midterm reviewer 1

• Stratum Basale (Germinativum)

  • Deepest layer in the epidermis
  • Single layer of columnar to cuboidal cells
  • Serve as stem cells for the epidermis with increased mitotic activity
  • Cells produce and contain intermediate keratin filaments
  • Cells divide and mature as they migrate up toward the superficial layers
• Stratum Granulosum

  • Cells become filled with dense basophilic keratohyalin granules
  • Three to five layers of flattened cells
  • Keratin formed is the soft keratin of skin
  • Contains membrane-bound lamellar granules formed by lipid bilayers
  • Lamellar granules are discharged into intercellular spaces to render the skin impermeable to water
• Stratum Corneum

  • Most superficial layer of skin
  • Cells are flattened, dead, and filled with soft keratin filaments
  • Continually shed and replaced by new cells from the deep stratum basale
  • Hydrolytic enzymes disrupt the nucleus and organelles during keratinization
• Stratum Lucidum


  • Translucent and barely visible in thick skin
  • Tightly packed cells lack nuclei or organelles and are dead
  • Contain densely packed keratin filaments
• Layers of the skin (bottom to top)

  • Stratum Basale (Germinativum)
  • Stratum Spinosum
  • Stratum Granulosum
  • Stratum Lucidum
  • Stratum Corneum
• Melanocytes


  • Derived from neural crest cells
  • Located between stratum basale and stratum spinosum
  • Synthesize dark brown pigment melanin from tyrosine
  • Melanin granules migrate to keratinocytes imparting a dark color to the skin
  • Exposure to sunlight promotes increased synthesis of melanin
• Stratum Spinosum

  • Consists of four to six rows of cells
  • Cells shrink in routine histologic preparations creating spines projecting from their surfaces
• Merkel’s cells

  • Found in the basal layer of the epidermis and are most abundant in the fingertips
  • Function as mechanoreceptors to detect pressure as they are closely associated with afferent (sensory) unmyelinated axons
• Tunica muscularis and tunica mucosa are much thicker in the stomach than in the small intestine
• Langerhans cells


  • Found mainly in the stratum spinosum
  • Participate in the body’s immune responses
  • Recognize, phagocytose, and process foreign antigens, and then present them to T lymphocytes for an immune response
  • Function as antigen presenting cells of the skin
• Intestine layers

  • Tunica serosa- outermost layer (PERITONEUM)
  • Tunica muscularis- thickest layer with thin longitudinal muscle layer and circular muscle layer
  • Tela submucosa- connective tissue, blood vessels, and lymph spaces
  • Tunica mucosa- epithelial tissues (columnar shape with free ends with flask-shaped depressions), Goblet Cells secrete mucus and create a protective mucus layer
• Melanocytes migration


  Migrate to their cytoplasmic extensions, from which they are transferred to keratinocytes in the basal cell layers of the epidermis
• Layers of the stomach

  • Tunica serosa- outermost layer
  • Tunica muscularis- thickest layer with spindle-shaped cells
  • Tela submucosa- smooth muscles and connective tissue layer
  • Tunica mucosa- layer with mucus glands(lining of the lumen of the stomach)
• Melanin


  Protects the skin from the damaging effects of ultraviolet radiation
• Stomach Ruga
• Testis
• Kidney components

  • Mesonephric duct- cuboidal cells
  • Renal portal vein-blood cells in the lumen
  • Malpighian body(Renal corpuscles)- numerous prominent rounded structures
  • Glomerulus-centrally located network of blood capillaries
  • Bowman’s capsule- delicate, thin, cup-shaped double membrane
  • Uriniferous tubule(start)
  • Collecting tubule(end)
• Liver components

  • Polygonal cells- liver cells
  • Sinusoids- tissues are clustered with spaces in between
  • Blood vessels - Big spaces with different shapes
  • Veins –squamous epithelial tissues, Red blood cells are present
  • Arteriole- small-round shaped blood vessels(thick wall)
  • Bile capillaries- small cavities with 5-6 cuboidal cells
  • Bile duct –bigger cavities-more than 6 cuboidal cells
  • Pigment granules- give color to the liver
• Liver
• Blood vessel
• Melanin imparts a dark color to the skin, and exposure of the skin to sunlight promotes increased synthesis of melanin
• Kidney
• Gastric glands
• Cell Functions

  • Metabolize and release energy
  • Synthesize molecules
  • Provide a means of communication
  • Reproduction and Inheritance
• Cell Organization


  • The cell is the basic structural and functional unit of life
  • Plasma membrane
  • Cellular organelles
  • Nucleus
  • Cytoplasm
• Fluid Mosaic Model


  Lipid bilayer with imbedded, dispersed proteins, consists mainly of phospholipids and cholesterol, proteins have various functions
• Parts of the Testis

  • Tunica albuginea
  • Mesentery
  • Seminiferous tubules
  • Interstitial tissues/cells of Leydig
  • Production of male sex hormones Testosterone
• Parts of the Renal System

  • Boidal cells
  • Renal portal vein-blood cells in the lumen
  • Malpighian body(Renal corpuscles)
  • Glomerulus
  • Bowman’s capsule
  • Uriniferous tubule
  • Collecting tubule
• Vesicular Transport

  Transport of large particles and macromolecules across plasma membranes, includes endocytosis
• Plasma Membrane

  Forms the outer boundary of the cell, supports the cell contents, regulates what goes into and out of the cell, plays a role in communication between cells
• Parts of the Spinal Cord

  • Dura mater
  • Subdural space
  • Pia mater
  • White matter
  • Gray matter
  • Canalis centralis
• Parts of the Ovary

  • Theca externa
  • Theca interna
  • Mesentery
  • Follicle cell
  • Vitelline membrane
• Functions of Membrane Proteins


  Proteins "float" among the phospholipid molecules, have various functions like marker molecules, attachment proteins, transport proteins, receptor proteins, and enzymes
• Vesicular Transport

  1. Transport of large particles and macromolecules across plasma membranes

  2. Endocytosis: the movement of materials into cells by the formation of a vesicle

  3. Phagocytosis: the movement of solid material into cells

  4. Pinocytosis: the uptake of small droplets of liquids and the materials in them

  5. Receptor-mediated endocytosis: involves plasma membrane receptors attaching to molecules that are then taken into the cell

  6. Exocytosis: the secretion of materials from cells by vesicle formation
• Functions of molecules

  • Marker molecules
  • Attachment proteins (cadherins and integrins)
  • Transport proteins
  • Receptor proteins
  • Enzymes