Unit 2 Lecture/Learning Objectives

Question 1

Describe the organization of the trunk

Answer 1

a. Thorax: Left and right pleural cavities, mediastinum
b. Abdomen: Peritoneal cavity
c. Pelvis: Pelvic cavity
d. Space occupied by organs, air, fluid, fat, foreign body, tumor, fetus

Question 2

Describe the anatomical boundaries of the mediastinum, and also what function it drives?

Answer 2

It is bounded by the sternum and vertebral bodies.
Sup & Inf defined by a plane from the sternal angle to intervetebral disc between T4/5.

It drives the conduit functions of the thorax: it is a conduit for the esophagus, thoracic duct, and nerves that are passing into the abdomen

Question 3

What are the contents of the superior subdivision of the mediastinum

Answer 3

i. Thymus, r&l brachiocephalic veins, superior vena cava, arch or aorta and br, trachea, esophagus, phrenic nerves, vagus nerve, left recurrent branch of left vagus nerve, thoracic duct, other vessels and lymphatics

Question 4

What are the contents of the inferior-anterior subdivision of the mediastinum

Answer 4

i. Thymus, lymph nodes, sternopericardial ligaments, internal thoracic vessels, fat, connective tissue

Question 5

What are the contents of the inferior-middle subdivision of the mediastinum

Answer 5

i. Pericardium: Heart, origins of great vessels, nerves, and smaller vessels

Question 6

What are the contents of the inferior-posterior subdivision of the mediastinum

Answer 6

i. Esophagus, trachea, thoracic aorta, azygous vein, thoracic duct and nodes, sympathetic trunk, thoracic lymph nodes

Question 7

Describe the anatomical relations of the pericardium to the heart

Answer 7

Surrounds heart except for where great vessels emerge
From outer to inner:
i. Fibrous pericardium
ii. Parietal layer (serous pericardium)
iii. Pericardial cavity
iv. Visceral layer of epicardium (serous pericardium)
v. Heart

Question 8

Describe the basic anatomy of the cardiac conduction system

Answer 8

a. Sinu-atrial (SA) node: In wall of right atrium near junction of SVC
b. Atrioventricular (AV) node: In interatrial septum, superior to opening of coronary sinus, between fossa ovalis and AV orifice
c. Atrioventricular bundle and branches
d. Subendocardial plexus/Purkinje Fibers

Question 9

Describe the flow of blood through the heart

Answer 9

a. Right to left
b. Atria to ventricles
c. Valves control flow

Question 10

Describe the areas of cardiac auscultation and their relationship to the valves.

Answer 10

a. Aortic area
i. Superior and to right of valve
ii. Right upper sternal border

b. Pulmonic area
i. Superior to valve
ii. Left upper sternal border

c. Tricuspid area
i. To the left of valve
ii. 4th left intercostal space

d. Mitral area
i. Inferior and to the left of valve
ii. 5th left intercostal space

Question 11

Describe the anatomical relations of the parietal and visceral layers of pleura to their associated structures

Answer 11

a. Fist (lung) and balloon (pleura) model
b. Parietal is outer layer
c. Visceral is internal layer
d. Reflect and are continuous at base of lung

Question 12

Describe the basic anatomy of the conduction system of the lung

Answer 12

a. Consists of trachea, right and left bronchi, lobar bronchi, segmental (tertiary) bronchi, and bronchopulmonary segments
b. Right lung has 3 lobes (inferior, middle, superior)
c. Left lung has 2 lobes (inferior, superior)
d. Right bronchus is wider and takes a more vertical course
e. Foreign bodies tend to lodge in right bronchus rather than left

Question 13

Define bronchopulmonary segment and relate bronchopulmonary segments to the flow of blood through the lung

Answer 13

a. Area of lung supplied by segmental bronchus and its accompanying pulmonary arterial branch
b. Tributaries of pulmonary veins pass intersegmentally between and around BPS
c. Smallest functionally independent area of lung

Question 14

Describe the anatomical basis for ventilation of the lung

Answer 14

a. Volume of thoracic cavity increases
i. Vertical axis via contraction of diaphragm
ii. Anterior/Posterior and laterally by elevation of ribs
b. Parietal and visceral pleura lubricated and can slide over each other
i. Surface tension keeps lungs in contact with thoracic wall
ii. Lung expands and fills with air when chest expands
c. Inspiration involves diaphragm, external intercostal, internal intercostal
d. Forced inspiration additionally involves sternocleidomastoid, pectoral and scalene muscles
e. Expiration involves relaxation of diaphragm and recoil of lung
f. Forced expiration additionally involves internal intercostal and abdominal muscles

Question 15

Define coarctation of the aorta and its most common location. Describe the clinical significance of a postductal coarctation

Answer 15

(A) Stenosis in arch of aorta or thoracic aorta
(B) Most often occurs near the ligamentum arteriosum
(C) Postductal coarctation is a coarctation inferior to that structure
(D) As a result, a good collateral circulation develops between proximal and distal aorta via intercostal and thoracic arteries
(E) Collateral vessels may increase in size to cause visible pulsation and erosion of the surface of adjacent ribs

Question 16

Describe the rationale and location for ligation of the internal iliac artery to control pelvic hemorrhage

