Anatomy Session 3 - Cardio/Resp

Question 1

What are the boundaries of the thoracic cavity?

Answer 1

The thoracic cavity is continuous with the neck via the superior thoracic aperture but is separated from the abdominal cavity by the diaphragm

Question 2

What does the thorax contain?

Answer 2

The major organs of the thorax are the heart and lungs.
It also contains:
● the trachea (windpipe), which passes from the neck to the thorax
● the oesophagus
● arteries and veins
● nerves – somatic and autonomic
● lymphatic vessels.

Question 3

What does the thoracic cage do?

Answer 3

The thoracic cage:

• protects the thoracic and some abdominal viscera (organs)
• provides an attachment for the muscles of breathing and muscles that move the upper limb

Question 4

What is the sternum composed of?

Answer 4

It is composed of three parts:
* manubrium – the superior part
* body – inferior to the manubrium
* xiphoid process (or xiphisternum) – inferior to the body.

Question 5

What are the ribs composed of?

Answer 5

● The anterior parts of the ribs are composed of costal cartilage. This gives the thoracic cage some ‘springiness’.

Question 6

Where do the thoracic vertebrae articulate with each other?

Answer 6

They articulate with each other at intervertebral joints

Question 7

What does the heart contain?

Answer 7

● The heart contains specialised nerve cells and fibres, which spontaneously generate and conduct the electrical activity that stimulates contraction of the myocardium (heart muscle). These specialised nerve cells are under autonomic control – sympathetic stimulation increases the heart rate and parasympathetic stimulation decreases the heart rate.

Question 8

What do valves do?

Answer 8

Valves within the heart ensure that blood flows only in one direction through the heart and cannot flow backwards.
* Atrioventricular valves lie between the atria and ventricles (the tricuspid valve on the right and the mitral valve on the left).
* Semilunar valves lie between the ventricles and the large blood vessels that carry blood from them (the pulmonary valve at the entrance to the pulmonary trunk and the aortic valve at the entrance to the aorta).

Question 9

What supplies the myocardium?

Answer 9

The myocardium is supplied with blood by the coronary arteries.

Question 10

What occurs in the cardiopulmonary circulation?

Answer 10

The cardiopulmonary circulation is the circulation between the heart and lungs. arteries carry deoxygenated blood and veins carry oxygenated blood.

Veins carry blood towards the heart and arteries carry blood away from it – this is true for both the systemic and cardiopulmonary circulations.

Question 11

What is the lung divided into?

Answer 11

Each lung is divided into lobes:
* the right lung has three lobes – a superior (upper), middle and inferior (lower) lobe
* the left lung has two lobes – a superior and an inferior lobe
* fissures separate the lobes.

Question 12

What is each lung served by?

Answer 12

Each lung is served by:
● one pulmonary artery (carrying deoxygenated blood into the lung from the right ventricle)
● two pulmonary veins (carrying oxygenated blood from the lung into the left atrium)
● one main bronchus (carrying air between the lung and the trachea).

Question 13

What is the bronchial tree?

Answer 13

The bronchial tree describes the branching system of tubes that conduct air into and out of the lungs.

Question 14

What are the walls of bronchial tree made up of?

Answer 14

The walls of the trachea and bronchi contain smooth muscle and cartilage. Cartilage acts as a scaffold and ensures that the trachea and bronchi remain open.
The walls of the bronchioles do not contain cartilage, only smooth muscle. The smooth muscle can contract and relax; this is under autonomic control.

Question 15

What causes the bronchioles to move?

Answer 15

• Parasympathetic stimulation narrows the bronchioles = bronchoconstriction.
• Sympathetic stimulation opens the bronchioles = bronchodilation.

Question 16

What are the key surface landmarks of the thorax?

Answer 16

• The sternal angle is a key surface landmark. This is because it lies at the same level as the second ribs - and from here we can count the rest of the ribs.

Question 17

What lines are on the surface of the thorax?

