SECTION 1: SHORT ANSWER QUESTIONS Question 1: Submandibular Gland Histology Describe the light microscopic features of the submandibular gland. Stroma: Connecti
SECTION 1: SHORT ANSWER QUESTIONS Question 1: Submandibular Gland Histology Describe the light microscopic features of the submandibular gland. Stroma: Connective tissue capsule; septae/trabeculae divide the gland into lobules. Parenchyma: Lobulated structure; lobules contain mixed acini (serous and mucous); serous acini form the demilunes; ductal system present. Question 2: Nasal Septum Blood Supply Outline the arterial blood supply to the nasal septum. Upper part: branches of anterior and posterior ethmoidal arteries. Posterior aspect: branches of sphenopalatine artery. Inferior aspect: branches of greater palatine artery. Anterior aspect: branches of superior labial artery. Anastomosis: All arteries converge at Little's area (Kiesselbach's plexus). Question 3: Thyroid Gland Development Describe the development of the thyroid gland. Begins in the endoderm of the floor of the primordial pharynx (dorsum of the tongue). Thyroid diverticulum extends downwards in front of the hyoid bone and larynx. Thyroglossal duct connects the gland to the tongue; later degenerates leaving the foramen caecum. Divides into two lobes connected by the isthmus. Invasion of cells from the ultimobranchial body (4th pharyngeal pouch) for parafollicular cells. Question 4: Skeletal Muscle Ultrastructure Describe the electron microscopic features of skeletal muscle. Sarcomere: Regular arrangement of actin (thin) and myosin (thick) filaments. Z-line (actin attachment), A-band (myosin region), and I-band (lacking myosin). Organelles: Extensive sarcoplasmic reticulum (SER); numerous mitochondria. T-system: T-tubules (sarcolemma invaginations) flanked by terminal cisterns to form triads. Question 5: Oesophageal Blood Supply Describe the arterial blood supply to the oesophagus. Cervical: Inferior thyroid artery; deep cervical artery. Thoracic: Oesophageal branches of thoracic aorta; bronchial arteries; posterior intercostal arteries. Abdominal: Left gastric artery. Question 6: Tracheal Histology Describe the histological organization of the tracheal wall. Mucosa: Pseudostratified ciliated columnar epithelium with goblet, brush, and basal cells; lamina propria. Submucosa: Dense connective tissue and blood vessels. Musculocartilaginous layer: C-shaped hyaline cartilage rings bridged posteriorly by trachealis (smooth muscle). Adventitia: Outer connective tissue layer. Question 7: Diaphragm Development Describe the development of the thoracic diaphragm. Septum transversum: Forms the central tendon. Dorsal mesogastrium: Forms the crura. Lateral body wall: Forms the peripheral muscular parts. Pleuroperitoneal folds: Contribute to the membrane. Innervation: Phrenic nerve (C3-C5) due to cervical origin. Question 8: Lymphatic Drainage of the Colon Describe the lymphatic drainage of the colon. Follows arterial supply. Levels of nodes: Epicolic (gut wall), Paracolic (marginal artery), Intermediate (along SMA/IMA), and Principal (root of SMA/IMA). Proximal colon drains to SMA nodes; distal colon drains to IMA nodes. Question 9: Elbow Joint Stability Describe the bony organization and stability factors of the elbow joint. Bony Articulation: Trochlear notch of ulna with humerus trochlea; radial head with humerus capitulum. Ligaments: Annular, ulnar collateral, and radial collateral ligaments. Muscles: Surrounding musculature provides dynamic stability. Question 10: Liver Development Describe the development of the liver. Arises from distal foregut endoderm (hepatic diverticulum) into the septum transversum. Pars hepatica: Forms liver parenchyma and hepatic ducts. Pars cystica: Forms gallbladder and cystic duct. Histogenesis: Endoderm forms hepatocytes; septum transversum forms Kupffer cells; vitelline veins form sinusoids. SECTION 2: LONG ANSWER QUESTIONS Question 11: The Parotid Gland Describe the relations, innervation, and clinical relevance of the parotid gland. Structures passing through (Superficial to Deep): Facial nerve (CN VII), Retromandibular vein, External carotid artery. Innervation: Parasympathetic (Secretomotor) via CN IX - Lesser petrosal nerve - Otic ganglion - Auriculotemporal nerve. Sympathetic via superior cervical ganglion. Sensory via Greater auricular nerve. Question 12: Neuroanatomy - Vagus Nerve and Ventricles Vagus Nerve (CN X): Branches in neck include Superior Laryngeal nerve. Nuclei include Nucleus Ambiguus (SVE) , Dorsal Motor Nucleus (GV E), and Nucleus Tractus Solitarius (SVA/GVA). Ventricular System: Flow: Lateral ventricles - Foramen of Monro - 3rd Ventricle - Aqueduct of Sylvius - 4th Ventricle - Foramina of Luschka/Magendie - Subarachnoid space. Hydrocephalus: Communicating (impaired absorption) vs. Non-communicating (obstructive). Question 13: Abdominal Wall and Viscera Rectus Sheath: Below umbilicus, the posterior wall is deficient (Arcuate line). All three aponeuroses (EOA, IOA, TA) pass anterior to the rectus abdominis. Hesselbach's Triangle: Boundaries are Inguinal ligament (inferior), Inferior epigastric artery (lateral), and Rectus abdominis lateral border (medial). Biliary Tree: Right/Left hepatic ducts - Common hepatic duct + Cystic duct - Common Bile Duct - Ampulla of Vater. Epiploic Foramen (Winslow): Anterior (Hepatoduodenal ligament), Posterior (IVC), Superior (Caudate lobe), Inferior (Duodenum 1st part).