Gross anatomy of the larynx PDF

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practice material for the Gross/microscopic anatomy of structures for the tests and final exam...

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Gross anatomy of the larynx (voice box) Location  

The larynx in found in the neck along the midline and a relatively superficial structure (anterior). The larynx is usually visible with a simple visual examination and its also palpable with care. The larynx is found between the laryngopharynx and the trachea. Shape size and appearance  The cross section of the larynx is roughly a triangular shape. It extends from C3 to C6. It is comprised of nine separate pieces of cartilages lined by the fibromuscular tissue. o Thyroid, epiglottis, cricoid, cuneiform (x2) arytenoid (vocal ligament) and corniculate cartilage  The hinge-like arrangement of the epiglottis and ability of the vestibular folds to close over the lumen combine to reduce the likelihood of food or drink getting into the airway.  Involved in speech formation o Ligaments attached to arytenoid cartilage and thyroid anterior- vocal cords o Stretched across lumen o In males the vocal cords are thicker and thyroid cartilage is longer Relations  Superior= hyoid bones  Anterior= neck wall and thyroid gland  Posterior= oesophagus  Lateral= carotid arteries  Inferior= trachea Blood supply and drainage  Supply & Venous return= Superior and inferior laryngeal A/V  Lymphatic= level VI (from AJCC system of classification) or paratracheal nodes

Gross anatomy of the trachea Location 

The trachea is a midline structure. It begins from the anterior region of the neck and runs inferiorly and posterior to mediastinum which is located in the thoracic cavity. Shape, size and appearance  The traches is tubular structure of about 10-11cm in length. It extends from the inferior region of cricoid cartilage at C6 to the T5 where it bifurcates (carina) into eft and right primary bronchi.  In cross section the trachea has a permanently open lumen which is about 2cm across. It resembles a "D" due to the arrangement of the c=shaped pieces of cartilage. There are about 16-20 C-shaped cartilages \. o The posterior wall is fibromuscular tissue which faces the oesophagus. Relations  Superior= larynx  Anterior= neck wall, thymus. Aortic arch and branches  Posterior= oesophagus  Lateral= carotid arteries, subclavian arteries, pleura and lungs  Inferior= inferior mediastinum Blood supply and drainage  SupplyBranches of the inferior thyroid artery and branches of bronchial artery - On occasion from branches of oesophageal arteries  Venous return- Inferior thyroid veins to brachiocephalic veins  Lymphatics o A series of paratracheal nodes on the left and right o Drain into main ducts o Superior section of trachea drain to nodes classified by level as per the head and neck AJCC system

Gross anatomy of the lungs Location  Paired structures in the that dominate the thoracic cavity. It lies lateral to the mediastinum. Shape, size and appearance  The lungs have conical shape with apex that projects into the thoracic inlet. It extends just superior to the sternal end of the of the first rib. The anterolateral and the posterior are smooth and conform to the thoracic cavity walls which is formed by the ribs and the intercostals cartilages. The lungs will extend inferiorly to the diaphragm (which form the floor of the thoracic cavity). The inferior base of the each lung for a conforms to the shape of the diaphragm resulting in a concave dome shape. The medial surface is also concave shape that has the hilum. The hilum is where the secondary bronchi, blood vessels, lymphatics and enervations enter and leave the lungs.  On average the combined lung volume is about ~6L in total. However the left lung be smaller volume by about 10%. This is because the left lung a cardiac notch which accommodates the heart. The lungs are separated into lobes by fissures. The left lung has two lobes and the right lung has three lobes. Note: these lobes are further subdivided into segments that compartmentalises the lungs even further. There a are 10 segments on the right lung and 8 or 9 in the left lung. Each segments has its own bronchial blood and lymphatic supply and drainage, thus making it a parallel structure. Relations  Superior= thoracic inlet  Anterior= costal cartilages and ribs  Posterior costal cartilages and ribs  Medial= thoracic vertebrae, mediastinum, bronchi, major vessels and oesophagus.  Inferior= diaphragm Blood supply and drainage  Dual blood supply  Right and left pulmonary arteries and right and left pulmonary veins o Deoxygenated blood in the arteries and oxygenated blood in the veins  To supply lung tissue with oxygenated blood: o Bronchial arteries which are branches of the descending aorta o Venous drainage is by azygous vein on the right and hemiazygos on the left.  Lymphatics o Superficial plexus drain visceral pleura o Deep plexus drains the bronchi o Both plexi drain to bronchopulmonary nodes then tracheobronchial nodes Microscopic anatomy of the LRT Structures  Larynx  Tracheas  Bronchi and bronchioles  Respiratory bronchioles  Alveoli  Make the bronchial tree Transitions 

