Respiratory System

What are the major organs and functions of the respiratory system? Organs: Air passages, lungs Function: Carries air into and out of lungs, where gases (oxygen and carbon dioxide are exchanged)

Introduction to Respiratory System Respiratory system consists of tubes that filter incoming air and transport it to microscopic alveoli where gases are exchanged. Process of exchanging gases between atmosphere and body cells is called respiration and consists of: 1. Ventilation - gas exchange between blood and lungs 2. Gas transport in bloodstream 3. Gas exchange between blood and body cells 4. Cellular respiration

Respiration consists of four parts. What are they? Were you listening? Respiration consists of four parts. What are they? 1. Ventilation - gas exchange between blood and lungs 2. Gas transport in bloodstream 3. Gas exchange between blood and body cells 4. Cellular respiration

Organs of the Respiratory System Two groups: Upper respiratory tract (nose, nasal cavity, sinuses, and pharynx) Lower respiratory tract (larynx, trachea, bronchial tree, and lungs)

Nose Bones and cartilage support nose Two openings (nostrils) Hair filters large particles Mucous traps smaller particles

Nasal Cavity Hollow space behind the nose Nasal septum – divides the nose (bone) Deviated Septum – when the septum bends to one side Air is warmed as it enters the nasal cavity, sticky mucus traps particles which are pushed toward the pharynx and swallowed.

Paranasal Sinuses Pairs of air filled sacs surrounding the nasal cavity, above and between the eyes, and behind the cheeks Reduce the weight of the skull Resonant chambers for voice

Pharynx Behind oral cavity Between nasal cavity and larynx Common passageway for air and food. Aids in producing sounds for speech.

Larynx Enlargement at top of trachea and below pharynx Conducts air in and out of trachea Houses vocal cords Composed of framework of muscles and cartilage Thyroid cartilage “Adam’s Apple”

Larynx False vocal folds (do not produce sound) – help close airway during swallowing True vocal folds (produce sound) – changing shape of pharynx and oral cavity changes sounds into words Contracting and relaxing muscles changes pitch (increased tension = higher pitch)

Trachea Epiglottis – flaplike structure above trachea, allows air to enter larynx, during swallowing it presses downward and prevents food from entering air passages Trachea (windpipe) – flexible cylinder, extends downward in front of esophagus (tube from mouth to stomach) Contains 20 C-shaped pieces of hyaline cartilage that prevent trachea from collapsing

Bronchial Tree Bronchial tree consists of branched tubes leading from trachea to alveoli. Bronchial tree begins with the two primary bronchi, each leading to a lung.

Alveoli - Gas exchange between blood and air occurs in the alveoli. Primary bronchii – left and right  bronchioles  alveolar ducts  alveolar sacs  alveoli (gases are exchanged between alveoli and blood stream)

Diffusion Gases diffuse from areas of higher pressure to areas of lower pressure.

Alveolar Gas Exchanges Alveoli are the only sites of gas exchange between atmosphere and blood. Alveoli are tiny air sacs clustered at the end of the bronchioles.

Lungs Soft spongy, cone-shaped organs in chest cavity Alveoli look like a cluster of grapes

Lungs Left Lung – smaller, 2 lobes Right Lung – larger than left, 3 lobes

Review Complete the chart below by describing the functions of the major respiratory organs.

Gas Transport Over 98% of oxygen is carried in blood bound to hemoglobin of red blood cells, producing oxyhemoglobin. Oxyhemoglobin is unstable in areas where concentration of oxygen is low, and gives up its oxygen molecules in those areas.

Breathing Mechanism - Ventilation (breathing) - movement of air in and out of lungs - Inspiration – inhalation - Expiration - exhalation

Inspiration (Inhalation) - Diaphragm moves downward and atmospheric pressure in lungs falls, forcing air into airways - Muscles around ribs contract, raising ribs and sternum and enlarging chest cavity. - Lungs expand with air

Expiration (Exhalation) Diaphragm and other muscles relax and move upward. Pressure forces air out. Contractions increase air pressure within chest cavity, forcing air out.

Respiratory Air Volumes and Capacities Spirometry: Measurement of different air volumes. It describes four distinct respiratory volumes. Respiratory cycle: One inspiration followed by one expiration. Tidal volume: Amount of air that enters or leaves lungs during one respiratory cycle.

Respiratory Air Volumes and Capacities Inspiratory reserve volume:During forced inspiration, an additional volume that can be inhaled into the lungs. Expiratory reserve volume During a maximal forced expiration, the amount of air that can be exhaled Residual volume: air that remains in lungs after maximum expiration.

Respiratory Air Volumes and Capacities Vital capacity: the maximum volume of air that can be exhaled after taking deepest breath possible Dead space: the air remaining in bronchial tree that does not contribute to gas exchange.

Give the definitions for each of the air volumes and capacities. Term Review! Give the definitions for each of the air volumes and capacities. Tidal Volume Inspiratory Reserve Volume Expiratory Reserve Volume Vital Capacity Dead Space Amount of air that enters or leaves lungs during one respiratory cycle During forced inspiration, an additional volume that can be inhaled into lungs. During a maximal forced expiration the additional volume that can be exhaled. maximum volume of air that can be exhaled after taking deepest breath possible air remaining in bronchial tree that does not contribute to gas exchange

Control of Breathing Breathing is involuntary act Muscles under some voluntary control (we can choose to hold our breath)

Respiratory Center Respiratory Center: groups of neurons in brain that control inspiration and expiration

Factors Affecting Breathing Chemosensitive Areas – detect concentrations of chemicals like carbon dioxide and hydrogen 1. Rise in CO2 2. Low blood oxygen 3. Inflation Reflex – regulates depth of breathing, prevents overinflation of lungs 4. Emotional Upset, fear and pain

Factors Affecting Breathing - Hyperventilation – increase breathing for a short time lowers the blood CO2 concentration. Following hyperventilation you can hold your breath for a longer period because it takes longer to increase the blood CO2 levels. People breathe into a paper bag to increase CO2 levels so that they will maintain the proper balance.

Review Question What is the respiratory center and in what area(s) of the brain is it based? The respiratory center is groups of neurons in brain that control inspiration and expiration

Hypoxia Oxygen deficiency Can be caused by inadequate blood flow or poisons

Asphyxia Excess C02 in the blood, lack of oxygen

Illnesses Related to the Respiratory System Cystic Fibrosis Asthma Bronchitis Apnea Emphysema Lung Cancer Altitude Sickness Chronic Obstructive Pulmonary Disease (COPD) Sinusitis Bacterial or Viral Infections (cold, flu, pneumonia)