Cardiorespiratory System

Question 1

What is the thyroid cartilage?

Answer 1

It is the cartilage that sits in front of the larynx and above the thyroid gland.
It is composed of two halves which meet in the middle to form the laryngeal prominence (Adam’s Apple).

Question 2

What cartilage is found below the the thyroid cartilage?

Answer 2

Cricoid cartilage - this cartilage surrounds the start of the trachea.
Between the cricoid and thyroid cartilage there is a depression covered by a membrane and this is where we can make an emergency cricothyrotomy for upper airway obstruction.

Question 3

How many ribs do we have?

Answer 3

12 pairs of ribs

Question 4

How to locate the second rib?

Answer 4

Move down the sternum until a ridge is felt; this is the eternal angle. The costal cartialage of the second rib articulates with the sternum at this position.

Question 5

How to locate the 4th rib?

Answer 5

The location of the nipple in men, locate the rib on the right side the horizontal fissure of the right lung runs along this cartilage.

Question 6

What is the midclavicular line?

What is the midaxillary line?

Answer 6

A line drawn down the midpoint of the clavicle

A line drawn down the midpoint of the axilla/armpit

Question 7

What is significant about the sternal angle?

Answer 7

Lines anteriorly nicely with the T4/T5 vertebrae. This is significant as because the trachea splits and the arch of the aorta ends and the thoracic aorta begins.

Question 8

Where does the heart lie?

Answer 8

The heart lies in the thoracic cavity, behind the sternum and between the two lungs. It lies further to the left, with 2/3 of its bulk left of the midline.
On the left side it extends to where the midclavicular line crosses the 5th intercostal space.

Question 9

Where is the heart beat best felt?

Answer 9

The Apex of the heart.

Where the midclavicular line crosses the the 5th intercostal space.

Question 10

What are the different heart sounds and where can you find them?

Answer 10

Aortic valve sounds - heard in the 2nd intercostal space at right sternum margin
Pulmonary valve - heard in 2nd intercostal space on the left sternum margin
Mitral valve sounds - heard over the heart apex
Tricuspid valve sounds - heard in the right sternal margin - 5th intercostal space

Question 11

Fissures definition?

Answer 11

A narrow split or groove that divides an organ such as the brain, lung, or liver into lobes.

Question 12

The oblique fissures

Answer 12

They start on the back at the 4th rib, travel deep to the 5th rib and end at the 6th costal cartilage at the front.
They separate the lower lobe from the upper lobe on the left and on the right separate the lower lobe from the upper and middle lobe.

Question 13

Horizontal fissure

Answer 13

On the right there is another fissure that separates the upper and middle lobe o father right lung.

Question 14

The inferior extent of the lungs?

Answer 14

6th rib anteriorly
8th rib laterally
10th rib posteriorly.

Question 15

What is the pleura and where is it located?

Answer 15

It is located below the lungs and forms the costo-diaphragmatic recesses. They extend to the 8th rib anteriorly, the 10th laterally and the 12th posteriorly.
It is needed for the lungs to expand into during deep inspiration.

Question 16

How highs do the lungs come up?

Answer 16

The lungs extends above the clavicle into the base of the neck and hence is it risk of stabs would to the neck.

Question 17

How does the trachea branch?

Answer 17

1 x midline trachea — right and left main bronchus — ten bronchi each — each then divides 22 more times t produce over 40 million terminal bronchioles — 300 million alveoli.

Question 18

What lines the trachea and bronchi?

Answer 18

Smooth muscle and cartilage.
Cartilage to hold airways open and smooth muscle to constrict/narrow to reduce the amount of air moving into the lungs (the smallest airways are made solely of smooth muscle). This is known as bronchoconstriction. Useful when sleeping.

Question 19

Artery supply of the lungs…

Answer 19

Supplied with oxygenated blood from the bronchial artery which branches from the thoracic artery. Oxygenates blood from the pulmonary artery.

Question 20

How is the pleural cavity formed and what is its function?

Answer 20

The parietal pleura covers the inner chest wall and the visceral pleura covers the lungs. Cavity between the two is called the pleural cavity and contains a small amount of serous fluid which sticks the lungs to the chest.

Question 21

How are the ribs arranged?

Answer 21

12 pairs which are angled down and forwards. The ribs articulate at the back with the thoracic vertebrae and at the front with the sternum.

Question 22

Different types of inspiration?

Answer 22

Breathing due to action of diaphragm = abdominal breathing

Breathing due to the action of the intercostal muscles = thoracic breathing

Question 23

Inspiration:

Answer 23

Diaphragm contracts - flattens
External intercostal muscles contract - ribs out and up
This increases the volume of the thorax and hence decreases the pressure below that of the atmosphere and air moves in along a pressure gradient.

Normal expiration is passive and there is no contraction of the diaphragm
Active inspiration requires both, particularly the intercostal muscles.

Question 24

What are the 4 chambers of the heart?

