C6 - Respiratory System

Question 1

What filters air in the nasal cavity?

Answer 1

Mucous membranes and nasal hairs (vibrissae)

Question 2

Where does the pharynx reside? And where how is it different from the larynx in terms of what contains food and air?

Answer 2

The pharynx is behind the nasal cavity and at the back of the mouth. It is a pathway for both food and air while the larynx which lies below the pharynx is only a pathway for air.

Question 3

How is food kept out of the respiratory tract?

Answer 3

This is due to the larynx being covered by the epiglottis during swallowing

Question 4

What does the larynx contain that is maneuvered using skeletal muscle and cartilage?

Answer 4

Vocal cords

Question 5

After the larynx where does the air go?

Answer 5

The trachea

Question 6

How does air get from the trachea to where gas exchange occurs?

Answer 6

After the trachea it goes into one of two mainstream bronchi, they then continue to divide into smaller structures known as bronchioles, which further divide until they end in tiny balloon like structures called alveoli (this is where gas exchange occurs)

Question 7

The bronchi and trachea are coated with what to catch material that has made it last the mucous membranes?

Answer 7

Ciliated epithelial cells

Question 8

What is each alveolus coated in? What is its purpose?

Answer 8

Surfactant, it is a detergent that lowers surface tension and prevents the alveolus from collapsing on itself

Question 9

What is the main difference between the right and left lung? And why is there this difference?

Answer 9

The left lung only has 2 lobes, while the right has 3. This is due to the position of the heart in the thoracic cavity

Question 10

What forms the outside of the thoracic cavity? (VERY outside)

Answer 10

Chest wall

Question 11

What membranes surround each lung? Which membrane is adjacent to the lung while which ones is the outer part? What space is in between these two membranes?

Answer 11

Pleurae. The surface adjacent to the lung is the visceral pleura while the outer part is the parietal pleura. In between is the intrapleural space

Question 12

What muscle divides the thoracic cavity from the abdominal cavity?

Answer 12

The diaphragm

Question 13

The what lubricates the two pleural surfaces?

Answer 13

The thin layer of fluid in the intrapleural space

Question 14

Inhalation is an active process, we use what muscles to expand the thoracic cavity?

Answer 14

Our diaphragm and external intercostal muscles

Question 15

Exhalation does not have to be an active process, but if we wanted to speed up the process, what muscles would we use?

Answer 15

The internal intercostal muscles and abdominal muscles (which expose the external intercostals)

Question 16

What part of breathing requires muscle contraction?

Answer 16

Inspiration, in order to create the negative pressure in the thoracic cavity driving air into the lunges muscles are need

Question 17

What is emphysema charcaterized by? Thus What part of the breathing process is hardest with a patient that presents with emphysema?

Answer 17

It’s characterized by the destruction of the alveolar walls, results in reduced elastic recoil of the lungs, making the process of exhalation extremely difficult

-mostly caused by cigarette smoking

Question 18

What is TLC?

Answer 18

Total lung capacity: it’s the maximum volume of air in the lunges when one inhales completely (usually around 6-7 liters)

Question 19

What is RV in terms of lung volume?

Answer 19

Residual volume: the volume of air remaining in the lungs when one exhales completely

Question 20

What is VC in terms of lung volume?

Answer 20

Vital capacity: the difference between the minimum and maximum volume of air in the lungs (TLC-RV)

Question 21

What is TV in terms of lung volume?

Answer 21

Tidal volume: the volume of air inhaled or exhaled in a normal breath

Question 22

What is ERV vs IRV in terms of lung volume?

Answer 22

ERV is expiratory reserve volume: the volume of additional air that can be forcibly exhaled after a normal exhalation

IRV is inspiration reserve volume: the volume of additional air that can be forcibly inhaled after a normal inhalation

Question 23

Breathing required input from our nervous control center, ventilation is primarily regulated by a collection of neurons where? How does it control the ventilation rate?

Answer 23

The medulla oblongata, called the ventilation center that fires rhythmically to cause regular contractions of respiratory muscles

The neurons contain chemoreceptors that are primarily sensitive to CO2 concentration, as the partial pressure of CO2 in the blood rises respiration rate will increase so that more CO2 is expelled

Question 24

What is the main function of the lungs

Answer 24

Gas exchange

Question 25

How does gas exchange occur in the process of blood from the heart and back to it?

