4. Respiratory system

Question 1

Describe the route of oxygen from the air into the alveoli

Answer 1

nostrils > nasal cavity > the pharynx > the larynx > the glottis > the trachea > the bronchi > bronchioles > alveoli

Question 2

How does oxygen get from the alveoli to the blood?

Answer 2

Oxygen diffuses through the membrane from the alveoli to the blood and carbon dioxide diffuses from the blood to the alveoli

Question 3

What is the air presssure at the end of inhalation in the alveoli om mammas?

Answer 3

about 101 kPa, equal to atmospheric pressure

Question 4

What are the two membranes that surround each lung?

Answer 4

Each lung is surrounded by the pleura. The parietal pleura is attached to the inside of the chest wall, the visceral pleura is attached to the surface of the lungs. Van buiten naar binnen: eerst parietal, dan visceral

Question 5

What is the mediastinum?

Answer 5

Separating the two lungs is a region of tissue that contains the oesophagus, trachea, aorta, vena cava and lymph nodes. This is called the mediastinum.

Question 6

Which regions control the rate of breathing?

Answer 6

Two regions in the hindbrain called the medulla oblongata and pons control the rate of breathing. –> called respiratory centres

Question 7

How do the respiratory centres control the rate of breathing?

Answer 7

The pons and medulla oblongata respond to the concentration of carbon dioxide in the blood. When this concentration rises during a bout of activity, for example, nerve impulses are automatically sent to the diaphragm and rib muscles that increase the rate and the depth of breathing. Increasing the rate of breathing also increases the amount of oxygen in the blood to meet the needs of this increased activity.

Question 8

What is the conductal zone of the respiratory system?

Answer 8

The part of the lungs that is distal from the trachea and before the alveoli i.e. the brochien and such

Question 9

What is the function of the cilia on the cells that line the bronchial tree?

Answer 9

The beating of the cilia moves mucus lying on the surface of the epithelium of the conducting zone, and any contained dust, up out of the bronchial tree.

Question 10

What term is applied to the volume of air that moves into the lungs while breathing at rest?

Answer 10

Tidal volume

Question 11

What is the difference between external respiration and internal respiration?

Answer 11

External respiration: gas exchange between alveolar air and blood in pulmonary capillaries
Internal respiration: gas exchange between blood and tissues

Question 12

How is the diaphragm innvervated?

Answer 12

The diaphragm is innervated by the phrenic nerves (not thoracic spinal nerves) which arise from the C3–C5 vertebrae. So, if the spinal cord is severed/damaged between these vertebrae, the organism won’t be able to breathe

Question 13

The goal of respiration is to control the concentration of which substances dissolved in the blood?

Answer 13

oxygen, carbon dioxide and hydrogen ions

Question 14

What constitutes the respiratory membrane?

Answer 14

The cells lining the alveoli and the capillaries and their fused basement membrane, along with the fluid (surfactant) lining the alveoli together are the membrane.

Question 15

What is the “cribriform plate”?

Answer 15

The cribriform plate of the ethmoid bone has many foramina through which pass olfactory nerves that transmit sensory information from inhaled air to the olfactory bulbs.

Question 16

Describe the structures in the bronchial tree, big to small

Answer 16

Brochii - secondary brochi - secondary bronchiole - terminal bronchiole - respiratory bronchiole - alveoli

Question 17

Which structures constitute the “upper respiratory tract”?

Answer 17

The upper respiratory tract includes the larynx and superior structures.

Question 18

Where are the conchae located?

Answer 18

The conchae are adjacent to the external nares (neusvleugels)

Question 19

What passes through the foramina of the cribriform plate of the ethmoid bone?

Answer 19

nerve fibres associated with the sense of smell. The olfactory bulbs rest upon the cribriform plate and nerves from the bulbs descend through it to the top of the nasal cavity.

Question 20

In what form is the majority of carbon dioxide that is generated by cellular respiration, transported to the lungs?

Answer 20

CO2 leaves cell as dissolved gas. About 7 % is transported in solution in plasma, 23 % bound to haemoglobin (HbCO 2) in rbc, while 70 % reacts
with water to form carbonic acid, which forms bicarbonate ions.

Question 21

What happens when carbon dioxide levels in the blood decrease to below normal?

Answer 21

Carbon dioxide reacts with water to form carbonic acid and thence hydronium ions. So a decrease in CO 2 will decrease the concentration of hydronium ions (and pH will increase).

Question 22

In a healthy person, which of these lung volumes should be the largest?

Answer 22

Vital capacity = expiratory reserve volume + tidal volume + inspiratory reserve capacity. So VC is the largest (RV is ~1.2 L).

Question 23

With regard to lung ventilation, what does “dead space” refer to?

Answer 23

air in the conducting zone of the bronchial tree. Dead space refers to air that is inhaled into the airways but does
not reach the alveoli, hence is exhaled again without participating in gas
exchange.

Question 24

What are the cells that produce surfactant called?

Answer 24

Type II pneumocytes produce the surface active agent (surfactant) that reduce the surface tension of the water that lines the alveoli.

Question 25

What does sympathetic nervous system stimulation to the smooth muscle layers in the bronchioles cause?

Answer 25

Bronchodilation is stimulated by sympathetic nerve impulses, adrenalin & noradrenalin. Bronchoconstriction triggered by parasympathetic nerve impulses.

Question 26

What is the effect of adrenaline and noradrenaline on respiration?

Answer 26

Adrenaline & noradrenaline cause bronchioles to dilate which allows for greater ventilation.