Chapter 3 b Compartmentation Cells and Tissues Golgi

Chapter 3 b Compartmentation: Cells and Tissues

Golgi Complex • Membranes surrounded by vesicles • Protein modification • Protein packaging into secretory vesicles

Golgi Complex Vesicle Lumen (a) Figure 3 -18 a

Golgi Complex Figure 3 -18 b

Cytoplasmic Vesicles • Secretory vesicles • Released from cell • Lysosomes • Digestive enzymes • Peroxisomes • Hydrogen peroxide • Detoxification • Fatty acid degradation

Cytoplasmic Vesicles • Lysosomes and peroxisomes Mitochondrion Lysosomes Peroxisomes Figure 3 -19

Nucleus • • Nuclear envelope Nuclear pore complex Chromatin Nucleoli • Control RNA synthesis

Nucleus Nuclear envelope is a double membrane that separates the nucleus from the cytoplasm. Nucleolus contains DNA that controls synthesis of ribosomal RNA. Chromatin is DNA and protein. Nuclear pores regulate movement of material into and out of the nucleus. Figure 3 -20

Primary Tissue Types • Epithelial • Lining and glands • Connective • Protection, support and storage • Muscle • movements • Nervous • Communication, sense internal and external environment

Histology • Four types of tissues: 1) Epithelial 1) Lining 2) glands 2) Connective 1) Protection 2) Storage 3) connections 3) Muscle 1) movement 4) Nervous 1) Sense 2) communication

Epithelial Tissues: Cell Junctions and CAMs • Cell to cell • Gap junction • Tight junction • Anchoring junction

Cell Junctions and CAMs Table 3 -3

Types of Cell-Cell Junctions Tight junctions prevent movement between cells. Claudin and occludin proteins Adherens junction Intercellular space Desmosomes anchor cells to each other. Cell 1 Cell 2 Cytosol Cell membrane (a) Tight junction Figure 3 -21 a

Types of Cell-Cell Junctions Tight junctions prevent movement between cells. Adherens junction Cadherin proteins Cell membrane Plaque glycoproteins Desmosomes anchor cells to each other. Cytosol Intercellular space Intermediate filament (b) Desmosome, an anchoring junction Figure 3 -21 b

Types of Cell-Cell Junctions Heart muscle has gap junctions. Cytosol Connexin proteins Clusters of gap junctions create cytoplasmic bridges between adjacent cells. Intercellular space Cell membrane (c) Gap junction Figure 3 -21 c

Cell Junctions and CAMs • A map of cell junctions CELL JUNCTIONS Function Communicating Occluding Location Cell-cell junctions Type Gap junction Tight junction Membrane protein Connexin Claudin, occludin Cytoskeleton fiber Matrix protein Anchoring Actin Cell-matrix junctions Adherens junction Desmosome Focal adhesion Cadherin Actin Hemidesmosome Integrin Intermediate filaments Actin Keratin (intermediate filaments) Fibronectin and other proteins Laminin Figure 3 -22

Epithelial Tissue: Structure • Basal lamina • Basement membrane • Cells in contact • junctions

Epithelial Tissue: Structure Epithelial cells attach to the basal lamina using cell adhesion molecules. Basal lamina is an acellular matrix layer that is secreted by the epithelial cells. Underlying tissue Figure 3 -23

Epithelial Tissue: Functions based on Layers, Shape and Features Table 3 -4

Distribution of Epithelia in the Body Integumentary System Respiratory system Circulatory system Digestive system Cells KEY exchange Musculoskeletal system Urinary system secretion secretory epithelium exchange epithelium Reproductive system transporting epithelium protective epithelium ciliated epithelium Figure 3 -24

Exchange Epithelia Capillary epithelium Blood Pore Extracellular fluid (a) Leaky exchange epithelium allows movement through gaps between the cells. Figure 3 -25 a

Transporting Epithelia Apical membrane Lumen of intestine or kidney Tight junction Basolateral membrane Transporting epithelial cell Extracellular fluid (b) Tight junctions in a transporting epithelium prevent movement between adjacent cells. Substances must instead pass through the epithelial cell, crossing two phospholipid cell membranes as they do so. Figure 3 -25 b

Ciliated and Protective Epithelia Cilia Microvilli Golgi apparatus Nucleus Mitochondria Basement membrane (a) Ciliated epithelium lining the airways Figure 3 -26 a

Ciliated and Protective Epithelia Cilia Microvilli (b) Scanning electron micrograph showing ciliated cells mixed with cells covered with shorter microvilli Figure 3 -26 b

Cilia and smoking • The following series of slides illustrate microscopic changes that happen when a person smokes. The first slide is showing an illustrated blow-up of the normal lining of the bronchus. On the top we see the cilia, labeled (H). They are attached to columnar cells, labeled (I). The cilia sweep the mucous produced in the goblet cells, labeled (J) as well as mucous coming from deeper glands within the lungs and the particulate matter trapped in the mucous. The bottom layer of cells, labeled (L) are the basal cells.

Cilia and smoking • Below we start to see the changes that occur as people begin to smoke. You will see that the columnar cells are starting to be crowded out and displaced by additional layers of basal cells. • Not only are fewer cilia present but the ones that are still functioning are doing so at a much lower level of efficiency. Many chemicals in tobacco smoke are toxic to cilia, first slowing them down, soon paralyzing them all together and then destroying them.

Cilia and smoking • • As you see with the cilia actions being diminished, mucous starts to build up in the small airways making it harder for the smoker to breathe and causing the characteristic smokers cough in order to clear out the airways. Eventually though, the ciliated columnar cells are totally displaced. As can be seen below ominous changes have taken place. Not only is the smoker more prone to infection from the loss of the cleansing mechanism of the cilia, but these abnormal cells (O) are cancerous squamous cells. These cells will eventually break through the basement membrane wall and invade into underlying lung tissue and often spread throughout the body long before the person even knows they have the disease.

Smoker’s lungs

Secretory Epithelia • Goblet cells Mucus Nucleus Basal lamina Golgi apparatus Goblet cells secrete mucus into the lumen of hollow organs such as the intestine. Figure 3 -27

Secretory Epithelia Epithelium • Development of endocrine and exocrine glands from epithelium Connective tissue Exocrine Endocrine Duct Connecting cells disappear Exocrine secretory cells Endocrine secretory cells Blood vessel Figure 3 -28