Respiration in Humans (Chapter 7)

Respiration in Humans: Purpose of respiration: Break down glucose and release the energy within. Oxygen and glucose are needed for this process to happen. The idea of a system for respiration is to allow for efficient cellular respiration for oxygen to enter the body. It allows us to take in oxygen and give out carbon dioxide. This is known as gaseous exchange. Parts: a. Lungs b. Nose i. the nostrils contain hairs that trap large particles of dust or dirt. c. Larynx d. Trachea (windpipe) i. Contains gland cells that secrete mucus to trap dust particles and bacteria ii. Lined with ciliated epithelium which sweep foreign particles and bacteria up the trachea and into the nostrils. iii. Cilia are hairlike structures. They are NOT microvilli as there is no absorption involved. They also sweep up mucus with the foreign particles and bacteria. iv. When inflamed/swollen, the passageway for air becomes narrower. Less air is able to enter or pass through to the lungs and in severe cases, can suffocate to death. It leads to reduced gaseous exchange. Less O2 for respiration, less energy blah blah blah. e. Bronchi (singular: bronchus) i. When inflamed/swollen, the passageway for air becomes narrower. Less air is able to enter or pass through to the lungs and in severe cases, can suffocate to death. It leads to reduced gaseous exchange. f. Bronchioles g. Alveoli (singular: alveolus) (mostly tested on 4 adaptations) i. To be clear, the adaptation must be linked to the function. The function is to facilitate gaseous exchange, with relies on diffusion. ii. This is where gaseous exchange occurs. The wall of the alveoli are one cell thick to have a shorter diffusion distance so that gaseous exchange will be more efficient. iii. Continuous blood flow around the alveoli allows for the maintenance of a steep concentration gradient . The red blood cells exchange carbon dioxide for oxygen in the alveoli.

iv. There is also a rich network of capillaries around the alveoli to provide a large surface area for diffusion to occur. Additionally, the numerous alveoli in the lungs increases the surface area to volume ratio for diffusion to occur during gaseous exchange, hence increasing the rate of diffusion during gaseous exchange (of O2 and CO2) v. The alveoli has an alveolar cavity, where air enters and exits. vi. There is a thin film of moisture lining the inner walls of an alveolus. This allows oxygen to dissolve for diffusion before being absorbed into the bloodstream. h. Diaphragm (MY GOAT IN VOCALS) i. A thick, dense piece of muscle located at the bottom of the ribcage ii. Only job is to contract and relax iii. When it contracts, it flattens itself (goes down) and creates a vacuum to force air into the lungs. iv. When it relaxes, it arches up (goes up) and forces air out of the lungs. i. intercostal muscles (ALSO MY VOCALS GOAT) i. external intercostal muscles are pointing away from the lungs ii. internal intercostal muscles are pointing towards the lungs YOU CANNOT HAVE AN AIR BUBBLE IN YOUR BLOOD OR ELSE YOU DIE A VERY PAINFUL DEATH. Other terms: 1. Thorax (TB pg 140. Annotated irl)

- Sometimes referred to as the thoracic cavity, it does not apply to trachea. - The chest wall is supported by the ribs. Between the ribs, two sets of muscles, the external and internal intercostal muscles, can be found. Once again, they are antagonistic muscles. - Taking in air: inhalation/inspiration. Releasing air: exhalation/expiration - Sternum (moveable) can move in breathing, but your backbone (fixed) will not move. 2. Inhaling and Exhaling also helps to maintain a steep concentration gradient. Inhalation : annotated on pg 141 note that with intercostal muscles, you have to talk about ribs immediately

Other stuff idk where this goes: - breathing occurs without conscious effort (reflex action, see: nervous system) - ribcage moves upwards and outwards (when standing upright) - Causes volume of thoracic cavity to increase - causing air to suck into the lungs - exhaling, diaphragm moves upwards and outwards - ribcage moves downwards and inwards - ribcage can only perform one set of moves at a time, hence cannot breath in and out at the same time. Cigarettes, tobacco smoke , and the lungs: Nicotine: - causes addiction - increases heart rate and blood pressure - Increases the risk of blood clots in the arteries, which leads to an increased risk of coronary heart disease - Since the blood clots block the lumens of arteries, it prevent blood from flowing back to the heart.

- Increases the risk of narrowing arteries - In a pregnant mother, narrow arteries decrease the amount of food substances reaching the fetus, thereby affecting fetal development and may cause miscarriage Tar: - increases risk of lung cancer (how?) - Tar can cause uncontrolled cell division - Increases risk of chronic bronchitis and emphysema - Emphysema is a chronic and progressive condition. It leads to the partition walls between the alveoli breaking down due to the persistent and violent coughing. The lungs also lose their elasticity (cannot revert back to normal shape) and become inflated with air. Breathing becomes very difficult. Wheezing and severe breathlessness are a result. - Increases the risk of chronic bronchitis after coughing so much. In chronic bronchitis: - Lining of air passages become inflamed - Excessive mucus is secreted by the epithelium - Cilia on epithelium are paralysed, so mucus, bacteria and dust particles cannot be removed. - Air passages become blocked, which make breathing difficult. - In an effort to breathe, persistent coughing will occur to clear air passages, which increases the risk of getting lung infections. - Tar paralyses the cilia lining the air passages. Hence, dust particles trapped in the mucus lining cannot be removed. Carbon Monoxide: - It binds to haemoglobin irreversibly, reducing the amount of haemoglobin readily available to transport oxygen and reducing the amount of oxygen available for body cells - In a pregnant mother, less oxygen reaches the fetus through the placenta which may affect fetal development Aerobic Respiration: Definition: The release of energy by the breakdown of glucose in the presence of oxygen. Carbon Dioxide and water are released as waste products. Aerobic Respiration releases a large amount of energy.

(i’m bumming out man i’m bored) Energy is not present in the equation as it is not a chemical. It is found in the bonds between elements/molecules, and is released when the bonds are broken. This takes place in a cell, specifically the mitochondria. Rate of R