Tissues Flashcards
Epithelial Tissue
-covers exposed surfaces ( skin )
-lines hollow organs, internal passageways and ducts ( digestive tract, urinary tract, reproductive)
-forms glands
Connective Tissue
-material found between cells
-supports and binds structures together
-stores energy as fat
-provides immunity to disease
Muscle Tissue
-cells shorten in length producing movement
-Two types: Voluntary – skeletal
- Involuntary – Cardiac and smooth
Nerve Tissue
-cells that conduct electrical signals
-detects changes inside and outside the body
Epithelial Tissue – General Features
Cellularity – composed almost entirely of cells
Special contacts – form continuous sheets held together by tight junctions and desmosomes
Polarity – apical and basal surfaces
Basement membrane– supported by connective tissue; reticular and basal laminae
Avascular – contains no blood vessels but supplied by nerve fibers
Regeneration – rapidly replaces lost cells by cell division
Functions
Physical protection – protects exposed and internal surfaces from abrasions, dehydration, and destruction from chemical agents.
Absorption – The lining of the gut and respiratory tract allow for nutrients to be absorbed from the gut and the exchange of gases between air in lungs and blood.
Excretion- The unique lining of the kidney tubules makes the excretion and concentration of excretory products in the urine possible.
Produces secretions – Glandular epithelial is adapted for secretory activity (hormones, mucus, digestive juices, and sweat)
Provides sensation – good nerve supply- sensory nerves of eyes, ears, nose, skin.
Specialized Epithelium – a) Microvilli – absorption/secretion – found in digestive and urinary tracts b) Cilia – Respiratory tracts, the synchronized beating moves mucous up from lungs to throat
Types of Epithelium
Covering and lining epithelium
-epidermis of skin
-lining of blood vessels and ducts
-lining respiratory, reproductive, urinary & GI tract
Glandular epithelium
-secreting portion of glands
-thyroid, adrenal, and sweat glands
Classified by arrangement of cells
simple = one cell layer thick.
stratified = more than one layer thick. Located where protection from mechanical or chemical stresses are needed. ( skin , mouth )
*pseudostratified = single layer of cells where all cells don’t reach apical surface
Classified by shape of surface cells
squamous =flat
cuboidal = cube-shaped
columnar = tall column
Simple Squamous Epithelium
lining ventral body cavities; lining heart and blood vessels; alveoli of lungs; inner lining of cornea
Simple Cuboidal Epithelium
Glands, ducts, portion of kidney tubules
Simple Columnar Epithelium
Lining of stomach, intestine, gall bladder, uterine tubes.
Stratified Squamous Epithelium
Surface of skin (epidermis); lining of mouth, throat, esophagus, rectum, anus and vagina.
Stratified Cuboidal Epithelium(rare)
Linings of sweat gland ducts and seminiferous tubule in testis.
Stratified Columnar Epithelium (rare)
small areas of pharynx, limited areas of larynx, anal canal, and male urethra
Pseudostratified Ciliated Columnar Epithelium
Lining of nasal cavity, trachea (windpipe), bronchi, portion of the male
Transitional Epithelium
Urinary bladder, ureters, umbilical cord
Connective Tissue classes
Loose, dense, blood, lymph, cartilage, bone
Connective Tissue Functions
1) structural framework – bones, tendons, ligaments
2) transports fluids and dissolved materials – blood
3) protects delicate organs
4) stores energy reserves especially in the form of lipids – adipose
5) defends body from invading microorganisms – WBC’s
Types of cartilage
hyaline cartilage
fibrocartilage
elastic cartilage
