Week 7 "Overview of the Respiratory System"

Question 1

What are the four levels of protein structure

Answer 1

Primary
Secondary
Tertiary
Quaternary

Question 2

What makes up primary structure and what bonds are involved

Answer 2

Primary structure is based on amino acid order (peptide bonds)

Question 3

What makes up secondary structure and what bonds are involved

Answer 3

Secondary structure is based on local coiling or folding of peptide chain (a helices and beta pleated sheets). they are mainly due to hydrogen bonding.

Question 4

What makes up tertiary structure and what bonds are involved

Answer 4

Overall 3D shape of a protein. lots of R group interactions with disulfide bonds etc

Question 5

What makes up quaternary structure and what bonds are involved

Answer 5

interaction of multiple polypeptides to form multi subunit proteins.

Question 6

What is haemoglobin?

Answer 6

major protein in red blood cell and main carrier of oxygen in mammals- each Hb molecule can bind 4 O2 molecules as it has 4 subunits.

Question 7

What is Cooperative binding of oxygen to haemoglobin?

Answer 7

It means once one oxygen is bound to haemoglobin the other 3 oxygen molecules bind more easily.
It is the reason the oxygen saturation curve is not linear.

Question 8

What causes haemoglobin to have higher affinity for O2

Answer 8

low temp
low CO2
higher pH

Question 9

What causes haemoglobin to have lower affinity for O2

Answer 9

high temp
high CO2
lo pH
high

Question 10

How is O2 transported in blood?

Answer 10

95% in haemoglobin

5% disolved in the plasma

Question 11

How is CO2 transported in the blood?

Answer 11

mostly in the form of Bicarbonate (buffer equation).
protein bound
disolved in plasma.

Question 12

Why is oxygen released at the tissues

Answer 12

High CO2 concentration and high H+ concentration at the tissues reduces haemoglobins affinity for oxygen.

Question 13

Why is carbondioxide taken up by haemoglobin at the tissues and released in the lungs?

Answer 13

High CO2 in tissue increases affinity

High PO2 in lungs reduced affinity for CO2

Question 14

What is Cyanosis and what causes it?

Answer 14

bluish tint of the skin and mucous membranes (nail beds, lips…) which results when the concentration of deoxyhaemoglobin is increased.

Question 15

What is the reasons for Peripheral cyanosis vs Central cyanosis?

Answer 15

Peripheral cyanosis:

1. decreased local circulation
2. and or increased extraction of oxygen in peripheral tissue

Central cyanosis:

1. when arterial O2 saturation drops below 80%.
2. Caused by hypoxaemia
3. resp disease/heart

Question 16

Define respiration

Answer 16

Production of energy. by means of intake of O2 and release of CO2

Question 17

What are the 5 stages of respiration?

Answer 17

1. Pulmonary ventilation (breathing):
   ventilation of the alveoli in the lungs with fresh air (high oxygen concentration and a low carbon dioxide concentration).
2. Gas exchange in the lungs: O2 diffuses from the alveolar air across the pulmonary membrane and into the pulmonary capillary blood, whereas CO2 diffuses in the opposite direction.
3. Transport of gases by the blood: O2 is transported by the blood from the lungs to the tissues, and CO2 is transported by the blood from the tissues to the lungs.
4. Gas exchange in the peripheral tissues: O2 diffuses from the systemic capillary blood across the capillary wall into the tissues, whereas CO2 diffuses in the opposite direction.
5. Internal respiration
   involved in producing energy in the form of ATP.

Question 18

Roles of O2 and CO2 in respiration

Answer 18

O2 - needed for ATP production

CO2- byproduct of this

Question 19

What is partial pressure

Answer 19

Is the PRESSURE that would be exerted by one of the gases in a mixture if it occupied the same volume on its own. So partial pressure is per gas in the mix (gas acts independently). Total pressure is the partial pressures added together (Daltons law)

Question 20

What is fractional concentration

Answer 20

fraction of a gas in a volume being measured (a concentration)

Question 21

What are the fractional concentrations of 02 CO2 and N2?

Answer 21

O2   = 21%
CO2 = 0.04%
N2    = 79%

Question 22

What dictates gas diffusion at the capillary level

Answer 22

Diffusion mainly - high to low.

