Respiratory SystemChapter 9

Air Intake

Air in the atmosphere is mostly Nitrogen (78%)

Only ~21% oxygen

Carbon dioxide is less than 0.04%

Air Intake

Oxygen is required for Aerobic Cellular Respiration to produce ATP (energy required for life-processes)

O2 is produced by plants through photosynthesis.

O2 in the atmosphere must constantly replenished for human cells to survive.

Breathing vs. Respiration

Breathing: the process by which air enters and leaves lungs

Breathing vs. Respiration

Respiration: the exchange of oxygen and carbon dioxide

2 types:Internal External Between cells in tissue and blood Between airway and cells in blood

Airway

Respiratory System - Structures

Nasal CavityPharynxEpiglottisTracheaLarynxBronchi

BronchiolesAlveoli

DiaphragmRib Muscles

Pleural Membranes

Respiratory System - Nasal Cavity

Air enters through the nasal cavity

Functions:

- Hair filters out large debris

- Mucus traps smaller particles

- Sensory cells detect smells

- Air is warmed and humidified

22oC

32oC

37oC

Respiratory System - Pharynx

Pharynx: cavity at the back of the mouth- leads to the esophagus and trachea

Trachea “windpipe”

Epiglottis: flap that covers the trachea opening when swallowing food

Respiratory System - Larynx

Larynx “voice box”

Composed 2 elastic ligaments stretching across opening to the trachea = vocal cords

Respiratory System - Larynx

The Larynx helps to:- Regulate breathing- Keep food out of lungs- Create sounds

Thicker or swollen vocal cordsproduce lower frequency

sounds

Respiratory System - LarynxEndoscopic views of the larynx

Open - inhale Narrow - exhale Closed - sound

Respiratory System - Larynx

The Larynx is also protected by the the thyroid cartilage

The cartilage grows more in males than females = Adam’s Apple

Respiratory System - Trachea and Bronchi

Air from the trachea passes into 2 Bronchi (singular: bronchus)

Trachea and Bronchi have cartilage rings to keep them open

They are lined bycilia and mucusto keep pathogensout of the respiratorysystem

Respiratory System - Bronchioles

The bronchi then branch off into smaller Bronchioles

The Bronchioles do NOT have cartilage rings. Instead they have muscular walls.

If the walls become inflamed(swollen) it becomes difficult to breathe

Ex. asthma, bronchitis

Respiratory System

Trachea

Bronchi

Bronchioles

Respiratory System - Alveoli

The Bronchioles lead into numerous small sacs called Alveoli (singular: alveolus)

The alveoli are extremely small and are surrounded by capillaries

= site of gas exchange (external respiration)

Alveoli during breathing

Respiratory System - Alveoli

The inner surface of alveoli is lined with a layer of lipoproteins which prevents them from “sticking closed” when you exhale

Respiratory System

Respiratory System - Pleural Membrane

Pleural Membrane: thin membranes surrounding the lungs and lining the inner surface of the chest cavity

“Stick” the lungs to the chest wall so they move when the chest walls move as youbreathe

Respiratory System - Pleural Space

Pleural space: fluid-filled space between the pleural membrane and the chest wall

Reduces friction between the lungs and chest wall

If there is fluid buildup in the lungIt becomes painful to inhale(lungs push on fluid and cannotexpand fully)

Respiratory System

PLEURAL MEMBRANE

Respiratory System - Lung Health

Quitting smoking is the single best thing you can do to improve your health and quality of life.Non-smokers have a much lower risk of getting dozens of smoking-related diseases like lung cancer, heart disease, and COPD (chronic obstructive pulmonary disease, including emphysema and chronic bronchitis)

From lung.ca

E-cigarettes (vapes)

Respiratory System - Structures

Nasal CavityPharynxEpiglottisTracheaLarynxBronchi

BronchiolesAlveoli

DiaphragmRib Muscles

Pleural Membranes

1

234

5

6

7

8

910

11 12

Respiratory System - Thoracic Cavity

Diaphragm: thick muscle that separates the chest (thoracic cavity) from the belly (abdominal cavity)

The lungs are surrounded by the ribs, sternum and Intercostal muscles

Respiratory System - Breathing

The ribs are hinged to the spine - allowing them to move up and down

Intercostal muscles control movement of the ribs

External and internal muscles work opposite to each other

Respiratory System - Breathing

Breathing (movement of air into and out of lungs) relies on differences in gas pressures. Atmospheric pressure remains constant but the pressure in the lungs changes as you inhale/exhale

More volume = lower

pressure

Less volume = higher pressure

Respiratory System - Breathing

Inhalation:

Diaphragm contracts

Chest volume increases

Gas pressure in chest is low

Gas moves from atmosphere INTO lungs

Exhalation:

Diaphragm relaxes

Chest volume decreases

Gas pressure in chest is high

Gas moves into atmosphere OUT OF

lungs

Gases move from area of HIGH to LOW pressure

Respiratory System - Breathing

When the external muscles CONTRACT they pull the ribs UP AND OUT

When the RELAX the ribs fall DOWN AND IN

(the external intercostal muscles contract/relax at same as diaphragm)Breathing video

Respiratory System - Breathing

In a pneumothorax air fills the pleural space

Air

Collapsed lung

Respiratory System - Lung Capacity

Normal lungs have a total air capacity of about 5L

Lung capacity is affected by age, height, gender and health

Lung disease, obesity and asthma are causes decreased lung capacity.

Respiratory System - Lung Capacity

A Spirometer is used to measure Lung Capacity. Called a Pulmonary Function Test

Not a recommended

method

Respiratory System - Lung Capacity and Volumes

A pulmonary function graph gives us the following information:

TLC - Total Lung CapacityVC - Vital Capacity

TV - Tidal VolumeERV - Expiratory Reserve VolumeIRV - Inspiratory Reserve VolumeRV - Residual Volume

Respiratory System - Tidal Volume

Tidal Volume

Tidal volume is normally ~500mL

Respiratory System - Pulmonary Function Graph

Deep inhalation

Deep exhalation

Respiratory System - Pulmonary Function Graph

Deep inhalationTidal Volume - the amount of air that is exchanged in a normal breath

Respiratory System - Pulmonary Function Graph

Deep inhalationInspiratory Reserve Volume - amount of air that can be inhaled forcibly

Respiratory System - Pulmonary Function Graph

Deep inhalationExpiratory Reserve Volume - amount of air that can be exhaled forcibly

Respiratory System - Pulmonary Function Graph

Deep inhalationResidual Volume - amount of air that remains in the lungs after exhaling (never is exchanged)

Respiratory System - Pulmonary Function Graph

Deep inhalationVital Capacity - the total amount of air that can be inhaled/exhaled

Respiratory System - Pulmonary Function Graph

Deep inhalationTotal Lung Capacity - total amount of air contained in the lungs

Respiratory System - Lung Capacity

Predict how the Lung Volumes might be different in

How would TLC, VC and RV change?

Marathon runner (Athlete) vs.Smoker with Emphysema (Lung disease)

Respiratory System - Lung Capacity

Average TLC 5 L Athletic TLC 5 L

VC 3 L VC 4 L (increased)

RV 2 L RV 1 L (decreased)

Lung Disease TLC 5 L

VC 2 L (decreased)

RV 3 L (increased)

Respiratory System - Lung Capacity

Graph the Pulmonary Function curves for these people:

Normal: TLC 5L, IC 2L, ERV:1.5, RV 1.5

Obese: TLC 4L, IC 2L, ERV: 0.5L, RV:1.5L

Note: IC = IRV + TV