Respiratory System

Question 1

What does the respiratory system do?

Answer 1

The respiratory system filters the incoming air and transports it to the lungs for gas exchange

Question 2

What are the organs of the respiratory system in order of incoming air?

Answer 2

• Nose
• Nasal Cavity
• Sinuses
• Pharynx
• Larynx
• Trachea
• Bronchial tree
• Lungs

Question 3

How do amphibians undergo gas exchange?

Answer 3

Amphibians may have lungs, but they are usually small and not very effective
- They mainly rely on gas diffusion across body surfaces such as skin to carry out gas exchange.

NB: Favorite DAT question

Question 4

What organisms rely on lungs for gas exchange?

Answer 4

The organisms that rely on lungs for gas exchange are:

• Most reptiles,
• Birds,
• All Mammals.

They use a negative pressure system called inspiration that draws air into the lungs.

Question 5

What is the nasal cavity?

Answer 5

The nasal cavity is two chambers, medially divided into a left and right portion by the nasal septum.

• Consists of ciliated epithelial cells and hair that filter out dust and particles from the air.
• Contains olfactory receptors that detect smell
• Contains a mucous membrane that is rich in blood vessels.
• Air that passes over it is quickly warmed
• Also acts to trap dust and small particulates from the air. The cilia moves the mucous entrapped particles toward the pharynx, which is the back of the throat. The mucus is then swallowed and all the dust and potentially harmful microorganisms are then subjected to gastric juices.

Question 6

Explain how the nasal cavity helps prevent respiratory infection.

Answer 6

Small breathable microorganisms are trapped by the mucous, cilia, and hair of the nasal cavity. The cilia move the mucous to the pharynx (back of the throat). The mucous is then swallowed and the microorganisms then have to contend with the powerful acids in the stomach.

Question 7

What are the sinuses?

Answer 7

The sinuses are air filled spaces within the facial bones

• their main function is to create mucus that flows into the nasal cavity to help fight infection.
• They also help lighten the skull and improve our voice.
• If the sinuses are blocked due to an infection, the fluid movement is impeded and the increased pressure can cause headaches.

Question 8

What is the Pharynx?

Answer 8

The Pharynx is the intersection of food and air.

• The first part is called the nasopharynx
• Air passes through the nasal cavity to here and then through the glottis to the larynx

Question 9

What is the glottis?

Answer 9

The glottis is a hole that connects the pharynx with the larynx.
- A flap of tissue called the epiglottis covers the glottis while swallowing to prevent food from entering the larynx.

Question 10

What is the larynx?

Answer 10

The larynx (voice box) is composed of hyaline cartilage and muscles bound together by elastic tissue.

• It sits on top of the trachea.
• It’s connected to the Pharynx via the Glottis.
• Vocal Cords are found here. The contracting or relaxing of these cords will determine the vocal sounds.
• Laryngitis: If the mucous membrane of your larynx becomes inflamed due to overuse or infection, the vocal cords can’t vibrate as freely and your voice sounds hoarse, and you have laryngitis.

Question 11

What is laryngitis?

Answer 11

Laryngitis is when your larynx’s mucus membrane become inflamed from overuse or infection
- Your voice becomes hoarse because the vocal cords aren’t able to vibrate as freely.

Question 12

What is the Trachea?

Answer 12

The Trachea is the tube that connects the larynx to the two bronchi.

• Made of Cartilage to prevent collapse
• Contains cilia bearing cells and goblet cells that make mucus
• branches into two bronchi that carry air into the left and right lungs.

Question 13

What are goblet cells?

Answer 13

These are cells in the trachea that create mucus

Question 14

What is Hyaline cartilage?

Answer 14

Hyaline cartilage is the most abundant cartilage found at the ends of long bones, larynx, trachea, bronchi, and in the ventral ends of the ribs.

Question 15

What are bronchi?

Answer 15

Bronchi are branches from the trachea that bring air into the left and right lungs.

