placenta, umbilical cord- discussion, viva

Placenta:

1. Give histological structures of the placenta
• Maternal surface irregular because of cotyledons separated by placental septa. It is formed by basal plate which includes decidua basalis
• Fetal surface is smooth, covered by amnion and gives attachment to umbilical cord. It is formed by amnion, chorionic plate, chorionic villi from outside inwards
2. What is decidua basalis?
• Decidua basalis is the part of endometrium present between the implanted embryo and myometrium
3. What are chorionic villi? What are the types? 
• Chorionic villi are the finger like projections from the chorionic plate formed by cytotrophoblast and syncytiotrophoblast. 
• 3 types of chorionic villi- primary, secondary, tertiary villi
4. Give the structure of the three villi
• Primary villi- simple cord with a solid core of cytotrophoblast surrounded by syncytiotrophoblast
• Secondary villi- projection with central core of mesoderm surrounded successively by cytotrophoblast and syncytiotrophoblast
• Tertiary villi- projection with fetal blood vessels in the core of mesoderm surrounded successively by cytotrophoblast and syncytiotrophoblast. along with fetal capillaries there are fibroblasts and phagocytic cells called Hofbauer cells
5. What are anchoring villi and floating or free villi
• Anchoring villi- villi attached to chorionic plate
• Floating or free villi- the branches from anchoring villi which float in intervillous spaces
6. Name the site of exchange occurring in placenta
• Exchange occurs between the embryonic blood in chorionic villi outside the embryo and maternal blood in lacunae called intervillous spaces of decidua basalis
7. Name the layers of placental barrier
• Upto 20 weeks
• Syncytiotrophoblast
• Cytotrophoblast
• Connective tissue of villi
• Endothelium of fetal capillaries
• After 20 weeks
• Syncytiotrophoblast
• Connective tissue of villi
• Endothelium of fetal capillaries
8. What are the functions of placenta?
• Exchange of nutrients, oxygen, carbon-dioxide, wastes between mother and fetus
• Passive immunity to fetus by transfer of maternal IgG antibodies
• Secretes human chorionic gonadotrophin (hCG), estrogen, progesterone and placental lactogen

Umbilical Cord:

1. Give the structure of umbilical cord
• It is surrounded by amnion
• It consists of two umbilical arteries and one umbilical vein
• The vessels are surrounded by primary mesoderm called Wharton's jelly which protects the vessels
2. What is Wharton's jelly?
• Wharton’s jelly is a mass of loose connective tissue with fibroblasts separated by fine collagen fibers and ground substance containing hydrated glycosaminoglycans rich in hyaluronic acid. It gives cushioning effect to vessels.
3. What are the functions of umbilical arteries and vein?
• Umbilical arteries- carry deoxygenated blood from fetus to placenta
• Umbilical vein- carry oxygenated blood from placenta to fetus

epithelial / salivary glands, serous gland, mucous gland, mixed gland- discussion, viva

Epithelial / Salivary glands

1. How many salivary glands are present and where are they located?
• Serous or parotid salivary gland- largest glands located anterior and inferior to external ear
• Mucous or sublingual salivary gland- smallest glands located inferior to tongue
• Mixed or submandibular gland- small glands located inferior to mandible in the floor of mouth
2. What type of glands are salivary glands functionally?
• They are exocrine glands
3. What type of glands are salivary glands structurally?
• They are compound tubuloacinar glands
4. Where and how do they pour their secretion?
• Secretions are poured into the mouth through their large excretory ducts
5. What are the components of salivary glands?
• Cellular secretory units- acini
• Excretory ducts
6. What are acini?
• Acini are small, sac like dilations at the terminal end of intercalated ducts.
7. What are intercalated ducts?
• Intercalated ducts are the first segments of the excretory duct system attached to acini
8. What are different types of acini?
• Serous acini- made up of serous cells which are pyramidal in shape. Spherical or round nuclei are present at basal half and secretory granules in the apical region of the cells
• Mucous acini- made up of mucous cells which are columnar or pyramidal in shape. Flat nucleus present near the basement membrane and cytoplasm completely filled with mucus
• Serous demilune- Serous cells form a crescent or moon shaped cap over the mucous cells which is called serous demilune. They discharge their secretion into lumen through canaliculi present between the mucous cells
9. What are myoepithelial cells?
• Myoepithelial cells are flattened cells that surround both serous and mucous acini.
• They are highly branched and contractile in nature
• They are also called basket cells
• They are located between the basement membrane and the secretory cells
10. Details about excretory ducts
• Intercalated ducts- they are lined by low cuboidal epithelium. Initially all acini empty their secretions into intercalated ducts and part related to acini is surrounded by myoepithelial cells
• Striated ducts- intercalated join to form striated and are lined by columnar epithelium with basal infoldings of the cell membrane with numerous mitochondria which gives striated appearance
• Intralobular ducts- striated join to form intralobular ducts and are lined by columnar epithelium
• Interlobular ducts- intralobular join to form interlobular ducts and are lined by columnar epithelium
• Interlobar ducts- interlobular join to form interlobar ducts and are lined by stratified cuboidal or columnar epithelium
11. What is the arrangement of connective tissue in the glands?
• The whole gland is surrounded by connective tissue capsule.
• The gland is divided into lobes and lobules by the connective tissue fibers.
12. What are the differences between the mucous, serous and mixed salivary glands?

Types	Serous	Mucous	Mixed
Connective tissue	Well developed connective tissue capsule. Interlobular connective tissue with vessels and adipose tissue.	Well developed connective tissue capsule. Well developed connective tissue septa.	Well developed connective tissue capsule and stroma.
Acini (alveoli)	Serous.	Mucous.	Seromucous.
Cells	Pyramidal in shape with round nuclei at the base. Darkly stained apical cytoplasm because of the zymogen granules.	Globular in shape. Flat and condensed nuclei, at the basement membrane. Cells appear empty in H and E staining, because during the   processing mucinogen granules are washed off.	Both serous and mucous alveoli present. Demilunes or crescents of Gianuzzi, are the appearance of the sectioned serous alveoli seen as half moon or crescent shape over the mucous alveoli.
Duct system	Numerous inter lobular, intra lobular and  intercalated ducts. Lined by stratified to simple columnar to low cuboidal   epithelium.	Intercalated ducts are very rare or absent, more nonstriated intralobular ducts. Lined by stratified to simple columnar to low cuboidal   epithelium.	Few intercalated, more striated ducts. Lined by stratified to simple columnar to low cuboidal   epithelium. Serous demilunes discharge the secretion through the intercellular canaliculi located between the mucous cells.
Secretion	Watery secretion rich in enzymes and antibodies.	Viscid secretion.	Both watery as well as the viscid secretions.
E.g. Salivary gland	Parotid.	Sublingual.	Submandibular.