Simple Epithelium and their Pathologies (HHistology/Pathology) - 10/04/23

apical surface is smooth, width greater than height, flattened nucleus, rest on the basement membrane

Describe simple squamous.

apical surfaces may have brush borders, width is equal to height is equal to depth, central and spherical nucleus, rest on the basement membrane

Describe simple cuboidal.

apical surface may have brush border, height is greater than width, elongated ovoid nucleus on the basal region of the cell, rest on the basement membrane

Describe simple columnar.

appears layered but is actually only one layer on the basement membrane, nonuniform cells, columnar and basal cells, usually ciliated

Describe psuedostratified columnar.

cornea and blood vessels (endothelium), air sacs of lungs

Examples of locations of simple squamous.

Kidneys

Example of location of simple cuboidal.

Digestive tract and fallopian tubes

Examples of location of simple columnar.

Respiratory tract

Example of location of psuedostraitifed columnar.

Keratin

dead cells on the epithelium with no nucleus (not always on top of alive cells)

junctions

epithelial cells rest on the basement membrane to which they are anchored via __________ called hemidesmosomes

Cilia

elongated, motile structures that transport material

Microvilli

smaller than cilia, composed of actin filaments, help with absorption

Sterocilia

long microcilia, also made of actin filaments

protects the body from injury, absorption of material, transportation of material along a surface, secretion of mucus, hormones, and proteins, gas exchange (in lungs), lubrication between surfaces

What are the 6 functions of epithelium?

By the number of layers and their shape

How do you classify epithelial tissue?

Epithelium

type of body tissue that covers all internal an external surfaces of the body, lines the body cavities and hollow organs and is the major tissue in glands

Continuously removed by mitosis

What is epithelium removed by?

Apical Domain

Free surface that is exposed to the luminal fluid

Lateral Domain

Orients perpendicularly to the apical and basal membranes

1. Tight 2. Desmosomes 3. Gap Junctions

Types of junctions:

Basal Domain

Attached to an extracellular matrix that supports the epithelial tissue mesothelium

Mesothelium

epithelial layer of serous membranes

Lines the body cavities and covers the organs that project into the cavities

What does mesothelium do?

Simple squamous epithelial tissue

What type of tissue is mesothelium?

Parietal and visceral

What 2 layers does mesothelium?

Face the cavities of the body

What does the parietal layer of mesothelium do?

Covers the organ

What does serosal/visceral layer of mesothelium do?

Lubrication: Prevents organs from touching, protects organs

What are the functions of mesothelium?

Flattened, pentagonal shape, forms irregular borders with one another, simple squamous

Describe mesothelial cells.

Pleural Effusion

Excessive fluid in a mesothelial lined cavity in lungs

Pericardisis

Name for the thing in perricardium (heart)

Peritonitis

Name for the thing in the peritoneum (digestive tract):

Mesothelioma

Cancer of the mesothelium (like a tumor)

Lungs, testes, heart, abdomen linings

Where could mesothelioma be found?

long, slender, and curved microvilli

What are the characteristics of cancer cells?

May invade nearby tissues and organs

What can cancer cells do?

Endothelium

simple squamous epithelium lining the lumen surface of all types of blood vessels and lymphatic vessels (also called vascular __________)

Circulatory system

Where does endothelium play a role in?

flattened and elongated, face parallel to the direction of blood flow, rest on the basement membrane by hemidesmosomes

Describe endothelial cells.

1st layer- endothelial cells

2nd layer- basement membrane

3rd layer-subendothelial connective tissue

4th layer- internal elastic lamina (wavy)

What are the 4 layers of Tunica intima?

Artherosclerosis

formation of deposits of yellowish plaques that contain cholesterol, lipoid material, and lipophages (macrophages)

Cholesterol, fatty, walls, clots, stroke

deposits of _________ and __________ material accumulate in the inner layers of a blood vessel resulting in damage to the vessel ____ (disruption of the endothelium)

when cholesterol hardens, it may occlude blood flow to distant tissues and blood _____ may form

clot formation/dislodged pieces of plaque may result in vascular occlusion and __________

Follicular cells

simple cuboidal cells that line the thyroid follicles of the thyroid gland

Colloid

Fluid that contains hormones