Anatomy and Histology

Question 1

Surface anatomy of right and left pleura

Answer 1

Anterior border:

right pleura: extends vertically from sternoclavicular joint, to xiphiosternal.

Left: similar course, but at the level of the 4th costal cartilage, deviates laterally, and extends to lateral margin of sternum to for cardiac notch. The turn to xiphesternal notch.

Inferior border: It passes around chest wall. At 8th rib mid clavicular, at 10th rib mid axillary, 12th rib at vertebral column.

Posterior border: Starts at T12 spine and extends to T1

Question 2

Courses and branches of typical intercostal nerve

Answer 2

Nerves come out through intervertebral foramen and runs behind sympathetic chain. It then runs through the costal grove under the cover of the lower border of the rib behind internal intercostal muscles. Then finally, anteriorly the nerve crosses in front of the internal thoracic vessels. It then pierces the intercostal muscles, and pec major to end as cutaneous branches.

Question 3

Give beginning course and end of internal mammary artery. Name it’s branches. Mention it’s clinical importance.

Answer 3

Origin: lower aspect of subclavian artery

It descends downwards and medially behind the clavicle in front of the apex of the lung. It enters thorax through thoracic inlet. It descends vertically behind upper 6 costal cartilages and intervein in the costal spaces

Mediastinal branches
Thymic branches
Pericardiacophrenic artery
Sternal branches
Bronchial branches
Tracheal branches

It ends by dividing into its terminal branches, superior epigastric and musculophrenic arteries.

Gives blood supply to parietal pleura

Question 4

Enumerate relations below arch of Aorta

Answer 4

1. Bifurcation of pulmonary trunk.
2. Left principal bronchus.
3. Ligamentum arteriosum.
4. Superficial cardiac plexus.
5. Left recurrent laryngeal nerve.

Question 5

Enumerate the openings of right atrium

Answer 5

1. Opening of SVC
2. Opening of IVC
3. Opening of coronary sinus
4. Opening of anterior cardiac veins

Question 6

Enumerate four events at sternal angle

Answer 6

Beginning of arch of aorta

End of arch of aorta

End of ascending aorta

Beginning of descending aorta

Bifurcation of pulmonary trunk.

Question 7

Enumerate four structures on right and left side of thoracic part of trachea

Answer 7

Right: right vagus nerve, right brachiocephalic vein, superior vena cava and azygos vein

Left: aortic arch, left recurrent laryngeal nerve, left common carotid artery and left subclavian

Question 8

Four constriction of esophagus

Answer 8

At its beginning

where it crosses arch of aorta

Where it crossed by left principle bronchus

Where it passes through the esophageal op of diaphragm.

Question 9

Give course and tributaries of the thoracic duct. Mention regions of the body drained by it.

Answer 9

It begins in the abdomen, at the level of the lower border of T12,

It enters the thorax by passing through the aortic opening of the diaphragm

It traverses the thorax first in the posterior mediastinum then in the superior mediastinum to enter the root of the neck.

1-Posterior intercostal nodes: drain parts of the thoracic wall.

2-Posterior mediastinal nodes: drain the esophagus, pericardium and diaphragm.

Question 10

Enumerate the structures found in lower concave aspect of arch of aorta

Answer 10

Lt principle bronchus

Ligamentum arteriosum

Superficial cardiac plexus

Lt recurrent laryngeal

Question 11

What are the structures posterior and to the right aspect of aortic arch

Answer 11

1. Trachea.
2. Deep cardiac plexus
3. esophagus
4. Left recurrent laryngeal nerve.
5. Thoracic duct

Question 12

Mention the branches and distribution of right coronary

Answer 12

Marginal Artery
Posterior interventricular artery
Right conus artery
Small branches

Distribution:

Whole right atrium

Whole right ventricle, except band on sternocostal surface

A band of the diaphragmatic surface of the left ventricle

Posterior 1/3 of interventricular septum

The whole conducting system.

Question 13

List branches of descending thoracic aorta

Answer 13

1- Nine pairs of posterior intercostal arteries (from 3rd to 11th).

2- One pair of subcostal arteries.

3- Two left bronchial arteries.

4- Four esophageal branches.

5- Few small twigs to the pericardium, mediastinum and diaphragm.

Question 14

Mention the site formation and branches of the superficial cardiac plexus

Answer 14

Site: it lies in the concavity of the arch of the aorta, on the right anterior surface of the ligamentum arteriosum.

Formation: 2 branches

Superior cervical cardiac branch
Inferior cervical cardiac branch

Branches: deep cardiac plexus, right coronary plexus and left pulmonary plexus.

