Respiratory System

Question 1

functions of respiratory system

Answer 1

cells need energy- maintenance, growth, defence, division
oxygen- obtained from air by diffusion across delicate exchange surfaces of lungs, carried to cells by CV system which returns co2 to lungs

Question 2

main functions

Answer 2

provides extensive gas exchange surface area between air and circulating blood
moves air to and from exchange surfaces of lungs
protects respiratory surfaces to outside environment
produces sound
participates in olfactory sense

Question 3

respiratory tract

Answer 3

passageway that carries air to and from exchange surfaces in lungs
consists of conducting portion- nasal cavity to terminal bronchioles
respiratory portion- respiratory bronchioles and alveoli
epiglottis- separates upper and lower resp system

Question 4

conducting and respiratory zones

Answer 4

lungs are a network of branches passageways
these airways branch a total of 23 times
have irregular dichotomous pattern
each airway gives rise to two daughter airways
air reaches alveoli surrounded by dense network of capillaries
alveoli appear as buds in the bronchiole wall from branch 17
from 20 onwards whole airway is alveoli

Question 5

differences between right and left lung

Answer 5

right= superior, middle, inferior lobes
left= superior, inferior lobes
can track progress of disease through loves of lungs +can remove portions/ lobes of lung

Question 6

respiratory mucosa

Answer 6

consists of epithelial layer and areolar layer
lines conducting portion of respiratory system
underlined by lamina propia
contains mucous glands in upper respiratory system
contains smooth muscle in lower respiratory system that controls dilation of branches (bronchorestriction and bronchodilation)
air enters respiratory sustem through nostrils/external nare into vestibule
air flows through 3 nasal meatuses
nasal conchae- create turbulence in the air to trap small particles in mucus

Question 7

oral cavity

Answer 7

hard palate- forms floor of nasal cavity; separates nasal and oral cavities
soft palate- extends posterior to hard palate, divides superior nasopharynx from lower pharynx

Question 8

pharynx

Answer 8

chamber shared by digestive and respiratory systems
extends from internal nares to entrances to larynx + oesphagus
has 3 divisions; nasopharynx, oropharynx, laryngopharynx
air flows from pharynx to larynx , first passes through epiglottis
glottis- voice box, produces sound, vocal folds change air flow

Question 9

sound/ speech

Answer 9

sound production- air passing through glottis, vibrates vocal folds + produces sound waves
sound variation- tension on vocal folds, voluntary muscles
speech- phonation - sound production at the larynx
articulation- modification of sound by other structures

Question 10

bronchi

Answer 10

right and left primary bronchi separated by internal ridge (carnia)
C shaped cartilaginous rings which keep airway open
right primary bronchus- larger in diameter to left + descends at steeper angle
each primary bronchus travels to a groove along medial surface of lung

Question 11

bronchial tree

Answer 11

formed by primary bronchi and branches
primary bronchus- branches to form secondary bronchi, 1 secondary goes to each lung (lobe)
extrapulmonary bronchi- left and right bronchi branch outside lungs
intrapulmonary- branches within lungs
secondary bronchi- branch to form tertiary bronchi (segmental bronchi)
each segmental bronchi supply air to single bronchopulmonary segment
right= 10 segments
left= 8/9 segments

Question 12

bronchial structure

Answer 12

walls of primary, secondary + tertiary bronchi; contains porgressively less cartilage and more smooth muscle, increasing muscular effects on airway constriction and resistance
each tertiary bronchus branches into multiple bronchioles which branch into terminal bronchioles
have no cartilage + dominated by smooth muscle
autonomic control regiulates smooth muscle, controlling diameter of bronchioles + airflow + resistance of lungs

Question 13

alveoli

Answer 13

air filled pockets within lungs where all gas exchange takes place
high capillary density covering surfaces of alveoli
open alveolar sacs

Question 14

external respiration

Answer 14

process involved in exchanging o2 and co2 with environment
pulmonary ventiltion, gas diffusion, storage and transport of o2 and co2

Question 15

internal respiration

Answer 15

cellular respiration
uptake of o2 and production of co2 within individual cells

Question 16

pulmonary ventilation

Answer 16

physical movement of air in and out of respiratory tract
provides alveolar ventilation- physical movement of air in and out of alveoli

Question 17

boyles law

Answer 17

defines relationship between gas pressure and volume
pressure of gas is inversely proportional to volume of a container
P= 1/V
in contained gas- external pressure forces molecules closer together, movement of gas exerts pressure on container
air moves from high to low pressure

Question 18

compliance of lung

Answer 18

indicator of expandability
low compliance requires greater force + high compliance requires less force
affected by connective tissue structure of lungs, level of surfactant production, mobility of thoracic cage

Question 19

inspiration

Answer 19

initiated by respiratory control centre in medulla (brain stem)
activation of medulla leads to contraction of diaphragm and intercostals
diaphragm moves downwards and rotates ribs towards horizontal plane
external intercostals move ribs up and out increasing thoracic cavity
increase in volume of lungs, decrease in pressure- air moves in

Question 20

expiration

Answer 20

normal breathing- expiration is passive
elastic fibres in connective tissue of lungs + surface tension of film of fluid coats alveoli- elastic recoil