• branch into smaller passages called the bronchioles.
• The bronchi and larger bronchioles both have ciliated linings and cartilage.
• Smaller bronchioles less than 5 mm have neither glands or cartilage, but do have goblet cells for making mucus..
• Clara cells containing short microvilli are noted in the small bronchioles. These are sometimes referred to as club cells.
• The smallest bronchioles terminate into the alveolar sacs.

Question 16

What are Clara cells?

Answer 16

Clara cells are dome shaped cells that contain short microvilli in the smaller bronchioles.

• They are also known as club cells.
• They help detoxify the lungs from harmful substances
• Toxins are degraded via P-450 enzymes.
• Also produce a surfactant like material which aids in reducing the surface tension of the bronchioles.

Question 17

What is Asthma?

Answer 17

Bronchioles constrict reducing the diameter of the air passages. A person has a difficult time breathing and produces a wheezing sound as air is passed through the constricted passages. Drugs such as epinephrine cause the smooth muscles to relax and breathing is improved.

Question 18

What are alveolar sacs?

Answer 18

The smallest bronchioles terminate into alveolar sacs that have bulges called alveoli.

• Hundreds of millions of alveoli represent the chambers where gas exchange occurs.
• Alveoli are highly vascular and very thin walled.
• Alveoli are responsible for the spongy structure of the lungs.
• Contain dust cells which act as macrophages to help prevent infection
• Contain surfactants to prevent the sacs from sticking together with hydrogen bonds.

Question 19

What are dust cells?

Answer 19

Dust cells are alveolar macrophages found on the alveolus surface, among other places.
- Dust cells phagocytose bacteria and dust and allow for a sterile lung environment.

Question 20

Why must newborns take a powerful first breath?

Answer 20

When babies are born, their lungs are collapsed. Hydrogen bonds in the fluid of the lungs hold the lungs in a collapsed position. A chemical called surfactant reduces the surface tension of the lungs and once the initial large breath inflates the lungs, they stay inflated.

Premature babies suffer from a lack of surfactants, but artificial surfactant is available.

Question 21

What are surfactants composed of?

Answer 21

Surfactants are composed of a mixture of proteins and phospholipids.

Question 22

What is negative pressure breathing?

Answer 22

In mammals, the diaphragm contracts and move downward. This creates a large volume in the thoracic cavity. The larger volume creates a negative pressure, causing air to flow into the lungs.

Question 23

What is the mechanism of breathing?

Answer 23

• The phrenic nerve carries an impulse to the skeletal muscle diaphragm, which cause it to contract and move downward
• The thoracic cavity is now increased.
• The external muscles called intercostal muscles contract too, raising the ribs and causing the thoracic cavity to increase some more.
• As the thoracic cavity increases in volume, a negative pressure is created in the space.
• The larger atmospheric pressure causes air to travel into the lungs from the outside.

When the diaphragm relaxes, the elastic nature of the cartilage springs the structures back to resting position and the volume suddenly decreases, increasing pressure and pushing air to the lower pressure of the outside environment.

Think PV=nRT

Question 24

What is Tidal Volume?

Answer 24

Tidal volume is the volume of air that flows into or out of our lungs with each breath.

Question 25

What is vital capacity?

Answer 25

The vital capacity is the tidal volume that occurs during maximum inhalation and exhalation.

Question 26

What is the residual volume?

Answer 26

The residual volume is the air that remains in the lungs after you exhale.

Question 27

What is the pleura?

Answer 27

The pleura is a serous membrane that surrounds the lungs.

Question 28

What's the difference between the right and left lungs?

Answer 28

- The right lung is larger than the left lung and has three lobes (superior, inferior, and middle) - The left lung is smaller than the right lung and has two lobes (superior and inferior) - The left lung is smaller to make room for the heart and all its vasculature.

Question 29

What are some non-respiratory air movements?

