RESPIRATORY ANATOMY

Sport Books Publisher 1

RESPIRATORY ANATOMY


The primary role of the respiratory system is to: 1. deliver oxygenated air to blood 2. remove carbon dioxide from blood, a by-

product of metabolism.

The respiratory system includes: 1. the lungs 2. several passageways leading from outside to the

lungs 3. muscles that move into and out of the lungs.


The term respiration has several meanings:

1. ventilation (breathing) 2. gas exchange (occurs between the air and

blood in the lungs and between the blood and other tissues of the body)

3. oxygen utilization by the tissues for cellular respiration.


The Lungs

located within the thoracic cavity/chest. the lungs are asymmetrical. The right lung is larger than

the left lung because the heart takes up more space on the left side.

The air passages of the respiratory system are divided into two functional zones:

1. The conduction zone 2. The respiratory zone


The Conduction Zone

the set of anatomical structures in which air passes before reaching the respiratory zone.

Air enters through the nose and or mouth, where it is filtered, humidified, and adjusted to body temperature in the trachea (windpipe).


The Conduction Zone

The trachea branches into the right and left bronchi that enter the lung and continue to branch into smaller and smaller tubes called bronchioles and finally the terminal bronchioles.

The whole system inside the lung looks similar to an upside-down tree that it is commonly called the “respiration tree”.


The Respiration Zone

The region where gas exchange occurs. The functional units of the lungs are the tiny air

sacs, known as alveoli. Alveoli are clustered in bunches like grapes, with

a common opening into an alveolar duct called an alveolar sac.


The Structure of the Respiratory System

BronchusBronchiole

Nose

Mouth

Trachea

Alveolus

Terminal Bronchiole


The Alveolus


Ventilation and the Gas Exchange

Oxygen In Carbon Dioxide Out


Ventilation includes two phases, inspiration and expiration. Gas exchange between the blood and other tissues and oxygen utilization by the tissues are collectively known as internal respiration.

Ventilation


Ventilation

Involves the movement of air into (inspiration) and out of (expiration) the lungs.

Changes in the size of the chest/thoracic cavity, and thus of the lungs, allow us to inhale and exhale air.

Lungs are normally light, soft and spongy to allow for expansion in the thoracic cavity.


Ventilation

The muscles surrounding the thoracic cavity which result in size change include the:

Diaphragm External Intercostal muscles

(expiration) Internal Intercostal muscles (inspiration)


Ventilation

During inspiration, the thoracic cavity expands via muscle contractions causing the air pressure inside to be lowered.

The greater outside pressure causes a flow of air into the lungs.

During expiration, thoracic cavity shrinks via muscle relaxation

The greater outside presure causes a flow of air out of the lungs


Gas Exchange in the Lungs

Gas exchange between the air and blood in the lungs occurs at the alveoli.

Each bubble-like alveolus is surrounded a vast network of pulmonary capillaries.

The atmospheric air which has made its way into each alveolus is rich in oxygen.



The blood in the pulmonary capillaries is loaded with the waste product of carbon dioxide. This difference in concentration of C02 and O2 gases sets up ideal conditions for gas diffusion.

Diffusion is the movement of molecules (in this case, gases) from a higher concentration to a lower concentration

Therefore, oxygen diffuses through the alveolar membrane into deoxygenated pulmonary capillaries.



Carbon dioxide diffuses in the opposite direction, from the carbon dioxide rich pulmonary blood into the alveoli

The oxygenated blood follows the pulmonary circulation to reach the heart (right ventricle) and is distributed through systemic circulation.

Carbon dioxide is exhaled out.


Gas Exchange at the Alveolus


Exercise Effects on the Cardiovascular and Respiratory Systems

The cardiovascular system ensures that adequate blood supply to working muscles, the brain and the heart is maintained.

Also, heat and waste products generated by the muscles are dissipated and removed.


Aerobic Training Effect on the Cardiovascular and Respiratory Systems


Cardiac Output Increase in heart size is one of the

benefits that may arise as a result of endurance training.

1. Larger atria and ventricles allow for a greater volume of blood to be pumped each time the heart beats.

2. Increased thickness of the walls of the heart (cardiac muscle) allows for increased contractility (rate of contraction)

Exercise Effects on the Cardiovascular and Respiratory Systems cont.


Exercise Effects on the Cardiovascular and Respiratory Systems cont.Capillary Supply Increased capillarization is another benefit that may

arise as a result of endurance training.

Increased capillarization allows for:

1. a greater surface area and reduced distance between the blood and the surrounding tissues

2. increasing diffusion capacity of oxygen and carbon dioxide

3. easing transport of nutrients to cells.



Capillary Supply cont

The a-vO2 difference of the body can be also improved by endurance training.

Endurance training increases circulation (blood flow) in the capillaries that are next to muscle fibers.

Capillarization also occurs in cardiac muscle, reducing the possibility of cardiac disease and heart attacks.



Blood Volume Increase in total blood volume

along with the number and total volume of red blood cells.

This is done through stimulation of erythropoiesis (formation of new red blood cells) in the bone marrow.



Ventilation increases with exercise in order to meet the

increased demand of gas exchange. During exercise ventilation can increase from 6 L /

min at rest to over 150 L/min during maximal exercise and to more than 200 L/min during maximal voluntary breathing

With exercise/endurance training, the lungs become more efficient in gas exchange.



Oxygen Extraction similar to ventilation in that the increased

air flow allows for more gas exchange. Additionally, during exercise, body

temperature increases. Increased body temperature promotes oxygen extraction, this is known as the Bohr effect.


Exercise Effects on the Cardiovascular and Respiratory Systems cont.Summary Endurance training stimulates many

positive adaptations in the cardiovascular system.

It is crucial that the health professional understand these adaptations in order to impart this knowledge to the general population allowing people to live with greater health and a better quality of life.


Cardiovascular Anatomy and Physiology

Discussion Questions

1. Describe the path and all related steps that a molecule of oxygen would take from the air in the lungs to a muscle cell.

2. Describe the path and all related steps that a molecule of carbon dioxide could take from a muscle cell to the air in the lungs.

3. Define and provide the units for blood pressure, heart rate, cardiac output, stroke volume, ateriovenous oxygen difference.

4. List the ways in which training improves the effectiveness of the cardiovascular system.


Cardiovascular Anatomy and Physiology

5. Describe the two components of blood pressure. What do they measure?

6. What is hemoglobin, where is it found, what is its purpose.7. What are erythrocytes and reticulocytes? Where are they

produced?8. What is hematocrit?9. Describe the ways in which carbon dioxide can be transported

through the blood.10. What is VO2max? What factors influence this measure? How

is it affected by training?

Discussion Questions cont.

Documents

RESPIRATORY ANATOMY