Body Tissues PART C. PowerPoint Lecture Slide Presentation by Patty Bostwick-Taylor, Florence-Darlington Technical College

Transcription

1 PowerPoint Lecture Slide Presentation by Patty Bostwick-Taylor, Florence-Darlington Technical College Body Tissues 3 PART C

2 I. Body Tissues A. Tissues (tissue = woven) Histology the study of tissues Groups of cells with similar structure and function B. Four primary types 1. Epithelial tissue (epithelium/epithelia) - covers 2. Connective tissue - supports 3. Muscle tissue produces movement 4. Nervous tissue - controls

3 II. Epithelial Tissues/Epithelia (epithe = laid on, covering) A. Locations sheet of cells that covers body surfaces, lines cavities & forms glands B. Functions - epithelia form boundaries between different environments, & nearly all substances received or given off must pass through an epithelium 1. Protection 4. Excretion 2. Absorption 5. Secretion 3. Filtration 6.Sensory Reception

4 C. Special Characteristics of Epithelium 1. Surfaces - cells fit closely together and often form sheets which all rest upon & are supported by connective tissue - the apical surface upper free surface of the tissue exposed to body exterior or cavity of an internal organ - some apical surfaces are slick and others have microvilli, fingerlike extensions of plasma membrane to increase surface area or motility - the lower attached surface - basal surface

5 Epithelium Characteristics Figure 3.17a

6 - basal lamina- thin, noncellular, adhesive, supporting sheet adjacent to the basal surface consists of glycoproteins - basal lamina (lamina = sheet) acts as selective filter determining which molecules diffusing from underlying connective tissues are allowed to enter the epithelium - reticular lamina- just deep to basal lamina layer of extracellular material, mainly collagen protein fibers belonging to underlying connective tissue - the two laminae form the basement membrane which reinforces it and resists stretching and tearing/defines the epithelial boundary

7

8 2. Vascularity - avascular - no blood vessels but is innervated, or supplied with nerve fibers - nourished by substances diffusing from blood vessels in the underlying connective tissue

9 3. Regeneration - high regenerative capacity - as long as epithelia is well nourished, they can replace lost cells by cell division

10 D. Classification of Epithelia - epithelia have two names: one for cell layers and the other for cell shape 1. Number of cell layers - Simple one layer - Stratified more than one layer Figure 3.17a

11 Classification of Epithelia 2. Shape of cells a. Squamous - flattened b. Cuboidal - cube-shaped c. Columnar - column-shaped d. Pseudostratified goblet- shaped * in stratified epithelia, look for cell shape at the apical surface The image cannot be displayed. Your computer may not have enough memory to open the image, or the image may have been corrupted. Restart your computer, and then open the file again. If the red x still appears, you may have to delete the image and then insert it again. Figure 3.17b

12 E. Types of Simple Epithelia 1. Simple Squamous Epithelium - Description single layer of flat cells - Function allows materials to pass by diffusion & filtration - Location lines lung air sacs, heart, blood vessels, lymphatic vessels & ventral body cavity

13 - Special Names a. Endothelium ( inner covering ) provides a slick, friction- reducing lining lymphatic & blood vessels and heart b. Mesothelium ( middle covering ) found in serous membranes lining the ventral body cavities & its organs

14 Simple Epithelia Figure 3.18a

15 2. Simple Cuboidal Epithelium - Description single layer of cubelike cells, with a spherical, central nucleus - Function - secretion & absorption - Location kidney tubules, glands and their ducts, surface of ovaries

16 Simple Epithelia Figure 3.18b

17 3. Simple Columnar Epithelium - Description - single layer of tall cells - some have cilia on the apical surface moves substances - Function - absorption & secretion of mucus, enzymes & other substances cilia propels substances - Location - Nonciliated è lines digestive tract (stomach to rectum) & gallbladder - Ciliated è lines small bronchi, uterine tubes & uterus

18 Simple Epithelia Figure 3.18c

19 4. Pseudostratified Columnar Epithelium - Description - single layer of cells with differing heights, some not reaching the free/apical surface - nuclei seen at different levels gives false (pseudo) impression that several cell layers are present - Function - secretion of mucus & propulsion of mucus - Location - Nonciliated è males sperm-carrying ducts and ducts of large glands - Ciliated è lines trachea & most of the upper respiratory tract