Answer 29

Non-respiratory air movements include: - Laughing - Crying - Yawning: Thought to aid in respiration, allows more O2 into the blood - Sneezing: clears upper respiratory passages - Hiccup: spasmodic contraction of the diaphragm caused by phrenic nerve stimulation

Question 30

What areas of the brain control breathing?

Answer 30

Breathing is controlled by the medulla oblongata and the pons.

Question 31

Describe what happens when CO2 levels increase?

Answer 31

When CO2 levels increase, it ultimately lowers the ph of the blood. The lowered ph of the blood is detected by chemoreceptors in the carotid body and sends signals to the brain for the medulla to increase respiration to expel excess CO2 and decrease the acidity of the blood.

Question 32

Describe what happens when O2 level decrease.

Answer 32

O2 sensors located in the carotid arteries and aorta signal to the brain to increase respiration

Question 33

How is CO2 carried in the blood?

Answer 33

- 70% carried in the form of bicarbonate HCO3- - 20% carried by hemoglobin (carbamino hemoglobin) - 10% free floating in the blood plasma

Question 34

What reaction occurs with CO2 in the blood?

Answer 34

CO2 + H2O H2CO3 (carbonic acid) HCO3- + H+ The H+ reacts with the Hemoglobin, and the HCO3- is left free floating in the plasma. The Hemoglobin acts as a buffer to prevent the blood from becoming too acidic. When the blood reaches the lungs, the H+ is released from the hemoglobin as O2 binds to the Hb, the H+ joins bicarbonate and reforms into H2CO3 and then ultimately into CO2 and H20. The CO2 is then expelled. As CO2 is leaving the blood, the reaction continually shifts toward the production of CO2 from Bicarbonate.

Question 35

Describe O2 transport.

Answer 35

- Almost all O2 transport is done by the erythrocytes. - The greater the PO2 the more O2 can combine with the Hb. - Oxygen combined with hemoglobin is called oxyhemoglobin Hb-O2

Question 36

Describe O2 release from hemoglobin.

Answer 36

Several factors determine how much O2 is released from Hb: - temperature: As temp increases more O2 is released - pH: As pH decreases, more O2 is released - CO2 levels: As CO2 levels increase, more O2 is released

Question 37

What is Carboxyhemoglobin

Answer 37

Carboxyhemoglobin is an association of CO with Hb. CO forms a very tight bond and can prevent O2 from binding to Hb. It can be very damaging to cells.

Question 38

What is Carbaminohemoglobin

Answer 38

Carbaminohemoglobin is the association of CO2 with hemoglobin. This is how 20% of CO2 in the blood is transported.

Question 39

What is oxyhemoglobin?

Answer 39

Oxyhemoglobin is oxygenated hemoglobin

Question 40

How do insects breath?

Answer 40

In insects, they have tracheal systems which are air tubes that branch through the insect. - Gas exchange works through diffusion

Question 41

How do fish breath?

Answer 41

Breathing in fish - Water is taken in through the mouth and forced through special organs called gills. - As water passes over the thin walled gills, dissolved 02 moves into the blood and travels to the fish's cells to allow cellular respiration to occur.

Question 42

How do birds breath?

Answer 42

Birds have a complex breathing system that is poorly understood. - Their breathing is unidirectional through chambers and tubes. - It has a ton of airflow that helps birds at higher elevations in the sky

Question 43

What is emphysema?

Answer 43

Emphysema is a lung pathology - Alveoli are damaged and lose their elasticity. - Their walls break down and the sacs become larger

Question 44

What is pneumonia?

Answer 44

Pneumonia is a lung disease that can be caused by a virus, bacterium, or fungus. - Alveoli fill with fluid or pus causing difficulty in breathing, fever, chills, etc.

Question 45

What is pleural effusion?

Answer 45

Pleural effusion is a fluid accumulation around the lungs | - can be caused by pneumonia, cancer, and other things.