1. BODY TISSUES

2. FUNDAMENTALS
Tissue: a group of similar cells that work in a coordinated way to carry out specific and limited functions
Group of tissues form organs
Histology: the study of tissue
Types of Tissue
Epithelial
Connective
Muscle
Neural

3. EPITHELIAL Functions Only tissues visible on the body
Covers exposed surfaces
Lines internal passageways
Produces glandular secretions
Provide physical protections against abrasion, dehydration, or destruction
Regulate permeability
Provide sensory feedback
Only tissues visible on the body

4. CLASSIFICATION OF EPITHELIA
Squamous
Irregularly shaped, flat, scale- like
Cuboidal
Cube shape, large nuclei
Columnar
Tall
Simple vs. Stratified
Transitional: special kind of stratified epithelium with cells of different shapes that permit tissue to stretch and recoil
Pseudostratified: all cells touch the basal lamina, but the cells grow to different height
CLASSIFICATION OF EPITHELIA

5. SQUAMOUS Most delicate type Cells are close together No blood vessels
Functions
Reduces friction
Controls vessel permeability
Performs absorption and secretion
Endothelium in blood vessels and inner surface of heart chambers
Location:
Air sacs of the lungs
Lining of thoracic and abdominopelvic body cavities
Lining of heart and blood vessels
SQUAMOUS

7. Provides limited protection and occurs where secretion or absorption takes place
Location:
Kidney tubules, thyroid, glands, and ducts
CUBOIDAL

8. COLUMNAR Appear rectangular, tall, and slender Elongated nuclei
Locations:
Lining of the stomach, intestine, gallbladder, uterine tubes, and collecting ducts of kidneys
COLUMNAR

9. TRANSITIONAL Functions Stratified Locations Urinary bladder
Permits expansion and recoil after stretching
Called transitional because the appearance of the epithelium changes as stretching occurs
Stratified
Locations
Urinary bladder
Accommodates the changing volume of urine
Renal pelvis
Ureters
TRANSITIONAL

10. PSEUDOSTRATIFIED COLUMNAR
Columnar epithelium that includes several types of cells with varying shapes and functions
Epithelium appears layered
But is NOT stratified
Every cell touches the basal lamina
Have cilia*
Locations:
Nasal cavity
Trachea
Bronchi
Male reproductive tract
PSEUDOSTRATIFIED COLUMNAR

11. CONNECTIVE TISSUE Connects the epithelium to the rest of the body
Provides structural support
Types
Bone – provide structure
Fat – provide energy
Blood – transports material throughout the body
Matrix: protein fibers + ground substance
Matrix determines the physical nature of the tissue
Fibers can be: elastic, collagen, reticular

12. CLASSIFICATION
Mesenchyme: unspecialized tissue where all connective tissue is derived from in the embryo
No visible protein fibers in its ground substance
Mucous connective tissue aka Wharton’s jelly found only in the umbilical cord
Connective Tissue Proper
Thick liquid matrix and a variety of cell types
Blood
Liquid tissues that flow through blood vessels and lymph vessels
Cartilage and Bone
Strong gel-like or solid that acts as support

13. CONNECTIVE TISSUE PROPER
Contains varied cell population & extracellular fibers
Function: protect, support, insulate, and bind together other tissues
Loose Connective Tissues
Dense Connective Tissues

14. CTP: LOOSE CONNECTIVE TISSUE CELLS
Aerolar Tissue
Adipose Tissue
Reticular Tissue

15. AREOLAR TISSUE Distributed throughout the body
Forms a layer that separates the skin from deeper structures
Contains elastic fibers which makes it resilient
Also contains collagen fibers
Provides support but permits independent movement
Cushions organs
Permits muscles to move freely without pulling on the skin
Locations
Deeper dermis layers
Covered by epithelial lining of the digestive, respiratory, and urinary facts
Between muscles
Around blood vessels, nerves, and around joints
AREOLAR TISSUE

16. ADIPOSE TISSUE Fat cells Functions
Provides padding, shock absorption & insulation
Energy storage (lots of mitochondria)
Also serves as packing or filler around structures
Abundant under the skin and in the buttocks, breasts, and abdomen
Key feature*: displacement of the nucleus and cytoplasm due to the storage of lipids
In adults, these adipocytes cannot divide
Why liposuction fails?
ADIPOSE TISSUE

17. Forms internal supporting framework for soft organs such as spleen, liver, and lymphatic organs
Also found in lymph nodes and bone marrow
RETICULAR TISSUE

18. CTP: DENSE CONNECTIVE TISSUE
Collagen fibers are most abundant
Often called collagenous tissues
Types
Dense regular connective tissue
Dense irregular connective tissue
Elastic tissue

19. DENSE REGULAR CONNECTIVE TISSUE
Protein fibers are parallel
Collagen fibers are interspersed
Functions
Provides firm attachment
Conducts pull of muscles
Reduces friction between muscles
Stabilizes relative positions of bones
Locations
Between skeletal muscles (tendons – attach muscles to bones)
Between bones or stabilizing internal organs (ligaments – support adjacent bones)
Deep fasciae that cover and isolates muscles from surrounding structures
DENSE REGULAR CONNECTIVE TISSUE

20. DENSE IRREGULAR CONNECTIVE TISSUE
Mesh of collagen fibers and interspersed fibroblasts
Functions
Provides strength to resist forces applied from many directions
Helps prevent overexpansion of organs such as the urinary bladder
Forms a thick fibrous capsule which surrounds internal organs and encloses the cavities of joints
Locations
Capsules of visceral organs
Membrane surrounding bones and cartilage
Nerve and muscle sheaths
Dermis (below the epidermis)
DENSE IRREGULAR CONNECTIVE TISSUE

21. FLUID CONNECTIVE TISSUES
Includes blood & lymph tissues
Blood is composed of cells called formed elements, supported in a liquid ground substance called plasma
Three types of formed elements
Red blood cells (erythrocytes)
Transport blood gases (i.e. CO2 and O2)
White blood cells (leukocytes)
Immune system cells and protect body from infection
Platelets
Injury mediators via the blood clotting response
When a blood vessel becomes damaged, platelets aggregate and form a plug to stop the bleeding
Most common cells in lymphatic system are lymphocytes (leukocytes formed in lymph tissue)

22. SUPPORTING CONNECTIVE TISSUE
Includes cartilage & bone
Cartilage – rubbery, avascular, with a gel-like matrix
Bone – solid matrix of calcium phosphate and calcium carbonate
Provides strong framework that supports the rest of the body
Bone: structural support, bone cell formation
Cartilage: tensile strength with ability to absorb compressive shock

23. MUSCLE TISSUE Skeletal Cardiac Smooth Attached to skeleton
Contraction involves movement of body parts
Voluntary movement
Cardiac
Found only in the heart
Striated
Contains “gap junctions”
Involuntary
Propels blood into vessels
Smooth
Found in walls of hollow organs (digestive /urinary tract organs, blood vessels)
No striations
Propels substances (food, urine) or a baby along internal passageways!

24. NERVOUS TISSUE Neurons Neuroglia
Communicating cells that have the ability to send and receive electrical signals
Neuroglia
Specialized cells that support, protect, and insulate neurons