1. Histology

2. Do Now: Don’t forget your clickers!
Use your book to answer the following questions in your notebook:
What are tissues?
What is the study of tissues?
What are the 4 main tissue types?

3. 4 Types of Tissues Neural Muscle Epithelial Connective
Human Body Tissues
Epithelial
Connective
Muscle
Neural

4. Epithelial Tissues To the lab tables! Materials: Microscopes Slides
Observation table
Pen/pencil

5. What are Epithelial Tissues?
Structure
Cover internal and external surfaces
Close together
Avascular
Easily regenerated
Life span: 1-2 days
Basement membrane: attaches epithelia to underlying connective tissue
Made of protein fibers
Functions
Protection
Permeability
Secretion
Exocrine glands

6. Epithelial Surfaces Basolateral Surface Apical Surface
Attached to underlying cells or tissues
Sides of the cell
Apical Surface
Microvilli
Increase surface area
Absorption and secretion
Cilia
Beat to move materials across the surface
Apical Surface
Basolateral Surface

7. Squamous Epithelium Simple Squamous Stratified Squamous
Shape: thin, flat cells; 1 layer
Function: diffusion; filtration
Found: forms capillary walls; lines air sacs in lungs
Stratified Squamous
Shape: thin, flat cells; multiple layers
Function: protection
Found: skin surface; lines tongue, mouth, esophagus, & anus

8. Cuboidal Epithelium Simple Cuboidal Stratified Cuboidal
Shape: box-shaped; 1 layer
Function: secretion; absorption
Found: covering the surface of ovaries; lining kidney tubules, salivary ducts, & pancreatic ducts
Stratified Cuboidal
Shape: box-shaped; multiple layers
Function: strengthen lumen walls
Found: ducts of large sweat glands, salivary glands, & pancreas

9. Columnar Epithelium Simple Columnar Pseudostratified Columnar
Shape: tall, rectangular; 1 layer
Function: absorption, secretion, & protection
Found: lines stomach, intestinal tract, excretion ducts, gall bladder
Pseudostratified Columnar
Shape: single layer, irregularly shaped (looks like multiple layers)
Function: protection, secretion
Found: lining respiratory passageways & auditory tubes

10. Transitional Epithelium
Shape: Numerous layers of rounded cells
Function: withstands stretching
Found: lines urinary bladder and portions of ureters & urethra

11. 4 Types of Tissues Neural Muscle Epithelial Connective
Human Body Tissues
Epithelial
Connective
Muscle
Neural

12. Connective Tissues To the lab tables! Materials: Microscopes Slides
Observation table
Pen/pencil

13. What are Connective Tissues?
Structure
Highly vascular
3 Components:
Cells
Protein Fibers
Ground Substance
Functions (lots of variation!)
Support & Protect – framework
Transport materials – fluid with dissolved materials
Energy reserve – fat in adipose tissue
Defense – responds to pathogens by releasing antibodies
Protection of organs

14. 3 Types of Connective Tissues
Connective Tissue Proper
Syrupy ground substance
Ex: Loose (areolar, adipose) & Dense (ligaments, tendons)
Fluid Connective Tissue
Cells suspended in watery ground substance with dissolved proteins
Ex: Blood & Lymph
Supporting Connective Tissue
Dense ground substance
Closely packed fibers
Ex: Cartilage (hyaline, elastic, fibrocartilage) & Bone

15. 1. Connective Tissue Proper – Cell Types
Fibroblasts
Produce and maintain connective tissue fibers & ground substance
Permanent
Local maintenance & repair
Macrophages
Defense: Engulf pathogens & damaged cells
Release chemicals to stimulate immune response
Fixed or migrating (reinforcement)
Adipocytes
Fat cells
Nuclei & organelles pushed to the side

16. 1. Connective Tissue Proper – Fiber Types
Collagen
Long, straight, unbranched
Flexible
Elastic
Protein – elastin
Wavy, branched, stretchy

18. 1. Connective Tissue Proper – Loose Connective Tissue
Areolar Tissue
Contains all cells and fibers of connective tissue proper
Separates skin from muscles
Provides padding
Allows movement
Extensive blood supply
Adipose Tissue
Adipose (fat) cells
Behind eyes, kidneys, heart, abdomen, buttocks, & breasts

19. 1. Connective Tissue Proper – Dense Connective Tissue
Mostly collagen
Regular – collagen fibers are parallel
Tendons – connect skeletal muscle to bone
Ligaments – connect bone to bone, contain elastin

20. 2. Fluid Connective Tissue
Blood
Plasma – watery matrix with dissolved proteins
Red Blood Cells
White Blood Cells
Platelets
Lymph
Interstitial fluid (water & solutes) enters lymphatic vessels

21. 3. Supporting Connective Tissue - Cartilage
Cartilage – gel with embedded fibers
Chondrocytes – cells found in lacunae
Difficult to repair – no blood vessels
3 Types:
Hyaline – closely packed fibers, tough but flexible
Connects ribs to sternum, supports trachea of respiratory tract, covers bone surfaces in joints
Elastic – elastic fibers, very flexible
External flap of outer ear, epiglottis, auditory tube
Fibrocartilage – little ground substance, collagen fibers, durable & tough
Between vertebrae, between pubic bones, around or within some joints

22. Hyaline Cartilage
Elastic Cartilage
Fibrocartilage

23. 3. Supporting Connective Tissue - Bone
Osseous Tissue – bone
Matrix – hard calcium & flexible collagen
Little ground substance
Osteocytes found in lacunae
Lacunae surrounded by blood vessels
Canaliculi extend from central canal

24. 4 Types of Tissues Neural Muscle Epithelial Connective
Human Body Tissues
Epithelial
Connective
Muscle
Neural

25. What are Muscle Tissues?
Specialized for contraction
3 Types:
Skeletal Muscle – striated, voluntary muscle
Large multinucleated cells (long & slender)
Striations (series of bands)
Cardiac Muscle – striated, involuntary muscle
Smaller striated cells, one nucleus
Interconnected by intercalated discs
only found in the heart
Smooth Muscle – nonstriated, involuntary muscle
Small, slender cells with one nucleus
walls of blood vessels, hollow tube-like organs

26. 4 Types of Tissues Neural Muscle Epithelial Connective
Human Body Tissues
Epithelial
Connective
Muscle
Neural

27. What are Neural Tissues?
Specialized for conducting electrical impulses
Neurons – communicate through electrical events
Long cell with 3 main parts
Cell body with nucleus
Dendrites – branching projections that receive info
Axon – long projections (with synaptic terminals) that relay signals to other cells
Limited ability to repair

28. 4 Types of Tissues Neural Muscle Epithelial Connective
Human Body Tissues
Epithelial
Connective
Muscle
Neural

29. Tissue Injury & Repair Inflammation
In response to pathogens, impact, abrasion, extreme temperatures, or chemical irritation
Mast cells release chemicals (i.e. histamine) that dilate blood vessels to induce swelling, redness, heat, & pain
Regeneration
Fibroblasts produce dense collagen fibers called fibrous tissue (aka scar tissue)