Histology II: Glands and membranes 35/pdf lecture/a35histII (2) 2010.pdfHistology II: Glands and...
Transcript of Histology II: Glands and membranes 35/pdf lecture/a35histII (2) 2010.pdfHistology II: Glands and...
Histology II:Glands and membranes
Histology II:Histology II:Glands and membranesGlands and membranes
Dr. Carmen E. RexachAnatomy 35
Mt San Antonio College
Gland• Cell or organ that secretes substance• Tissue
– Epithelial– Supportive CT
• Endocrine vs. exocrine– Endocrine
• Secrete hormones• No contact with surface• No ducts• Invaded by capillaries• Secrete products into blood
– Exocrine• Ducted to surface or into a lumen
Exocrine glands• Unicellular
– Ex) goblet cells• Multicellular
– Secretory portion– Ductal portion– Larger glands usually lined by stratified
epithelium
Unicellular Exocrine Glands
Goblet cells
Multicellular Exocrine Glands• Acinar
– pyramid shaped cells– form rings called acini
• Tubular– cuboidal cells
Classification by duct structure
• Simple– Unbranched duct– Straight or coiled– Tubular gland = if secretory portion is tube
shaped• Compound
– Duct displays repeated branching pattern
Branching patterns
• Simple
• Branched
• Compound branching
Classification by mechanism of secretion
• Merocrine• Apocrine• Holocrine
Merocrine• Majority of glands in body• Secretion by exocytosis
without any loss of cellular components
• Examples– Salivary glands– Pancreatic acini
Apocrine• Secretion includes
partial cell loss• Products are milky• Most glands originally
classified as apocrinehave been reclassified as merocrine
• Cellular products support bacterial growth so that these secretions are often associated with an odor
Holocrine• Entire cell is secretory
product• Oily, waxy product• Sebaceous and
ceruminous glands• Secretions = sebum
Epithelial Membranes• Line body “tracts” and surrounding
organs– protective membranes composed of CT
covered with epithelium.– (1) Mucous membranes– (2) Serous membranes
(1) Mucous membranes (mucosae)• Line passageways opening to exterior
– digestive, respiratory, urinary, reproductive tracts
• Goblet cells secrete mucus • Functions:
– Absorption– Secretion– Protection
• Two to three layers– Epithelium (columnar or squamous)– Lamina propria
• Areolar CT– Muscularis mucosae
(2) Serous membranes• Serosa secrete serous fluid derived
from serum• covering and lining epithelium
– simple squamous epithelium on thin layer of areolar CT
– Two parts• Visceral
– Covers organs• Parietal
– Loose fitting fibrous CT lines body walls
– Ex) pericardium, peritoneum, pleura
Pericardium
Parts of the peritoneum
• Mesenteries– where parietal portions of the peritoneum
come together (attach) the organ to the posterior body wall
• omenta (omentum s.)– folds of the peritoneum that extend from
the stomach
mesentery
greater omentum
Lesser omentum
Serous membranes associated with the liver
• falciform ligament– a serous membrane suspending the liver
from the diaphragm• ligamentum teres hepatis
– extends from the falciform ligament to umbilicus
Additional epithelial membranes
• Endothelium– Simple squamous epithelium lining blood
vessels– Tunica interna of blood vessels and
endocardium of the heart• Mesothelium
– Simple squamous epithelium lining pleura, peritoneal cavity and pericardial cavity