20 Simple Epithelia Figure 3.18d

21 F. Types of Stratified Epithelia - two or more cell layers, regenerate from below basal cells divide & push apically to replace older surface cells

22 1. Stratified Squamous Epithelium most widespread stratified epithelium - Description thick membrane composed of several cell layers - cells at the apical surface are flattened - basal cells are cuboidal or columnar & metabolically active - surface cells are full of keratin, a tough protective protein (keratinized) and dead - Function - found as a protective covering where friction is common -Locations: Nonkeratinized è forms the moist linings of esophagus, mouth & vagina Keratinized è epidermis (superficial layer of skin)

23 Stratified Epithelia Figure 3.18e

24 2. Stratified Cuboidal Epithelium - Description two layers of cuboidal cells - rare in the body Location ducts of larger glands (sweat & mammary)

25 3. Stratified Columnar Epithelium - Description only cells at the apical surface are columnar - rare in the body - Location pharynx, male urethra & gland ducts

26 4. Transitional Epithelium - Description - shape of cells depends upon the amount of stretching - resembles both stratified squamous & stratified cuboidal - Function stretches readily, permits stored urine to distend bladder - Location - lines the ureters, bladder and part of urethra

27 Stratified Epithelia Figure 3.18f

28 Glandular Epithelium Gland One or more cells responsible for secreting a particular product

29 2. Major Gland Types a. Endocrine gland Ductless since secretions diffuse into blood vessels All secretions are hormones b. Exocrine gland Secretions empty through ducts to the epithelial surface Include sweat and oil glands

30

31 DYGI? What two criteria are used to classify epithelial tissues? How do endocrine and exocrine glands differ in structure and function?

32 III. Connective Tissue - Includes the most abundant and widely distributed tissues A. Four Main Classes 1. Connective Tissue Proper 2. Cartilage 3. Bone 4. Blood

33 Connective Tissue B. Functions 1. binding & supporting 2. protecting 3. insulating 4. storing reserve fuel 5. transporting substances

34 C. Common Characteristics of Connective Tissue 1. All connective tissues arise from mesenchyme/ embryonic tissue 2. Degrees of Vascularity - some tissue types are well vascularized - some have a poor blood supply or are avascular (ex. cartilage - avascular, dense poorly vascular & others rich supply)

35 3. Extracellular Matrix - non-living material that surrounds living cells 4. Main Components of Connective Tissue a. Ground substance unstructured material that fills space between cells and contains the fibers

36 b. Fibers - produced by the cells & made of protein - three types 1. Collagen fibers tough & provide high tensile strength (ability to resist being pulled apart) 2. Elastic fibers rubberlike protein elastin 3. Reticular fibers short, fine collagenous fibers used to form delicate networks

37 c. Cells 1. immature blast forms actively mitotic secrete the ground substance and fibers - connective tissue proper fibroblast - cartilage chondroblast - bone osteoblast 2. mature cyte forms maintains health of the matrix 3. Other Cells fat cells, white blood cells, mast cells (detect foreign microorganisms & initiate inflammatory response), macrophages (eat foreign material)

38 C. Connective Tissue Proper 1. Loose Connective Tissues a. Areolar Connective Tissue (areola = a small open space) - Description - gel-like matrix with all three fibers types arranged loosely - Function - packing tissue, wraps & cushions organs, macrophages phagocytize bacteria, inflammation, holds tissue fluid - Location - widely distributed under epithelia of body forms lamina propria of mucous membranes

39 Connective Tissue Types Figure 3.19e

40 b. Adipose Connective Tissue - Description - made up primarily of adipocytes or fat cells which contain triglycerides - also called white fat which stores nutrients for other cells vs. brown fat which contains abundant mitochondria to heat the bloodstream - Function - provides reserve food fuel, insulates against heat loss, and supports & protects organs - Location - under skin, around abdominal organs, & breasts

41 Connective Tissue Types Figure 3.19f

42 c. Reticular Connective Tissue - Description - delicate network of interwoven reticular fibers - Function - forms a soft internal skeleton or stroma ( bed or mattress ) which supports cells like lymphocytes (white blood cell), mast cells & macrophages - Location - lymphoid organs (lymph nodes, bone marrow & spleen)

