Respiratory System

April 16-17, 2015

Respiratory Anatomy

Flow of air

1. Air enters through the external nares (nostrils)

2. Nasal cavity.• Nasal cavity is lined with ciliated,

mucosal epithelial tissue that trap inhaled particles and sweep them towards the throat to be swallowed and digested.

• Contains three lobes (conchae) which increase the surface area of mucosa exposed to air to better trap particles

3. Pharynx (upper throat)• Passage for both food and air• Contains tonsils

The cilia in the nasal cavity don’t work as well in cold weather, which is why you may get a runny nose in the cold.

Flow of air

4. Larynx (aka voice box)• Acts to prevent food and liquid from

going into trachea.

• Epiglottis is located at the top of larynx. Normally it allows free passage of air, but when we swallow, the larynx is pulled up and the epiglottis tips over, sealing off the larynx.

• The vocal cords – a pair of membranes that vibrate as we expel air are also in the larynx. The passage between the vocal cords is the glottis.

If food / liquid does get past the epiglottis, it triggers the cough reflex.

Put your hand over your throat and swallow – what you feel moving is your larynx!

Swallowing animation!

Flow of air

5. Trachea• also contains ciliated mucosa to

trap particles

6. Bronchi• Largest air tubes of lungs

7. Bronchioles• Smallest of the air tubes

8. Alveoli• Site of gas exchange• Take up most of the space of the

lungs• Covered with capillaries to

exchange gasses with blood.

Bronchitis = inflammation of bronchi

Other important structures

» Sinuses• Spaces in the skull bones• Act as resonance chambers for

speech and produce mucus• Sinusitis = inflammation of sinus

membranes

Pleural membranes• Sac surrounding lungs

• Fluid-filled space reduces friction as lungs expand and contract

• Tightly bound to thorax wall, which is essential to breathing b/c it allows the lungs to expand and contract with muscular movement.

Making Connections

» What structures in the respiratory system help with disease prevention? Are those structures specific or non-specific defenses?

» Name some similarities between the cardiovascular and respiratory systems.

Inspiration & Expiration

» Inspiration• Diaphragm & external

intercostals contract, expanding the chest cavity and the lung capacity.

• Causes a decrease in pressure within the lungs.

• Air rushes into the lungs.

» Expiration• Diaphragm & external

intercostals relax, reducing the chest cavity and the lung capacity.

• Causes a increase in pressure within the lungs.

• Air rushes into the lungs.

Watch me!

Exhalation is normally passive (we just relax muscles, we do not contract any), but we CAN actively exhale and do after exercise.

How does the process of breathing help the cardiovascular system?

Regulation of Breathing

» Breathing rate is controlled by respiratory centers in the pons and medulla.

» There is a ‘normal’ rate of inspiration (12 -15 breaths / min) maintained by self-exciting cells

» Many sensory inputs act to increase or decrease this normal • Low O2 ↑

• High CO2 ↑

• Low blood pH ↑• Irritants/stretch ↑• High body temp ↑• Emotions ↑↓• Volition ↑↓ Usually, Our body is more sensitive to

CO2 / blood pH levels than to O2

Revisit Do Now – How is breathing regulation similar to and different from heart beat regulation?

COPD

Chronic Obstructive Pulmonary Disorder» 3rd or 4th leading cause of death (after heart disease and cancer,

about tied with stroke)» Inability of air to get to capillaries of lungs» Two major diseases associated with COPD

• Chronic bronchitis – inflammation of bronchi & excessive mucus production

• Emphysema – destruction of alveoli

COPD is strongly associated with smoking, but it can also be caused by air pollution

How does each disease reduce gas exchange?

COPD

Shortness of breath

Enlargement of right side of heart

COPD is also characterized by high CO2 levels – so high, that overtime, the body starts to ignore that information and focus on O2 levels

COPD

Pulmonary rehabilitation breathing exercisesSurgery removal of part of the lungs or lung transplant

Closure

1.What were our objectives and what did you learn?

2.How does this relate to our unit question? (How do body systems work together?)

3.How did we demonstrate our learner profile trait?