The Respiratory system: Anatomy

Question 1

Upper respiratory tract components

Answer 1

Nose , pharynx and larynx

Question 2

Upper respiratory tract functions

Answer 2

Humidify and warm air
defence-mucus and cilia
sensory, speech

Question 3

Lower respiratory tract components

Answer 3

Trachea, lungs and primary bronchi (first 2 branches from trachea)

Question 4

Lower respiratory tract functions

Answer 4

GE
defence
metabolic

Question 5

Trachea

Answer 5

Rings of cartilage surrounding it interspersed by smooth muscle which can constrict trachea and shut off air supply to lung- incr velocity flow with constriction

Question 6

Parenchyma

Answer 6

Part of lungs involved in GE: alveoli, alveolar ducts and terminal ad respiratory bronchioles, pulmonary arteriole and vein
ie respiratory bronchioles down

Question 7

Conducting zone

Answer 7

air passages

top of trachea to start of respiratory bronchioles

Question 8

Lung branches

Answer 8

Tube divides up to 23x till get to terminal part of the lung
1st 15 or so just to get tubes to right place
Change from psuedostratified columnar in bronchi to cuboidal in terminal and respiratory bronchioles
LArge incr in volume for respiratory bronchioles

Question 9

What type of blood supply do respiratory bronchioles have

Answer 9

Pulmonary

Question 10

Airway resistance mathematically

Answer 10

1/resistance

1/radius^4

Question 11

why is conduction summative

Answer 11

small airways make a small contribution to total resistance

Many respiratory bronchioles

Question 12

What bronchioles have the largest influence over conduction

Answer 12

conducting zone ones

Question 13

What happens in diseases

Answer 13

airway resistance increases
inflammation/thickening of airway wall eg in asthma
Tightened smooth muscles constrict airway
Obstruction with mucus
All these factors narrow airway
Get smooth muscle growth and fibrosis (thickening and scarring of connective tissue)

Question 14

lung epithelium

Answer 14

lining cells in the airway

Question 15

Bronchi epi

Answer 15

ciliated, goblet and glandular (good diagram)

Question 16

Bronchioles epi

Answer 16

ciliated, non-ciliated, goblet , club cells (secretory)

Question 17

Alveoli

Answer 17

Squamous, cuboidal

Question 18

Airway innervation (conducting airways)- to and from CNS

Answer 18

Sensory afferent nerves from airway epithelium and smooth muscles signal to brain
Autonomic fibres to glandular epithelium and smooth muscles from CNS

Question 19

Innervation parasympathetic/sympathetic?

Answer 19

Parasympathetic nervous system drives contraction
Parasympathetic branches of the vagus nerve
Little sympathetic innervation: B adrenoreceptors on airway smooth muscle stimulated by circulating adrenaline

Question 20

Parasympathetic NS receptors

Answer 20

muscarinic and nicotinic cholinergic receptors.

Question 21

Sympathetic NS receptors

Answer 21

alpha, beta 1 and beta 2

Question 22

Respiratory unit

Answer 22

Massive network of airways and air sacs

Question 23

Pneumocytes

Answer 23

alveolar epithelial cells

Question 24

Type I pnuemocytes

Answer 24

Large SA, cover 95% of alveolus but only 10% of cells, squamous
GE

Question 25

Type II pnuemocytes

Answer 25

Cuboidal mostly Secretory: surfactant Precursors for type I- differentiate to produce them

Question 26

Surfactant

Answer 26

90% lipid, mostly phospholipid Reduces surface tension and prevents alveolar collapse Innate immunity function

Question 27

Infant Respiratory Distress syndrome

Answer 27

Give premature babies surfactant via tubes to help lung function because not fully formed Beractant (bovine- cow/animal) Pumactant (synthetic, lipid only)

Question 28

Lung at birth

Answer 28

Lung epi develops in last trimester of pregnancy: Maturation stimulated by corticosteroids given to premature babies Lung is fluid filled in foetus- needs to rapidly empty: surge in corticosteroids and catecholamines (circulating adrenaline) at birth, activation of absorptive channels incl ENaCs, pressure changes (squeeze through birth canal) Caesarian- reduced drive for fluid absorption