Question 21

surface tension

Answer 21

thin film of liquid lines alveoli and surface tension of film is important
attractive forces between adjacent molecules of liquid are stronger than those between liquid and gas
contributes ti passive recoil force and helps to stabilise alveoli
- greater lung compliance when alveoli is inflated with saline

Question 22

muscles of respiration- quiet breathing

Answer 22

active inhalation and passive exhalation
diaphragmatic breathing/ deep breathing
costal breathing or shallow breathing- dominated by ribcage movement + diaphragm
known as eupnea

Question 23

forced breathing

Answer 23

hypernea
active exhalation and inhalation
assisted by accessory muscles
maximum levels occur in exhaustion

Question 24

muscles involved

Answer 24

muscles of inspiration

sternocleidomastoid
scalenes
internal and external intercostals
diaphragm

muscles of expiration
internal abdominal oblique
transversus abdominis
rectus abdominis
internal intercostals

Question 25

respiratory rate + volume- calculations

Answer 25

Ve= f x Vt Ve= volume of air moved each minute f= breaths per minute Vt= tidal volume Va= f x (Vt-Vd) va= alveolar ventilation Vd= dead anatomical space

Question 26

lung volumes

Answer 26

Fev1- forced expiratory volume in 1 second FVC- forced vital capacity- max volume of gas that can be expelled from the lungs after maximum inspiration forced expiratory ratio- FEV1/ FVC

Question 27

composition of air

Answer 27

nitrogen= 78.6% oxygen= 20.9% water vapor= 0.5% carbon dioxide= 0.04%

Question 28

alveoli

Answer 28

air filled pockets in lungs where gas exchange takes place large surface area due to large number of alveoli capillary endothelium is very thin making gas exchange efficient

Question 29

alveolus

Answer 29

extensive network of capillaries surrounded by elastic fibres fibres recoil during exhalation, reducing size of alveoli to push air out of lungs efficient gas exchange- alveoli walls thin + surface area large

Question 30

alveolar epithelium

Answer 30

simple squamous epithelium with thin, delicate type 1 cells patrolled by alveolar marcrophages (dust cells) involved in phagocytosis contains septal cells- type 2- that produce surfactant

Question 31

henry's law

Answer 31

when air under pressure comes in contact with liquid gas dissolved in liquid until equilibrium is reached at a given temp amount of gas in solution is proportional to partial pressure of that gas increasing pressure drives gas molecules into solution until equilibrium is reached when gas pressure decreases dissolved gas molecules leave the solution until new equilibrium is reached

Question 32

reasons for effiecncy of gas exchange

Answer 32

1. substantial difference in partial pressure across respiratory membrane 2.distances involved in gas exchange are short (lungs + tissues) 3. o2 and co2 are lipid soluble- can diffuse through membrane 4. total surface area is large- endurance training can increase capillary density, increasing SA 5. blood flow and airflow are coordinated- HR increase when inspiring + decreases when expiring

Question 33

partial pressure- external

Answer 33

between alveoli and pulmonary capillary blood arriving in pul artery has low po2 and high pco2 meaning o2 enters and co2 leaves blood at altitude, lower po2 of oxygen meaning less o2 to the tissues

Question 34

partial pressure - internal

Answer 34

systemic - between capillary and tissues o2 enters tissues, co2 leaves tissues oxy and deoxy blood mix in passageways lowers po2 of blood entering systemic circuit, blood enters tissues intersitial fluid- intercellular fluid, co2 and o2 diffuse through conc gradient in peripheral capillaries is opposite of lungs

Question 35

gas pickup and delivery

Answer 35

blood plasma can't transport enough o2 or co2 to meet physiogical needs RBC transport o2 to and co2 from peripheral tissues + remove co2 from plasma allowing gases to diffuse into blood

Question 36

haemoglobin

Answer 36

Oxyhemoglobin, deoxyHB, carbaminoHB CO is dangerous as Hb has higher affinity for CO than o2 increased po2- hb binds o2 decreased po2- hb releases o2

Question 37

oxyhb saturation curve

Answer 37

higher po2 results in greater Hb saturation curve as Hb changes shape as each molecule of o2 is bound each o2 bound makes the next o2 binding easier allows Hb to bind o2 when o2 levels are low

Question 38

hb curve- temp

Answer 38

increase in temp- Hb will release more o2 (lower affinity) decrease in temp- Hb will hold more o2 (higher affinity) temp effects are only significant in active tissues as they are generating large amounts of heat

Question 39

hb curve- pH

Answer 39

Bohr effect- result of change in pH caused by increase in co2, co2 diffuse into RBC enzyme carbonic anhydrase catalyses reaction with h2o and produces carbonic acid dissociates into H+ ion and bicarbonate ion, H+ diffuse out of RBC lowering the pH low pH= lower affinity high pH= higher affinity

Question 40

co2 transport

Answer 40

co2 generated by aerobic metabolism 3 pathways- dissolved in plasma, bound to hb, converted to carbonic acid (reversible) co2 is picked up from tissues and transported in systemic capillaries and taken to lungs in pulmonary capillaries co2 is transported into alveolar air space to be breathed out

