respiratory physiology

Question 1

external respiration

Answer 1

exchange of oxygen and CO2 between organism and env

Question 2

control of respiration:pacemaker for breathing

detection of partial pressure

how much lungs expand

Answer 2

found in brain
changes volume of thorax and lungs

in respiratory centres

stretch receptors in respiratory muscle feed into brain

Question 3

part of spinal cord responsible for breathing

expiratory rhythm generated by?

Answer 3

pre-Bot. C controls inspiration

pFRG

Question 4

3 neurones involved in sensing arteriole gases

Answer 4

RM
Rob
RPa

in medulla

Question 5

3 central controls of breathing

Answer 5

reflex/automatic - brainstem

voluntary/behavioural - motor cortex

emotional - limbic system (overrides everything)

Question 6

brainstem

Answer 6

pons and medulla

Question 7

2 types of pulmonary stretch receptors

Answer 7

fire quickly and for some time, long term changes

same inflation but quick bursts and die off, acute changes

Question 8

lung compliance

Answer 8

how much can stretch something for a given pressure
very compliant if can stretch something a lot with not a lot of pressure

magnitude of change in lung volume produced by given change in transpulmonary pressure (Ptp)

like blowing up balloon (hard at first then easy)

2 determinants - stretchability of tissues and surface tension within alveoli

Question 9

alveoli

Answer 9

surface is moist
surface tension at air-water interface resists stretching

surface tension lowered (by water) and lung compliance is increased by pulmonary surfactant

want bubble - water with air inside not just water droplet

Question 10

pulmonary surfactant

Answer 10

phospholipids and protein
makes lung easier to expand
secreted by type II alveolar cells
deep breath increases secretion

like lipid bilayer

Question 11

hypercapnia

hypoxia

Answer 11

CO2 excess

lack O2

Question 12

how much does partial pressure of O2 have to fall before breathing is stimulated?

Answer 12

half

Question 13

accessory respiratory muscles

Answer 13

sternocleidomastoid and scalenes

pull lungs up

Question 14

human inspiration and expiration control

Answer 14

active inspiration but passive expiration (relaxing and recoiling)

sometimes active expiration when extreme exercise

Question 15

phrenic nerve

Answer 15

innervates diaphragm

70% of your tidal volume

Question 16

internal intercostal muscles

external

Answer 16

active expiration
close ribs, move down and in

for inspiration

Question 17

external and internal obliques

Answer 17

bottom of ribcage

force lower ribs inwards when contract

Question 18

transverse abdominis

Answer 18

stitch when running
force abdomen in and liver up into thorax
pushes air out

Question 19

genioglossus

Answer 19

tongue
inspiration and active expiration
contracts and strengthens airways so resist change of pressure, keep wide open
widens airway so more air movement

Question 20

thorax

Answer 20

closed compartment
separated from abdomen by diaphragm
lungs and walls of thorax covered by thing membranes (pleurae)

fluid inside pleurae sticks lungs and muscle together

lung and muscle not physically connected but vacuum connects them

Question 21

visceral pleura
parietal pleura
pleural cavity
intrapleural fluid

Answer 21

epithelium covering lung

inner surface of walls of thorax, muscle, diaphragm, heart, bones

partial vacuum helps lungs keep expanding

creates vacuum and freedom of pleurae to slide over one another

Question 22

what stops lung collapsing?

Answer 22

ribs being pulled outwards by muscles
lung being pulled in due to recoil
but vacuum keeps connected so doesn’t pull anywhere

Question 23

pneumothorax

Answer 23

collapsed lung
break vacuum
so air comes in
elastic recoil of lung takes over

decrease in pressure also pulls heart over centrally

Question 24

transpulmonary pressure

lung stay inflated if?

Answer 24

alveoli pressure (in lungs)
intrapleural (outside lungs in thorax)

alveoli higher than intrapleural

Question 25

more flow if

Answer 25

higher difference in pressure

Question 26

why is there a delay in pressure change of alveoli after volume change?

