A Few Additional Slides to Help Your Study for BIOL 232 Lecture Exam #1 Please note that there are notes associated with these slides. They are embedded within the PowerPoint file. If you do not know how to access them, look below this slide to the large grey line and move your cursor over this line until you can click on it and move the line upwards. This will reveal the notes for each slide. Yes! This is the area where the notes will be for these slides.

Figure 4.5 Types of multicellular exocrine glands. Simple duct structure (duct does not branch) Compound duct structure (duct branches) Tubular secretory structure Simple tubular Simple branched tubular Compound tubular Example Intestinal glands Example Stomach (gastric) glands Example Duodenal glands of small intestine One thing that is very interesting as we see cells organize into more complex structures like tissues is that you can have the formation of ducts (we see these a lot in glands). In the above slide, please note how there are three different cell aspects (epithelia)… light yellow is surface epithelia, dark yellow shows the ducts, and red shows secretory epithelia. What I want you to notice is how the duct branching and the types of secretory structures can be mixed and matched to form a variety of different ducts. The two secretory types are tubular and alveolar. The types of ducts are simple, branched, and compound branched. Be sure to look at the above different types of ducts. Notice that the most complex type is the compound tubuloalveolar ducts that are seen in our salivary glands. Alveolar secretory structure Simple alveolar Simple branched alveolar Compound alveolar Compound tubuloalveolar Example No important example in humans Example Sebaceous (oil) glands Example Mammary glands Example Salivary glands Surface epithelium Duct Secretory epithelium

Figure 4.6 Chief modes of secretion in human exocrine glands. Secretory cell fragments Secretory vesicles (a) Merocrine glands secrete their products by exocytosis. Glands can also produce their secretions in two different ways. These are seen in the above. Merocrine glands release their secretions using secretory vesicles that exocytotically release their contents. Holocrine glands, by contrast, release cell fragments filled with the secretory material. Our sweat glands would be an example of a merocrine gland. An example of a holocrine gland is seen in some of our sebaceous glands. (b) In holocrine glands, the entire secretory cell ruptures, releasing secretions and dead cell fragments.