Respiratory System

Question 1

What are the functions of the respiratory system?

Answer 1

obtain energy from food
deliver oxygen
remove carbon dioxide
regulate pH of body fluids
temperature control
phonation

Question 2

What is respiration?

Answer 2

the chemical process by which energy is obtained and released from food

Question 3

What is breathing?

Answer 3

pulmonary ventilation (inhaling and exhaling)
the process of taking air into and out of the lungs

intimately connected with nervous system and cardiovascular system

Question 4

What is external respiration?

Answer 4

1. gas exchange between blood and air in the lungs

2. Transport of O2 and CO2 between the lungs and cells

Question 5

What is internal respiration?

Answer 5

• cellular respiration
• O2 used in conversion of glucose to cellular energy (ATP)
• CO2 produced as a waste product

Question 6

What is the conducting zone?

Answer 6

respiratory passages that carry air to the site of gas exchange
filters, humidifies and warms air

Question 7

What is the respiratory zone?

Answer 7

site of gas exchange
composed of
- Respiratory bronchioles
- Alveolar ducts
- Alveolar sacs

Question 8

How is breathing regulated?

Answer 8

Control centres in the medulla oblongata (breathing, heart rate, autonomic systems) and in the pons (movement, attention, sleep, alertness)

Question 9

What are chemosensors?

Answer 9

detect o2, co2, pH and P
aortic bodies
gloms cells type 1
carotid bodies

Question 10

How is breathing coordinated?

Answer 10

breathing is largely autonomic
rhythmic volleys of impulses sent to intercostal muscles and diaphragm
influenced by stretch receptors in the wall of the bronchial tree in deep breathing
breathing can be deliberate or prevented- impulses from cerebral cortex bypass breathing centre, direct to breathing muscles

Question 11

What happens in inhalation?

Answer 11

1. contraction of respiratory muscles
   - sub atmospheric pressure in lungs so air rushes in
2. air is warmed and moistened
3. alveoli in the lungs expand easily due to surfactant
4. gases exchange

Question 12

What are the stages of breathing?

Answer 12

1. diaphragm contracts and flattens
2. chest cavity enlarges
3. lung pressure reduces
4. air enters the lungs
5. diaphragm relaxes and returns to dome shape
6. chest cavity reduces
7. lung pressure increases
8. air leaves the lungs

Question 13

What happens in exhalation?

Answer 13

1. lungs shrink under own elasticity
2. forced expiration- aided by contraction of intercostal muscles
3. also abdominal wall muscles contract forcing organs up against the diaphragm

Question 14

How does inhalation and exhalation effect intra-alveolar pressure?

Answer 14

Inhalation- pressure in lungs (and alveoli) becomes negative relative to atmospheric pressure (air flows in)

Exhalation- pressure in the lungs (and alveoli) becomes positive relative to atmospheric pressure (air flows out)

Question 15

What is tidal volume?

Answer 15

volume of air inspired or expired at rest

Question 16

What is residual volume?

Answer 16

volume of air remaining in lungs following maximum expiration

Question 17

What is dead space?

Answer 17

volume of air that never reaches the alveoli

Question 18

What are pressure gradients?

Answer 18

gases diffuse down pressure gradients

concentration and pressure drives the movement of gases into and out of blood

Question 19

How is O2 transported?

Answer 19

low solubility of o2 in water

1. 5% in plasma
2. 5% bound to Hb which allows reversible binding and a drop in pH results in lower affinity of Hb for O2

Question 20

How is CO2 transported?

Answer 20

23% bound to HB
7% plasma
70% as bicarbonate

Question 21

What is the upper respiratory tract?

Answer 21

nasal passages
pharynx
larynx
trachea

Question 22

What is the lower respiratory tract?

Answer 22

bronchi

lungs

Question 23

What does the mucosal surface do?

Answer 23

warms and humidifies inspired air
regulates mucous production
olfactory epithelium

Question 24

What are the three parts of the pharynx and what do they do?

Answer 24

nasopharynx- common passageway for air
oropharynx- common passageway for food and air
laryngopharynx- common passageway for food and air

all house the tonsils that respond to inhaled antigens

Question 25

What are the openings into the pharynx?

Answer 25

caudal nares
auditory tubes
oral cavity
larynx
oesophagus

Question 26

What is larynx?

Answer 26

extends from C4 to C6
superiorly attached to hyoid bone
inferiorly continues with trachea
prevents inhalation of food by closing during swallowing
phonation

Question 27

What is the trachea and where does it bifurcate?

Answer 27

16-20 c shaped hyaline cartilage sections
tracheal muscle can decrease diameter
mucus producing goblet cells
ciliated cells
bifurcates at the CARINA

Question 28

What are the lungs made up of?

Answer 28

pleural sac- double walled closed sac
primary bronchi
secondary bronchi
tertiary bronchi
bronchioles
terminal bronchioles
respiratory bronchioles
alveolar ducts
alveolar sacs
alveoli

Question 29

What are Alveolar ducts and alveoli?

Answer 29

fine respiratory bronchioles terminate here
connect alveolar sacs containing alveoli
pulmonary connective tissue has numerous elastin fibres that maintain shape and elastic recoil
alveoli contain alveolar pores

Question 30

What are type I and II pneumocytes?

Answer 30

Type I; 
overlay of capillaries
simple squamous
95% of alveolar wall
permit gas exchange

Type II-
septal cell
cuboidal
surfactant- reduces surface tension

Question 31

How does external respiration occur?

Answer 31

exchange of O2 and CO2
alveoli and capillaries have very thin walls and are very abundant
occurs by simple diffusion along partial pressure gradients

Question 32

What do pores of Khon do?

Answer 32

allow collateral ventilation between alveoli

Question 33

What are the three stages of internal respiration?

Answer 33

1. Glycolysis
2. Krebs cycle
3. Electron transport chain