Unit 2 Flashcards
Functions of Epithelial Tissue
-Protection (stratified provides protection) -Absorption -Filtration -Secretion
Epithelium
-Cells fit closely together and often form in sheets -The apical (top) surface is the free surface of the tissue -The lower surface of the epithelium rests on a basement membrane -Avascular (no blood supply) -Regenerate easily if well nourished (every 6 weeks)
Classification of Epithelia
Number of cell layers -Simple: one layer -Stratified: more than one layer -Shape of cells -Squamous -Flattened -Cuboidal -cube-shaped -Columnar -column-like
Simple Squamous
-Single layer of flat cells -Usually forms membranes -Lines body cavities -Lines lungs and capillaries
Simple Cuboidal
-Single layer of cube-like cells -Common in glands and their ducts -Forms walls of kidney tubules -Covers the ovaries
Simple Columnar
-Single layer of tall cells -Often includes mucus-producing goblet cells -Lines digestive tract
Pseudo-Stratified Columnar
-Single layer but some cells are shorter than others -Often looks like a double layer of cells -Sometimes ciliated, such as in the respiratory tract -Many function in absorption or secretion -Nuclei tend to be in upper or lower
Stratified Squamous
-Stratified squamous -Cells at the apical surface are flattened -Found as a protective covering were friction is common -Locations: -Skin: outer layer epidermis -Mouth -Esophagus
Stratified Cuboidal & Stratified Columnar
-Stratified cuboidal-two layers of cuboidal cells -Stratified columnar: surface cells are columnar, cell underneath vary in size and shape -Rare in human body -Found mainly in ducts and large glands -Oviducts -Cystic -Bile duct -Pancreatic Duct
Transitional Epithelium
-Shape of cells depends upon the amount of stretching -Lines organs of the urinary system- 250 ml
Glandular Epithelium
-Gland -One or more cells responsible for secreting a particular product -Two major gland types -Endocrine gland - Ductless since secretions diffuse into blood vessels -All secretions are hormones -Exocrine gland -Secretions empty through ducts to the epithelial surface -Includes sweat and oil glands (salivary, gastric)
Endocrine vs. Exocrine System (Types of Glandular Tissue)
-Ductless vs. Duct -Hormones vs Juice -Bloodstream vs Locally -Target vs Locally
Locations of Epithelial Tissue
-Body covering -Body lining -Glandular tissue
Connective Tissue Functions
-Found everywhere in the body -Includes the most abundant and widely distributed tissues -Functions: -Binds body tissues together -Supports the body -Provides protection
Connective Tissue Characteristics
-Variations in blood supply -Some tissue types are well vascularized -Some have a poor blood supply or are avascular (cartilage) -Extracellular matrix -Non-living material that surrounds living cells
Extracellular Matrix
-Two main elements -Ground substance: -Mostly water along with adhesion proteins and polysaccharide molecules -Fibers -Produced by the cells -Three types -Collagen (white) fibers -Elastic (yellow) fibers -Reticular fibers
Bone (Type of Connective Tissue)
1.Osteocytes 2.Osteoblast (bone forming) 3.Osteoclast (bone absorption) -Composed of: -Bone cells in lacunae (cavities) -Hard matrix of calcium salts -Large numbers of collagen fibers -Used to protect and support the body
Hyaline Cartilage (Types of Connective Tissue)
Name for cartilage cell: chrondocyte -Most common type of cartilage -Composed of: -Abundant collagen fibers -Rubbery matrix -Locations: -Larynx -Entire fetal skeleton prior to birth
Elastic Cartilage (Types of Connective Tissue)
-Provides elasticity -Location: -Supports the external ear
Fibrocartilage (Type of Connective Tissue)
-Highly compressible -Location: -Forms cushion-like discs between vertebrae
Dense Connective Tissue (Dense Fibrous Tissue) *Type of Connective Tissue
-Dense Fibrous Tissue -Main matrix element is collagen fiber -Fibroblasts are cells that make fibers -Locations: -Tendons: Attach skeletal muscle to bone -Ligaments: Attach bone to bone joints -Dermis: Lower layers of the skin (under the Epidermis)
Areolar Tissue (Type of Connective Tissue) *Loose Connective Tissue
- Loose Connective Tissue
- Most widely distributed connective tissue
- Soft, pliable tissue like “cobwebs”
- Functions as a packing tissue
- Contains all fiber types
- Can soak up excess fluid (causes edema/ swelling)
Adipose Tissue (Connective Tissue) * Loose Connective Tissue
-Loose Connective Tissue Matrix is an areolar tissue in which fat globules predominate -Many cells contain large lipid deposits -Functions: -Insulates the body -Protects some organs -Serves as a site of fuel storage
Reticular Connective Tissue (Type of Connective Tissue) *Loose Connective Tissue
-Loose Connective Tissue -Delicate network of interwoven fibers -Forms stroma (internal supporting network) of lymphoid organs -Lymph nodes -Spleen -Bone marrow
Blood (Vascular Tissue) *Type of Connective Tissue, Loose Connective Tissue
-Loose Connective Tissue -Blood cells surrounded by fluid matrix called blood plasma -Fibers are visible during clotting -Functions as the transport vehicle for materials
Muscle Tissue
-Function is to produce movement -Three types -Skeletal Muscle -Cardiac Muscle -Smooth Muscle
- Skeletal Muscle Tissue
Where: Attached to bones Appearance: Striated Shape: Long Columnar Action: Voluntary Nucleus: Multi-nucleated Rhythmic: Non-rhythmic Intercalated Discs: No Speed of Contraction: Slow to Fast
- Smooth Muscle Tissue
Where: Visceral (Internal Organs) Appearance: Non-striated Shape: Tapered point Action: Involuntary Nucleus: Uni Rhythmic: Either due to Blood Vessels (related to heart) Intercalated Discs: No Speed of Contraction: Slower
3.Cardiac Muscle Tissue
Where: Heart Appearance: Striated Shape: Branching Y Action: Involuntary Nucleus: Uni-Bi Rhythmic: Rhythmic Intercalated Discs: Yes Speed of Contraction: Slow
Nervous Tissue
Composed of neurons and nerve support cells -Function is to send impulses to other areas of the body -Irritability -Conductivity: Afferent neurons (in)- pickup interneurons: connected- central - Spinal cord- brain Efferent neurons : out- actions- gland or muscle Neurons= transmission Neuroglial: protect brain
Tissue Repair (Wound Healing)
-Regeneration: -Replacement of destroyed tissue by the same kind of cells (Mitosis) -Fibrosis: -Repair by dense (fibrous) connective tissue (scar tissue) -too much collagen creates scar tissue -Determination of method: -Type of tissue damaged -Severity of the injury
Events in Tissue Repair
-Capillaries become very permeable -Introduce clotting proteins -A clot walls of the injured area -Formation of granulation tissue -Growth of new capillaries -Rebuild collagen fibers -Regeneration of surface epithelium -Scab detaches
Regeneration of Tissue
-Tissues that regenerate easily -Epithelial Tissue (skin and mucous membranes) -Fibrous connective tissues and bone -Tissues that regenerate poorly -Skeletal muscle -Tissues that are replaced largely with scar tissue -Cardiac muscle -Nervous tissue within the brain and spinal cord
Developmental Aspects of Tissue
-Epithelial tissue arises from all three primary germ layers -Muscle and connective tissue arise from the mesoderm(middle layer) -Nervous tissue arises from ectoderm (outside layer) -With old age, there is a decrease in mass and viability in most tissues
Hypertrophy vs. Atrophy
-Atrophy: Loss of muscle tone -Hypertrophy: Increase density of muscle
