Histolo Long Exam 2 Reviewer PDF

HISTOLO LONG EXAM 2 REVIEWER Dr. Magbanua | Academic Year 24’ -25’ Term 1 OUTLINE Digestive System - Oral Cavity - General plan of the gastro-intestinal tract (GIT) - Esophagus - Stomach - Small Intestine - Large Intestine - Glands ass...

HISTOLO LONG EXAM 2 REVIEWER Dr. Magbanua | Academic Year 24’ -25’ Term 1 OUTLINE Digestive System - Oral Cavity - General plan of the gastro-intestinal tract (GIT) - Esophagus - Stomach - Small Intestine - Large Intestine - Glands associated with the digestive tract Respiratory System - Nasal cavity - Larynx - Epiglottis - Trachea ESOPHAGUS - Bronchial tree - Lungs Characteristic features: ○ Mucosa Lined by nonkeratinized stratified squamous epithelium THE GIT ○ Submucosa With esophageal glands (varies as to segment) Esophagus ○ Muscularis externa Esophageal-gastric junction/(Gastro-esophageal) Upper portion: with skeletal muscles Stomach Middle third: with mixed skeletal and smooth muscle ○ Cardia, Fundus, pylorus Lower third: with smooth muscle Small Intestine ○ Duodenum, jejunum, ileum Large Intestine ○ Colon and rectum Anus ○ Recto-anal junction HISTOLO| DALISAY 1  COMPARISON BETWEEN VARIOUS PORTIONS OF ESOPHAGUS * Presence of glands at transition between middle and lower 1/3 Points of Uppermost Middle 1/3 Lower 1/3 Comparison Portion Absent in the Muscularis mucosae Present Present beginning Skeletal & Skeletal muscle smooth muscle Smooth muscle (inner circular & Muscularis externa (inner smooth (inner circular & thick outer muscle & outer outer longitudinal) longitudinal) skeletal muscle) Submucosal glands Absent Few Abundant Adventitia Only fibrosa Only fibrosa Only serosa STOMACH Characteristic features: ○ Mucosa Complex; lined with simple columnar epithelium 2-3 layers muscularis mucosae Gastric glands Gastric pits Presence of rugae Muscularis externa (3 layers) - Inner oblique - Middle circular - Outer longitudinal 2  ○ Chief cell/ zymogenic cells Secretes pepsinogen and gastric lipase ○ G cells/ Enteroendrocrine cells Secrete gastrin into the blood ○ Undifferentiated cells GASTRIC MUCOSA Epithelial cell types: ○ Surface mucous cells Secretes alkaline fluid containing mucin ○ Mucous neck cells/ Neck mucous cells Secretes acidic fluid containing mucin ○ Parietal cell/ oxyntic cells Secretes intrinsic factor and hydrochloric acid 3  ○ Typically with leaflike to fingerlike villi SMALL INTESTINE (DUODENUM, JEJUNUM, ILEUM) ○ Relatively few goblet cells Characteristic features: ○ Composition and organization of mucosa ○ Plicae circularis/valves of Kerchring ○ Muscularis externa (2-layered) Jejunum ○ Neither Brunner’s glands nor Peyer’s patches ○ With tall cylindrical villi ○ Many plicae circularis ○ Moderate number of goblet cells Muscosa of the Small Intestine: ○ Presence of villi ○ Intestinal glands/Krypts of Lieberkuhn ○ Enterocytes/absorptive cells ○ Goblet cells ○ M cells ○ Paneth cells ○ Enteroendocrine cells & Undifferentiated cells Ileum ○ Lamina propia with many Peyer patches ○ With short, broad-tipped villi ○ Relatively abundant goblet cells Brush border = striped appearance of the border of the lumen due to the abundance of microvilli LARGE INTESTINE/COLON Paneth cells = in the bases of crypts; contain acidophilic secretory granules with antibacterial enzyme to control intestinal flora Mucosa ○ With simple columnar epithelium REGIONAL DIFFERENCES ○ Abundant goblet cells Duodenum ○ Absence of villi ○ Presence of Brunner’s gland in the submucosa ○ Deep crypts of Lieberkuhn ○ No mucosal folds except in the rectum (rectal columns of 4  Morgagni) HISTOLOGICAL COMPARISON BETWEEN SMALL AND LARGE Submucosa INTESTINES ○ Hemorrhoidal plexus of veins (in the lower rectum) Muscularis externa FEATURES Small Intestine Large Intestine ○ Smooth muscle (longitudinal bands) ○ *** teniae coli Villi With villi Without villi Adventitia/Serosa Without folds (except in Plica circularis/valves the rectum; rectal folds Intestinal folds of Kerckring called rectal columns of Morgagni) Relatively shallow Relatively deep crypts Mucosal crypts Relatively few goblet