8. Respiratory System

Question 1

Anatomy

Answer 1

Question 2

Anatomy

Answer 2

Question 3

What are Alveoli?

Answer 3

Alveoli - small, thin-walled sacs that have capillary beds in their walls; site of gas molecule (O2 & CO2) exchange between air and blood; there are millions of alveoli

Question 4

Cartilage and Smooth Muscle

Answer 4

cartilage provides structural support and flexibility to various body parts

smooth muscle is responsible for involuntary movements in organs like the digestive tract and blood vessels.

Question 5

what is dead space

Answer 5

no air exchange taking place but air is still being breathed in

Question 6

What is the Respiratory membrane?

Answer 6

The main function of the respiratory membrane is to enable the exchange of oxygen and carbon dioxide between the air in the lungs and the blood in the pulmonary capillaries.

• average thickness is 0.6 micrometers.
• Very thin – optimized for diffusion
• very large surface area
• 70 square meters in the normal adult - size of one side of a tennis court.

Question 7

What is Pulmonary ventilation?

Answer 7

• Pulmonary ventilation is the movement of air into and out of the lungs.
• Molecules move from areas of high pressure to areas of low pressure.
• Boyle’s Law - the pressure of a gas is
  inversely proportional to its volume.

Question 8

What is Boyle’s Law?

Answer 8

the pressure of a gas is inversely proportional to its volume.

Question 9

Why does air move into and out of the lungs?

Answer 9

• The movement of air into and out of the lungs results from a pressure difference between the pulmonary air and the atmosphere.
• Compliance – the amount of volume
  change in the lung for a given change in alveolar pressure.

Question 10

How does the diaphragm work?

Answer 10

Question 11

Muscles of Inspirations vs Expiration

Answer 11

Question 12

What is Inspiration?

Answer 12

Inspiration - active process
– diaphragm descends and external intercostal muscles contract thus increasing the volume of the thoracic cavity

– decreased pressure in thoracic cavity causing a one or two mm Hg drop in intra-alveolar pressure at rest compared to the outside atmospheric pressure

• can produce a negative pressure as great
  as -30 mm Hg below atmospheric pressure within the alveoli when working their hardest
  – air molecules move through the
  respiratory tubes into the lungs from
  the atmosphere following the pressure
  gradient.

Question 13

What is Expiration?

Answer 13

Expiration – passive process at rest
– diaphragm and external intercostal muscles relax thus decreasing the volume of the thoracic cavity
—> the pressure in the thoracic cavity increases above atmospheric pressure
—> air molecules move out of the
lung following the pressure gradient.

Question 14

Expiration during Exercise?

Answer 14

Expiration – active process during exercise
– Secondary muscles, such as abdominal muscles and internal intercostals become involved in exercise.

– Forced expiration can produce intra-alveolar pressure as great as +50 mm Hg above atmospheric pressure

Question 15

mouth breathing tends to replace nasal breathing

Answer 15

During exercise, mouth breathing tends to replace nasal breathing - less resistance to airflow.
* Air that enters the respiratory passages via either the nose or the mouth is quickly saturated with water vapor and warmed to body temperature, 37 degrees centigrade, even under conditions when very cold air is inspired.

Question 16

What is Tidal volume?

Answer 16

Tidal volume (VT) is the amount of air that is breathed in or out during a normal, quiet breath.
– 500 ml per inspiration or expiration at rest

Question 17

What is the Breathing frequency (FR)?

Answer 17

Breathing frequency (FR)
– 12 - 16 breaths per minute

Question 18

What is Minute Ventilation (VE)?

Answer 18

Minute Ventilation (VE )
– is the volume of gas either inspired or expired (but not both) per minute
– Tidal Volume X Breathing Frequency

Question 19

Lung Volumes at Rest

Answer 19

Rest
* (VT X FR)
* (. 5 L x 12-16 breaths/min)
* 6 - 8 liters/min

Question 20

Lung Volumes at max exercise

Answer 20

Max exercise
* (VT X FR)
* (3 L x 60 breaths/min)
* 180 liters/min

Question 21

What is Expiratory reserve volume (ERV)?

