Anatomy and Embryology Examination Questions and Marking Scheme

## 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/M