Chapter 5Tissues
Intercellular Connections
• Individual cells connect to form tissues 3 ways:– Tight junctions-
– Desmosome- adhesion between cells in spots. Allows from some permeability.
– Gap junctions- cytoplasms of adjacent cells are connected through transport proteins. • Ions can pass freely through cells.
Intercellular Connections
Tissue TypesA tissue is a group of cells with a common
structure & functionThe human body is composed of four
main tissue types:
1. 2. Connective 3. 4. Nerve
Epithelial Tissue
Epithelial Tissue
Characteristics Always has a free (apical) surface
exposed to outside or open space. Has a basement membrane to
anchor underlying tissue
Functions Covers body surfaces Protects Absorbs Excretes
Classified by Shape Squamous – Cuboidal – Columnar –
Classified by ShapeMay occur in layers: Simple – Stratified – 2 or more layers Pseudostratified –
Example – simple cuboidal Example – stratified columnar
Examples of Epithelial Tissue
s
Simple Squamous- Thin, flattened cells. Allow for diffusion and filtration. Line air sacs of
lungs and walls of capillaries.
Simple cuboidal-single layer of cube shaped cells. Lines follicles of thyroid gland, kidneys and ducts of certain glands.
Simple columnar- single layer of elongated cells. Can contain cilia, used for protection and absorption in digestive tract.
Stratified squamous- Layers of squamous cells. Make up epidermis and line cavities exposed to external environment.
Stratified columnar- Several layers of columnar cells overlying cuboidal cells near the basement membrane.
Pseudostratified ciliated columnar- Appear stratified but are not. Often contain cilia and goblet cells which secrete mucus.
Pseudostratified ciliated columnarw/goblet cells- Line Respiratory passages to trap
unwanted particles
Transitional tissue- Changes in response to change in tension. Line urinary bladder and urethra.
Glandular Epithelium• Specialized to secrete substances•
• Those that secrete substances into ducts that open onto a surface are
• Those that secrete into tissues or blood are
Classifying Glands by Structure• Simple-
• Compound- duct that does branch before secretory portion.
Classifying Glands by Type of Secretions
3 types:
• • • Small portions of cells • in secretions• No loss of cytoplasm Ex. – mammary glands
in secretions• Ex. – pancreas
Classifying by Secretions
• Secretions w/entire cells filled w/secretoryproducts; ex. – sebaceous (oil) glands
Connective Tissue
Functions 1. connects 2. 3. protects 4. 5. fills spaces
Functions 6. stores fat 7. 8. protects against infection 9. 10.helps repair damaged tissue
Characteristics 1. Consists of cells in a matrix
(intercellular material) 2. Cells some distance apart 3. 4.
Types of Fibers:1. collagenous – composed of
collagen (protein); have great tensile strength; slightly elastic; compose bones, tendons & ligaments
Types of Fibers - continued
elastic – composed of elastin (protein); very elastic but weaker; compose vocal cords & air passages of lungs
Types of Fibers - continued Reticular – composed of very fine
collagenous fibers.
Types of Cells1. Fixed cells – stay in one place &
have stable numbers; 2 types:
fibroblasts – large & star-shaped; most prevalent
Types of Cells - continued mast cells – may release heparin
(for blood clotting) & histamines (promotes allergic reactions & inflammation); usually located near blood vessel walls
Types of Cells - continued2. Wandering cells – macrophages –
(Purple cells – macrophages, Green cells – T-lymphocytes)
Examples of Connective Tissue
Areolar tissue- binds the skin to underlying organs and under epithelium to provide bloodflow.
Adipose tissue- connective tissue composed of fats, cushion joints and provide insulation
Regular dense connective- strong fibers bind body parts together. Found in ligaments and tendons.
Irregular dense connective- disorganized and strong. Found in the dermis
Hyaline cartilage- Most common, found on ends of bones, nose cavity and supporting rings of resp. system.
Fibrocartilage- tough tissue containing collagenous fibers. Shock absorbers between vertebrae.
Elastic cartilage- flexible cartilage make up ears and larynx
Blood - platelets
Blood – red cells & white cell
Elastic connective
Reticular connective
Bone- A- central canal (contains blood vessels) B- Canaliculi- minute tubes allow for movement between cells.
Bone- D- Lamellae (layers of osetocytes), C- osteocytes
Muscle & Nerve Tissue
Muscle Tissue3 types: Skeletal-
Used for movement Smooth- lacks striations found in
skeletal, used for involuntary movements Ex- move food through digestive tract
Cardiac-
3 Types of Muscle Tissue
Smooth muscle- B- nucleus
Skeletal muscle- A- striations, B- nucleus
Cardiac muscle
Nervous Tissue
• Found in the brain, spinal cord and peripheral nerves.
• Cells called neurons–
• Also include neuroglia cells (support cells)– Support the function of the neurons
Nerve tissue – A- neuron, B- Axon, C- neuroglia