Vet Tech Anatomy- Tissues I

What type of cellular attachment allows exchange of ions and nutrients between cells?

Gap junction

Where in the body would stratified squamous epithelium be found?

regions that are subject to chemical stress: vagina, mouth, esophagus, rectum

Epithelial cells are polar meaning they have both an apical surface and a basal surface. Which surface faces the underlying connective tissue?

Basal Surface

True or false: All epithelial cells have blood vessels and capillaries. They are vascular

False

what are the three basic shapes of epithelial cells?

Squamous, Cubodial, columnar

What is microscopic anatomy also called?

Histology

Epithelial Tissue ______

covers and lines

Connective tissue ______

provides support/structure

Muscle Tissue _______

Enables movement

Nervous Tissue ______

Controls work

Epithelial tissue functions

• protects, covers, and lines

• filters biochemical substances

• absorbs nutrients

• provides sensory input

• manufacters secretions

• manufacers excretions

Apical Surface

away from the underlying connective tissue, towards lumen (exposed side)

Basal Surface

faces the underlying connective tissue

Characteristics of epithelial tissue

• avascular

• Relies on the underlying connective tissue for oxygen and nutrients

• provides body with sensory input

Major types of cellular junctions

• tight junctions

• desmosome

• gap junctions

Tight junctions

• formed by the fusion of the outermost layers of plasma membranes of adjoining cells

• The space between cells is lost

• no leaks

• ex: urinary bladder, GI tract

Desmosome

connect the plasma membranes of adjacent cells

-strong mechanical coupling

• tonofilaments (anchors)

Mostly found in tissues that undergo repeating tension/stretching

ex: heart, uterus, skin

Gap junctions

-cells linked by tubular channel proteins

• connexions

-Allow exchange and passage of ions and nutrients

-quickly transport electical signals between cells

Basement membrane

• The foundation of the epithelial cell

• non-living network of fibers

• helps prevent cells from being torn off

• partial barrier to underlying tissue

What type of cellular junction is associated with tissues that undergo repeated episodes of tension and stretching?

Desmosome

What disease that we talked about in ANIMLSCI 125 likes to invade and destroy rapidly dividing epithelial cells of the GI tract?

Canine parvovirus, feline panleukopenia

Classifications of epithelia

-number of layers of cells

-shape of cells

-presence of surface specialization

Simple squamous epithelium

• delicate and thin

• flat and smooth

• found lining surfaces involved in the passage of either gas or liquid

• Mesothelium: lining of body cavities (pleural, pericardial)

• Endothelium: Lines blood and lymphatic vessels

Simples cubodial Epithelium

• single layer of cube-shaped cells

• nuclei aligned in a single row

• found in areas where secretion and absorption occur

  • absorption: renal tubules

  • secreion: endocrine and exocrine glands

Simple columnar epithelium

• Cells are elongated and closely packed together

• more protective than simple squamous, cuboidal

• nuclei aligned in row at base of cell

• some cells associated with absorption and secretion

Which type of simple epithelial tissue has specific names, such as mesothelium and endothelium, based on location and lines surfaces involved in passage of either gas or liquid?

Simple squamous epithelium

Stratified squamous epithelium

• multilayered

• protect underlying tissues

• occurs in areas of the body subject to mechanical and chemical stresses

  • skin, mouth, esophagus, vagina

• outer layer is continually being torn off

Stratified cubodial epithelium

• generally occurs in two layers

• protects underlying tissues

• found primary along large excretory ducts

  • sweat glands, mammary glands, salivary glands

stratified columnar epithelium

• A rare type of epithelia

• in select parts of the respiratory, digestive, and reproductive

• functions in secretion and protection

Pseudostratified columnar epithelium

• The layer is not truly stratified

  • nuclei at varying levels

  • Not all cells reach the luminal surface

  • Each cell attaches to the basement membrane

• Most are ciliated

• respiratory tract and portions of the male reproductive tract

Transitional epithelium

• basal layer of cuboidal or columnar cells

• superficial layer of squamous cells

• found in regions require to expand and contraction as art of their normal function

  • ureters, urethra, bladder