Cell Biology and Epithelial Structure Quiz

Cells

• Glycoproteins and glycolipids form glycocalyx.
• Lipids form lipid rafts.
• Mitochondria are present in all cells except red blood cells and terminal keratinocytes.
• Endoplasmic reticulum (ER) is involved in protein degradation.
• Golgi apparatus modifies and completes protein synthesis.
• Microtubules guide vesicle movement, form near the nucleus, and extend.
• Actin filaments are involved in cell processes, movement, and anchorage.
• Intermediate filaments provide support and structure.
• Keratin is found in epithelial cells.
• Vimentin is found in mesoderm-derived cells.
• Neurofilaments are found in neurons.
• Lamins are found in the nucleus of cells.
• The nucleus is enclosed by an envelope with a perinuclear space.
• Nuclear pores regulate transport.
• Chromatin is chromosomal material.
• The nucleolus is the site of rRNA synthesis.
• Nucleoplasm is material inside the nucleus.

Epithelial

• Avascular.
• High capacity for renewal.
• Two types: covering (e.g., skin, gut) and glandular (e.g., glands).
• Papillae are evaginations in the connective tissue.
• Lamina propria binds epithelium to underlying connective tissue (contains type IV collagen, glycoproteins, and proteoglycans).
• Basement membrane forms from basal and reticular lamina.
• Intercellular junctions include tight junctions (zonula occludens), zonula adherens, desmosomes (macula adherens), hemidesmosomes, and gap junctions.
• Cadherins anchor cells together to suppress epithelial tumors.
• Integrins interact with basal lamina (laminin and type IV collagen) and extracellular matrix (ECM) of connective tissue.
• Gap junctions form diffusion channels between adjacent cells.
• Cilia move mucus and other substances.
• Microvilli increase surface area.
• Stereocilia are long microvilli found in specific locations.

Connective Tissue

• Connects tissues.
• No free surface.
• Has nerve supply (except cartilage).
• Highly vascular (except cartilage).
• Provides support, surrounds, and connects tissues.
• Forms the framework of the body.
• Defends against invasion.
• Protects delicate organs.
• Transports.
• All connective tissue develops from mesenchyme.
• ECM consists of protein fibers (collagen, elastic, reticular) and ground substance (filler).
• Fixed cells include fibroblasts/fibrocytes, chondrocytes, osteocytes, and adipocytes.
• Wandering cells include macrophages, mast cells, and plasma cells.
• Adipose tissue (fat) includes white (unilocular) and brown (multilocular) adipocytes.
• White fat stores energy; brown fat produces heat.

Cartilage

• Apert's syndrome: Adjacent bones fuse.
• Chondroblasts produce extracellular matrix (ECM); chondrocytes reside in lacunae.
• Cartilage is avascular and has no nerves or lymphatic vessels.
• Perichondrium surrounds cartilage, except fibrocartilage and articular cartilage
• Types include hyaline, elastic, and fibrocartilage.
• Hyaline cartilage is the most common type and forms parts like tracheal rings and articular surfaces.
• Elastic cartilage is found in structures where flexibility is needed
• Fibrocartilage is found in structures with high stress (e.g., intervertebral discs).

Bone

• Osteoblasts form bone tissue; osteocytes reside in lacunae.
• Bone matrix (ECM) is calcified, composed of type I collagen, and provides structural support.
• Bone functions include support, protection, mineral homeostasis, and hematopoiesis.
• Compact (cortical) and spongy (cancellous/trabecular) bone are the two main types.
• Bone remodeling involves resorption and formation of bone tissue (osteoclasts and osteoblasts).
• Periosteum covers the outer surface of bone; endosteum lines the inner surface.