1. Tissues
Tissue = A collection of cells that perform related functions, and are similar in structure
Histology = The study of tissues
The Four Primary Tissue Types
Epithelial
Connective
Muscular
Nervous

2. Epithelial Tissue Epithelium / -a = cell layer (barrier)
Protection: covering or lining—inside and out
Permeability control: selective secretion and absorption
Sensation: touch receptors etc. and neuroepithelium of special senses
Glands = secretory structure
Specialized secretions

3. Structural Characteristics of Epithelia
apical
Cellularity
Cell to cell contacts
Polarity
Support by connective tissue
Avascular (esp. skin)
Regeneration/repair
basal BM

4. Polarity of Epithelial Cells

5. Classification of Epithelia
The function of the epithelium determines which type.
Typically classified according to 1. Number of cell layers Simple vs. Stratified 2. Shape of cell Squamous, cuboidal, columnar

6. Simple Squamous Epithelium
Location:
Lining of ventral body cavities, e.g. peritoneum
Lining of blood vessels (endothelium)
Alveoli

7. Lung

8. Function of Simple Squamous E.
Friction reduction (cavity lining)
Blood vessel permeability control (capillaries)
Gas absorption and secretion (lung)
Not very protective—only one cell thick

9. Simple Cuboidal Epithelium
Function:
Secretion
Absorption
Location:
Lining of ducts
Glands (salivary, pancreas, thyroid)
Kidney tubules

10. Thyroid Follicle

11. Simple Columnar Epithelium
Function:
Secretion
Absorption
Location:
GI tract
Many excretory ducts

13. Pseudostratified Ciliated Columnar Epithelium
Function: Mucociliary Blanket
Mixture of cell types  nuclei located at various distances from surface. Yet: all cells contact BM
Location: Respiratory tract except for lungs

16. Stratified Squamous Epithelium
Function Protection against abrasion, pathogens, chemicals, heat/cold…
Keratinized vs. non-keratinized
Location ? Where we need protection!
Skin surface
Entrances/exits of body, e.g. mouth, vagina

19. Stratified cuboidal and columnar:
quite rare, found in glands and ducts
Sweat gland

20. Transitional Epithelium
Function ?
Extreme expansion & recoil
Layered appearance due to overcrowding. All cells contact BM.
Location ?
Bladder, ureters, renal pelvis

21. stretched

23. Glandular Epithelia Types of Glandular Secretions: Exocrine Endocrine
Glands have ducts
Secretion to the “outside” of the body
Simple or compound
Endocrine
Glands have no ducts
Hormones (into the bloodstream)

24. Location in the Body

26. Connective Tissue: Supports, protects, binds tissues
Structural characteristics:
Specialized cells
Extracellular protein fibers (collagen)
Ground substance (fluid-like)
extracellular matrix

27. Functions of C.T. Structural framework for body (p77)
Transport of fluids and dissolved materials
Support and protection for organs
Energy storage (fat)
Defense

28. Classification of C.T.
C.T. proper (viscous matrix with fibrous, insoluble proteins)
Areolar (loose), reticular, dense, adipose
Supporting C.T. (gelatinous or solid matrix)
Cartilage, bone
Fluid C.T. (watery matrix with dissolved proteins)
Blood, lymph

29. Classification of Connective Tissue

30. Connective Tissue Proper. - viscous matrix
Connective Tissue Proper - viscous matrix -Includes loose, reticular, dense C.T.
Types of Fibers:
Collagen Elastic Reticular
Defense:
Macrophages Plasma Cells Mast Cells Other WBC
Think about dermis

31. Fluid C. T.
Blood (Ch 17)
Lymph (Ch 20)

32. Supporting C.T. Cartilage Bone (Chapter 5) Hyaline, cells in lacunae
Articular cartilage, symphysis pubis
Elastic
Ear, larynx
Fibrocartilage
Intervertebral discs
Bone (Chapter 5)
Mineral matrix

33. Study individual types of c.t. in lab

34. Membranes = Combination of Epithelia & C.T.
Mucous membranes,
Lining of cavities that communicate with exterior
Serous membranes,
Lining of sealed, internal cavities
Cutaneous membranes,
Skin

35. Membranes, cont’d
Know special names of serous membranes depending on location
Also know difference between “parietal” and “visceral”

36. Mucous vs. Serous Membrane

37. Cutaneous & Synovial Membranes

38. C.T. Framework of Body
Also: Hypodermis
or subcutaneous layer

39. Muscle Tissue Three types:
Skeletal
Cardiac
Smooth (not striated)

40. Skeletal Muscle Voluntary Heavily striated Multinucleate
periphery of the cell

41. Cardiac Muscle Heart (Only) Involuntary Striated Intercalated disks
Heavily branched
Single central nucleus

42. Smooth Muscle Involuntary Esp. digestive system No striations
Very slow
Single central nucleus

43. Nervous Tissue (ch 12) Neurons Neuroglia Transmit electrical impulses
Supportive cells of the nervous system

44. Neural Tissue