06/13/2023 Notes Flashcards
What is the trachea?
A flexible, slightly rigid tubular organ that extends through the mediastinum and is anterior to the esophagus, inferior to larynx, and superior to primary bronchi
What are the 15-20 C-shaped hyaline cartilage that support the anterior and lateral walls of the trachea called?
Tracheal cartilages
What is the purpose of tracheal cartilage?
Reinforce and provide rigidity to tracheal wall to ensure that the trachea remains patent at all tiimes
What binds the C-shaped cartilage together at the open ends?
Trachealis muscle and an elastic, ligamentous membrane
What happens to the trachealis when swallowing?
Bulges into the lumen of trachea to allow for expansion of esophagus
When the trachealis is contracted, what happens to airflow?
when the trachealis is contracted, it becomes more narrow and causes air to flow more rapidly and forcefully through the trachea to expel a foreign object or mucus
What lines the trachea?
Ciliated epithelium with mucin-secreting goblet cells and underlying mucin secreting glands
What does cilia do in the trachea?
Propel mucus with particles towards the larynx and pharynx where it is either coughed out, or swallowed
Where does the trachea bifurcate into right and left primary bronchi?
Sternal angle
Why are inhaled objects more likely to travel into the right lungs?
The left primary bronchus travels at a more acute angle since it travels over the heart, but the right primary bronchus is more vertical which leads directly to the right lungs
What is the bronchial tree?
A highly branched system of air-conducting passages that originate from the primary bronchi ad progressively branch into smaller tubes as they diverge through the lungs before ending at the terminal bronchioles
What supports the walls of primary bronchi to ensure they remain open?
Incomplete rings of cartilage
What is the hilum?
Medial surface of each lung
What structures enter/lead to the medial surface of each lung?
Primary bronchi, pulmonary vessels, lymphatic vessels, and nerves
What do primary bronchi branch into?
Secondary bronchi
How many secondary bronchi are in each lung?
Left lung has 2 since it has two lobes and right lung has 3 since it has three lobes
What do secondary bronchi branch into?
Tertiary bronchi
What are bronchioles?
The smallest bronchi that have a diameter of less than 1 mm and contain no cartilage or cilia, but have a thicker layer of smooth muscle
What does the thicker layer of smooth muscle do in bronchioles?
Regulate airway constriction/dilation and the amount of air traveling through the bronchial tree
What is bronchoconstriction?
Smooth muscle contraction that narrows bronchioles
What is bronchodialtion?
Smooth muscle relaxation that dilates bronchioles
What is the final segment of the conducting pathway of the respiratory system?
Terminal bronchioles
What do terminal bronchioles do?
Conduct air into respiratory portion of the respiratory system
Respiratory bronchioles, alveolar ducts, and pulmonary alveoli are part of what portion of the respiratory system?
Respiratory portion
How is gas diffusion facilitated in the respiratory portion?
The respiratory portion contains thinner epithelium compared to the conduction portion
Terminal bronchioles branch into what?
Respiratory bronchioles
Respiratory bronchioles branch and divide until they form what?
Alveolar ducts
Where do alveolar ducts terminate?
Within a dilated alveolus
What forms alveoli?
Respiratory bronchioles and alveolar ducts
Alveoli are specialized to do what?
Promote diffusion of gasses between alveoli and surrounding pulmonary capillaries
How many alveoli can be found in the lungs?
300-400 million
What are alveolar macrophages?
Migratory cells that continually crawl within the alveoli and engulf microorganisms/particulate matter that has reached the alveoli
What structures are found within the lungs?
Bronchial tree and respiratory portion of the respiratory system
Where are the lungs located, and what separates them?
Lungs are found on the lateral sides of the thoracic structure and separated from each other by the mediastinum
What covers the outside surface of the lungs and the inside surface of the thoracic walls?
Pleura (serous membranes)
What does the visceral pleura cover?
Outer surface of the lungs
What covers the internal thoracic walls, lateral surfaces of mediastinum, and superior surfaces of the diaphragm?
Parietal pleura
What is the pleural cavity?
A potential space located between the pleura that has pressure lower than the lungs
What does the lower pressure in the pleural cavity create?
A partial vacuum that causes the visceral and parietal layers to pull towards each other
What are the primary organs of respiration?
Lungs
Where does the base of the lungs rest?
Upon the diaphragm
What structure supports the lungs?
Ribcage
What separates the left and right lungs from each other?
mediastinum
What 3 lobes make up the right lung? Which one is not present in the left lung?
