4. Levels of structure • 11 organ systems

5. Tissue types (4) • 1) Epithelial tissue • Covers outer and inner ____________ of body • Cells tightly joined together (no blood vessels in intercellular spaces: materials must diffuse in and out) • Two major types: covering and lining, and glandular

6. Tissue types • 1) Epithelial tissue types (covering and lining) • Simple epithelial (1 cell layer). Further subdivided based on cell shape • Squamous (flattened) • Cuboidal (cube shaped) • Columnar (rectangular)

7. Tissue types • 1) Epithelial tissue types (covering and lining) • Stratified epithelial (multiple cell layers). Further subdivided by cell shape • Ex., squamous (flattened) • Pseudostratified epithelial (one cell layer but looks like 2 because __________ not all in same position) • Ex., pseudostratified columnar (rectangular)

8. Tissue types • 1) Epithelial tissue • Glandular (secretes materials) epithelial tissue • Exocrine glands: connected to epithelium surface by duct (Ex., sweat glands, salivary glands) • Endocrine glands: not connected to epithelium surface (Ex., adrenal gland of kidney). Secretions called hormones, enter blood and stay within body

9. Tissue types • Epithelial tissue functions: • Protection: invasion, dehydration, physical injury, etc. • Secretion of chemicals: ex., digestive tract • Note: usually with great regenerative ability • Ex., stomach lining replaced every ______ days

10. Tissue types • 2) Connective tissue • Used to bind and support all other tissues • Other special functions too • Composed of cells and matrix (extracellular material) • Two types: • Connective tissue proper • Special connective tissues

11. Tissue types • Connective tissue proper • 1) Loose connective tissue • Matrix often contains: collagen (strong protein fibers), elastin (elastic protein fibers)

12. Tissue types • Connective tissue proper • 1) Loose connective tissue • Cells include: ______________ (cells that secrete matrix), mast cells (make histamine: blood vessel dilator), macrophages (phagocytic cells), adipose cells (contain a fat droplet) Adipose Loose connective

13. Tissue types • Connective tissue proper • 2) Dense connective tissue • Collagen fibers tightly packed (very strong) • Ex, tendons and ligaments

14. Tissue types • Special connective tissues: cartilage • Matrix: collagen fibers in parallel arrays and glycoproteins

15. Tissue types • Special connective tissues: cartilage • Chondrocytes: living cartilage cells. Live in chambers (lacunae). Note lack of blood vessels: diffusion supplies cells with materials (slow process!)

16. Tissue types • Special connective tissues: bone • Matrix hardened with calcium phosphate salts • No __________ occurs through bone matrix. Blood vessels present in central canals

17. Tissue types • Special connective tissues: bone • Cells called osteocytes, located in chambers (lacunae) • Osteocytes connect with cellular processes through canalaliculi

18. Tissue types • Special connective tissues: blood • Blood is connective tissue, with fluid matrix (plasma) • Erythrocytes (red blood cells): carry oxygen and carbon dioxide • Leukocytes (white blood cells): ___________ cells • Thrombocytes (platelets): fragments of bone marrow cells

19. Tissue types • Connective tissue functions: • Connect parts (tendons connect muscle to bone) • Support body (skeleton) • Protection (cranium around brain) • Circulate materials (blood).

20. Tissue types • 3) Muscle tissue • Most abundant _________ in humans • Basic structure: bundles of myofibrils, composed of protein filaments (actin and myosin).

21. Tissue types • 3) Muscle tissue types: • Skeletal (striated) muscle: multinucleated, produce voluntary movements

22. Tissue types • 3) Muscle tissue types: • Cardiac (also striated): single nucleus, have intercalated discs (heart muscle)

23. Tissue types • 3) Muscle tissue types: • Smooth muscle: no striations. Usually not under voluntary control

24. Tissue types • Functions: • Movement (of body, fluids within body, etc.)

25. Tissue types • 4) Nerve tissue • Transmits electrochemical impulses • Neuron (name of cell type) • Dendrite (process: brings impulse to cell body) • Axon (process: carries impulse from cell body)

26. Tissue types • 4) Nerve tissue • Neuroglia: support cells • Often associate with axons, form sheath (_________ sheath) • Note Nodes of Ranvier (gaps in sheath).