Walls of conducting zone bronchi are multi layered: o Mucosa  Pseudostratified, ciliated columnar epithelium with goblet cells  Ciliated, simple cuboidal epithelium  Muscle and connective tissue lamina propria o Sub mucosa  Connective tissue

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Cartilage (hyaline)  C sections and complete rings  Incomplete rings  Plates  Reducing in size (RESPIRATORY ZONE HAS NO CARTILAGE)

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Adventitia  Connective tissue Wall of respiratory bronchioles is multi layered: o Mucosa  Simple squamous epithelium o Submucosa o Smooth muscle o Adventitia Terminal bronchiole is the final part of the conducting zone which open into the respiratory bronchioles that open into series of alveolar ducts. It supplies number of alveolar sacs which are comprised of 2-3 individual alveoli. The alveoli are surrounded by capillary beds. The alveoli is made up of primary type 1 alveolar cells which are specialised squamous epithelium. The pouch like alveoli are filled with air by mechanical ventilation. In order to prevent the collapse of the alveoli, type 2 cells produce surfactant which increases the surface tension across the type 1 cells membranes allowing them to maintain its pouch like structure during exhalation. The alveoli are surrounded by capillaries where gas exchange happens. There are also alveoli macrophages which protect the respiratory tract from potential pathogens and pollutants.

Gross anatomy of the testes Location  Paired organ  External (for temperature regulation)  Scrotal sac  Lie either side of the midline  Anterior pubic region Shape, side and appearance  Ellipsoid shape  Smooth outer surface  5cm long, ~2.5cm diameter  ~15-25ml volume  Posterior aspect has epididymis  Connected to spermatic cord and cremaster muscle superiorly Relation  Superior= spermatic cord, pubic symphysis  Posterior= epididymis  Anterior= ventral penis Blood supply and drainage  Supply o Testicular arteries  Drainage o Testicular veins

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Both extend to the abdomen Both wrapped alongside vas deferens, enervation and lymphatic drainage by connective tissue sheath to form the spermatic cord. Lymphatic drainage o Lymphatic vessels track with blood vessels o Drain directly to the para-aortic nodes o Note: do NOT get confused with inguinal nodes which drain the scrotum

Microscopic anatomy  Tunica vaginalis- outer serios membrane  Tunica albuginea- fibrous capsule of dense irregular connective tissue o Compartmentalises interior of texts into 200-300 lobules o Each lobule contains 1-3 seminiferous tubules o Lead to ductal network Seminiferous tubules  Site of spermatogenesis  Connective tissue contain vascularisation and Leydig cells (responds to LH and FSH and is the primary of T).  Epithelial lining- spermatogenic and sustentacular cells  Stem cells meiotic division  Sertoli cells- support and isolate  Lumen- beginning of ductal network Gross anatomy of the prostate gland Location  Male pelvis  Midline and deep  Close to the pelvic floor Size, shape and appearance:  Size of a kiwifruit  Max between 7 to 16g  The superior surface is called the base  The inferior portions is called the apex  It has a smooth surface to its connective tissue capsule  Surrounds the urethra o Ducts open from the gland into the prostatic urethra  Direction connection to the ejaculatory ducts o Ejaculatory ducts and prostatic urethra merge internally before emerging from the inferior surface of the gland.  Zones Relation  Superior= urinary bladder  Inferior= urethra and pelvic floor  Anterior= pubic symphysis  Posterior= rectum  Posterolateral= seminal vesicles Blood supply and drainage  Inferior vesical arteries o Branches of the internal iliac artery  Drainage o Visceral venous plexus to internal iliac veins  Lymphatic drainage

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Obturator (bilateral) External iliac nodes (bilateral) Internal iliac nodes (bilateral) Common iliac noes Lumber/para aortic noes