Superior, middle, and inferior lobes make up the right lung; the middle lobe is absent in the left lung
What are found in bronchopulmonary segments?
Tertiary bronchus, arterial/venous blood supply, and is all surrounded by connective tissue
What is the function of the pulmonary circulation in the lungs?
Conduct blood to and from the gas exchange surfaces of the lungs to replenish the depleted supply of oxygen and get rid of carbon dioxide
What is the function of bronchial circulation?
Part of the systemic circulation and consists of tiny bronchial arteries/veins that supply bronchi and bronchioles
Why is the bronchial circulation much smaller than the pulmonary system?
The tiny respiratory structures in the bronchial circulation exchange respiratory gasses directly with the inhaled air
What branches off the wall of the descending thoracic aorta to form capillary beds that supply blood to structures in the bronchial tree?
Bronchial arteries
Where do bronchial veins drain blood into?
Azygos system of veins
Where are lymph nodes found in the respiratory system?
Connective tissue of the lungs, bronchi, and pleura
What do lymph nodes do in the respiratory system?
Collect carbon dioxide, dust particles, and pollutants not filtered out by ciliated epithelium
Where does the lympathic drainage of the right and left lung drain into?
Left lung drains into thoracic duct while the right lung drains into right lymphatic duct
What is breathing?
Movement of air into and out of the respiratory system
How many times does the average adult breath a minute?
16 times
How much air is exchanged with each breath?
500 mL
What causes airflow exchange?
Muscular actions (inhaltion/exhalation) and differences in atmospheric air pressure and lung air pressure
What are the 5 steps of gas exchange?
- oxygen is drawn into lungs via inhaltion
- oxygen is transported to body cells from blood
- cells use oxygen and generate carbon dioxide
- blood transports carbon dioxide back to lungs
- carbon dioxide leaves the body via exhaltion
The thoracic cavity expands and forms a larger space for lungs during what phase of breathing?
Inhalation
What happens to the diaphragm during inhalation?
Contracts and flattens to press against abdominal viscera
What happens to the diaphragm during exhalation?
Relaxes and returns to original position
Elevation of the ribs _____ lateral dimensions of the thoracic cavity
Increase
What are the primary muscles that move the ribs?
Internal and external intercostals
When are internal intercostals used?
During forceful exhalation to depress the ribs
Normal exhalation requires _____ muscular effort and occurs by the elastic recoil of lung tissue
No
What structures of the respiratory system is innervated by the autonomic nervous system?
Trachea, bronchial tree, and lungs
What does sympathetic innervation do for bronchioles?
Bronchodilation
What does parasympathetic innervation do for bronchioles?
Bronchoconstriction
What brain structure regulates involuntary activities that deliver and remove respiratory gasses?
Brainstem
Where are respiratory centers located in the brain, and what does each do?
medulla oblongata establishes the rate and depth of breathing; pons influences breathing rate
Why does the respiratory system become less efficient with age?
Decrease in elastic connective tissue which reduces amount of gas that can be exchanged and reduces ventilation rate;
Carbon, dust, and pollution builds up in lymph nodes
Emphysema and chronic bronchitis encompass what disease linked to tobacco use?
Chronic Obstructive Pulmonary Disease (COPD)
What does COPD do?
Exhalation is difficult due to airflow obstruction from inflammation to lung structures
Does the body use everything that we eat?
No, cellulose and fiber are not usable by the body
What organs compose the GI tract?
Oral cavity, pharynx, esophagus, stomach, small intestines, and large intestines
What are the accessory organs of the digestive system?
Teeth, tongue, salivary glands, liver, gallbladder, and pancreas
What are the 6 functions of the digestive system?
Ingestion, digestion, propulsion, secretion, absorption, and elimination
What is ingestion?
Introduction of solid and liquid nutrients to the oral cavity
What is digestion?
Breakdown of large food items into smaller structures and molecules through mechanical and chemical digestion
What is mechanical digestion?
The physical breakdown of ingested materials by mastication
What is propulsion
Movement of swallowed materials through the GI tract
What is peristalsis
Process of muscular contraction that forms ripples along part of the GI tract
What is segmentation
Churning and mixing movements in the small intestines which help dispense the material being digested and combine it with intestinal secretions
What is secretion?
Process of producing/releasing fluid products like bile, acid, digestive enzymes, and mucin
What is absorption?
Passive/active transport of electrolytes, digestion products, vitamins, and water across the GI tract epithelium into GI tract blood vessels and lymphatic system
What is elimination?
Removal of waste in the final function of digestion
What happens to indigestible material and waste products?
Secreted from the body as feces in defecation