Plenty of goblet cells cells (of the ileum as (most numerous of all compared with) the GIT segments) Smooth muscles in the Smooth muscles outer muscularis ANAL CANAL Muscularis externa appearing in bands, externa not appearing teniae coli Mucosa in bands ○ With short crypts – disappearing (1st 2cm) ○ Stratified squamous epithelium (to the opening) The lamina propia of Large intestine has Submucosa Lymphoid nodules of the lymphoid cells & more than that of the ○ With sebaceous glands and sweat glands the lamina propia nodules intestine, small extend into the Muscularis externa these may aggregate crypts of Lieberkuhn ○ With thickened inner circular smooth muscle APPENDIX (evagination of the interior end of cecum) Resembles the colon except for: ○ Relatively small lumen ○ Fewer and shorter crypts ○ More lymphoid nodules ○ Without teniae coli l 5  TO REMEMBER ILLU PARTS OF OTHER STR TYPE OF MAIN CELL TYPES GASTROINTES DISTINCTIVE ATIO EPITHELIUM OF EPITHELIUM TINAL TRACT FEATURES N Stratified Submucosal Osesophagus (a) - Squamous cell squamous glands - Surface mucous Lymphoid cells THE DIGESTIVE SYSTEM cells Body/fundus of Glandular – very sparse (b) - Neck mucous cells Associated organs and structure of the mouth and buccal cavity stomach straight tubular No lymhoid - Parietal cells ○ Lips aggregates - Chief (peptic) cells ○ Tongue ○ Tooth Lymphoid cells Glandular – - Mucous cells very sparse Pylorus (c) coiled, branched - Occasional parietal LIPS No lymphoid tubular cells aggregates - Enterocytes with Glandular with villi microvilli Duodenum (d) and crypts of Brunner’s glands - Goblet cells Lieberkuhn - Paneth cells - Enterocytes with Glandular with villi Peyer’s patches Jejunum and microvilli (e) and crypts of become more Ileum - Goblet cells Lieberkuhn prominent distally - Paneth cells Upper Lip Colon and Glandular – - Goblet cells ○ Extends from the base of the nose superiorly to the nasolabial (f) Teniae coli rectum straight - Absorptive cells folds laterally and to the free edge of the vermilion border inferiorly Lower Lip Glandular – - Goblet cells Prominent ○ Extends from the superior free vermilion edge superiorly to the Appendix (g) straight crypts - Tall columnar cells lymphoid tissue commissures laterally, and to the mandible inferiorly Glandular – - Absorptive and Columns of Anus (h) straight Stratified goblet cells Morgagni squamous - Squamous cells 6  2. Fungiform papillae TONGUE ○ More globular than filiform Muscular organ covered with mucosa ○ With thin, non-keratinized epithelium (interlacing bundles of skeletal muscle) ○ With richly vascularized core of supporting CT 3. Circumvallate papillae ○ Contain most of the taste buds ○ The largest and least common type Anterior 2/3 of mucosa is formed into papillae ○ Surrounded by deep clefts associated with serous von Ebner’s Sulcus terminalis glands ○ Groove that divides the tongue into an anterior 2/3 and a posterior - Foliate is rudimentary in human; found in some animal 1/3 species TYPES OF PAPILLAE THE DIGESTIVE SYSTEM 1. Filiform papillae ○ Short bristles ○ Most numerous type IMPORTANT TERMS TO REMEMBER ○ Heavily keratinized projections Lobes and lobules Adenomeres ○ Secretory subunits of lobules ○ All the secretory cells that release their products into a single intralobular duct ○ (one adenomere = may include one or more acini) 7  Acinus/Acini/Alveoli ○ Smaller secretory subunits ○ One acinus = spheric collection of secretory cells that surround a blind-ended termination of a single intercalated duct - Mucous: larger; acidophilic cells foamy/spongy cytoplasm Serous demilunes: crescent-shaped cap of mucous denomeres - Serous: relatively small, basophilic cells granulated cytoplasm Myoepithelial cells: ○ Submandibular and submaxillary - Branched tuboloacinar glands - Both mucous and serous cells (mostly serous) Produce 70% of the salivary volume Exocrine Ducts - Serous demilunes cap mucous ○ Intralobular (inside lobules) adenomeres - Intercalated - Striated ○ Interlobular (within connective tissues) ○ Sublingual - Branched tuboloalveolar glands - Both mucous