Simple Epithelium Quiz

simple squamous epithelium

1 layer of flat cells on a basement membrane

smooth apical surfaces

width>length

flattened nucleus

found in cornea

simple cuboidal epithelium

1 layer of cube cells on a basement membrane

apical surface may have a brush border

width = length

central and spherical nucleus

simple columnar epithelium

1 layer of tall cells on a basement membrane

apical surface may have a brush border

width<length

elongated/oval nucleus located in basal region (closer to basement membrane)

mesothelium

extra layer of protection of serious membranes that line body cavities and cover organs within the cavities

parietal layer: cavity wall

visceral layer: (serosa) organs

provides lubrication

cells are pentagonal and form irregular borders

effusion

excessive fluid in a mesothelial lined cavity

• in lining of lungs/chest cavity (pleura) = pleurisy

• in lining of digestive tract/abdominal cavity (peritoneum) = peritonitis

  • in lining of heart (pericardium) = pericarditis

mesothelioma

cancer of the mesothelium

pleural mesothelioma: lungs

peritonial mesothelioma: intestines

pericardial mesothelioma: heart

testicular mesothelioma: testes

people who smoke or are exposed to asbestos are more likely to contract this

cancer cells have long, thin, and curved microvilli and easily spread to other areas of the body (metastasize) by way of the lymphatic system

endothelium

innermost layer of blood vessel walls

cells are positioned parallel to blood flow and rest on a basement membrane (two connected by hemidesmosomes)

connective tissue underneath has an internal elastic lamina

atherosclerosis

formation of yellow plaque deposits full of cholesterol, lipids, and lipophages (macrophages) in the endothelium

• these damage the vessel wall and when hardened, occlude blood flow to distant tissues because the vessel can no longer be flexible and expand

• formation of clots or dislodged pieces stop blood flow (vascular occlusion) and stroke

happens to everyone, some develop this quicker based on genetics or lifestyle; dyslipidemia, endothelial disfunction, inflammatory and immunologic factors, and hypertension

can lead to myocardial infarctions when too bad

simple cuboidal cells in the thyroid

cells surround the perimeter of larger follicular cells with a lumen in the center called a colloid (produces hormones)

adjacent follicles are separated by connective tissue

hyperthyroidism

taller/more columnar cells

cells are in a state of hyperfunction —> excessively high levels of hormones from the thyroid are produced

people develop thyroid nodules (benign tumors) or goiters

these people have trouble sleeping, are overactive, don’t easily gain weight, are nervous, and can have hair loss

hypothyroidism

smaller/more squamous cells

cells are inactive or in a state of hypofunction —> excessively low levels of hormones from the thyroid are produced

these people are sleepy, unmotivated, depressed, and easily gain weight

simple cuboidal cells in the kidney

the appearance and function of cells differ based on which segment of uriniferous tubules they belong to

proximal tubules: pink stained-cytoplasm with long microvilli on the apical surface (in the middle of the larger structure) —> filled lumen

distal tubules: less pink with short microvilli on the apical surface —> empty lumen

you can also see ball-shaped glomeruli structures in the kidney that are encased in Bowman’s capsule

proximal tubules continued

pink cytoplasm because many mitochondria to make ATP to power ion pumps

these pumps operate in the basolateral membrane and help the cell reabsorb substances like: water, chloride, sodium, amino acids, proteins, glucose which are transported to the underlying connective tissue

microvilli serve to absorb and secrete

renal fanconi syndrome

when not all “reabsorbed” substances are reabsorbed and passed on to the blood stream

they instead go to the urine and are wasted

from an abnormality in the proximal tubule epithelial cells

genetic or environmental factors

leads to decreased bone mineralization that materializes as rickets in children or osteomalacia in adults

cells are squamous instead of cuboidal, there’s a thicker basement membrane, distorted nucleii, smaller and fewer microvilli

simple columnar cells in the lining of the digestive tract

villi: fingerlike projections made up of a layer of simple columnar cells

apical surface has a brush border with microvilli (on the outside edge of the structure this time)

cells are referred to as enterocytes/absorptive cells

cells interspersed with “empty” cytoplasms are goblet cells that secrete mucous

celiac’s disease

in the small intestine when villi suffer atrophy (shrink)/cells become flat after exposure to gluten that leads to an immune attack

other cells become inflamed

if untreated, can lead to malabsorption, anemia, bone disease, or even cancer

avoid gluten!