Anatomy Study Guide #2 PDF

Lecture 8: Thoracic Myology and Respiration 1. Be able to differentiate between epaxial and hypaxial muscles. Epaxial - DORSAL to transverse processes of vertebrae, EXTEND Hypaxial - VENTRAL to transverse processes of vertebrae, FLEX 2. Identify and describe t...

Lecture 8: Thoracic Myology and Respiration 1. Be able to differentiate between epaxial and hypaxial muscles. Epaxial - DORSAL to transverse processes of vertebrae, EXTEND Hypaxial - VENTRAL to transverse processes of vertebrae, FLEX 2. Identify and describe the discussed hypaxial muscles and their primary function(s). Scalenus - pull ribs cranially, inspiration Serratus dorsalis cranialis - pulls craniolaterally, inspiration Serratus dorsalis caudalis - pulls caudally, expiration External Intercostal - inspiration Internal Intercostal - expiration 3. Identify and describe the discussed epaxial muscles and their primary function(s). Differentiate them based on their anatomic region. Transversospinalis - directly against spinous and transverse process Longissimus - over costal fovea, between trans and ilio Iliocostalis - over proximal portion of rib Function Extend, laterally flex, rotate vertebral column Woven appearance allows for small, precise, “slinky” movements 4. Describe the muscle fiber direction of the intercostal muscles and the abdominal muscles. External Intercostal Caudoventral ↘ fiber direction, INspiration Internal Intercostal Cranioventral ↙ fiber direction, EXpiration 5. Discuss the role(s) the individual muscles of respiration play in both inspiration and expiration. INspiration Scalenus - pull ribs cranially Serratus dorsalis cranialis - pull craniolaterally External Intercostal - pull caudoventrally Diaphragm - main muscle of inspiration EXpiration Serratus dorsalis caudalis - pull caudally Internal Intercostal - pull cranioventrally 6. Identify the nerve and vessels associated with the intercostal space(s) and discuss why the location is important to consider in practice. Intercostal arteries and nerves run directly caudal to rib body Important for placing needles, doing surgery, etc. Remind you to start at cranial aspect of rib to avoid severing arteries or nerves 7. Identify and describe the abdominal muscles and their roles in various functions. External abdominal oblique Caudal-ventral fiber, runs below rectus sheath Flex/laterally bend trunk, compress abdominal contents, support abdominal wall Internal abdominal oblique Cranial-ventral fiber, runs above rectus sheath Flex/laterally bend trunk, compress abdominal contents, support abdominal wall Transversus abdominis Deepest, run transverse from spine to linea alba, forks around lateral aspect of rectus sheath Compress abdominal contents, provide support, stabilize trunk Rectus abdominus Runs along sides of linea alba, surrounded by rectus sheath Linea alba Lecture 9: Thoracic Organs and Blood Flow 1. Describe the embryologic origin, development, and final form of the lungs. Derived from endoderm tube Pinches off (diverticulum) from esophagus, forms principal bronchi Principal bronchi will form lobar bronchi (lung lobes) Additional bronchi (bronchioles) branch off from lobar bronchi Lobar bronchi become lung lobes Right: cranial lobe, middle lobe, caudal lobe, accessory lobe Left: Cranial part of cranial lobe, caudal part of cranial lobe, caudal lobe 2. Identify, diagram, and describe the location, external & internal structures, of the adult heart. Location: ventral middle mediastinum, intercostal 3-6, breed variation External Structures: base (broad, round), apex (point), atria (L, R), auricle (L, R), Ventricle (L, R), Aorta (oxygenated blood to body), pulmonary trunk (deoxygenated to lungs), sulci (hold a. v.) Veins/Arteries: Left coronary (from aorta) → paraconal interventricular, circumflex Circumflex branch → subsinuosal interventricular branch Great cardiac vein → coronary sinus (parachute before right atrium) Internal Structures: Right atrioventricular valve, pulmonary valve, left atrioventricular, aortic Chordae tendinae (only in AV valves), papillary muscles (prevent backflow), trabecula septomarginalis (shortcut for nervous impulse that make heart beat) 3. Describe and diagram the blood flow from the main venous return, through the heart and lungs, and back to the aortic arch. Cranial vena cava → right atrium → right atrioventricular valve → right ventricle → pulmonary valve → pulmonary trunk → pulmonary artery → lungs → pulmonary vein → left atrium → left atrioventricular valve → left ventricle → aortic valve → aortic arch → aorta 4. Know the lymphatic structures of the thoracic cavity and their location. Thoracic Duct Continuation of cisterna chyli (located near lumbar vertebrae) Once you hit diaphragmatic crura, becomes thoracic duct Terminates in mediastinal venous system 5. Identify and describe the major arterial branching pattern from the heart to the distal aorta. ON HEART Aorta → right + left coronary artery ⇉ paraconal interventricular, circumflex → subsinuosal interventricular Aortic arch → brachiocephalic trunk (first branch on arch) → common carotid (first off of brachiocephalic trunk) → splits into right subclavian (parallel to right carotid) and left subclavian (branches after brachiocephalic trunk) DISTAL AORTA IN CAVITY Celiac - branch off aorta to stomach and liver Cranial mesenteric - below celiac, to intestines Caudal mesenteric - much below cr. mesenteric, to intestines External iliac - first set of parallel branches at bottom, to hind limbs Internal iliac - second set, to pelvic viscera Capillary beds - stomach, spleen, gi, liver Exchange between venous and arterial system before it hits the heart 6. Describe and diagram the venous return via the portal system back to the heart. Venous area between capillary beds and liver Filter deoxygenated blood that has come from GI and return it to heart Begins where cranial and caudal mesenteric VEINS become one Portal vein tributaries → gastroduodenal, splenic, r. Gastric Portal vein enters the liver, exits as hepatic veins, which join caudal vena cava Some veins unpaired (vena cava, cranial (thoracic part) and caudal (pelvic part)) 7. Describe where the four heart valves are heard best via auscultation. PMI - point of max intensity LEFT THORAX Pulmonary - 3rd intercostal, aortic - 4th, left AV - fifth RIGHT THORAX Right AV - 4th Lecture 10 Objectives - Fetal Circulation 1. Describe/diagram the fetal circulatory system. Compare and contrast it with the adult blood flow. THORACIC Foramen Ovale - between right and left atria, blood away from lungs Ductus Arteriosus - pulmonary trunk to aorta, blood away from lungs, some drips back to feed lungs ABDOMINAL Umbilical Veins - right atrophies, carry OXygenated blood from umbilical cord Ductus Venosus - continuation of left umbilical vein, bypass liver, goes to hepatic vein which goes to caudal vena cava which goes to the heart Umbilical Arteries - originate from internal iliac arteries, carry DEoxygenated blood back to umbilical cord Urachus - bladder to allantoic cavity 2. Identify and describe the adult remnants of the respective fetal structures. Foramen ovale → Fossa ovalis Ligamentum arteriousm → ductus arteriosus Umbilical vein (left) → round lig of liver (found near falicorm lig, NOT a fetal structure) Ductus venosus → ligamentum venosum Umbilical arteries → round lig of bladder (found near lat lig), looks like a nerve but it comes from internal iliac artery, so you know it is not a nerve Urachus → remnant in median lig of bladder 3. Discuss the clinical importance of persistent fetal structures in the adult. Patent Urachus - found immediately after birth, susceptible to infection, male foals Patent Ductus Arteriosus - causes ventricular hypertrophy due to increase in pressure from built up blood, heart has to beat harder, gets jacked. “Washing machine” murmur. Patent Foramen Ovale - murmur, right ventricular hypertrophy (due to needing to pump extra blood out, left to right is typical shunt) 4. Describe how you might best identify issues with persistent fetal structures in a newborn or adult. Patent urachus - dribbling from umbilicus, high susceptibility to uti Patent ductus arteriosus - washing machine murmur, ventricular hypertrophy Patent foramen ovale - murmur, RIGHT ventricular hypertrophy Lecture 11 Objectives: Autonomic Nervous System 1. Be able to differentiate between the CNS, PNS, and ANS through their primary purpose and physical location(s). CNS: contained in bones, brain (cerebrum, brainstem, cerebellum), spinal cord PNS: cranial nerves, spinal nerves (throughout entire body after neck) ANS: parasympathetic (rest and digest), sympathetic (fight or flight) 2. Describe the components of the ANS and list their corresponding nerve(s). Parasympathetic - CN 3, 7, 9, 10, vagus nerve, and pelvic nerve (S1-S3) Vagosumpathetic trunk, laryngeal nerve, dorsal/ventral vagal branch/trunk Sympathetic - cervicothoracic ganglion, ansa subclavia, vertebral nerve, middle cervical ganglion, sympathetic trunk, vagosympathetic trunk, splanchnic n (major, minor, lumbar), abdominal plexus, hypogastric, celiocomesenteric