and serous cells (mostly mucous) Produce 5% of the salivary volume SALIVARY GLANDS - Serous demilunes cap mucous adenomeres TYPES: ○ Parotid - Branched acinar gland - Almost exclusively serous - Produce 25% of the salivary volume Amylase, sialomucin, 8  FEATURES ○ Trypsin, chymotrypsin (zymogen granules) ○ Numerous adenomeres CENTROACINAR CELLS ○ Lobule separated by CT septa ○ Release secretions thru intercalated, striated and interlobular Duct-lining cells with condensed nucleus and clear cytoplasm ducts Secrete bicarbonate-rich fluid CELL TYPES: ○ Serous & mucous cells - Predominant cells - Serous: relatively small, basophillic cells - Mucous: larger, acidophilic cells ○ Myoepithelial Cells - Contractile cells between basal lamina and epithelial cells of adenomeres and ducts ○ Other cells - Antibody-secreting cells in the CT septa THE PANCREAS Serous, compound acinar gland Without striated ducts With excocrine and endocrine functions ○ Endocrine portion (Islets of Langerhans) THE LIVER ○ Exocine portion (pancreatic acinar and centroacinar cells) Largest gland Glisson’s capsule Made up of lobules (hepatic lobules) With dual blood supply (Hepatic PVein & Hepatic Artery) PANCREATIC ACINAR CELLS With 3 drainage system (Hepatic Vein, Lymphatic Vein & Bile Duct) Pyramid-shaped cells with luminal apices Enzyme-secreting cells 9  HEPATOCYTES HEPATIC SINUSOIDS - Liver’s blood capillaries - Receive blood from HA & HV (mixed blood flow) - Chief functional cells of the liver - With discontinuous endothelial walls - Carry out most of the liver’s function, knowledge of their structure Lined with Kuppfer cells and functions is a prerequisite for understanding liver functions Space of Disse (between endothelium and hepatocytes) - Serve as the liver’s lymphatic capillaries - Space between sinusoidal endothelium and hepatocytes - Arranged in cell cords or plates (1-2 cell layers) - Separated by sinusoids - Polygonal shapes with 1-2 nuclei HEPATIC PORTAL TRIAD - FUNCTIONS: - Occupies a portal space at each corner of a lobule Metabolism of absorbed nutrients - 3 components Storage of excess glycogen and lipid Portal venule/portal vein Synthesis and secretion of plasma proteins Portal arteriole/portal artery Production and secretion of bile Bile ductule/duct Degradation of metabolic wastes Marked by the positions of portal triads Each lobule marked with a central vein Radiating hepatocyte plates with sinusoids in between 10  BLOOD SUPPLY AND DRAINAGE SYSTEM HEPATIC PORTAL VEIN - Supplies 75% of liver’s total blood volume - Blood supply of liver - Formed by the junction of mesenteric and splenic veins THE RELATIONSHIP BETWEEN HEPATIC STRUCTURE & FUNCTION: DEMONSTRATED BY 3 MODELS OF LIVER SUBSTRUCTURE HEPATIC ARTERY LIVER HISTOARCHITECTURE AND ITS FUNCTIONS - Supplies about 25% of liver’s blood volume - A branch of the celiac artery - Empties oxygen-rich blood into the sinusoids 11  - Based on the content of oxygen, nutrients and toxins - Zones arranged according to their distance to the distributing channels Three Models: 1. Classic lobule THE GALLBLADDER - Based on the direction of blood flow - Sinusoids receive flow from the portal vessels to the CV Blind-ending sac at the lower surface of liver Hollow organ with layered wall ○ Without definitive submucosa Functions: ○ Store and concentrate the bile Mucosa ○ Consists of simple columnar epithelium ○ Deep invaginations forming the glands ○ With large sinuses Muscularis 2. Portal lobule ○ Interwoven smooth muscle fibers - Based on the direction of bile flow Adventitia and serosa - Bile production by Hepatocytes to the Bil cannalliculi to ○ Outer layer consists of adventitia that attaches to the liver the hepatic plates toward bile duct of the portal triad ○ Serosa covers its peritoneal surface 3. Hepatic lobule (of Rappaport) 12  ○ Conducting Portion ○ Respiratory Portion QUESTIONS ASKED DURING THE LECTURE What’s the use of peyer’s patches? ○ Immune system What is the longest segment of the small intestine? ○ Ileum Why is there no villi in the large intestine? ○ There are no nutrients to