Answer 26

resistance by airway so no more gas molecules, so pressure decreases then high pressure to low pressure so air moves in - till difference is 0 same happens with exhaling creates wave graph of pressure but semicircle volume graph

Question 27

inspiration

Answer 27

muscles and diaphragm contract ribs pulled upwards and diaphragm flattens thorax enlarges intrapleural pressure decreases so transpulmonary pressure increases

Question 28

expiration

Answer 28

muscles and diaphragm relax volume of thorax decreases intrapleural pressure increases so transpulmonary pressure decreases

Question 29

FEV1

Answer 29

volume expired in first second

Question 30

FVC

Answer 30

forced vital capacity total volume expired 80% healthy

Question 31

lung structure

Answer 31

3 lobes in right lung | 2 lobes in left lung

Question 32

bronchioles structure

Answer 32

divide to terminal bronchioles then split to respiratory bronchioles then alveoli

Question 33

conducting zone functions

Answer 33

from mouth and nose to end of terminal bronchioles conducts air but doesn't exchange gas low-resistance pathway for airflow warms and moistens air defends against microbes

Question 34

most resistance in conducting zone

Answer 34

in upper parts - larger but lots of bronchiles larger than 1 trachea

Question 35

disorders of the conducting zone - asthma

Answer 35

chronic inflammation of airways smooth muscle is hyper-responsive to lots of triggers thickened airway wall and less open area

Question 36

disorders of conducting zone - bronchitis

Answer 36

inflammation of bronchial walls, thickened walls increase mucus secreting cells and loss ciliated cells obstruction of airway

Question 37

respiratory zone function

Answer 37

respiratory bronchioles to alveolar sacs provides O2 and removes CO2 regulate blood pH in coordination with kidneys influence arterial conc. of chemical messengers like converts angiotensin 1 to vasoconstrictor angiotensin 2 dissolves blood clots

Question 38

how many alveoli?

Answer 38

500 million

Question 39

pulmonary circulation

Answer 39

blood from right ventricle to left atrium low pressure from heart to lungs to get oxygen

Question 40

ventilation-perfusion mismatching

Answer 40

stop blood supplying areas with poor gas exchange hypoxia (lack O2) shuts down blood supply to that region bottom of lung has low flow

Question 41

ventilation

Answer 41

amount of gas getting to lungs

Question 42

perfusion

Answer 42

amount of blood getting to lungs

Question 43

TUC

Answer 43

time of useful consciousness | decreases as altitude increases

Question 44

3rd man factor

Answer 44

hallucinate someone else when extreme stress from little O2 at high altitude

Question 45

sleep at high altitude

Answer 45

impaired, frequent awakenings, unpleasant dreams, no feeling of refreshment periodic breathing is the cause

Question 46

high altitude and lung capacity

Answer 46

increased erythrocytes and increased blood oxygen carrying capacity develops over several weeks

Question 47

high altitude diseases

Answer 47

acute mountain sickness pulmonary edema cerebral edema

Question 48

acute mountain sickness cure

Answer 48

higher than 3000m headache, fatigue,insomnia,nausea last 2-3 days reverse symptoms if go to low altitude so not long term acetazolamide - carbonic anhydrase inhibitor so increase excretion of HCO3 and reduce alkalosis, maintain normal pH

Question 49

high altitude pulmonary edema

Answer 49

above 3000m people who suffer once likely to suffer again laboured breathing, reduced exercise tolerance, dry cough, rapid breathing and heartbeat, raised body temp treat by moving to low altitude

Question 50

high altitude cerebral edema

Answer 50

potentially fatal above 4500m confusion, rapid mood changes, hallucination, loss control of body, coma only rapid descent will cure it

Question 51

birds

Answer 51

highest rate of O2 consumption relative to body weight air only goes in 1 direction so air coming in not same tube as going out (like humans) 2 cycles: air sac expands and draws air in, contracts and blow through system, both sacs expand and suck air in sack, air out, only travels 1 way through system also very thing blood gas barrier powerful heart less sensitive to lowered PCO2

Question 52

Cx26

Answer 52

CO2-gated receptor that releases ATP | ATP signals to breathe more

Question 53

mole rats

Answer 53

underground | rebreathe own air

Question 54

elephants

Answer 54

don't have pleural space | filled with dense connective tissue instead