Respiratory system: Function and control

Question 1

4 major functions

Answer 1

pulmonary ventilation
diffusion of O2 and CO2 between alveoli and the blood
transport of O2 and CO2 in the blood and body fluids
regulation of ventilation

Question 2

organs of upper respiratory system

Answer 2

nose
nasal cavity
oral cavity
pharynx
larynx
trachea

Question 3

organs of Lower respiratory system

Answer 3

primary bronchus
lungs

Question 4

conducting zone

Answer 4

warms and humidifies inspired air
37 degrees
water vapour

Question 5

protective function of the upper airways

Answer 5

conducting zone: condition inspired air
nose: filter, entrap and clear particles
nasal resistance increases with viral infections and increased airflow e.g. exercise
nasal secretions: contain important immunoglobulins, inflammatory cells and interferons

Question 6

upper airways

Answer 6

have a ciliated lining
white blood cells

Question 7

function of the ciliated lining

Answer 7

mucus secretion from epithelial cells and glands
cilia proper the mucus up towards the trachea at 1cm/min

Question 8

function of white blood cells in the upper airways

Answer 8

leave nearby capillaries to populate the surface of the airway and alveoli

Question 9

how many lobes does the left and right lung have

Answer 9

right has 3: superior middle and inferior
left has 2: superior and inferior

Question 10

respiratory zone components

Answer 10

terminal bronchiole
respiratory bronchioles
alveolar sacs
alveolus

Question 11

components of conducting zone

Answer 11

nose
pharynx
larynx
primary bronchi

Question 12

pressure gradient

Answer 12

flow of o2 across barrier separating the blood from the air or water occurs by diffusion down a pressure gradient from high partial pressure of o2 to lower partial pressure o2
occurs throughout respiratory system

Question 13

what is the basic functional unit of the lungs

Answer 13

acinus

Question 14

acinus structure

Answer 14

resembles bunch of grapes
visualises as tiny air bubbles

Question 15

acinus function

Answer 15

site of gas exchange
arise from single terminal bronchiole
stem of branch branches into around 100 alveolar ducts

Question 16

2 types of alveolar cells

Answer 16

type 1 and type 2

Question 17

alveolar type 1

Answer 17

structural cells
epithelial cell CHIEF structural cell of the alveolar wall
main function is mechanical support
rarely divides and not very metabolically active
when damaged is replaced by type 2 cells

Question 18

alveolar type 2

Answer 18

secrete surfactant
contains lamellate bodies that contain phospholipids which forms surfactant

Question 19

gas exchange at the alveoli

Answer 19

alveolar sacs are lined with simple squamous epithelium
lined with surfactant to prevent closing in
have large capillary network to allow oxygen passage

Question 20

role of surfactant

Answer 20

within the alveoli surface tension is due to attraction between water molecules at the surface of alveolar fluid: draws water molecules closer together, if lined with pure water it would collapse

Question 21

what is surfactant

Answer 21

mixture of phospholipids and lipoproteins
lowers the surface tension of alveolar fluid

Question 22

types of receptors involved in controlling respiration

Answer 22

central chemoreceptors
peripheral chemoreceptors
lung receptors

Question 23

chemical control of respiration

Answer 23

negative feedback control system
controlled variables are blood gas tensions especially co2
chemoreceptors sense values of gas tension

Question 24

chemoreceptors

Answer 24

specialised tissue that respond to changes in the chemical composition of blood or other fluids
e.g. central and peripheral

Question 25

central chemoreceptors

Answer 25

situated close to the surface of the medlla
respond to pH changes in the cerebrospinal fluid (CSF)
changes the rate and depth of ventilation

Question 26

CSF

Answer 26

separated from the blood by the blood-brain barrier
relatively impermeable to H+ and HCO3-
CO2 diffuses readily, activating central chemoreceptors

Question 27

regulation of respiratory centre

Answer 27

chemoreceptor to input to increase ventilation
central receptors in the medulla oblongata
sensitive to pH or PCO2 in CSF

peripheral receptors in the arch of aorta and common carotids: respond to lowers PO2 and increased H+ or PCO2 in blood

Question 28

peripheral chemoreceptors

Answer 28

monitor pH, PCO2 and PO2 of arterial blood
vagus and glossopharyngeal nerves
sense tension of oxygen and CO2 and H+ in the blood
set the respiratory pace

Question 29

glomus cell

Answer 29

activated in response to decreased PO2 or pH
increased PCO2

Question 30

process of gloms cell

Answer 30

1. Calcium channels – inactivated
2. Cell depolarization
3. Opens – voltage gated calcium channels
4. Exocytosis of neurotransmitter onto sensory neurons
5. Signals to sensory neurons to increase ventilation