Answer 16

(A) Ligated near proximal end
(B) Numerous anastomoses maintain blood supply
(C) Allows for a large decrease in local blood pressure

Question 17

Define portal hypertension and describe the most common physical examination findings and clinical implications of this abnormality

Answer 17

(A) An abnormally high blood pressure in portal venous system
(B) Blood cannot pass through liver, causing reversal of flow into esophageal tributary
(C) Submucosal veins enlarge markedly leading to esophageal varices
(D) Rupture leads to severe hemorrhage
(E) Also can result in varicose veins
(F) Occurs in relation to hepatic cirrhosis

Question 18

Describe the most common path/route of lymphatic drainage from breast cancer

Answer 18

(A) Breast (104)

i. Spreads via lymphatic vessels to lymph nodes (primarily axillary)
ii. Can spread to supraclavicular lymph nodes, opposite breast, or abdomen

Question 19

Describe the most common path/route of lymphatic drainage from bronchiogenic cancer

Answer 19

(B) Bronchogenic (125)

i. Metastasizes early to bronchopulmonary lymph nodes and subsequently to other thoracic lymph nodes
ii. Infection also often spreads to supraclavicular lymph nodes

Question 20

Describe the most common path/route of lymphatic drainage from ovarian cancer

Answer 20

(C) Ovarian (vs. labial) (401)

i. Ovarian drains to the lumbar lymph node groups along ovarian vessels
ii. Labial drains to superficial inguinal nodes

Question 21

Describe the most common path/route of lymphatic drainage from testicular cancer

Answer 21

(D) Testicular (vs. scrotal) (215)

i. Testis drain first to the peritoneal lumbar lymph nodes
ii. Scrotom drains first to superficial inguinal lymph nodes

Question 22

Describe the most common path/route of lymphatic drainage from sigmoid colon cancer

Answer 22

(E) Sigmoid colon (401)

i. Drains to inferior mesenteric node group

Question 23

Describe the process by which the coelom (body cavity) forms

Answer 23

Cranial (foregut), caudal (hindgut), and lateral (midgut) folding

Question 24

List and describe the embryonic structures that contribute to the formation of the diaphragm. Describe the embryological basis for and consequences of congenital diaphragmatic hernias.

Answer 24

a. Septum transversum
b. Pleuroperitoneal membranes
c. Myotomes of cervical region (C3-C5)
i. Similiarly innervated
ii. Phrenic nerve
d. Dorsal mesentery of esophagus
e. Body wall mesoderm
f. Sometimes pleuroperitoneal folds are incomplete
i. Congenital diaphragmatic hernia
1. Pulmonary hypoplasia
2. Intestine migrates up
3. Compresses lung and heart

Question 25

Describe the process by which the pleuropericardial membranes partition the thoracic cavity into pleural and pericardial compartments.

Answer 25

Pleuropericardial folds compartmentalize primitive pericardial cavity into pericardial cavity and pleural cavity

Question 26

Describe the early development of the heart through the establishment of the primitive heart chamber regions and looping of the heart tube

Answer 26

a. Splechnic lateral plate mesoderm
b. Vasculogenic cell clusters fuse to form endocardial tube
c. Folds down during cranial fold
d. Lateral fold fuses two sides to form tube (primitive heart tube)
e. Unfused sections (first aortic arch arteries)
f. Also fuse in back (dorsal aorta)
g. Three pairs of veins drain into heart tube (cardiac, umbilical, placental)
h. One artery leaving (aortic sac)
i. At day 22 cardiac looping begins
i. Atria curve up
ii. Single atrium divides into two
iii. Ventricles curve ventrally

Question 27

Describe the early development of the lung from the respiratory diverticulum of the foregut.

Answer 27

a. Ventral out-pocketing of foregut
b. Folds separate esophagus from lung bud below the larynx
i. Tracheoesophageal ridge/septum
ii. Begin to branch left and right
iii. Left branches into two (two lobes)
iv. Right branches into three (three lobes)
v. Branching is repeated
vi. Tertiary branches lead to segments
vii. Terminal branches are alveoli
viii. Ferive from endoderm (lining) and splechnic lateral plate mesoderm (vessels and connective tissue)
ix. Four stages
1. Pseudoglandular-developing lung resembles glands
2. Canalicular-terminal sacs begin to form but are too immature for gas exchange
3. Terminal sac stage-increased number of alveoli and terminal sacs that can perform gas exchange
4. Alveolar stage-drastic increase alveoli

Question 28

Describe the pathway of fetal circulation, the changes that occur after birth, and the remnants of fetal circulation that may be found in the adult.

Answer 28

a. Foramen ovale between left and fight atrium bypasses pulmonary circulation
i. After birth closes to form fossa ovalis
b. Blood goes from placenta to left atria to systemic circulatory system
c. Ductus arteriosus also from pulmonary trunk to aorta also bypasses pulmonary circulation
i. After birth becomes ligamentum arteriosum
d. Ductus venosus bypasses hepatic portal system
i. After birth becomes Ligamentum venosum
e. Umbilical vein
i. Delivers oxygen and nutrient rich blood from placenta to fetus
ii. After birth becomes round ligament
f. Umbilical arteries
i. Delivers blood from fetus to placenta
ii. After birth becomes medial ligaments