Question 15

Mention the site formation and branches of the deep cardiac plexus

Answer 15

In front of bifurcation of trachea

Formed by all cardiac branches

Branches:

Right and left atrial branches

Right and left coronary plexus

Right and left anterior pulmonary plexus.

Question 16

Enumerate branches of the arch of aorta

Answer 16

Brachiocephalic artery
Left subclavian
Left common carotid

Question 17

Define bronchopulmonary segments and describe their shape and distribution in right and left lung. Give a clinical related significance.

Answer 17

Def: bronchopulmonary segment is a functionally independent unit of lung tissue supplied by segmental bronchus.

Each segment is wedge shaped having an apex at the hilium and a base at surface of lung.

Right 10:
upper lobe: apical, posterior and anterior
middle lobe: lateral and medial
Lower: superior basal, medial basal anterior basal, lateral basal and posterior basal

Left 8:
Upper lobe: apicoposterior anterior superior lingular and inferior lingular
Lower: superior basal, anterior basal , lateral basal and posterior basal.

Clinical imp: if one segment is diseased, it can be removed and rest of lung is kept.

Question 18

Give an account of the sinuses of the serous pericardium

Answer 18

There are two types:

Transverse sinus: a transverse passage between the arterial and the venous end of the heart. It connects the right and left sides of the pericardial cavity.

Oblique sinus: it is a blind recess of the pericardial cavity which extends upwards between the left atrium and fibrous pericardium.

Question 19

Give an account on the azygos and hemiazygos venous system

Answer 19

The azygos vein is a vein that connects the back of the IVC with the SVC. It has two main branches: the superior and inferior hemiazygos veins

If there is an obstruction above the entrance of the azygos vein, the venous drainage of the upper 1/2 of the body is diverted to reach the heart via the azygos vein

Question 20

Compare necrosis and apoptosis

Answer 20

Necrosis: pathological due to anoxia, mechanical injury

LM: Swell and burst, darkly stained nuclei with condensed chromatin

Fate: phagocytosed by macrophage

Apoptosis: can be patho or physiological

LM: do not swell decrease in size: darkly stained nuclei with condensed chromatin.

fate: phagocytosed by macrophage

Question 21

Difference between meiosis and mitosis in site, division number, crossing over separation and daughter cell.

Answer 21

Mitosis:
Site: somatic
Single division
NO cross over or exchange of genes
Centromeres divide into chromatids
Two somatic cell diploid

Meiosis:
testes or ovaries
Two successive divisions with no S phase
crossover leads to gene exchange
Chromosomes moves towards one pole
Four haploid cell

Question 22

Explain what Barr bodies are

Answer 22

inactive coiled X chromosome present in nuclei of female cells.

Question 23

Describe and define alveolar epithelium and the blood air barrier

Answer 23

Alveolar epithelium:

Type I pneumocyte: flat nuclei, tight junctions, provide thin membrane for gas exchange

Type II pneumocyte: Central round nucleus, rich in organelles. lined with microvilli, secrete surfactant.

Blood air barrier components: cytoplasm of type I pneumocyte, surfactant, basal lamina of pneumocyte type I and basal lamina of capillary endothelial cells.

Question 24

Describe the blood thymic barrier

Answer 24

its a wall that separates T-lymphocytes in the cortex from antigens in the circulating blood. It allows T lymphocytes to multiply and differentiate without being attacked by foreign antigens.

It contains endothelium, basal lamina, pericyte

Question 25

Difference between medium sized artery and vein

Answer 25

Medium sized artery:

T media is thicker than adventitia
Elastic lamina, so they retain shape

Medium sized vein:

Thin wall. T advenatia is thicker than media, has valves T media is high in collagen.

Question 26

Mention site and function clara cell

Answer 26

Clara cell are dome shaped non-ciliated, found in bronchiolar epithelium

Function: may act as stem, protect against emphysema, protection of bronchiolar epithelium, degregation of inhaled toxins

Question 27

List the differences between the olfactory mucosa and respiratory mucosa. in thickness of epithelium, goblet cells, cilia and basement membrane.

Answer 27

Olfactory mucosa: thicker epithelium, absent goblet cells, non motile cilia, thin basement membrane

Respiratory: Thinner epithelium, present goblet cell, has lots of cilia. thick basement

Question 28

What is the blood air barrier

Answer 28

 structures through which gas exchange occurs.  It comprises four layers:

1) pulmonary surfactant.
2) The cytoplasm of Type II pneumocytes
3) basal lamina of type I alveolar cells and capillary
4) endothelial cells of blood capillaries