Epithelial Tissues and Exocrine Glands

Question 1

What are the 3 layers in the mucous membrane?

Answer 1

Epithelium, Connective tissue: lamina propria (one layer), Smooth muscle: alimentary tract

Question 2

Give examples of serious membranes

Answer 2

Peritoneum: envelops many abdominal organs, Pleural sacs: lungs, Pericardial sac: heart

Question 3

What are the 2 layers of the serous membrane

Answer 3

parietal (outer) visceral (inner)

Question 4

What is endothelium?

Answer 4

simple squamous cells that line vessels, can exchanges gases, nutrients

Question 5

What are pseudostratified cells?

Answer 5

All cells touching basement membrane, squashed. Upper respiratory with cilia + goblet cells that secrete mucous blanket. Function: secretion (respiratory), absorption

Question 6

What are simple squamous cells?

Answer 6

Simple squamous, 1 layer, thin, flat cells, nucleus sometimes protruding. Endothelium, peritoneum, pulmonary alveoli. Function: lubrication (pericardium, pleura), gas exchange

Question 7

Describe Cuboidal cells

Answer 7

Cuboidal, square cells, lining pancreatic duct, thyroid follicles, small ducts of exocrine glands. Function: absorption, barrier (ovary), hormone synthesis (thyroid)

Question 8

What are columnar cells?

Answer 8

Column like cells, intestinal glands in mucosa of colon, lining fallopian tube of uterus, can have microvilli, line most of lower GI tract. Functions: absorption, secretion

Question 9

What are transitional cells?

Answer 9

Relaxed (vertical), stretched (horizontal), ureters, bladder. Function: protecting underlying tissue from toxic chemicals

Question 10

Describe stratified squamous cells

Answer 10

More than 1 layer, flat cells. Lining vagina, rich in glycogen, maintain low pH, atrophy in absence or hormone stimulation. Function: protection against abrasion, reduces water loss but remains moist

Question 11

What is the epidermis?

Answer 11

Keratinized stratified squamous, skin. Layers: horny layer (stratum corneum), granular layer(stratum granulosum), prickle cell layer (stratum spinosum), basal layer (stratum basale). Function: UV protection, prevents water loss

Question 12

How can you classify glands?

Answer 12

DESTINATION: exo/endo. STRUCTURE: unicellular/multicellular, coiled/branched, acinar (round secretory unit of exocrine gland)/tubular. SECRETION: merocrine (exocytosis), apocrine (droplets covered by plasma lemma e.g. fat in milk), holocrine (whole cell breaks down).

Question 13

Describe cystic fibrosis

Answer 13

ion channel molecules = cystic fibrosis transmembrane regulator (CFTR) is ABSENT, chloride ion transport substantially compromised, water does not leave the epithelium = mucus becomes viscous, less readily moved = serious pulmonary infection, mucous of GI becomes viscous, poor reabsorption of Cl ions = sweat rich in Cl and Na ions = abnormally salty, exocrine pancreas = little water, thickened, blocked ducts = painfully inflamed, gut gets insufficient pancreatic digestive enzyme = malabsorption, vas deferens often absent

Question 14

What are the stages of epidermis development?

Answer 14

28-40 days: BASAL LAYER: keratinocytes mitosis = daughter keratinocyte. PRICKLE LAYER: terminal differentiation begins, cell lose ability to divide. Keratinocytes synthesise keratins (strength). GRANULAR LAYER: keratinocytes lose plasma membrane, differentiate into corneocyte. Layer contains keratohyalin granules. HORNEY LAYER (stratum corneum): contains flattened corneocytes

Question 15

What does stratified mean?

Answer 15

Many layers

Question 16

What parts of the body does cystic fibrosis affect?

Answer 16

Lungs, pancreas, liver, kidneys, intestine, vas deferens

Question 17

How is cystic fibrosis caused?

Answer 17

Autosomal recessive inheritance of mutations in both genes for CFTR proteins: deletion of 3 nucleotides = loss of AA phenylalanine at position 508

Question 18

What is the basement membrane?

Answer 18

Thin, flexible, acellular layer between epithelial cells and connective tissue

Question 19

Define epithelia

Answer 19

Contiguous cells that cover external and internal surfaces, also forms the secretory portion of glands and lines their ducts

Question 20

Define endothelium

Answer 20

Simple squamous cells that line vessels, can exchange gases and nutrients

Question 21

What is a mucous membrane?

Answer 21

Lines internal tubes that open to the exterior: vaginal, nasal, oesophageal, gastric, anal

Question 22

What are serous membranes?

Answer 22

2 part membrane, line closed body cavities, secret lubricating fluid, simple squamous epithelium