43 Connective Tissue Types Figure 3.19g

44 2. Dense Connective Tissues - all have fibers as their prominent element and are sometimes called fibrous connective tissue

45 a. Dense Regular Connective Tissue - Description - primarily parallel collagen fibers - major cell type is the fibroblast - poorly vascular - Function - withstands great tensile strength when pulling force is applied - Location - tendon connecting muscle to bone, ligaments - connecting bone to bone, and in fasciawhich is a wrapping binding structures together

46 Connective Tissue Types Figure 3.19d

47 b. Dense Irregular Connective Tissue - Description - irregularly arranged collagen fibers - Function - withstands tension exerted in many directions - Location - dermis - skin layer, forms fibrous capsulesof organs & joints

48

49 E. Cartilage - stands up to tension & compression - poorly vascular - chondroblasts (immature-produces matrix) & chondrocytes (mature)

50 1. Hyaline Cartilage - gristle (hyal = glass or transparent) - Description - collagen fibers, matrix appears glassy - Function - pliable with strength - Location - embryonic skeleton, ends of long bones, forms costal cartilage, nose trachea & larynx & in growth plates

51 Connective Tissue Types Figure 3.19b

52 2. Elastic Cartilage - Description - nearly identical to hyaline but with more elastic fibers - Function - maintains shape of structure allowing flexibility - Location - external ear and epiglottis (flap covering trachea)

53

54 3. Fibrocartilage - Description - matrix less firm than hyaline, thick collagen fibers - Function - absorbs compressive shock - Location - intervertebral discs, pubic symphysis, knee joint

55 Connective Tissue Types Figure 3.19c

56 F. Bone Osseous Tissue - Description - rocklike hard matrix contains collagen fibers & calcium salts (calcified matrix) - well-vascularized - osteoblasts (produce the matrix) & osteocytes (live in concentric rings) - Function - support & protect - Location - bones

57 Connective Tissue Types Figure 3.19a

58 G. Blood - Description -consists of red & white blood cells surrounded by fluid matrix blood plasma - Function - transportation - Location - contained within blood vessels

59 Connective Tissue Types Figure 3.19h

60 Muscle Tissue Function is to produce movement Three types Skeletal muscle Cardiac muscle Smooth muscle

61 Muscle Tissue Types Skeletal muscle Under voluntary control Contracts to pull on bones or skin Produces gross body movements or facial expressions Characteristics of skeletal muscle cells Striated light & dark bands/striped Multinucleated (more than one nucleus) Long, cylindrical cells are called fibers

62 Muscle Tissue Types Figure 3.20a

63 Muscle Tissue Types Cardiac muscle Under involuntary control Found only in the heart Function is to pump blood Characteristics of cardiac muscle cells Cells are attached to other cardiac muscle cells at intercalated disks Striated One nucleus per cell

64 Muscle Tissue Types Figure 3.20b

65 Muscle Tissue Types Smooth muscle Under involuntary control Found in walls of hollow organs such as stomach, uterus, and blood vessels Characteristics of smooth muscle cells No visible striations One nucleus per cell Spindle-shaped cells

66 Muscle Tissue Types Figure 3.20c

67 DYGI? How do connective tissues differ significantly from other tissues? Which of the three types of muscle tissue is striated? Which is voluntary?

68 Nervous Tissue Composed of neurons and nerve support cells Function is to send impulses to other areas of the body Irritability (responsiveness) Conductivity

69 Nervous Tissue Figure 3.21

70 Tissue Repair (Wound Healing) Regeneration Replacement of destroyed tissue by the same kind of cells Fibrosis Repair by dense (fibrous) connective tissue (scar tissue) Determination of method Type of tissue damaged Severity of the injury

71 Events in Tissue Repair Capillaries become very permeable Introduce clotting proteins A clot walls off the injured area Formation of granulation tissue Growth of new capillaries Rebuild collagen fibers Regeneration of surface epithelium Scab detaches

72 Regeneration of Tissues Tissues that regenerate easily Epithelial tissue (skin and mucous membranes) Dense/Fibrous connective tissues and bone Tissues that regenerate poorly Skeletal muscle Tissues that are replaced largely with scar tissue Cardiac muscle Nervous tissue within the brain and spinal cord