BIO FINAL REVIEW

Tissues

1. Epithelial tissue
-Covers and protects surfaces both inside and outside the body.
-Protecting underlying structures
-Acting as barrier
-Permitting the passage of substances
-Secreting substances
-Absorbing substances

2. Connective tissue-
-Most abundant
-Enclosing and separating other tissues
-Connecting tissues to one another
-Supporting and moving parts of body
-Storing compounds
-Cushioning and insulating
-Transporting
-Protection

3. Muscle tissue
-Skeletal muscle- moves the body(conscious,voluntary)
-Cardiac muscle- provides the major force for moving blood through the blood vessels(unconscious,involuntary)
-Smooth muscle-moves food through digestive tract, empties urinary bladder, controls glands(unconscious,involuntary)

4. Nervous tissue
-Conduct action potentials
-Neurons-transmits electrical signals throughout the body.
-Neuroglia-support cells

Epithelial Tissue

Dominant component of Epithelial Tissue
-Mostly composed of cells with very little extracellular matrix between them.

Characteristics:
A. Mostly composed of cells, very little extracellular matrix between them.
B. Covers body surfaces and form glands. - Cover exterior surface
- Lining of the: digestive tract, respiratory tract, heart, blood vessels and many body cavaties
C. Distinct cell surfaces -Free(apical)surface-not attached to other cells -Lateral surface-attached to other epithelial cells -Basal surface-attached to basement membrane
D. Cell and matrix connections -Epithelial cells bind together and to extracellular matrix of basement membrane.
E. Nonvascular -No blood vessels -Nutrients and gases carried in blood must diffuse through basement membrane.
F. Capable of regeneration -Mitosis replaces old epithelial cells with new ones. -Stem cells(Undifferentiated) divide to produce new cells. Types of Epithelium Tissues 1.Simple Squamous
-Single layer of flat scale like cells
-diffusion, filtration
-lining of blood vessels and heart 2. Simple Cuboidal -Single layer of cube shaped cells -secretion and absorption -kidney tubules, glands and ducts 3. Simple Columnar -Single layer of tall narrow cells -Movement of particles out of bronchioles of lungs by ciliated cells -Glands and ducts, bronchioles of lungs

4. Stratified Squamous -Multiple layers of flat like cells towards the membrane but flat and scale like toward surface -Protection against abrasion and infections -Primarily in skin-keratinized -in mouth- non-keratinized

5. Stratified Cuboidal -Multiple layers of cube shaped cells -Secretion and absorption -Sweat glands, salivary ducts

6. Stratified Columnar -Multiple layer of tall, thin narrow cells -Protection -Mammary glands

7. Pseudostratified Columnar -Single layer of cells, some cells are tall and thin and reach the surface -nuclei of cells are at different levels and appear stratified -Secrete mucus to free surface with cilia -Lining of nasal cavity 8. Transitional Epithilium -Stratified cells that appear cube shaped when organ is not stretched and squamous when organ is stretched by fluid. -Urinary bladder

GLANDS:
Merocrine Gland
-Products are released but no cellular material is lost
-Occurs either by active transport or packaged into vesicles and released by exocytosis.
-Sweat secretion

Apocrine Gland
-Products are released as fragments of gland cell
-Secretory products are retained within the cell, and portions of the cell are pinched off to become part of the secretion.
-Milk secretion

Holocrine Gland
-Involves the shedding of the entire cells
-Products accumulate in the cytoplasm of each epithelial cell, the cell ruptures and dies, and entire cell becomes part of secretion.
-Sebacious gland (oil) secretion
CELL CONNECTIONS:

Tight Junctions
-hold cells together and form a permeability barrier

Gap Junctions
-small, specialized contact region between cells containing protein channels
-communication by allowing ions and small