27. Tissue types • 2 nerve networks: • Peripheral Nervous System (PNS): perceives environment and communicates to body • Central Nervous System (CNS): processes information and coordinates activities

28. Tissue types • 4) Nerve tissue: Types of neurons • Sensory (receive information: send to CNS) • Motor (stimulate muscles/glands) • Association (integrate information and connect to other neurons)

29. Tissue types • 4) Nerve tissue • Nerves: bundles of ___________ • Ganglion (plural: ganglia): collection of neuron cell bodies

30. Tissue types • 4) Nerve tissue • Functions: Send electrical signals to convey information, make things happen in body, etc.

31. Integumentary System

32. Integumentary System • Human skin: largest organ of body (2 square yards, 16% of body weight) • Distribution: “Rule of _____s” Note: diagram %s are for only one side of body

33. Integumentary System • Many functions in animals: • Protection. Forms boundary of individual, barrier to external dangers and valuable internal materials • Sensing. Can gather information about environment: temperature, pressure, light, damage to integument • Communication. Since visible to others, can send signals with skin color or structures (hairs, scales, feathers) • Regulate body temperature. Can be used to gain/lose energy. Integument structures (hairs, scales, feathers) can provide ____________

34. Integumentary System • Many functions in animals: • Excretion: Sweat contains water, urea (nitrogenous waste material), salts. These eliminated during sweating

35. Integumentary System • Skin layers • Epidermis • Dermis

36. Integumentary System • Human skin layers: Epidermis • Upper boundary: Stratum corneum. Dead cells that provide protective layer. Shed as skin scales or flakes

37. Integumentary System • Human skin layers: Epidermis • You will shed about 40 lbs. of skin scales during your lifetime • Good news for dust mites (Phylum Arthropoda, Class Arachnida, Order Acari)!

38. Integumentary System • Human skin layers: Epidermis • Lower boundary: Stratum germinativum (basal cells). Living cells doing rapid _________. Daughter cells fill with keratin (tough water resistant protein: also found in hair, fingernails, hooves, claws), flatten and die

39. Integumentary System • Human skin layers: Epidermis • Contains melanocytes: cells that produce melanin and transfer it to other skin cells. Darken skin color in response to UV exposure (tanning)

40. Integumentary System • Human skin layers: Epidermis • UV exposure increases skin cancer chances • Melanoma: ____________ that divides out of control • Recall ozone thinning problem

41. Integumentary System • Human skin layers: Dermis • Contains connective tissue, blood vessels, nerve endings.

42. Integumentary System • Human skin also contains: hairs • Follicle: invagination of skin surface containing hair • Shaft: body of hair (mostly protein: ____________) • Bulb: base from which hair grows by cell division (each cell divides every 1-3 days!) • Papilla: contains blood supply

43. Integumentary System • Human skin also contains: hairs • Arrector pili muscle: smooth muscle. Can change angle of hair

44. Integumentary System • Human skin also contains: exocrine glands • Sweat glands: empty onto skin surface at sweat pore.

45. Integumentary System • Human skin also contains: exocrine glands • Sebaceous glands: associated with hair follicle, secrete oil to lubricate/protect skin and hair

46. Integumentary System • Human skin also contains: sense organs • Free nerve endings: sense _____________ • Hair follicle receptors: can sense movement of hair

47. Integumentary System • Human skin also contains: sense organs • Merkel cell, Meissner’s corpuscles, Pacinian corpuscles. Sense pressure/stretch of skin

48. Integumentary System • Human skin also contains: sense organs • Temperature: End-bulb of Krause (cold), Organ of Ruffini (hot)

49. Integumentary System • Below the skin: Subcutaneous __________ • Contains adipose tissue • Stores energy, cushioning (soles of feet, palms of hands), provides insulation

50. Integumentary System • Nails: Special keratinized layer of cells produced by fold of skin (nail root) Fingernail magnified 1000 X