Module 3 Section 1

Question 1

what is internal respiration

Answer 1

• O2 is necessary for the production of cellular energy which takes the form of ATP
• this production of ATP creates CO2 that must be expelled from the cell

Question 2

what is external respiration

Answer 2

involves all of the processes that bring oxygen from the atmosphere into the body, the transport of O2 to the tissues, and the removal of CO2 from the tissues and its release back into the atmosphere

Question 3

what is the first step of external respiration

Answer 3

ventilation

• air is moved in and out of the lungs
• this is called breathing, or ventilation, and moves air between the atmosphere and the air sacs (alveoli) in the lungs

Question 4

what is the second step of external respiration

Answer 4

exchange of O2 and CO2 between air and blood

• the diffusion of O2 from the alveoli to the pulmonary capillaries and the movement of CO2 in the opposite direction

Question 5

what is the third step of external respiration

Answer 5

transport of O2 and CO2

• the transport of O2 int he blood to the tissues and the movement of CO2 in the opposite direction

Question 6

what is the fourth step of external respiration

Answer 6

exchange of O2 and CO2 between blood and tissues

• the exchange of O2 from the blood to the tissues and CO2 from the tissues into the blood via diffusion

Question 7

explain the divisions of the respiratory system

Answer 7

• can be divided into 3 anatomical parts: lungs, chest wall, pleural space
• the respiratory system consists of the airways and the alveoli
• the airways carry air between the atmosphere and the alveoli, where O2 and CO2 are exchanged

Question 8

explain the upper airway

Answer 8

• includes the nose, nasal cavities, pharynx, which is the common tube for respiration, and the digestive system
• from the pharynx, air travels to the larynx, which is the location of the vocal cords

Question 9

explain the lower airway

Answer 9

• begins with the trachea, which divides into the left and right bronchi, each of which supplies a lung
• the bronchi branch into progressively narrower airways known as bronchioles
• the smallest bronchioles are known as the respiratory bronchioles as their walls are so thin that some gas exchange can occur
• at the end of the terminal bronchioles are the alveoli, the air sacs where the majority of gases are exchanged between air and blood

Question 10

explain the branching of the airways

Answer 10

• described as the respiratory tree or tracheobronchial tree
• serves similar function to the branching of circulatory system
• each branch gets smaller and smaller, but the overall cross sectional area increases
• this allows for convective flow, which requires energy in the form of muscle contraction to maintain air flow, to diffusive flow, which occurs passively to allow air to flow into the alveoli
• this diffusive zone begins at the level of the respiratory bronchioles

Question 11

what is the chest wall

Answer 11

• anything that contributes to respiration and it includes the thorax (chest) and the abdomen
• the thoracic cavity contains the lungs and the heart and is protected by the rib cage
• chest wall contains the muscles that are necessary in generating pressures that allow air flow
• the thoracic cavity and abdominal cavity are separated by the diaphragm, a large sheet of skeletal muscles

Question 12

what are intercostal muscles

Answer 12

• found between the ribs and are divided into the inner intercostal muscles and the external intercostal muscles, which lie over the inner most intercostals

Question 13

what are the muscles of inspiration

Answer 13

• the main inspiratory muscles are the diaphragm and the external intercostal muscles
• during inspiration (breathing in), the diaphragm descends to enlarge the thoracic cavity
• contraction of the external intercostal muscles elevates the ribs to further enlarge the thoracic cavity

Question 14

what are the muscles of expiration

Answer 14

• these muscles are responsible for decreasing the volume of the thoracic cavity
• the main expiratory muscles are the internal intercostal muscles and the abdominal muscles

Question 15

explain the muscles of expiration in healthy individuals

Answer 15

these muscles are generally inactive and only get recruited when there is an increase in ventilator demand as during exercise or during coughing, sneezing and vomiting

Question 16

what is the pleural space

Answer 16

• the lung is covered by the visceral pleura, or membrane, and the inside wall of the thorax is lined by the parietal pleura
• between these two membranes is the pleural space, which is relatively small and is filled with fluid, the pleural fluid
• this fluid allows the membranes to rub against each other during breathing with reduced friction

Question 17

explain 2 processes of respiration

Answer 17

1. the ability of the respiratory muscles to generate the necessary pressure gradient to move air through the airways (overcoming the resistance to flow) and to inflate the lungs
2. the ability of O2 and CO2 to diffuse across the alveolar-capillary barrier