Question 41

control of respiration

Answer 41

normally- rates of o2 absorption and co2 production at cells is equal to o2 absorption and co2 excretion at lungs if normality is removed, cardiovascular and respiratory systems must adjust increased activity of tissue= decreased po2 and increased pco2, changes in gas exchange, increased blood flow

Question 42

metabolic activity in RBCs

Answer 42

HB and 2,30 bisphosphoglycerate (BPG) RBCs generate ATP by glycolysis – forming lactic acid and BPG BPG directly affects o2 binding and release – more BPG, more o2 released by Hb (lower affinity) BPG levels BPG levels rise when pH increase + when stimulated by certain hormones If BPG levels are too low then Hb will not release o2 (higher affinity)

Question 43

neural control of resp

Answer 43

respiratory centres- when o2 demand rises, cardiac output and respiratory rates increase involuntary- regulates respiratory muscle activity, frequency + depth, responding to info from lungs + respiratory tract (specific receptors) - during quiet breathing voluntary- reflects activity in cerebral cortex, affects output of respiratory centres (medulla + pons) and motor neurons

Question 44

control in pons

Answer 44

apneustic and penumotaxic centres paired nuclei that adjust output of respiratory rhythmicity centres regulate respiratory rate and depth of respiration

Question 45

respiratory centres of medulla

Answer 45

dorsal respiratory group- inspiratory centre, functions in quiet and forced breathing ventral respiratory group- inspiratory and expiratory centre, functions in forced breathing

Question 46

regulatory patterns- quiet breathing

Answer 46

1. diaphragm and external intercostals contract, inhalation 2. dorsal respiratory group inhibited 3. diaphragm and external intercostals relax, passive exhalation occurs 4. dorsal respiratory group active

Question 47

regulatory patterns- forced

Answer 47

1. muscles of inhalation contract, opposing muscles relax, inhalation 2. DRG and inspiratory centres of VRG are inhibited, expiratory centre of VRG is active 3. muscles of inhalation relax and muscles of exhalation contract, exhalation occurs 4. DRG and inspiratory centre of VRG are active, expiratory of VRG is inhibited

Question 48

respiratory reflexes

Answer 48

chemoreceptors- sensitive to pco2, po2 or pH of blood or cerebrospinal fluid baroreceptors- sensitive to changes in blood pressure stretch receptors- respond to changes in lung volume irritating physical or chemical stimuli in nasal cavity, larynx or bronchial tree other sensations including pain, changes in body temp + abmormal visceral sensations

Question 49

mechanoreceptors

Answer 49

baroreceptors in aortic or carotid sinuses are sensitive to changes in blood pressure stretch receptors respond to changes in lung volume

Question 50

hering breuer reflexes

Answer 50

2 mechonrecpetor reflexes involved in forced breathing (not eupnea or when Vt <1000ml) inflation reflex- prevents overexpansion of lungs, as lung volume increases DRG is inhibited, VRG stimulated deflation reflex- inhibits expiratory centres, stimulates inspiratory centres during lung deflation

Question 51

chemoreceptor reflexes

Answer 51

respiratory centres are strongly influences by chemoreceptor input from: cranial nerve IX- (glossopharyngeal nerve)- carotid bodies cranial nerve X (vagus nerve)- aortic bodies central chemoreceptors that monitor cerebrospinal fluid

Question 52

chemoreceptor stimulation

Answer 52

a drop in Po2 to around 40mmHg increases respiratory rate by 50-70% a rise of 10% in arterial Pco2 will increase respiratory rate by 100% chemoreceptor stimulation is subject to adaptation- decreased sensitivity due to chronic stimulation increases in lactic acid also affect respiration

Question 53

chemoreceptors response to increase in pco2

Answer 53

increase arterial pco2 stimulation of arterial chemoreceptors --> stimulation of respiratory muscles increase pco2 + decreased pH + stimulation of CSF chemoreceptors increased respiratory rate with increased elimanation of co2 at alveoli

Question 54

response to decrease in pco2

Answer 54

decreased arterial pco2 - hypocapnia decreased pco2, increased pH in CSF --> decreased stimulation of CSF chemoreceptors inhbition of arterial chemoreceptors + inhibition of respiratory muscles decreased respiratory rate with decreased elimination of co2 at alveoli

Question 55

respiratory changes with age

Answer 55

before birth- pulmonary vessels collapsed, lungs contain no air at birth- new born overcomes force of surface tension to inflate bronchial tree and alveoli to take first breath in elderly- deterioration in elastic tissue, arthritic changes and decreased flexibility, emphysema

Question 56

respiration pace

Answer 56

basic pace of respiration is established by the interplay between respiratory centres in pons and medulla oblongata pace is modified in response to input from chemorecptors, baroreceptors and stretch receptors co2 levels are primary drivers for respiratory activity,

Question 57

bronchodilation and restricion

Answer 57

bronchodilatiuon- widening of bronchiole airways caused by symp ANS, reduces restriction Bronchoconstriction- caused by para ANS, activation/ histamine release (allergic reaction)