1. 4.5 Extracellular Junctions, Glands, and Membranes Objectives: Describe the structure and function of three types of extracellular junctions. Describe the difference between an exocrine and an endocrine gland with examples. Describe the way the body’s membranes are organized. Name and describe the major types of membranes in the body.

2. Extracellular Junctions Tight Junction: Impermeable barrier forms because adjacent plasma membrane proteins join together. Keeps things from leaking (stomach or kidney tubules). Gap Junction: Two adjacent plasma membrane channels joins. Allows ions, sugars, and small molecules to pass between the two cells. Strengthens the cells but also allows them to share resources. Adhesion Junction: Adjacent plasma membranes do not touch but are joined by extracellular filaments. Allows the tissues to stretch.

3. Glands Consists of one or more cells that produce and secret a product. Exocrine: secrete their product onto the outer surface or into a cavity. Sweat glands, mammary glands Endocrine: secrete their products internally and are transported by the bloodstream. Pituitary gland or thyroid Composed of epithelial tissue, but supported by connective.

4. Membranes Line the internal spaces of organs and tubes that open to the outside. Mucous Membranes: line the interior walls of the organs and tubes that open to the outside of the body Serous Membranes: line cavities Synovial Membranes: line freely movable joint cavities and are composed of connective tissues.

5. Membranes Continued Meninges: membranes found within the posterior cavity. Composed of connective tissue and serve as a protective covering for the brain and spinal cord. Cutaneous membrane: skin. Forms the outer covering of the body. Next chapter!

6. In Class Work The next two slides are your work for today before you are allowed to work on your Tissue Competency. Please complete the questions on a sheet of paper and turn them in before the end of class.

7. Medical Focus. P 74-75 Name the four major types of cancer and state the type of tissue they are found in. Differentiate between a malignant and benign tumor. What is metastasis and why is it important to catch cancer before it occurs? Why are chemo and radiation double-edged swords?

8. Content Check-ups Page 65 Page 73 Now you can work on your sketches. The slides are also posted online, as are the rubrics for the past two competencies. Last day for grading/fixing before conferences: Wednesday.