The Respiratory System

Role of the Respiratory System The main role of the respiratory system is to get oxygen from the atmosphere and place it in a dissolved form into the blood. The main role of the respiratory system is to get oxygen from the atmosphere and place it in a dissolved form into the blood. The blood will then deliver the oxygen to the cells of the body so they can run cellular respiration and make energy in the form of ATP. The blood will then deliver the oxygen to the cells of the body so they can run cellular respiration and make energy in the form of ATP. Ironically, the other thing needed to make ATP is glucose and we already learned how that was dealt with by the digestive system and placed into the blood. Ironically, the other thing needed to make ATP is glucose and we already learned how that was dealt with by the digestive system and placed into the blood. Glucose + O 2  CO 2 + H 2 O + ATP!!!

Types of Respiration There are three types of respiration: There are three types of respiration: 1. External Respiration – The exchange of gases across the inner surface of the lungs. (Alveoli & Blood) 2. Internal Respiration – The exchange of gases between the blood and cells. (Capillaries & Cells) 3. Cellular Respiration – The use of the oxygen to make energy (ATP) inside of the cell and the mitochondria. Carbon dioxide is a waste gas that is produced by this process and it must be removed from the cells because it is toxic to the cells. The movement of both oxygen into the cells, and carbon dioxide out of the cells is carried out by diffusion. The movement of both oxygen into the cells, and carbon dioxide out of the cells is carried out by diffusion. Diffusion is a mode of passive transport in which substances move from an area or high concentration to an area of low concentration. Diffusion is a mode of passive transport in which substances move from an area or high concentration to an area of low concentration.

The Respiratory Pathway (I) Air enters the body through either the oral cavity (mouth) or nasal cavity (nose). Air enters the body through either the oral cavity (mouth) or nasal cavity (nose). The nasal cavity does a better job of preparing the air for the “wimpy” lungs. The nasal cavity does a better job of preparing the air for the “wimpy” lungs. –It warms the air with increased surface area and the large numbers of capillaries inside. –It moistens the air with mucus. –It cleans the air with nose hair, ciliated cells and mucus – sounds funny but it’s snot! Both the nose and mouth lead back to the pharynx – the intersection at the back of the throat. Both the nose and mouth lead back to the pharynx – the intersection at the back of the throat.

The Respiratory Pathway (II) After the pharynx, air moves down past the larynx (voice box). After the pharynx, air moves down past the larynx (voice box). There are a pair of cartilage flaps called the vocal cords inside the larynx that vibrate as air is pushed by them. There are a pair of cartilage flaps called the vocal cords inside the larynx that vibrate as air is pushed by them. Your teeth, lips and tongue mold the noise produced by the vocal cords help you pronounce various sounds. Your teeth, lips and tongue mold the noise produced by the vocal cords help you pronounce various sounds. The epiglottis lies above the larynx. The epiglottis lies above the larynx. The trachea lies below the larynx. The trachea lies below the larynx.

The Respiratory Pathway (III) The trachea is the windpipe. It extends down from the throat to the chest cavity. The trachea is the windpipe. It extends down from the throat to the chest cavity. The trachea is protected by cartilage rings that keep it from collapsing and cutting off you air supply. The trachea is protected by cartilage rings that keep it from collapsing and cutting off you air supply. It also has mucus-producing cells and cilia lining its inner surface to trap dirt and pathogens and prevent lung infection. It also has mucus-producing cells and cilia lining its inner surface to trap dirt and pathogens and prevent lung infection. The base of the trachea divides into two branches – the left and right bronchi – each of which leads into the left and right lung. The base of the trachea divides into two branches – the left and right bronchi – each of which leads into the left and right lung.

The Bronchial Tree The bronchi, at the base of the trachea, begin to branch out into smaller bronchioles inside of the lungs. The bronchi, at the base of the trachea, begin to branch out into smaller bronchioles inside of the lungs. The bronchioles spread outward to the outer edges of the lungs until you reach the alveoli. The bronchioles spread outward to the outer edges of the lungs until you reach the alveoli. This branching pattern is known as the. This branching pattern is known as the bronchial tree.

Gas Exchange Gas exchange takes place in the alveoli of the lungs. This is where oxygen (O 2 ) is put into the body while carbon dioxide (CO 2 ) is removed from it. This movement is governed by diffusion. (HI  LOW) Gas exchange takes place in the alveoli of the lungs. This is where oxygen (O 2 ) is put into the body while carbon dioxide (CO 2 ) is removed from it. This movement is governed by diffusion. (HI  LOW) The alveoli look like small bunches of grapes that are surrounded by capillary nets. The alveoli look like small bunches of grapes that are surrounded by capillary nets. Capillaries are exchange sites in blood vessels. Capillaries are exchange sites in blood vessels.

The Physiology of Respiration

Muscular Control of Breathing Breathing is under control of a layer o smooth muscle, called the diaphragm, that lies just below the lungs. Breathing is under control of a layer o smooth muscle, called the diaphragm, that lies just below the lungs. The lungs reside in the thoracic cavity – the hollow compartment in the chest. The lungs are like sponges and can expand or constrict to fit within the space of the thoracic cavity. The lungs reside in the thoracic cavity – the hollow compartment in the chest. The lungs are like sponges and can expand or constrict to fit within the space of the thoracic cavity. The diaphragm contracts and moves downward – this makes the thoracic cavity larger and the lungs expand and take in more air to fill the space. This is inhalation. The diaphragm contracts and moves downward – this makes the thoracic cavity larger and the lungs expand and take in more air to fill the space. This is inhalation. When the diaphragm relaxes, it moves back up and makes the thoracic cavity smaller – the lungs are now squeezed and the air is forced out of them. This is exhalation. When the diaphragm relaxes, it moves back up and makes the thoracic cavity smaller – the lungs are now squeezed and the air is forced out of them. This is exhalation.

Muscular Control of Breathing

Nervous Control of Breathing The medulla oblongata is the part of the brain that controls your breathing rate. It has chemoreceptors in it that measure the acid levels of blood. (pH is the key.) The medulla oblongata is the part of the brain that controls your breathing rate. It has chemoreceptors in it that measure the acid levels of blood. (pH is the key.) As more CO 2 is dumped into the blood by the cells, there is more need to breathe and get rid of that CO 2. The CO 2 mixes with the water in the blood to form carbonic acid. As more CO 2 is dumped into the blood by the cells, there is more need to breathe and get rid of that CO 2. The CO 2 mixes with the water in the blood to form carbonic acid. CO 2 + H 2 O  H 2 CO 3 (aq) More CO 2 means more carbonic acid in the blood and a lower pH. This is sensed by the medulla oblongata and it sends an impulse down to the diaphragm to move faster and your breathing rate increases. More CO 2 means more carbonic acid in the blood and a lower pH. This is sensed by the medulla oblongata and it sends an impulse down to the diaphragm to move faster and your breathing rate increases.

That’s All I Got…