seminal vesical- accessory sex gland Location (note position will shift according to the bladder and rectal filling).  Paired organ  Pelvic cavity  True pelvis  Lateral to midline  Posterior section  Found at the end of the vas deferens. Size, shape and appearance  Coiled and folded glands  5-8cm long and 3-5cm diameter  ~13ml volume  Lobular appearance  Run parallel tp the ampullae of the vas deferens  Inferior ducts merge with the ampullar to for, ejaculatory ducts. Relations  Superior= ureter  Inferior= ejaculatory ducts  Anteromedial= prostate  Anterior= urinary bladder  Posterior= rectum  Medial= ampullae of vas  Lateral=pelvic bones Blood supply and drainage  Supply o Inferior vesical artery (branch of internal iliac artery)  Drainage o Inferior vesical plexus (drain to internal iliac veins)  Lymphatic drainage o Internal and exterior iliac nodes o Draining to common iliac nodes Microscopic anatomy Three main layers  Outer connective capsule  Middle smooth muscle  Inner mucosa o Lined by pseudostratified columnar epithelium o Interspersed by secretory cells- forming glands  Cross section resembles a honey comb o Convoluted nature of ductal network Cellular appearance characteristic  Secretory cells often have liquid droplets in the cytoplasm o "foamy" appearance  May encounter sperm cells in the lumen o Not produced there, backflow from ampullar of vas

Gross anatomy of the breast Location  The breast are paired structure that sit on the external surface of the chest wall.  The superior and inferior extent of the breast is from the second rib to the sixth rib.  The medial border of the breast is considered to be the lateral edge of the sternum running laterally to a line along the mid-axillary axis which forma the lateral margin Shape, size and appearance  The breast hemispherical in shape with the inferior aspect being convex.  Quadrants: o A line running along the superior inferior axis which starts about 2cm lateral to the mid clavicular line will go through the nipple which is the most prominent surface feature of the breast. o A horizontal line runs from medial to lateral dividing the breast into upper and lower quadrant. o Note: the upper outer quadrant is more irregular shape which is knows as the tail; it extends obliquely towards the axilla.  The gap between the inferior attachment and the rounded part of the breast is called the inframammary fold or crease. o Ptosis is the term used to describe the extent to which the breast changes from what is considered normal (when the nipple lie superior to the inframammary fold) Relations  Posterior= anterior chest wall  Medial= sternum  Lateral=axilla Blood supply and drainage  Supply and drainage o Can be broken into medial and lateral supplies o Internal mammary (A & V) is also known as the internal thoracic (A & V)  Lymphatic drainage o Can be divided into lateral medial drainage o Strong connection to axillary and upper limb drainage. o The Rotter's and internal mammary chain (also known IMC)= drains the medial side of the breast o The lateral side is drained by the pectoral (anterior), subscapular (posterior), lateral, central axillary, sub-clavicular and supraclavicular nodes.  Note: that the lateral and central nodes also serves as part of the lymphatic drainage for the upper limb.

Microscopic anatomy of the breast  Modified sudoriferous glands  15-20 lobes  Smaller lobules which contain the alveoli  Ductal network draining to the nipple  Myoepithelial cells (have the ability to contract and help to expel the secretion of the gland into the ductal)  The adipose tissues separates the lobes and determines breast size  The connective tissue forms suspensory ligaments  Skin covering the sebaceous glands

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Genetic, lifestyle and hormonal status can causes changes in both volume composition and activity of the breast.  Aging (and resulting hormonal changes) will cause changes (adipose tissue in the body which can also affect the breasts). Gross anatomy of the uterus Location  The uterus is found in in the true pelvis of a female, the true pelvis lies inferior to the pelvic brim  The uterus lied across the middle and between the sacrum and the pubic symphysis, the this is the usual location of the uterus, pregnancy can cause it to expand into false pelvis and abdomen. Shape, side and appearance  The uterus is approximately 7.5cm along the longest axes and is pear shaped, with a anteriorly rounded fundus (fallopian tubes attach nearby). The body is more tapered and with the narrow isthmus opening into the cervix. The cervix has internal os (uterus side) and an external os where it enters into the vagina .  The uterus has smooth muscular outer surface covered in peritoneum.  The fundus is "normally" orientated anterior which can be changed after pregnancy to be in retroflexion.  Ligaments o A key features of the appearance of the uterus is a series of attachments known as ligaments that run between the uterus and the surrounding anatomy. There are four ligaments that are involved in to maintaining the position of the uterus in the pelvis. o The broad ligament folding of the peritoneum which attaches to the pelvic bones. The uterosacral ligaments that extend on either side of the rectum to the sacral parts of the vertebral column. The cardinal ligament which attaches he cervix to the pelvic bones and the round ligaments which attaches the fundus to vulva (labia minora). Relations  Anterior: small intestines  Posterior= rectum  Superolateral= fallopian tubes  Inferior= urinary bladder  Posteroinferior= vagina  Lateral= pelvic bones Blood supply and drainage  Supply and drainage o Uterine arteries which is a branch of the internal iliac arteries o Ovarian arteries- directly from abdominal aorta o Can anastomose o Venous return by reciprocal veins  Lymphatic drainage o Upper part of the body and fundus to para-aortic chains o Lower part to external iliac nodes o Around the fallopian tubes into inguinal nodes o Drainage of the cervix is complex  Lateral= external iliac nodes  Posterolateral= internal iliac nodes  Posterior= sacral nodes o Can expand during pregnancy. Microscopic anatomy of the uterus  The uterus is composed of three layers. The most superficial layer is perimetrium, a visceral layers of peritoneum. The second layer is the myometrium which is a thick muscular layer. The inner most layer is the endometrium layer which thinner than myometrium but thicker than the perimetrium. The thickness of this layer varies over the course of menstrual cycle.

