Function of the Respiratory System

What Does The Respiratory System Do?
●
The respiratory system takes in oxygen to circulate around the body for many uses such as creating
ATP, supplying systems with oxygen for smelling and speaking.
●
Also, includes that fibers that filter particles from the outside air to and from the lungs
●
Encompasses the whole process by which oxygen is delivered to the cells and used to break down glucose from food, releasing energy.

Structures of the Respiratory System

●
They are covered by fluid-filled double transparent membrane called the pleura.
Beneath the pleura is a dome shaped muscle structure called the diaphragm which contracts and relaxes to expand and relax the lungs.

●
The bronchial tree consists of branched air passages that lead from the trachea to the airs sacs.

●
The nasal concha divide the nasal cavity into passageways and help increase the surface area of the mucous membrane. The mucous membrane with hairlike projections called cilia, lines the nasal cavity and moistens, filter and warms incoming air.
Particles caught in mucous is carried away to the pharynx as a result of the ciliary action, and are eventually swallowed.

●
The mucous traps invading germs with antibacterial enzymes, cilia then allows for mucous to be swallowed.

●
Behind nasal nasal cavity, oral cavity, and larynx
●
●
Passageway for air and food
Consists of nasopharynx, oropharynx, and larynopharynx

●
Conducts air and helps prevent foreign objects from entering the trachea
●
Composed of muscles and cartilages
●
Lined with mucous membrane

●
●
Covered with a ciliated mucous membrane
Cilia move mucus and trapped foreign matter to the pharynx

●
Bronchus branches from the lower trachea and carry air to the lungs.
●
They divide into smaller branches called segmental bronchial , and subdivide smaller and smaller into bronchioles.

●
Approx 600 million
Alveoli sacs exist on the tips of bronchioles.
●
Capillaries in the walls of Alveoli absorb oxygen, and release Co2 and H2O to be exhaled.

Mechanics of breathing

●
The action of breathing in and out is due to changes of pressure within the thorax, in comparison with the outside
●
●
When you inhale, intercostals muscles move rib cage upwards and out
Increase in size and decreases internal pressure and air from outside rushes into the lungs to equalize the pressures

●
●
When you exhale, the diaphragm and intercostal muscles relax and return to their resting positions
Reduces size of
Thoracic cavity, increasing pressure and forcing air out of the lungs

●
With each breath...
–
Person clinches diaphragm, making a vacuum that air is drawn into
–
The air enters trachea moving through one of the two bronchial tubes
–
They branch into smaller into smaller bronchioles ending in alveoli (small sacs)
–
Alveoli contain capillaries in the walls. Red blood cells that carry carbon dioxide from the body trades the carbon for oxygen in air by diffusion

●
●
Oxygenated blood travels all over the body, supply oxygen when needed
Diaphragm relax, carbon dioxide rushes out of the alveoli, through bronchioles and bronchial tubes, out of the trachea and out of the body

The Respiratory System in the brain

Groups of neurons scattered through the pons and
Medulla Oblongota make up the respiratory center of the brain.
The Medullary Rhythmycity area have two neuron groups: Dorsal and Ventral that extend the length of the Medulla Oblongota

This controls the basic rhythms of inspiration.
Neurons emit bursts of impulses that signal the
Diaphragm and the other breathing muscles to contract .

This group usually is very quiet when breathing normally, but if you are more active and have more forceful breathing, like in exercise, this group is activated.

Function and structure of Respiratory Membrane

●
The respiratory membrane is absorbent tissue where gases are exchanged between alveolar air and the blood

●
Alveolar epithelial wall
●
●
Alveolar epithelial basment membrane
Capillary basement membrane
●
Endothelial cells of capillaries

Air and blood gas exchange

●
Blood that is low in oxygen is pumped from the right side of the heart, through pulmonary veins
●
External respiration
–
Carbon dioxide fuses from the Pulmonary Capillaries into the alveoli, oxygen diffuses from the alveoli into the pulmonary capillaries

●
Internal Respiration
–
Oxygen-rich blood is pumped through the systemic circuit to tissues throughout the body.
–
Internal respiration occurs within tissues, as oxygen diffuses from the systemic capillaries into the cells, and carbon dioxide diffuses from the cell and into the systemic circuit.

●
Each breath draws down through the bronchi and bronchioles into the alveoli. Here, in the air sacs, occurs the central process of external respiration.

Oxygen & Carbon dioxide transportation

●
Usually, air is about 78% Nitrogen, 21% oxygen, and
0.04% Carbon Dioxide
When air is inhaled, the gas molecules are filtered through, come into the Alveoli, and dissolve into the blood stream and diffuse with the stream in areas of differentiating pressure.
98% of oxygen binds to the Iron in Hemoglobin, and is pumped through the body by the heart. The other 2% of
Oxygen dissolves into the plasma

●
Oxygen is released faster over time as the Carbon Dioxide concentration increases, the environment becomes more acidic, or as blood temperature increases. This is why you breathe harder to bring in more oxygen when exercising
Blood flow picks up Carbon Dioxide and transported in three different forms.
Some dissolves into plasma, some attach to Hemoglobin and makes its way back out to the lungs, and the third becomes Bicarbonate ions.
CO2 bonds to the amino acids in Hemoglobin, and can be carried out on Hemoglobin with Oxygen already on it.

●
The Bicarbonate ions are when CO2 react with
H2O to create a carbonic acid, then results in the ions. This then travels out with the blood stream, through capillaries of the lungs, dissolves in the alveoli, and exhaled.

●
Partial pressure difference
●
●
Large surface area of alveoli
Diffusion distance (Membrane thickness)

Factors that affect breathing

Asthma: Narrowed airways caused by an allergic reaction
(i.e Dust, Pollen, Smoke).
Infections or a large amount of physical activity can cause an attack.
Whooping Cough: Attacks the Bronchi, inflame lung tissues, and create thick fluid to weaken breathing.

Tuberculosis: Bacterial infection of the lung cavities, and potentially fatal.
Bronchitis: Inflammation of
Bronchi and coughing of yellow mucosa fluid.
Pneumonia: Inflammation of lungs from infection. Parts of lungs fill with fluid and become airless.

●
You have five to ten minutes to study before taking the quiz.