 Objective: ◦ To understand how cells combine to form tissues ◦ To differentiate between types of tissues  Journal: What are the levels of organization that are found in an organism?

Cells

 Cells are the smallest unit of life that can carry out all of the processes of life.  Some organisms are so simple, they are only made up of one cell  Humans are multicellular

1. ALL LIVING THINGS ARE COMPOSED OF ONE OR MORE CELLS. 2. CELLS ARE AN ORGANISMS’ BASIC UNIT OF STRUCTURE AND FUNCTION 3. CELLS COME FROM OTHER CELLS

 SIZE - Human cells are microscopic, but they vary in exact size  SHAPE - Most are cuboidal or spherical. ◦ The size is limited by ratio between surface area and volume. Supplies to support the volume must be able to enter and exit through the surface area of the cell membrane

 Cytoplasm  Nucleus  Cell Wall  Mitochondria  Cell Membrane

 Tissues differ from each other in size, shape and the kind of material between their cells  FOUR MAIN TYPES OF TISSUES 1. Epithelial - covers/lines body 2. Connective - most abundant - connects body part 3. Muscle - responsible for movement 4. Nervous - responsible for sending quick messages

 Packed closely together  Little or no intracellular material (matrix)  Form continuous sheets, contain no blood vessels

 Squamous – flat and scalelike  Cuboidal – cube shaped  Columnar – higher than they are wide

 Simple – single layer of cells of the same shape  Stratified – many layers of cells of the same shape  Transitional – several layers of cells of different shape

 FORM: ◦ Flat and scale- like ◦ Thin, irregular shape  FUNCTION: ◦ Absorption ◦ Substances can readily pass through  Ex: Oxygen absorbed into blood from lungs

 FORM: ◦ Several layers of closely packed, scale-like cells  FUNCTION: ◦ Protection  Ex: SKIN - protects against microorganisms ◦ Microbes can’t go through this type of tissue

 FORM: ◦ Single layer of cells that are higher than wide  FUNCTION: ◦ Absorption  Make up lining of stomach, intestines, some of respiratory and reproductive tract

 FORM: ◦ About 10 layers of cuboidal, a few layers of squamous  FUNCTION: ◦ Ability to stretch, withstand stress  Ex: Found in wall or urinary bladder, keeps bladder from tearing

 FORM: ◦ About 2 layers thick ◦ Have cilia to move mucous  FUNCTION: ◦ Protects lungs against dust, etc  Ex: Lining of trachea

 FORM: ◦ Single layer of cube shaped cells  FUNCTION: ◦ Allow for secretions  Ex: saliva, digestive juices, sweat, hormones

 Most abundant and widely distributed  Many different forms ◦ Found in skin, membranes, muscles, bones, nerves, and all internal organs

 FORM: ◦ Delicate webs of fibers and cells in a loose matrix of soft, sticky gel  FUNCTION: ◦ “glue” that gives the form to internal organs ◦ Provides strength, elasticity and support  Most widely distributed ◦ Found around blood vessels, nerves, organs; in mucus membrane; subcutaneous layer

 FORM: ◦ Large storage cells  FUNCTION: ◦ Stores lipids (fats), insulation, protection, energy reserve, generates heat in newborns  Found around organs, in yellow marrow, in subcutaneous layer

 FORM: ◦ Bundles of strong, white collagen fibers(for flexibility) in parallel rows  FUNCTION: ◦ Flexible and strong connections  Makes up tendons, ligaments, scar tissue

 FORM: ◦ Matrix is hard and calcified ◦ Made up of bone cells called osteocytes  FUNCTION: ◦ Support, protection, storage for calcium

 Different from bone because: ◦ Matrix is gel-like or like firm plastic ◦ Breaks down over time ◦ Fibers are invisible at regular magnification

 Blood has a liquid matrix ◦ Most unusual connective tissue

 3 Kinds: ◦ Skeletal, cardiac, smooth  Movement specialists of body  Ability to shorten or contract  Slow to heal ◦ If injured – usually replaced by scar tissue

 Also known as striated or voluntary ◦ Voluntary muscle contractions possible  FORM: ◦ Individual cells known as FIBERS ◦ Long and threadlike ◦ Contain many nuclei per cell  FUNCTION: ◦ Control body movements and move bones  Attached to bones

 FORM: ◦ Branched, lightly striated, irregular shaped fibers  FUNCTION: ◦ Regular, involuntary contractions of heart to pump blood  FOUND: the heart muscle

 Also known as involuntary ◦ Not under conscious control  FORM: ◦ Long, narrow fibers ◦ No cross striations ◦ Only one nucleus per fiber  FUNCTION: ◦ Contraction of digestive tract, bronchioles in lungs; changes diameter of blood vessels, pupils, shape of lenses  FOUND in the walls of blood vessels and hollow organs such as digestive system, respiratory system, urinary system etc

 FORM (2 kinds): ◦ Neurons – nerve cells  Cell body made up of one axon (transmits impulses away from body) and one or more dendrites (carry impulses towards body) ◦ Glial cells – connecting and supporting cells  FUNCTION: ◦ Rapid communication between body structures and control of body functions  Makes up brain, spinal cord and nerves