PLE Histology

Question 1

Basal lamina (lamina densa) vs Reticular lamina

Answer 1

Basal lamina (in lamina densa): type IV collagen
Reticular lamina: thicker fibrous meshwork of type III collagen and bound to basal lamina by anchoring fibrils of type VII collagen

Question 2

epithelial tissue

Answer 2

only basic tissue to be derived from all 3 germ layers

Question 3

epidermis, epithelium of oral and anal canal (below pectinate line), major salivary glands, mammary glands, sweat glands

Answer 3

ectoderm

Question 4

peritoneum, pericardium, pleura

Answer 4

mesoderm

Question 5

gut tube epithelium, dermis, muscle, bone, connective tissue, upper 2/3 of vagina

Answer 5

endoderm

Question 6

brain, spinal cord, retina (minus microglia)

Answer 6

neural tube from ectoderm

Question 7

ELMOPASSES

Answer 7

neural crest from ectoderm
enterochromaffin cells, leptomeninges, melanocytes, odontoblasts, PNS ganglia, adrenal medulla, schwann cells, spiral membrane, endocardial cushion, skull bones

Question 8

covering of the ovaries, thyroid gland follicles, collecting tubules of the kidneys, some ducts of salivary glands, and pancreas

Answer 8

simple cuboidal epithelium

Question 9

mouth, esophagus, larynx, vagina, anal canal

Answer 9

non-keratinized stratified squamous epithelium

Question 10

stratified cuboidal epithelium

Answer 10

secretory ducts of sweat glands, developing ovarian follicles

Question 11

stratified columnar epithelium

Answer 11

conjunctiva

Question 12

pseudostratified columnar epithelium

Answer 12

trachea, bronchi, nasal cavities

heavily ciliated to transport particles trapped in mucus

Question 13

exocrine glands

Answer 13

connected to surface epithelium via ducts

Question 14

examples of exocrine glands

Answer 14

mammary glands, sweat glands, sweat glands, digestive glands

Question 15

endocrine glands

Answer 15

no ducts (no -D-), deliver hormones into blood or lymph
i.e. thyroid gland, adrenal gland, pituitary gland

Question 16

crypts of lieberkuhn or intestinal glands, mucus glands of colon

Answer 16

simple tubular

Question 17

mechanisms for excretion of exocrine glands

Answer 17

merocrine (secretory vesicles fuse with the plasma membrane, pancreas)
apocrine (part of the PM, the apical cytoplasm, is shed off, mammary glands)
holocrine (entire cell disintegrates together with the secretion, only sebaceous)

Question 18

types of glands by type of secretion

Answer 18

exocrine: with ducts
endocrine: no ducts
paracrine: - release products which reach other cells by diffusion
through the extracellular space or immediately subadjacent connective tissue

Question 19

pancreas

Answer 19

both an endocrine and exocrine gland

Question 20

Hereditary disorder characterized by lung congestion and infection and malabsorption of nutrients by the pancreas

Answer 20

cystic fibrosis (disorder of exocrine gland)

Question 21

mixed seromucous

Answer 21

submandibular gland (high in serous)
sublingual gland (high in mucus)

Question 22

endocrinopathies

Answer 22

Diabetes mellitus: Insulin deficiency (pancreas)
Obesity: Leptin deficiency (adipose tissue)
Goiter: Iodine deficiency (thyroid)

Question 23

MUST KNOW collagen fiber types

Answer 23

type 1: skin, tendon, bones (bONE)
type II: cartilage and vitreous (carTWOlage, 2 eyes)
type III: reticulin fibers (reTHREEculin)
type IV: basement membrane (type FLOOR)
type V: fetal tissue and placenta (VeVe)
type VII: connects basement membrane to reticular lamina

Question 24

argyrophilic (stains black in silver stain)
PAS positive (stains polysacc)

Answer 24

reticular fibers (found in reticular lamina, liver, endocrine glands, vasculature, stroma of hematopoietic and immune organs)

Question 25

glycoproteins

Answer 25

fibronectin: Implicated in the movement of cells and fibers in the CT for repair and growth laminin: cross-shaped trimer, found in basal lamina thrombospondin: secreted by platelets

Question 26

smooth muscle

Answer 26

no striations, no T-tubules

Question 27

1) absence of T-tubules 2) less extensive Sarcoplasmic reticulum (SR) 3) MLCK works slowly

Answer 27

contraction in smooth muscle is slower due to: smooth muscle: only muscle requiring myosin to be phosphorylated first before interaction with actin can occur

Question 28

two types of innervation in smooth muscle

Answer 28

unitary: gap junctions where action potential spreads - GI tract, uterus, ureter multiunit: individual fibers with own motor unit terminals - walls of large blood vessels, arrector pili muscle, iris and ciliary body

Question 29

lipofuscin

Answer 29

fine yellow-brown pigment granules composed of lipid-containing residues of lysosomal digestion. "wear-and-tear" pigment

Question 30

no change in length during contraction

Answer 30

A band

Question 31

shortens during contraction

Answer 31

H-zone, I-band, sarcomere

Question 32

light band due to only thin filaments

Answer 32

I-band

Question 33

A-band

Answer 33

thick and thin filaments | does not change length during contraction

Question 34

only thick filament, shortens during contraction

Answer 34

H zone

Question 35

M-line

Answer 35

only thick filaments | where thick filaments on either side of M line connect

Question 36

accessory proteins in the sarcomere

Answer 36

titin, alpha-actinin, myomesin

Question 37

titin

Answer 37

gives elasticity to the sarcomere and prevents overstretching keeps A-band in the center of the sarcomere runs from M line to Z line

Question 38

myomesin

Answer 38

runs through thick filament and binds it to the M line

Question 39

alpha-actinin

Answer 39

attaches thin filament to Z line

Question 40

troponin

Answer 40

TnC: Ca2+ binding to initiate contraction TnI: inhibits binding of myosin to actin during relaxation TnT: binds complex to tropomyosin