HSCI 100 Respiratory

2 parts of respiratory system

upper respiratory tract:

nasal cavity

pharynx

Glottis

Larynx

lower respiratory tract:

Trachea

Bronchus

Bronchioles

Lung

Diaphragm

Pathway of air

Inhale:

nose/mouth → trachea → Bronchus → Bronchiole → Alveolus in lung → (diffusion) blood capillary

Exhale:

blood capillary (diffusion) → nose/mouth → trachea → Bronchus → Bronchiole → Alveolus in lung

Nasal turbinates 

bony structures that help filter, warm, and humidify air (critical for efficient gas exchange)

mucosa 

can become swollen due to allergies or infections, leading to nasal

congestion and breathing difficulties

Epiglottis

When you swallow, the larynx moves up against the epiglottis to close off the opening to the trachea

Trachea

A “tube” connecting the larynx with

the primary bronchi

Lined with cilia and goblet cells that produce mucus

keeping lungs clean

Cilia move trapped debris upward toward the throat to

be swallowed or expelled

Lungs

The bronchi, bronchioles, and

alveoli beyond the primary

bronchi make up the lungs

The right lung has 3 lobes while the left lung has 2 lobes.

Each lung is enclosed by a pleura(membrane).

The pleura help keep lungs

expanded and inflate

The alveoli

small sacs where oxygen enters the bloodstream and carbon

dioxide is expelled

lined with surfactant preventing their collapse - it breaks

the surface tension created by water molecules

Inspiration/Inhalation

1) diaphragm and intercostal muscles contract

2) the diaphragm flattens and the move ribcage moves upward and outward

3) volume of lungs increase

4) a partial vacuum is generated within the lungs, and air flows in

5) With muscle relaxation, expiration happens due to volume lessening

breathing Nervous control

-voluntary and involuntary

-Input signals from blood chemistry

-autonomic respiratory control centers in the brain send out nerve

impulses to contract muscles for inspiration.

– Sudden infant death syndrome is thought to occur

when these centers stop sending out signals

breathing: chemical control

chemoreceptors are sensitive to (CO2) levels that change blood pH

– Hyperventilating pushes the reactions to the right – alkalosis results

(pH goes up).

– Hypoventilating pushes the reaction to the left – acidosis results (pH goes down).

– The drop in pH [ H+] is perceived by chemoreceptors which trigger an increase rate and depth of breathing. This is why you cannot hold your breath forever: involuntary control overrides voluntary control of breathing.

Exchange of gases, O2 and CO2, in the body

exchange of gas is dependent on diffusion

partial pressure = amount of pressure each gas exerts

O2 and CO2 will diffuse from the space of higher

partial pressure to the space of lower partial

pressure

External respiration

-exchange of gases betwen alveoli(lungs) and capillaries where oxygen enters the blood and carbon dioxide is removed

Internal respiration

-gas exchange between tissue capillaries and cells throughout the body

-oxygen is delivered to cells and carbon dioxide is collected as a waste product

The movement of O2 and CO2 in the body

At lungs:

CO2 capillary > CO2 air

O2 air > O2 capillary

At tissue:

CO2 cells > CO2 capillary

O2 capillary > O2 cells

Lower respiratory tract disorders

Pneumonia: infection of lungs with thick fluid build up

Tuberculosis: bacterial infection that leads to tubercles

Pulmonary fibrosis: when lungs thicken and scar usually due to buildup from inhaled particles

Emphysema: chronic, incurable disorder in which alveoli are damaged and thus the functional surface area for gas exchange is reduced. Most common cause is smoking

Asthma

-bronchial tree becomes irritated causing breathlessness, wheezing and coughing. Can be triggered by allergic or hyperactive immune response.

Bronchitis

bronchi become inflamed due to infection

Lung cancer

uncontrolled cell division in the lungs that is

often associated with smoking- deadliest of all cancers

COPD

Chronic Obstructive Pulmonary Disease

-emphysema, asthma and chronic bronchitis 

-frequently recurring disorders