Histology Self Quiz: Intro to Histology and Epithelium.

  1. What is histology?

The study of cells and tissues and how they work together to form organs

  1. Describe the dyes used most commonly to stain histological slides:

Hemotoxylin is a dye that is basic. It stains structures that are acidic (basophilic) blue/purple

Eosin is a dye that is acidic. It stains structures that are basic (eosinophilic) pink/reddish.

  1. Describe the 5 steps of tissue preparation
  1. Fixation- proteins are crossed linked, enzymes are inactivated, and the cell structure is preserved (use of formalin or formaldehyde)
  2. Dehydration: the tissue sample is passed through an ethanol series to remove the water
  3. Clearing: The alcohol is removed from the tissue
  4. Infiltration: The tissue sample is soaked in paraffin to stabilize the tissue
  5. Embedding: The tissue sample is embedded in solid wax, which is then cut into small sections that are viewable under a light microscope.
  1. What are the four tissue types of the body? Describe them.

1.Nervous tissue: Tissue that interprets sensory info and produces motor output

2.Muscle tissue: Tissue that is contractile. Can increase or decrease in length. This produces movement.

3. Epithelial tissue: Sheets of cells that line cavities and cover organs.

4. Connective tissue: Tissue that has many functions but mostly serves as a space filler and connects tissues to tissues and organs to organs.

  1. Label the microscope

  1. What is the main instrument used to study histology?The light microscope
  2. What is the total magnification of a light microscope?The magnification of the eyepiece multiplied by the magnification of the objective lens being used.
  3. The optical system of a normal light microscope consists of ___The eyepiece____ and__the objective lens_____.
  4. The illumination system of the Microscope consists of the ____Consolable lamp____, _iris diaphragm, and ___the condenser__. Describe what each of them do.

  1. What is epithelium?

Epithelium cells are sheets of cells that line cavities and cover organs.

  1. What are the seven functions of epithelium?
  1. Absorption
  2. Excretion
  3. Secretion
  4. Protection
  5. Lubrication
  6. Diffusion
  7. Filtration
  1. What are the characteristics of epithelia?

Epithelia are avascular, cells adhere tightly to their neighbors and there is little intercellular space. Has distinct polarities and they self-replicate quickly.

  1. What are the two major layers of the Basement membrane?

-Basal lamina: Composed of the lamina lucida and the lamina densa

-Reticular lamina: Lamina secreted by connective tissue underneath epithelium. It is made of type 1 and 3 collagen, and connects to the lamina densa through type 4 collagen.

  1. What is the lamina propria?

A thin vascular layer of connective tissue beneath the epithelium of an organ that nourishes the epithelium above.

  1. What are the 2 major classifications of epithelium?

Number and shape!! Shapes: squamous, cuboidal, columnar Number: simple or stratified

  1. Name the types of epithelium and give an example of each!!!
  1. Simple squamous- one layer of flat cells. Ex. Endothelium and mesothelium
  2. Simple cuboidal- one layer of cubed cells. Ex. Kidney tubules
  3. Simple columnar- One layer of column like cells Ex. Digestive tract
  4. Stratified squamous- Several layers of flat cells Ex. skin
  5. Stratified cuboidal- Several layers of cubed cells Ex. Sweat glands
  6. Stratified columnar- Several layers of columnar cells Ex. Mammary glands
  7. Pseudostratified columnar- One layer of stratified columnar that look like there are two distinct layers but really all cells touch the basement membrane. Ex. Respiratory system
  8. Transitional epithelium- Domed top epithelial cells, Ex. Urinary system.
  1. What is SSNK and SSK and where are they found?

SSNK : Stratified squamousnonkeratinizing, it is stratified squamous tissue that has not turned partially into keratin. Ex. Mouth, anal canal, esophagus.

SSK: Stratified squamous keratinizing. It is stratified squamous tissue that has undergone morphogenesis into a tough outer layer of keratin. Ex. Epidermis.

  1. Name and Describe all the surface modifications of epithelium:
  1. Microvilli: very small fingerlike projections that aid in increased absorption.
  2. Villi- fingerlike structures that aid in absorption Ex. Digestive system
  3. Cilia-Hairlike structures that are capable of movement and actually all beat in the same direction. Ex. Respiratory tract.
  4. Stereo cilia- very large immobile hairlike projections. They are found in the ear and male repro system.