Answer 25

Each alveolus is surrounded by a metwork of blood capillaries, these capalaries bring deoxygenated blood from the pulmonary arteries which originates from the right ventricle of the heart. Facilitation of CO2 goes from the blood into the alveoli, and oxygen into the blood from the alveoli. Oxygenated blood then returns to the left atrium of the heart via the pulmonary veins

Question 26

What is the driving force for gas exchange?

Answer 26

The pressure differential of the gasses

Question 27

Because the gradient between the blood and air in the lungs is already present as the blood enters the lungs, what does this mean in terms of energy needed for gas exchange?

Answer 27

There is no energy that is needed

Question 28

What is the natural response of hemoglobin to decreased carbon dioxide concentration in the environment?

Answer 28

To decrease the unloading of oxygen into tissues

Question 29

In the short and long term what is the main way that our respiratory systems would adjust if we moved to higher altitudes where less oxygen is available?

Answer 29

Short term: body makes more red blood cells to ensure adequate delivery of oxygen

Long term: body could develop more blood vessels to facilitate more distribution of oxygen to tissues

Question 30

Describe the thermal energy retainment and dissipation in the process of vasodilation and vasoconstriction

Answer 30

Vasodilation: as capillaries expand, more blood can pass through the vessels and a larger amount of thermal energy can be dissipated

Vasoconstriction: as capillaries contract, less blood can pass through them, conserving thermal energy

Question 31

The first line of defense for immune function in the respiratory system is what?

Answer 31

The small hairs (vibrissae) in the nasal cavity that help to trap particulate matter and potentially infectious particles

Question 32

The nasal cavity also contains an enzyme called lysozyme, where else is it found, and what immune function does it have?

Answer 32

Also found in tears and saliva, lysozyme is able to attach the peptidoglycan walls of gram-positive bacteria

Question 33

Describe the mechanism referred to as the mucociliary escalator

Answer 33

Internal airways are linked with mucus, which traps particular matter, underlying cilia then propel the mucus up the respiratory tract to the oral cavity, where it can be expelled or swallowed

Question 34

What are the main 2 immune cells that populate the lungs and alveoli? Describe their functions

Answer 34

Macrophages, they engulf and digest pathogens and signal to the rest of the immune system that there is an invader

Mast cells, these cells have preformed antibodies in their surfaces, when the right substance attaches to the antibody, the mast cell releases inflammatory chemicals into the surrounding area to promote an immune response

Question 35

Unfortunately, mast cells antibodies are often reactive to substances such as pollen and molds, what does this mean?

Answer 35

That they provide the inflammatory chemicals that mediate allergic reactions

Question 36

What type of antibodies are on the mucosal surfaces?

Answer 36

IgA

Question 37

Atypical pneumonia is often caused by a very small bacteria called mycoplasma pneumoniae. What is the underlying concept behind how it causes a prolonged cough?

Answer 37

This is because it damages epithelial cells lining the lung and paralyzes the cilia lining the respiratory tract. The lack of cilia makes it much more difficult to clear mucous from the lungs, the cough lasts until the respiratory epithelial cells have recovered and the cilia are once again functional

Question 38

What is the bicarbonate buffer system equation?

Answer 38

CO2 (g) + H2O (l) >/< H2CO3 (aq) >/< H+ (aq) + HCO3- (aq)

Question 39

The human body aims to maintain a pH in what range in the blood?

Answer 39

7.35-7.45

Question 40

What happens when pH is lower?

Answer 40

When pH is lower, hydrogen concentration is higher. The acid sensing chemoreceptors just outside of the BBB send signals to the brain to increase respirations. (Increase hydrogen ion concentration will cause a shift in the bicarbonate buffer system, generating more CO2)

Increase in respiration causes more CO2 to be blown off, shifting the buffer equation to the left

Question 41

If the blood is too basic it will seek to increase acidity, how will it do this?

Answer 41

Decrease in respiration, more carbon dioxide will be retained, shifting the buffer equation to the right and produce more bicarbonate ions and hydrogen ions decreasing pH

Question 42

If H+ is an acid and HCO3- is a base, then why doesn’t increasing both of them yield a constant pH?

Answer 42

This is because H+ is a strong acid while HCO3- is a weak base