Bellwork Define tissue. (Hint – look at your crossword or your notes from chapter 1!) Tissue: A group of cells that work together for the same function.

Tissues 4 Main Tissue Types 1 – Epithelial 2 – Connective 3 – Muscle 4 – Nervous Tissues differ from each other in size, shape, amount, kind of material, and function.

1 – Epithelial Tissue Covers body and parts. Packed tightly together No blood vessels Basement membrane anchors to tissue underneath Regenerate easily

1 – Epithelial Tissue Shape Squamous – Flat and scale like Cuboidal – Cube shaped Columnar – Higher than wide Arrangement Simple – Single layer of same shaped cells Stratified – Many layers of same shaped cells Transitional – Several layers of different shaped cells

1 – Epithelial Tissue Simple Squamous Single layer, flat, scale-like Function – Absorption Ex. Oxygen into blood from lungs (capillaries and alveoli) Stratified Squamous Several layers of closely packed cells Function – Protection from microorganisms Ex. Skin and mucous membranes

1 – Epithelial Tissue Stratified Transitional Found in areas needed to stretch Usually ten or more layers (protection) when not stretched When stretching occurs, epithelial sheet expands to form a few layers Ex. Urinary bladder Simple Columnar Contain “goblet cells” which produce mucous. Specialize in absorption. Ex. Inner surfaces of stomach, intestines, and parts of respiratory and reproductive tracts.

1 – Epithelial Tissue Pseudo-stratified Appears to be two layered but actually is not (pseudo – false) Absorption and secretion Contain cilia Ex. Trachea and windpipe Glandular Act alone or in groups (glands). Exocrine glands – Release products into ducts. (Ex. Liver) Endocrine glands – Release hormones into bloodstream. (Ex. Thyroid)

Interesting Fact Up to 90% of human cancers originate in epithelial cells.

Exit Ticket Describe as many general characteristics about epithelial tissue as you can. (Hint – We had 5 in our notes)

Connective, Muscle and Nervous Tissue

2 – Connective Tissue Most abundant type of tissue Vary in blood supply Extracellular matrix – non-living material surrounding living cells Protein fibers and ground substance (mostly water)

2 – Connective Tissue A) Areolar Thin delicate membranes “Glue” that anchors internal organs. Ex. Subcutaneous layer below skin B) Adipose Space between cells so they may swell, nucleus pushed to one side Specialized to store lipids, insulation Reticular Thin network of fibers Provides support in organs which hold free blood cells (lymph nodes, spleen)

2 – Connective Tissue D) Bone (osseous tissue) Matrix is hard and calcified. Store Calcium and Phosphorus Provide protection and support. Dense Make up tendons and ligaments

2 – Connective Tissue F) Blood Liquid matrix Function – Transportation and Protection Ex. Red and White blood cells Cartilage 3 types: Hyaline – fetal skeleton Elastic – ears Fibrocartilage – intervertebral discs

3 – Muscle Tissue 3 Types Skeletal (Striated) Voluntary -can be willfully controlled. Many nuclei Individual cells appear threadlike. Attached to bones - create movement.

3 – Muscle Tissue B) Cardiac Only in heart Involuntary Striations and intercalated disks. Allows the heart to beat

3 – Muscle Tissue C) Smooth (Visceral) Form walls of hollow organs (blood vessels, intestines) Involuntary Non- striated

4 – Nervous Tissue Neurons and support cells Send impulses to other areas of the body

Nerve Tissue Neurons contain 1 axon (carry impulses away from cell body) and 1 or more dendrites (carry impulses to cell body)

Tissue Discussion Three patients in an ICU are examined by the doctor. One pt has brain damage from a stroke, another had a heart attack that severely damaged his heart muscle, and the third has a severely damaged liver (a gland) from a crushing injury in a car accident. All 3 pts have stabilized and will survive, but only one will have full functional recover through regeneration. Which one and why?

Tissue Discussion Cancer-causing agents (carcinogens) usually act on dividing cells. Which of the four tissues would carcinogens most influence? Why?

Tissue Discussion Joints such as the shoulder, elbow, and knee contain considerable amounts of cartilage and dense regular connective tissue. How does this explain that joint injuries are often slow to heal?

Tissue Repair Regeneration Fibrosis Replacement of destroyed tissue by the same kind of cells Fibrosis Repair by dense fibrous connective tissue (scar)