Answer 17

● Midsternal (anterior median) line – drawn straight down the centre of the sternum.
● Midclavicular line – drawn inferiorly from the midpoint of the clavicle.
● Anterior axillary line – drawn inferiorly from the anterior axilla (armpit).
● Midaxillary line – drawn inferiorly from the middle of the axilla.
● Posterior axillary line – drawn inferiorly from the posterior axilla.
● Scapular line – drawn inferiorly through the scapula.
● Midvertebral (posterior median) line – drawn straight down along the spinous processes of the vertebrae.

Question 18

What is the diaphragm?

Answer 18

– a sheet of skeletal muscle that is vital for breathing. Openings in the diaphragm allow structures to pass between the thorax and abdomen.

Question 19

What is the course of the oesophagus?

Answer 19

It carries swallowed food and fluid to the stomach; it passes from the neck, into the thorax and through the diaphragm

Question 20

What is the thoracic cage?

Answer 20

The thoracic cage (rib cage) is the bony skeleton of the thorax. It is semi-rigid and moves with breathing to allow the lungs to expand.

Question 21

What is the thoracic cage composed of?

Answer 21

is composed of the sternum (breastbone), 12 pairs of ribs and the thoracic vertebrae.

Question 22

What does the manubrium articulate with?

Answer 22

● Laterally, the manubrium articulates with the clavicle (collarbone) at the sternoclavicular joint.
● The manubrium and body of the sternum articulate with each other at the manubriosternal joint, also known as the sternal angle (or the ‘angle of Louis’).

Question 23

Where is the suprasternal notch?

Answer 23

● The superior border of the manubrium has a notch in it – this is the suprasternal (jugular) notch.

Question 24

Where does the sternum lie?

Answer 24

The sternum lies anteriorly in the midline of the thoracic cage.

Question 25

What forms the walls of the thoracic cage?

Answer 25

Twelve pairs of ribs form the anterior, lateral, and posterior walls of the thoracic cage.

Question 26

What lies in the intercostal spaces?

Answer 26

Intercostal muscles lie in the intercostal spaces between the ribs and move the thorax for breathing.

Question 27

What does costal relate to?

Answer 27

(costal = relating to the ribs)

Question 28

Where do the ribs articulate with the costal cartilage?

Answer 28

at costochondral joints.

Question 29

What do the costal cartilages of the upper ribs articulate with?

Answer 29

The costal cartilages of the upper ribs articulate with the sternum at sternocostal joints.

Question 30

What do the ribs articulate with posteriorly?

Answer 30

The ribs articulate posteriorly with the thoracic vertebrae at costovertebral joints.

Question 31

How many thoracic vertebrae are there?

Answer 31

There are twelve thoracic vertebrae.

Question 32

What is the heart?

Answer 32

The heart is a sophisticated muscular pump. It is composed of specialised smooth muscle and contracts constantly to keep blood moving through the lungs and body.

Question 33

What is the heart composed of?

Answer 33

● The heart is composed of four chambers – the right and left atria (singular = atrium) and the right and left ventricles. The anatomy of the atria and ventricles is different (they look different) because they function differently.

● The ventricles are the pumping chambers, so their muscular walls are thic

Question 34

Where do thoracic vertebrae articulate with the posterior parts of the ribs?

Answer 34

with the posterior parts of the ribs at costovertebral joints.

Question 35

Describe cardiopulmonary circulation

Answer 35

1. The right atrium receives deoxygenated blood from the body via large veins (the superior and inferior vena cavas).
2. From the right atrium, blood flows into the right ventricle.
3. The right ventricle pumps deoxygenated blood to the lungs via the pulmonary arteries.
4. Gas exchange occurs in the lungs.
5. Oxygenated blood from the lungs returns to the left atrium via the pulmonary veins.
6. From the left atrium, blood flows into the left ventricle.
7. The left ventricle pumps oxygenated blood to the body via the aorta.

Question 36

What is systemic circulation?

Answer 36

Direction?

(the opposite is true for the systemic circulation that serves the rest of the body).

Question 37

Describe the bronchial tree

Answer 37

The trachea bifurcates into the left and right main bronchi, which enter the left and right lungs, respectively. Each main bronchus divides into a series of smaller bronchi, which in turn divide into smaller tubes called bronchioles. With each division, the bronchioles become smaller and smaller – the very smallest conduct air to and from the alveoli - the site of gas exchange within the lung.