absorb; water is the only one to absorb Why does the appendix have a lot of lymphatic nodes? ○ Immune system WALL STRUCTURE What does pancreas produe? ○ Insulin With epithelium With lamina propia With cartilage With smooth muscle RESPIRATORY SYSTEM Adventitia COMPONENTS OF THE RS ○ Each layer undergoes gradual changes in thickness ○ Ventilatng mechanism RESPIRATORY EPITHELIUM Pseudostratified ciliated columnar epithelium Epithelial cell types: ○ Ciliated columnar ○ Mucous goblet cells ○ Brush cells ○ Basal cells ○ Small granule cells 13  ○ bone/cartilage in the nasal cavity ○ Cartilage only in the larynx → bronchi ○ Disappears at the level of the bronchioles Smooth muscle ○ Begins in the trachea → alveolar ducts Skeletal muscle ○ Absent in nasal cavities ○ Nasopharynx → larynx NASAL CAVITY Divided by nasal septum → 2 cavities 2 chambers within each cavity ○ Vestibule Smaller, wider, more anterior chamber Lined by keratinized to non-keratinized stratified squamous → respiratory epithelium Bownman’s glands in the lamina propia With short hair (vibrissae) Lamina propia ○ With glands from nasal cavity → trachea Skeletal CT 14  ○ Nasal fossa Larger, narrower, more posterior chamber Lined by respiratory epithelium Venous sinuses and Bowman’s glands in the lamina propia Supported by bones - Specialized olfactory epithelium in the roof of each fossa ○ Naso-pharynx TRACHEA Upper part of the pharynx; overlying the soft palate Lined by respiratory epithelium (thinner, with few goblet Lined by respiratory epithelium cells) Lamina propia with Lamina propia constraints (few small glands) ○ Mixed serousmucous glands - Lymphoid nodules Presence of 16-20 C-shaped cartilages - Mucous With fibroelastic ligament and smooth muscle (trachealis muscle) - Serous glands With skeletal muscles Function: connects nasal and oral cavities to larynx and esophagus; passageway for air and food and acts as resonating chamber for speech LARYNX Lies between base of oropharynx and trachea Opening protected by epiglottis Walls supported by laryngeal cartilages Skeletal muscles around cartilages Houses the vocal apparatus Line by respiratory epithelium 15  Terminal bronchioles ○ Smallest component of the conducting portion ○ Lined by ciliated cuboidal or columnar epithelium - With cilia - With goblet cells - With Clara cells (exocrine bronchialar cells) ○ Each terminal bronchiole → 2 + respiratory bronchioles RESPIRATORY PORTION Respiratory bronchiole ○ Lined by cuboidal epithelium, interrupted by alveoli Alveolar ducts ○ Extensions of RB, with alveoli almost entirely lining the walls Alveolar atria and sacs ○ Distal terminations of alveolar ducts BRONCHIOLES Lined by simple columnar with cilia and goblet cells Lamina propia without glands Each bronchiole → 5-7 terminal bronchioles 16  THE ALVEOLI BLOOD-AIR BARRIER 1. Lined by simple squamous epithelium Layers: ○ Film of pulmonary surfactant ○ Cytoplasm of simple squamous cells ○ Fused basal laminae between Type I alveolar cells and endothelial cells Alveolar Cell Types: ○ Type I cells - Aveolar type I cells/Type I pneymocytes/squamous alveolar cells ○ Are chambers of simple squamous epithelium - Make up 97% of alveolar surfaces ○ Connect to one another to the alveolar duct - Specialized to serve as blood-air barrier ○ Form a sponge-like arrangement of gas filled spaces in lung tissue ○ Type II cells - Type II alveolar cells/type II pneumocytes/great alveolar cells/alveolar septal cells - Cover remaining 3% of alveolar surfaces - Secretory cells Pulmonary surfactants ALVEOLAR MACROPHAGES 2. Alveoli are connected by interalveolar septum Dust cells ○ Specialized for gas exchange Monocyte-derived (MPS) ○ Consists of nonfenestrated capillaries Found on the surface of alveolar septa and in the interstitium Removes debris that escape the mucus and cilia in the conducting portion Phagocytose blood cells that enter the alveoli due to heart failure 3. Alveolus with alveolar type II cell (type II pneumocyte) that secretes surfactant and capillaris that form the blood-air barrier ○ Distal terminations of alveolar ducts 17