ganglion, caudal mesenteric ganglion 3. Identify and describe the origin, course of and function of the phrenic nerve. Origin: C5, 6, 7 (cervical plexus) Course: caudally towards diaphragm Function: innervate diaphragm (responsible for hiccups_) 4. Describe and understand the differing effects sympathetic vs. parasympathetic activation may have on various organs and senses. Iris: dilate (sym), constrict (para) Heart: increase rate (sym), decrease rate (para) GI: reduce peristalsis (sym), increase motility (para) 5. Identify and describe the sympathetic and parasympathetic structure discussed. Lecture 12 Objectives: Thoracic Limb Nerves and Vessels 1. Describe, diagram, and discuss the importance of the brachial plexus. Plexus: a place where things come together and leave as something else Brachial Plexus is the most important in the dog, gives rise to thoracic limb nerves Formed by C6, 7, 8 and T1-2 2. Identify and describe the Big 6 nerves of the brachial plexus, the spinal cord origins, and their respective muscle group(s). 1. Suprascapular n.: origin (C6, 7), innervates lateral muscle s of shoulder 2. Musculocutaneous n.: origin (C6, 7, 8), innervates medial shoulder mm., cranial brachium mm. 3. Axillary n.: origin (branch from C7, 8), innervates lateral and medial mm of shoulder 4. Median n.: origin (common trunk from C8, T1, 2), innervate caudomedial antebrachial mm. 5. Ulnar n.: origin (common trunk from C8, T1, 2), innervate caudomedial antebrachial mm. 6. Radial n.: origin (C7, 8, T1, 2), innervate caudal mm. of brachium, craniolateral antebrachial mm. Radial is the LARGEST nerve bundle 3. Describe the loss of function(s) which would be seen if any one of the above nerves were damaged. 1. Suprascapular - “shoulder sweeny”, muscle atrophy in shoulder, highly palpable scapula 2. Musculocutaneous - loss of elbow flexion and decreased medial forelimb sensitivity 3. Axillary - impaired shoulder flexion, sensation loss on lateral shoulder 4. Median - weakened flexion/pronation of carpus, sensation loss on palmar paw 5. Ulnar - weakened flexion of carpus/digits, sensation loss lateral paw 6. Radial - loss of elbow/carpus/digit extension, difficulty weight bearing, dorsal paw sensation loss 4. For each of the cutaneous nerves of the thoracic limb be able to: a) identify it, b) specify its parent nerve and c) describe its autonomous zone. 1. Radial n. → radial, lateral cutaneous antebrachial Middle of dorsal paw, cranial and lateral antebrachial 2. Axillary → lateral cutaneous brachial Lateral brachium 3. Median → Median Middle of palmar paw 4. Ulnar → caudal cutaneous antebrachial Caudal cubital joint to antebrachium, abaxial digit 5 5. Musculocutaneous → medial cutaneous antebrachial Medial antebrachium 5. Identify the subclavian artery, its main thoracic cavity branches, and describe how and when it becomes the primary supply of the thoracic limb. Left subclavian - branches after brachiocephalic trunk Vertebral - first branch off subclavian Costalcervical trunk - second branch on same side of vertebral Superficial cervical and internal thoracic are next at 180 degrees from one another Becomes the primary supply after passing the first rib and becoming axillary artery 6. Describe and identify the primary arterial supply of the thoracic limb, taking note of each name change, where this occurs, and what physical marker is used to delineate this change. At 1st rib: left subclavian → axillary artery At Cranial circumflex humoral artery (humoral joint): axillary → brachial artery At Common interosseous a. (cubital joint): brachial → median Left subclavian (first rib) axillary artery (cranial circumflex humoral a.) brachial artery (common interosseous a.) median 7. Describe the primary venous return of the thoracic limb, taking note of the clinical significance of the cephalic vein. Understand the various routes blood may return to the heart from this cephalic vein. Cephalic vein - commonly used for blood draws Can return to heart many ways: omobrachial, axial brachial, median cubital vein, axillary vein (all lead to cranial vena cava) 8. Identify and describe the superficial cervical and axillary lymph nodes and their respective drainage areas. Understand how they tie into the lymphatic structures within the thoracic cavity. Superficial Cervical: drains head, neck, part of thoracic limb Axillary: drains thoracic limb, thoracic wall Additional LN: tracheobronchial (at bifurcation of principal bronchi), cranial mediastinal (above trachea, cranial to heart, mediastinal region), cranial sternal (cranial sternum) ****IT IS ALL CONNECTED**** Lecture 13 and 14 Objectives - Alimentary System 1. Define and understand the clinical importance of ‘orad’ and ‘aborad’. Orad - TOWARDS the mouth Aborad - AWAY from the mouth 2. Describe how the abdominal mesothelial fold connects to the primitive endoderm and how it transforms to create the final structures in the neonate. Understand how this forms the Root of the Mesentery. Initial endoterm tube suspended dorsally by mesothelium Tube elongates and sinks in the middle, pulling mesothelium with Tube twists over on itself and forms loops with mesothelium still attached Increase surface area and give body a chance to digest/absorb properly Can not remove too much intestines, be mindful This initial dorsal suspension becomes the root of mesentery Root of mesentery is important bc it is the anchor point that provides blood, nerves, and lymphatic drainage Blood supply is cranial mesenteric artery 3. Identify and describe the different mesothelial portions throughout the abdominal cavity with their respective segment of intestines. Connects duodenum - mesoduodenum Connects jejunum - mesojejunum Connects colon - mesocolon Connects intestines, generally - mesentery 4. List the components of the digestive system in the order that they would normally be encountered by ingesta and state the general direction (cranial, caudal, right or left) that ingesta moves within each segment of the alimentary canal. 1. Oral cavity - tongue moves bolus to back of throat (caudal) 2. Pharynx, then larynx 3. Esophagus - caudal continuation of movement of ingesta a. Esophageal hiatus allows esophagus through diaphragm 4. Stomach - left from esophageal sphincter to right towards pyloric sphyncter 5. Duodenum - cranial duodenum, cranial duodenal flexure, descending duodenum, caudal duodenal flexure, ascending duodenum, duodenal jejunal flexure 6. Jejunum 7. Ilieum - length of antimesenteric iliac artery, ileocolic sphincter a. The cecum falls in here 8. Colon - ascending, right colic flexure, transverse, left colic flexure, descending 9. Rectum 5. Describe the following features for each organ which is normally located within the abdominal cavity: (NOTE: Emphasize the spleen, liver, gallbladder and biliary passages, stomach, small intestine, colon, pancreas, kidneys and female reproductive system) a. The organ system to which it belongs (e.g., digestive system) b. Its normal location within the abdomen (i.e., is it normally in the cranial or caudal aspect of the right or left quadrants of the abdominal cavity? c. Its blood supply d. The bold-faced features (from the dissection guide) 6. Trace the flow of bile through the hepatic duct, cystic duct and bile duct into the duodenum. Some free bile in the gall bladder Drains down into cystic duct Hepatic ducts (from each liver lobe) Drain into cystic duct Cystic duct will become bile duct At the last hepatic duct Bile duct drains into major duodenal papilla and into duodenum 7. Identify and describe the structures associated with both major and minor duodenal papillae. Major Duodenal Papilla Located in descending duodenum (closer to cranial flexure) Receives from pancreatic duct and bile duct Bile duct receives from hepatic duct, cystic duct, and gallbladder Minor Duodenal Papilla Located in descending duodenum (closer to caudal flexure Receives from accessory pancreatitis duct 8. Describe the hepatic portal system and its associated capillary beds. Identify which two veins form the initial portal vein and explain why venous blood from the supplying organs does not simply drain directly into the caudal vena cava. Hepatic Portal System Allows for blood to be filtered before returning to heart to be oxygenated Nutrients and toxins are both processed Cranial mesenteric vein (blood from small/large intestine, pancreas) Caudal mesenteric vein (blood from descending colon, rectum) First Capillary Bed (in digestive organs, where blood picks up toxins) Second Capillary Bed (in liver, where toxic blood is filtered and sent to vena cava) Blood can not be dumped into the vena cava bc its full of toxins lol 9. Provide the structure(s) that delineates the canine ileum from the jejunum. Anti-mesenteric iliac artery Where this artery ends, the ileum begins 10. Understand the clinical importance of the vasculature and other related structures as it would relate to a surgical procedure of the respective organ. Spleen - ligate as close to spleen as possible to avoid stomach arteries Intestines - cut on side away from mesentery, cut at 45 degree angle