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The perimetrium has outer epithelial later supported by an underlying connective tissue component and is early the thinnest layers of the uterine wall. T o The myometrium has three layers in which the outer layer superficial layer is longitudinally arranged, the middle layers is arranged in circular fashion and the third deep layer is longitudinal. This is allows immense capability of stretching during pregnancy. o The endometrium has two layers: the stratum functionalis and stratum basalis. Stratum functionalis can double its thickness over menstrual cycle and it’s the layer that is shed off. Stratum basalis is the superficial layer. Internal blood supply o Main supple is rich. There are up to 5 orders of branching: branches of the ovarian arteries is directed to the arcuate arteries--> radial--> straight arteriole --> spiral arteriole which are in the endometrium. During the proliferative phase of the cycle the spiral arterioles are stimulated to grow and extend (build of the stratum functionalis and high levels of E2 and progesterone in the blood circulation).

Gross anatomy of the oesophagus Location  The oesophagus is located in the midline and runs from the neck to the abdomen (C6 to T1).  It lies between the vertebrae and the trachea.  Series of deviation along the route. Shape, size and appearance  The oesophagus is collapsible muscular tube which changes during deglutition. It about 12cm long (C6 to T11). It has a upper and a lower sphincter. Relations  Superior= laryngopharynx  Inferior= diaphragm and stomach  Anterior= trachea, right pulmonary artery and left atrium  Posterior= vertebrae (C and T), thoracic duct and descending aorta.  Lateral= lings and primary bronchi Blood supply and drainage  Branches of inferior thyroid, descending aorta and left gastric arteries depending the level.  Venous return is into the azygous, hemi-azygous and left gastric veins depending on the level.  Lymphatic drainage o Depend on level o Level IV (from o Posterior mediastinal o Paraesophageal o Gastric Gross anatomy of the stomach Location  The stomach is found in the upper left anterior portion of the abdomen or can be described as being in the left upper quadrant or as having sections in the left hypochondriac and umbilical region and with majority of its volume in the epigastric region. It is found between the oesophagus and the duodenum.  The most upper part of the stomach lies just inferior to the diaphragm.  A significant portion of the stomach is protected by the ribcage.  The stomach lies between T11 and L2. Shape, size and appearance  It has form of a J shape. It consists of a fundus, cardia (where the oesophagus attaches to the stomach), body and pyloric section (where the opens to the duodenum).

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It has an inferiorly orientated convex greater curvature (inferior) and lesser curvature on the superior aspect. It is orientated in the posterior to anterior axis. The entry and exit points of the stomach are controlled by the lower oesophageal sphincters and the pyloric sphincters.

Relations  Superior= diaphragm  Inferior= pancreas, transverse colon  Anterior= diaphragm, left costal margin, left lobe of the liver, anterior abdominal wall  Posterior= diaphragm, left kidney, left portion of the transverse colon, splenic flexure and spleen.  Lateral; spleen (left and duodenum (right). Blood supply and drainage  Lesser curvature-->left and right gastric arteries  Greater curvature-->branches of the hepatic and splenic arteries  Venous return-->left and right gastric vein which drains into the portal system  Lymphatic drainage depends on the section of the stomach o Lesser curvatures--> left and right gastric nodes o Greater curvature--> pyloric, gastroepiploic and pancreatic nodes o All draining to the coeliac nodes.

Gross anatomy of the small intestines Location  The small intestine is located across the anterior portions of the lower abdomen and upper pelvic with the majority of the structures falling within the umbilical and pubic regions of the abdominopelvic regional system  Sections of the colon can be found lateral to the small intestines. The superior limit of the small intestines is marked by the inferior most of the costal margin and the inferior limit is marked by the pubic bones just superior to the pubic symphysis. Shape, size and appearance  The small intestines stands out to be the longest part of the GI tract (3-5m). The term "small" applied to the cross se...