Capillaries have thin membranes which the gas needs to cross (easy)

Question 23

Describe gas exchange in the lungs in regards to O2 and CO2 concentration.

Answer 23

Air = high pO2 , low pCO2
Blood = low pO2, high pCO2
O2 moves into blood, CO2 moves out.

Question 24

Describe gas exchange in tissues

Answer 24

CO2 into blood

O2 out of blood into tissue.

Question 25

What muscles are involved in inhalation. (give both principle and accessory)

Answer 25

Principle- diaphragm + external intercostals

Accessory = sternocleidomastoid and scalenes

Question 26

What muscles are involved in active expiration

Answer 26

During active - abdominal muscles and internal intercostals

Question 27

What is the function of the epiglottis and where does it sit

Answer 27

(reflex)The epiglottis closes over the trachea to ensure non gaseous material is propelled into the esophagus during swallowing.
It is located at the superior end of the larynx.

Question 28

What is the cough reflex?

Answer 28

1. Stimulation - general irritant sensors in the larynx or irritant receptors in the lower airways.
2. Afferent signals to the brain stem
3. Reflex efferent signal to muscles
4. Stimulating the rapid opening of the glottis- this explosive expiratory blast of air acts to remove the material from the airways.

Question 29

What is the gag reflex

Answer 29

INAPPROPRIATE stimulation of pharyngeal receptors can also evoke the gag reflex. Acts to remove the material from the throat through vomiting.

Question 30

what is lung compliance

Answer 30

the elastic ability of the lungs. the ease in which it stretches

Question 31

why is lung surface tension important?

Answer 31

if there is too much surface tension the lungs and more importantly the alveoli require larger pressures to open.

Question 32

What is pulmonary surfactant

Answer 32

It is a mixture of phospholipids and protein which reduces the surface tension in the lungs.
it begins being produced at weeks 27-28 in gestation.

Question 33

Describe a pressure-volume compliance curve of the lungs

Answer 33

Line at 45 degrees
curved line below that (inspiration)
curved line above that (expiration)
This difference is due to less pressure being needed to allow for expiration as it is more passive.
(the further to the right (more pressure) the more decreased compliance is)

Question 34

What are the main central controllers of respiration?

Answer 34

medulla (mainly)

pons.

Question 35

What do peripheral chemoreceptors detect in regards to respiration?

Answer 35

Mainly sensitive to arterial pO2 changes but to a lesser extent CO2 and pH.

Question 36

Where are peripheral receptors located

Answer 36

Both side of the carotid bodies (adjacent to carotid arteries)
Also in the aortic arch

Question 37

How does the peripheral receptors transfer signals to the respiratory centres of the brain?

Answer 37

VIA the Hering’s and glossopharyngeal nerves

aortic arch chemoreceptors send via the vagi

Question 38

What does the central chemoreceptors respond to?

Answer 38

CO2 can pass to the brain but H+ cant.
It passes then makes H+ through its buffer equilibrium. Central very sensitive to CO2/H+ change. They do not respond to O2 concentration.

Question 39

What is meant by conscious and unconscious breathing

Answer 39

There is a homeostatic control of breathing - controlled by central and peripheral chemoreceptors. AUTOMATIC = unconscious

HOWEVER - respiratory muscles are somatic (skeletal) so therefore are also under voluntary control (conscious)

Question 40

What is the physiological response to airway obstruction?

Answer 40

Obstruction –> hypoxaemia (low o2)/hypercapnia (high co2) –> increase in respiratory drive

Question 41

What happens with increased respiratory drive?

Answer 41

Increased force generated by the primary inspiratory muscles (diaphragm and external intercostals)
Recruitment of both accessory (SCM + scalene) and expiratory muscles (abdominals)

Question 42

What happens in an obstruction to the smaller bronchioles?

Answer 42

Pulmonary hyperinflation. (higher than normal lung volume to help keep smaller airways open)
this is achieved by:
1. continuous inspiratory muscle contraction
2. insufficient expiratory time)
3. expiratory braking (glottis narrowed)

Question 43

What are the key signs used to assess respiratory function?

Answer 43

Rate
Colour
Grunting
Nose flair
Sweating
Wheeze
Body position
Excess secretions

Question 44

What is measured by pulse oximeter vs arterial blood gas?

Answer 44

PO - oxygen saturation of haemoglobin

ABG- partial pressure of gasses.