The Respiratory System. Presented by Toni Davis and Niamh McDonald

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

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

Nasal Cavity ● 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.

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

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

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

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

Bronchioles ● 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.

Alveoli ● 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

Breathing Mechanism ● 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

Breathing Mechanism ● 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

The Pathway of air ● 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

The Pathway of Air (cont.) ● 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

Respiratory Center of 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

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

Ventral Respiratory 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

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

4 Layers of the Respiratory Membrane ● Alveolar epithelial wall ● Alveolar epithelial basment membrane ● Capillary basement membrane ● Endothelial cells of capillaries

Air and blood gas exchange

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 ● 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.

External Respiration ● 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

How Oxygen diffuses ● 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 Increase ● 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.

Bicarbonate Ions ● 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.

Rate of Diffusion depends on ● 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.

Factors that affect 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.

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