Histology Flashcards
Describe the histological structure of the lips
The outer surface: is covered by hairy skin with hair follicles sebaceous and sweat glands
The inner surface: is lined by the oral mucosa - underlying C.T. contains labial glands
- The red line (vermilion): transition zone between the epidermis of the skin and the oral mucosa.
- hairless very thin skin with deep papillae.
- Its epidermis is transparent so it shows the red color of the blood capillaries present in the dermis
Compare between the dorsal and ventral surface of the tongue
Dorsal: rough, covered by partially keratinized stratified squamous epithelium, has papillae, has lingual tonsils on posterior
Ventral: smooth, covered by non-keratinized stratified squamous epithelium, no tongue papillae, has lingual glands
Compare between al tongue papillae
Filiform papillae: elongated conical, covered by keratinized stratified squamous, most numerous, no taste buds
Fungiform papillae: resemble mushrooms, covered by nonkeratinized stratified squamous epithelium, contains scattered taste buds
Circumvallate papillae: has circular valley, covered by non keratinized stratified squamous, taste buds at sides
Follate papillae: two or more parallel ridges and furrows, covered by non-keratinized stratified squamous epithelium, many taste buds
Give the shape of the taste buds
Onion shaped, pale neuroepithelial structures present in tongue papillae.
It is formed of dark supporting cells, neuroepithelial taste cells and basal cell
Give an account on the mucosa of esophagus
a. Epithelium: Non-keratinized stratified squamous. - protects against injury, which may occur due to passage of rough food.
b. lamina propria: loose C.T. which contains blood vessels and lymphatics that supply the mucosa as well as simple tubular mucous glands (cardiac glands) in upper & lower ends of the esophagus.
c. Muscularis mucosa: inner circular (I.C.) outer longitudinal (O.L.), thin layers of smooth muscle
Give an account on the musculosa (muscularis externa) of esophagus
- formed of inner circular (I.C.) & outer longitudinal (O.L.) muscle layers:
- In upper 1/3 muscles are striated
- In middle 1/3 muscles are mixed (smooth & striated) - In lower 1/3 muscles are smooth
- Myenteric autonomic Auerbach’s plexus is present between the I.C.) and the O.L layers which regulates peristaltic movements.
Give the layers of the fundus of the stomach
- MUCOSA: * Thick, dark and highly folded.
2- SUBMUCOSA: loose C.T. containing blood vessels, lymphatics and Meissner’s parasympathetic plexus of nerve supplying muscularis mucosa.
3- MUSCULOSA: Smooth muscle fibers, arranged into 3 layers: Inner oblique, Middle circular, Outer longitudinal.
- Auerbach’s nerve plexus is found between circular & longitudinal layers controlling movements of musculosa.
4- SEROSA: thin layer of loose CT covered with mesothelium (simple squamous epithelium).
Compare the fundus and pylorus in terms of mucosa, corium, glands, submucosa and musculosa
Fundus: highly folded, has fundic glands, very crowded and simple branched tubular glands, wider submucosa and thinner musculosa with three layers (internal oblique, middle circular and outer longitudinal)
Pylorus: less folded, contains pyloric glands, less crowded and coiled branched tubular glands, narrower submucosa, thicker musculosa with two layers (IO & OL)
Explain the changes at the Gastro-esophageal junction
- The epithellum of the esophagus (stratified squamous epithelium) changes to simple columnar mucous secreting epithelium in the gastric part.
- The corium of the stomach is wide and contains gastric glands.
- The muscularis mucosa passes unchanged
- submucosa of the esophagus contains mucous glands, then it disappears in the submucosa of the stomach.
- The musculosa is thicker in the stomach, being formed of three layers: inner oblique, middle circular & outer longitudinal.
Give an account on Burner’s gland
Compound tubuloalveolar glands found in the submucosa of the first part of the duodenum.
By E.M.; the acinar cells display well developed rER, Golgi apparatus with numerous mitochondria.
- They secrete mucous, in which ducts of these glands pierce the muscularis mucosae to reach the base of crypts
Give an account on the changes at the pyloro-duodenal junction
- Appearance of intestinal villi in the duodenum.
- The columnar cells acquire brush border (microvill)
- Goblet cells start to appear in the duodenum.
- in the corium, the byloric glands are replaced by intestinal crypts.
- Brunner’s gland appear in the duodenal submucosa.
- Musculosa is thinner in the duodenum.
Compare between Oxyntic and peptic cells in shape, nuclei, cytoplasm and secretion
Oxyntic: large rounded, central rounded nuclei, cytoplasm deeply acidophilic and secrete HCl
peptic: pyramidal, basal nuclei, deep basophilic and secrete pepsinogen
Compare between pylorus and fundus
Pylorus: less folded, less crowded, coiled branched tubular, side and deep
Fundus: highly folded, very crowded, simple branched tubular and very narrow
Describe cells that are in both villi and crypts of intestinal mucosa (Enterocytes vs goblet)
Enterocyte: tall columnar, basal oval nuclei, apical microvilli with junctional complex in lat border
Goblet: expanded flask, triangular dark, apical granules, high number of rER
Define Malpighian corpuscles and describe renal glomerulus
Malpighian corpuscles: a vascular pole formed by invagination of blind spherical end of nephron by glomerulus changing it into Bowman’s capsule
Renal glomerulus: has afferent arteriole–> divides forming tuffs of capillaries–> drain into efferent arteriole which carries filtered blood.
Afferent arterioles have thicker medial and larger diameter than efferent. It is lined by simple squamous epithelium surrounded by thick continuous BM