Answer 21

Expiratory reserve volume (ERV) is the maximal volume that can be exhaled from the resting end-expiratory position.
– approximately 25% of vital capacity (VC) at rest

Question 22

What is Inspiratory capacity (IC)?

Answer 22

Inspiratory capacity (IC) is the maximal volume of gas that can be inspired from the resting end-expiratory position.
– approximately 75% of vital capacity (VC) at rest

Question 23

What is Vital capacity (VC)?

Answer 23

Vital capacity (VC) is the greatest volume of gas that can be expelled by voluntary effort after maximal inspiration.
– The vital capacity is the sum of the inspiratory capacity and the expiratory reserve volume.

Question 24

What is Residual Volume?

Answer 24

Residual volume (RV) is the volume of gas remaining in the lungs after forced expiration.

Question 25

What is Functional residual capacity (FRC)?

Answer 25

Functional residual capacity (FRC) is the volume of gas remaining in the lungs at the end of a quiet exhalation. – It is composed of the expiratory reserve volume plus the residual volume

Question 26

What is Total lung capacity?

Answer 26

Total lung capacity = vital capacity plus residual volume

Question 27

What is Forced vital capacity (FVC)?

Answer 27

The forced vital capacity (FVC) maneuver is one in which the subject is instructed to expire as hard and as fast as possible for four seconds.

Question 28

What is Forced expiratory volume in one second (FEV1.0)

Answer 28

Forced expiratory volume in one second (FEV1.0) is the volume of air expired during the first one second of a forced vital capacity manoeuvre.

Question 29

What is Alveolar ventilation (VA)?

Answer 29

Alveolar ventilation (VA) – – the volume of air that reaches the alveoli per minute. – this is the only air that participates in gas exchange with the blood. – Anatomical dead space (VD) is subtracted from tidal volume (VT) to obtain VA.

Answer 30

Question 31

Lung Volume standing vs Sitting

Answer 31

Most volumes and capacities decrease when a person lies down and increase when standing. * Reasons: 1. Abdominal contents push up against diaphragm 2. There is an increase in intrapulmonary blood volume in the horizontal position which decreases the space available for pulmonary air.

Question 32

Pulmonary function test norms

Answer 32

Pulmonary function test norms are usually based on sex, age, and height. It is important to know the size and make-up of the population used to construct the norms.

Question 33

Problems with Pulmonary function test norms

Answer 33

Problems with pulmonary function norms: – don’t consider the “size” of the subject, particularly the chest size – would be better to use sitting height rather than standing height * Pulmonary function tests must be interpreted in relation to a patient's medical history, occupational history, smoking habits, and a chest X-ray

Question 34

Ventilation During Incremental Exercise

Answer 34

* During exercise, minute ventilation increases linearly with increasing exercise intensity (oxygen consumption) * until approximately * 50-60% of VO2 max. in untrained subjects * 75-80% of VO2 max. in endurance athletes. * Ventilatory threshold – * the point at which minute ventilation increases disproportionately with oxygen consumption during graded exercise.

Question 35

What is the Ventilatory threshold?

Answer 35

is the point during exercise when the body's demand for oxygen exceeds its ability to deliver oxygen, leading to an increased reliance on anaerobic energy production and a buildup of lactic acid in the muscles and bloodstream.

Question 36

What are Obstructive disorders? (exam)

Answer 36

Obstructive disorders - blockage or narrowing of the airways causing increased airway resistance * More difficult to move air in and out * Blockage due to inflammation and edema, smooth muscle constriction or bronchiolar secretion. * asthma, bronchitis, emphysema.

Question 37

What are Restrictive disorders? (Exam)

Answer 37

Restrictive disorders - damage to the lung tissue * loss of elasticity and compliance limiting the expansion of the lung * pulmonary fibrosis, pneumonia.

Question 38

Obstructive disorders

Answer 38

Question 39

Restrictive disorders

Answer 39

Question 40

Answer 40