The Respiratory System

Question 1

what make up the Upper Respiratory System

Answer 1

Nasal cavity, Pharynx, Larynx

Question 2

what is the function of the upper respiratory system

Answer 2

Humidify & warm air
Defence – mucus and cilia
Sensory
Speech

Question 3

what is part of the lower respiratory system

Answer 3

trachea, primary bronchi, lungs

Question 4

what are the functions of the lower respiratory system

Answer 4

GAS EXCHANGE
Defence
Metabolic

Question 5

Airway resistance

Answer 5

is the resistance to the flow of air through the respiratory tract during inhalation and expiration.
Proportional to 1/radius4
But conduction summative
huge numbers of respiratory bronchioles
small airways make a small contribution to total Resistance
Conducting zone bronchioles largest influence

Airway Resistance (=1/conduction)

Question 6

Lung epithelium

Answer 6

Lining cells in airway
Specialisation changes down the airway

Bronchi:ciliated, goblet, glandular

Bronchioles:ciliated, non-ciliated, goblet, club cells

Alveoli:Squamous, cuboidal

Question 7

Mucous-producing goblet cells:

Answer 7

The normal mucous film has two layers – the sol layer and the gel layer The superficial gel layer, produced by the goblet cells, is a sticky mucoid substance which contains chemicals, antibodies and immune cells to destroy any bacteria and viruses. This helps to protect the underlying cells and the sticky nature assists with the trapping and removal of inhaled foreign particles.

Question 8

Parenchyma

Answer 8

Respiratory Bronchiole (RB)
Alveolar Duct (AD)
Alveoli

Question 9

Alveolar epithelial cells (pneumocytes)- Type I

Answer 9

Very large surface area
cover 95% of alveolus
10% of cells
squamous
gas exchange

Question 10

Alveolar epithelial cells (pneumocytes)- Type II cells

Answer 10

cuboidal-majority of cells
secretory-surfactant
precursors for type I

Question 11

Surfactant

Answer 11

Produced by type II alveolar epithelial cells
Lipid (90%) – mostly phospholipid
Proteins – SP-A, -B, -C, -D
Reduces surface tension
prevents alveolar collapse (atelectasis)
Innate immunity function
Instilled into babies with Infant Respiratory Distress Syndrome
Beractant (bovine)
Pumactant (synthetic, lipid only)

Question 12

Lung epithelium develops in the last trimester of pregnancy; by

Answer 12

Maturation stimulated by corticosteroids in premature babies

Question 13

Blood supply to the lungs – two circulatory systems

Answer 13

Pulmonary circulation, Bronchial circulation

Question 14

Pulmonary circulation

Answer 14

Artery flows directly from the right ventricle
LOW oxygen
HIGH flow
LOW pressure
Capillaries pass around the alveoli
Pulmonary vein returns oxygenated blood to left heart

Question 15

Bronchial circulation

Answer 15

From aorta (left ventricle)
HIGH pressure
Supplies oxygen and nutrients the conducting airways
Not involved systemic respiration processes
Only 2% of cardiac outflow

Question 16

Muscle innervation

Answer 16

1-Somatic motor nerves
2-Autonomic nerves
3-Sensory output

Question 17

1-Somatic motor nerves

Answer 17

Innervate skeletal muscles in the thorax
Phrenic
innervates the diaphragm
irritation => hiccough
Intercostal

Question 18

2-Autonomic nerves

Answer 18

Bronchial
supply smooth muscle & secretory cells
branch from vagus
reflex bronchospasm and mucus secretion
important in asthma

Question 19

Cough reflex

Answer 19

Stimulation of irritant receptors
Sensory nerves conveys signal to medulla
Motor nerves signal to skeletal muscles
Glottis closes
Abdominal and internal intercostal muscles contract rapidly
Intrapulmonary pressure rises
Glottis opens

Question 20

Pleural membranes

Answer 20

Double membrane surrounding the lungs
Left & right pleura anatomically distinct
Collapsed lung (pneumothorax) usually only affects one lung
Normally very small amounts of pleural fluid between membranes (few ml)
Serous fluid
Lubricant

Question 21

Ventilation

Answer 21

Fluid in the pleural sac helps the lung wall “stick” to the inside of the thorax
Contraction of the diaphragm and the external intercostal muscles
Increased lung volume
Internal pressure falls (Boyles Law)
Air drawn into lungs
Exhalation passive at rest
Elastic recoil

Question 22

What is the Respiratory System?

Answer 22

The respiratory system includes a series of conducting airways which carry air from the mouth and nose to the lungs
The respiratory system also includes the muscles that enabled breathing, including, most importantly, the diaphragm and the intercostal muscles between the ribs