Respiratory System

Question 1

Anatomy of the Respiratory System- Respiratory Tract:

Answer 1

Upper Respiratory Tract= Nose, Nasal Cavity, Sinuses and Pharynx.
Lower Respiratory Tract= Larynx, Trachea, Bronchus, Bronchioles and Alveoli

Question 2

Lung Shape and size?

Answer 2

Men have a larger lung capacity than women about 1.5 L more.
The right lung has 3 lobes but left lung has 2 lobes.

Question 3

What is Mucociliary Escalator?

Answer 3

Moves debris from small bronchioles to the top of the trachea to be swallowed.

Question 4

Respiratory Tree?

Answer 4

Primary bronchi divide to form secondary, tertiary bronchi. Terminal bronchioles divide into respiratory bronchioles which divide into alveolar ducts that supply air to alveoli.

Question 5

Alveoli structure?

Answer 5

250 Mm wide and surrounded by capillaries.
Alveolar epithelium maximises gas exchange:
1) Large surface area 100-140m2
2) Thin cellular membrane0.5-1Mm
3)Excellent blood supply
4)Wet surface

Question 6

Breathing?

Answer 6

Breathing is required to maintain high Oxygen levels and low CO2 at respiratory surfaces or arterial blood.

Question 7

INSPIRATION:

Answer 7

.active process
.diaphragm and external intercostal muscles which expands the thoracic cage.
.Air flows into lungs by negative pressure.

Question 8

EXPIRATION:

Answer 8

.passive process
.external intercostal muscles relax, which allows the thoracic cavity to recoil to its resting position.
.air flows out of lungs by positive pressure.

Question 9

CNS Control of breathing:

Answer 9

1)Pons enables voluntary control and smooths the transition between breathing in and out.
2)Medulla detects pH changes(due to increase in co2 levels) and controls breathing rate- chemoreceptors in the VRG.
3)Nerves from medulla respiratory groups stimulate the diaphragm and rib muscles to inhale and exhale.

Question 10

Peripheral control of breathing rate:

Answer 10

.sensors in carotid artery detect o2 and co2 and pH levels to help regulate the activity of medulla.
.sensors in muscles and tendons(proprioceptors) increase respiratory rate during movement.
.Carotid body sensors stimulate breathing when o2 levels fall to low levels.

Question 11

Thoracic cavity:

Answer 11

.it is in an enclosed cavity
.each lung sits inside a pleural cavity
.the cavity is lined by pleural membrane
~ space between layers is contains intrapleural fluid which lubricates lung movement
.thoracic wall contains elastic tissue.

Question 12

Atmospheric Pressure (P atm)

Answer 12

All pressure values are made relative to atmospheric pressure.

Question 13

Alveolar (Intrapulmonary) pressure (P alv)

Answer 13

.Determines direction of air flow.
.P alv - P atm = +/-1
.pressure within alveoli, equalizes between breaths.

Question 14

Intrapleural Pressure (P ip)

Answer 14

.pressure in intrapleural space that keeps lungs from collapsing
.respiratory pump

Question 15

Transpulmonary pressure (P tp)

Answer 15

.Ptp = Palv - Pip
.Helps the lungs remain inflated.

Question 16

Boyle’s law:

Answer 16

In a sealed system
. increased volume= decreased pressure
. decreased volume= increased pressure

Question 17

Breathing air flows towards lower pressure:

Answer 17

Inspiration:
. increase thoracic volume and pressure in the lungs decreases.
. air flows in through airway towards lower pressure.
Expiration:
. decrease thoracic volume and pressure in the lungs increases.
.air flows out through airway.

Question 18

Spirometry:

Answer 18

Can be used to measure lung volumes and parameters
including Minute Ventilation and FEV1

Question 19

Breathing disorders:

Answer 19

1)Acid-base disorders caused by insufficient or excess breathing= respiratory acidosis(acidic blood) and alkalosis (alkaline blood)
2)Restrictive lung diseases due to poor lung expansion and lung tissue stiffness= respiratory distress syndromes and pulmonary fibrosis.
3)Obstructive(OLD) and chronic obstructive pulmonary diseases(COPD) forced vital capacity(FVC) is reduced= asthma, cystic fibrosis, emphysema, bronchitis and pneumonia.
4) Smoking= lung cancer, emphysema and bronchitis.

Question 20

Upper and Lower Respiratory Tract Obstructive Disorders:

Answer 20

1)Lower airway obstruction: Asthma, Chronic bronchitis, Emphysema and Cystic fibrosis.
2)Upper airway obstruction: Epiglottitis, foreign body obstruction and upper airway tumour.

Question 21

Metabolic rate and glucose oxidation:

Answer 21

.breathing provides oxygen for metabolism (ATP synthesis)
.Oxidation of glucose releases co2, metabolic h2o and atp.
.Metabolism is normally aerobic but during exercise it can be anaerobic which produces lactic acid and less Atp.

Question 22

Gas transport:

Answer 22

.circulatory system delivers oxygen to tissues and removes carbon dioxide from tissues.
.pulmonary circulation absorbs oxygen from air and removes carbon dioxide from body.
.systemic circulation delivers oxygen to tissues and removes carbon dioxide from tissues.
.gases diffuse down partial pressure gradients.

Question 23

Red blood cells and haemoglobin:

Answer 23

.RBC contain haemoglobin that carries oxygen bound to an iron atom in a haem group.
.Haemoglobin has 4 protein subunits-
2 alpha subunits and 2 beta subunits.
. each subunit has a haem group and a iron binding site for oxygen.
Oxygen molecules bind to all 4 iron atoms.

Question 24

Oxygen-Haemoglobin Dissociation Curves

Answer 24

Oxygen combines with iron in haemoglobin
and each Hb molecule contains 4 iron atoms
*Oxygen -Hb
dissociation curves are plots of the binding relationships
between Hb and O2
levels
* Oxygen-Hb plots are sigmoidal with a steep slope and a plateau
~ as Po2 increases, saturation goes up
~ as Po2 decreases, saturation falls
* Oxygen-Hb binding is co-operative