Chapter 4 Histology: The study of body tissues

Transcription

1 Chapter 4 Histology: The study of body tissues

2 Body Tissues Cells are specialized for particular functions Tissues = groups of cells with similar structure and function Four primary types 1.Epithelium 2.Connective tissue 3.Nervous tissue 4.Muscle Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 3.41

3 Epithelial Tissues Epi = above the outermost layer of organs Found in different areas: Body coverings, body linings, glandular tissue (sweat glands, oil glands) Functions 1.Protection 3.Filtration 2.Absorption 4.Secretion Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 3.42

4 Epithelial Characteristics -Cells fit closely together -Tissue layer always has one free surface (not attached to other cells) -Lower surface bound to basement membrane -Avascular: has no blood supply (diffusion from capillaries allows O2 and food to pass). -Regenerate easily if well nourished Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 3.43

5 But there are so many types- do I need to know them all?

6 YES!

7 Types of Epithelium Notice Just one cell layer thick (just one nucleus thick) Classified by number of cell layers. Two layer types: Simple one layer Stratified more than one layer Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Notice many layers thick. Slide 3.44a

8 Classification of Epithelium They are further classified by the shape of the cell: Squamous flattened Cuboidal cube-shaped Columnar column-like Transitional cells change shape: flat to cuboidal, and back Figure 3.16b Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 3.44b

9 Layer + Shape = Name

10 Simple Epithelium 1. Simple squamous Single layer of flat cells Usually forms membranes Lines body cavities Lines lungs and capillaries Figure 3.17a Looks scaly- like parched earth Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 3.45

11 Simple Squamous Parched Earth

12 2. Simple cuboidal Single layer of cubelike cells Common in glands and their ducts Forms walls of kidney tubules Covers the ovaries Figure 3.17b Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 3.46

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14 I am a pancreas cross section by the way

15 3. Simple columnar Single layer of tall cells Often includes goblet cells, which produce mucus Lines digestive tract Look how tall we are. Figure 3.17c Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 3.47

16 Don t our nuclei look small compared to how big we are??? Look how our nuclei line up in neat tidy rows

17 But now comes the tricky little buggers

18 4.Pseudostratified Single layer, but some cells are shorter than others Nuclei are scattered. Sometimes ciliated, such as in the respiratory tract May function in absorption or secretion Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 3.48

19 CILIA

20 Stratified Epithelium 1. Stratified squamous Cells at the free edge are flattened Protective covering where friction is common Locations: Skin Mouth Esophagus Figure 3.17e Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 3.49

21 Notice we are flat (squamous) at the free edge

22 Stratified Epithelium 2. Stratified cuboidal Two layers of cuboidal cells 3. Stratified columnar Surface cells are columnar, cells underneath vary in size and shape Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 3.50

23 Stratified Epithelium 4.Transitional epithelium Shape of cells depends upon the amount of stretching Lines organs of the urinary system Figure 3.17f Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 3.51

24 2? 1? 3?

25 1. Stratified cuboidal 2. Stratified cuboidal 3. Stratified columnar

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27 Glandular Epithelium

28 Connective Tissue Found everywhere in the body (b/c it connects stuff together). Functions: 1. Binds body tissues together 2. Supports the body 3. Provides protection Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 3.53

29 You with connective tissue!!!

30 You without connective tissue!!!

31 Connective Tissue Types 1. Bone 2. Cartilage a. Hyaline b. Fibrocartilage c. Elastic 3. Dense Connective Tissue Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings 4. Loose Connective Tissue: a. Areolar b. Adipose c. Reticular d. Blood Slide 3.58a

32 Remember- the point of connective tissue is to CONNECT STUFF. But how does it connect tissues together? Hint: another characteristic of connective tissue:

33 Muscle Tissue: Functions: -produce movement -maintain posture -generate heat -offer protection I m little, but my muscles make me quick!!! Three types 1.Skeletal muscle 2.Cardiac muscle 3.Smooth muscle Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 3.64

34 Muscle: skeletal Skeletal muscle Can be controlled voluntarily, to move skeleton Cells attach to bone (connective tissue). Cells are striated (striped) Cells have more than one nucleus Figure 3.19b Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 3.65

35 Muscle: Cardiac Cardiac muscle Found only in the heart walls. Function is to pump blood (involuntary). Cells attached to other cardiac Intercalated discs are where??? muscle cells at intercalated disks (allow cells to quickly pass ions) Cells are striated One nucleus per cell Figure 3.19c Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 3.66

36 Muscle: Smooth Smooth muscle Surrounds hollow organs(stomach, blood vessels, uterus) Ex. Peristalsis: movement of food through digestive tract. Attached to other smooth muscle cells No visible striations One nucleus per cell Figure 3.19a Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 3.67

37 Nervous Tissue Made of: neurons and nerve support cells Composes: brain, spinal cord, nerves) Function: sends electrochemical impulses to other areas of the body Figure 3.20 Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 3.68

38 This is a Pap smear. The cytologic features of normal squamous epithelial cells can be seen at the center top and bottom, with orange to pale blue plate-like squamous cells that have small pyknotic nuclei. The dysplastic cells in the center extending to upper right are smaller overall with darker, more irregular nuclei.