Answer 24

Right and left atrium and the left and right ventricles.

Question 25

How does the heart function?

Answer 25

The right atrium receives deoxygenated blood from the superior, inferior vena cavae and the coronary sinus. It pumps this blood put of the RA and into the the RV through the tricuspid valve. The right ventricle then pumps this blood through the pulmonary valve and into the pulmonary artery. Blood returns via the pulmonary veins which drains oxygenated blood into the left atrium. The blood then passes through the mitral valve to enter the left ventricle and is then pumped around the body via the aortic vale.

Question 26

What is the anterior surface of the heart called?

Answer 26

The sternocostal surface as it faces the sternum.

Question 27

What is the inferior surface called?

Answer 27

It sits on the diaphragm and hence is known as the diaphragmatic surface.

Question 28

What is the pericardium?

What is its function?

Answer 28

The pericardium is a fibrouserous sac consisting of two layers.
It allows unrestricted contraction of the heart it als limits how much the heart can fill.

Question 29

What blood vessels supply the heart?

Answer 29

The right and left coronary arteries.
These arteries branch off just after the aortic valve.
These arteries fill during diastole when the ventricular wall is relaxed.

Question 30

How do the coronary arteries branch?

Answer 30

Right coronary artery — loops around right side and the marginal artery supplies front.

Left coronary artery — circumflex artery which loops round left back side.
Left coronary artery — left anterior descending artery - supplies left font.

Question 31

What is an ECG?

Answer 31

Electrocardiogram — wires are placed on different parts of the chest to measure electrical activity at different parts of the heart.

Question 32

X-ray overview….

Answer 32

The normal chest film is taken with the patient standing, during inspiration with the x-rays passing in through the the back and put of the front onto the x-ray plate. So you get a posterior to anterior view.
Those that absorb most the x-rays appear white those that don’t appear black.

Question 33

Cardiac silhouette size…

Answer 33

Varies greatly between individuals, but us all the size of your clenched fist.

Question 34

Cardio-thoracic ratio, what is it?

Answer 34

It is a measure of heart size and can be used to investigate various pathologies such as heart failure.
It is calculated by measuring the widest part of the heart and dividing this by the widest part of the lungs, a value of less than 55% is normal.

Question 35

Where are the intercostal muscles located?

Answer 35

They are found between the ribs

Question 36

What is the apex of the heart?

Answer 36

It is a projection inferiorly, anteriorly and more lateral than the left ventricle.

Question 37

Why is the left lung smaller?

Answer 37

Because the heart takes up more if it’s space.

Question 38

Why is narrowing of the air ways a benefit?

Answer 38

When your sleeping it decreases the effort of breathing.

Question 39

What are the three main structures in the lung hilum?

Answer 39

The bronchus, pulmonary artery and the pulmonary vein.

Question 40

What is the costal cartilage?

Answer 40

The costal cartilage attaches the ribs to the sternum.

Question 41

External intercostal vs internal intercostal muscles anatomically

Answer 41

External more lateral, internal more medial. They are also 90 to one another.

Question 42

What do the “accessory muscles” of breathing do?

Answer 42

The shoulders and neck can pull the ribs up increasing ventilation further. This often happens during asthma attacks.

Question 43

What is intercostal recession?

Answer 43

During inspiration the intercostal muscles can be pulled/sucked in and hence will slightly contract to stop this taking place. If they are being sucked in this can show failure of the lungs.

Question 44

Tidal volume=

Answer 44

Is the amount of air that moves in and out of the lungs during each respiratory cycle. Usually about 500ml.
If you divide the area/500 it will give you the movement of the diaphragm (only if no ribs movement).

Question 45

How does heart rate increase - physically?

Answer 45

The contraction time does not change only the time of diastole will change.
This however is limited by the amount of oxygen supplied to the heart during diastole.

Question 46

What is an angiogram?

Answer 46

To complete a coronary angiogram, a catheter is inserted in an artery in your groin or arm and threaded through your blood vessels to your heart. A radioactive substance is then inserted and will be shown on the X-ray screen.
Photos can be taken to observe the blood vessels of the heart.

Question 47

A little bit about ECGs…

Answer 47

10 wires placed on to the patient, 4 on limbs and 6 on chest. Each produce a different signal. Where the signal is effected will indicate an issue in that particular blood vessel. The sharp peak is when the ventricles contract and the slower curve is due to the movement of Na, K, Ca ions

Question 48

When taking an X-ray you should be weary of…

Answer 48

Magnification - for the least effect the patient should be as close to the screen as possible and and the X-ray machine should be as far away as possible.

Question 49

How do ribs appear on X-rays?

Answer 49

Darker patches are more dense and are attached to the spine. If you look closely you will see lighter ribs bending around the front.

Also note when the right lung collapses the trachea will move to the right. If the left collapsed it is more likely to just fill with air which can be seen due to its lighter appearance and a line may be visible showing boundary. The sharp angles in the corners will also disappear if lungs fill with fluid.