Question 29

2 circulatory systems for blood supply to the lungs

Answer 29

Pulmonary circulation and bronchial circulation

Question 30

Pulmonary circulation

Answer 30

Artery flows directly from right ventricle Low O2, high flow, low pressure Low pressure because huge network, so high flow Capillaries pass around alveoli and pulmonary vein returns oxy blood to heart

Question 31

Bronchial circulation

Answer 31

From aorta (left ventricle) high pressure supplies O2 and nutrients to the conducting airways Not involved in respiration

Question 32

Ventilation

Answer 32

Automatic and controlled by CNS

Question 33

Neuronal control of breathing | add to this

Answer 33

(see diagram) Respiratory center in medulla sends nerve impulses down spinal cord to respiratory muscles Chemoreceptors in blod detect pH, CO2 and O2 changes, signal to respiratory center Mechanoreceptors in lung and chest wall also signal

Question 34

Muscle innervation

Answer 34

somatic motor nerves and autonomic nerves

Question 35

Somatic motor nerves

Answer 35

innervate skeletal muscles in thorax Phrenic nerve: innervates diaphragm,pulls muscle downwards and draws air into lungs, allowing ventilation and Intercostal nerves

Question 36

Autonomic nerves

Answer 36

``` Bronchial Supply smooth muscle and secretory cells: - branch from vagus -reflex bronchospasm and mucus secretion -important in asthma ```

Question 37

Sensory afferent pathways from the lung (myelinated)

Answer 37

send impulses via vagus to medullary centres

Question 38

Slowly adapting myelinated

Answer 38

stimulated by stretch receptors in airway smooth muscle Elicit reflexes: Hering Breuer reflex: -promotion of expiration following steady inflation -prevents over inflation of lung

Question 39

Rapidly adapting stretch receptors

Answer 39

stimulated by sudden, sustained inflation ALso by irritant receptors among epithelium Elicit reflexes: cough, bronchoconstriction, mucus secretion

Question 40

Sensory afferent pathways- unmyelinated fibres

Answer 40

Pulmonary and bronchial C fibres located close to BVs Exogenous, endogenous stimuli Reflex bronchoconstriction and mucus secretion

Question 41

Exogenous stimuli

Answer 41

Noxious agents in air

Question 42

Endogenous stimuli

Answer 42

Inflammatory agents generated by the body

Question 43

Cough reflex

Answer 43

Stimulation of irritant receptors- sensory nerve conveys signal to medulla Motor nerves signal to skeletal muscle Glottis closes Abdominal and internal intercostal muscles contract rapidly Intrapulmonary pressure rises Glottis opens leading to cough

Question 44

Pleural membrane

Answer 44

double membrane around the lungs

Question 45

Collapsed lung

Answer 45

only affects one lung, other can still function because anatomically distinct

Question 46

Pleural fluid

Answer 46

Between 2 membranes, allows them to move along side each other, surface tension holds them together Lubricant

Question 47

contraction of diaphragm and external intercostal muscles leads to

Answer 47

incr lung volume internal pressure falls (Boyle's Law) Air drawn into lungs

Question 48

What is elasticity an indication of

Answer 48

how well performing the lung is

Question 49

static compliance

Answer 49

at zero flow | end of inspiration or expiration

Question 50

Dynamic compliance

Answer 50

compliance during active flow

Question 51

What is compliance altered by

Answer 51

increased by surfactant incr in emphysema (loss of elastic tissue, easier to stretch) decr in pulmonary fibrosis (scarring, harder to stretch)

Question 52

Metabolic function of the lung | club, vascular cells, fibrinolytic

Answer 52

club cells detoxify inhaled substances Vascular cells inactivate some circulating hormones Vascular cells activate Angiotensin I, converted to Ang II by Ang converting enzyme Fibrinolytic function: breakdown of fibrin in blood clots, lung source of fibrinolytic enzymes

Question 53

What is pulmonary compliance

Answer 53

measure of elasticity of lung