Respiratory System Flashcards
What is the respiratory system responsible for?
- System responsible for gas exchange
- Bringing oxygen into the body and removing carbon dioxide from the body
- also removes excess heat from the body
Why do we need oxygen?
We need oxygen for cellular respiration to occur
What are the two requirements for gas exchange?
Large enough surface area and a moist environment
Why is a large surface area needed for gas exchange?
To meet body‘s needs
Why is a moist environment needed for gas exchange?
For oxygen and carbon dioxide to dissolve in water
What are the four stages in respiration?
- Breathing
- External respiration
- Internal respiration
- Cellular respiration
What is breathing?
- inspiration and expiration, also known as inhalation or exhalation
- Exchange of air between external environment and lungs inside body
What is external respiration?
- Exchange of oxygen and carbon dioxide between air and blood
What is internal respiration?
- Exchange of oxygen and carbon dioxide between the blood and other tissue cells of the body
What is cellular respiration?
- series of energy-releasing chemical reactions that take place inside of cells, providing energy for all cellular activities
- Helps maintain homeostasis
How is cellular respiration help maintain homeostasis?
- since it provides energy for all cellular activities, Energy is needed for many processes in the body to maintain balance
What is the respiratory tract?
- passageway for air to move from the external environment into the lungs in the thoracic cavity
How does air enter in the upper respiratory tract? (5)
- Air enters nostril in nose or mouth
- Nasal passages warm, moisten, and clean air
- Turbinate bones warm air with blood vessels (concha) (sinuses as well)
- Pharynx (throat) common for air and food
- Epiglottis
How do nasal passages warm, moisten, and clean the air?
Lined with ciliated cells and goblet (mucus) cells to trap particles that can be sneezed or coughed out
How do turbinate bones warm air?
Increase surface area for warming air with blood vessels (concha)
- Sinuses as well
What is a pharynx? (2)
- throat
- common for air and food
What is the epiglottis?
- cartilage flap closes over glottis during swallowing
What is the glottis?
- opening to the trachea or windpipe
What is the larynx? What is it made from?
Voice box
- Contains vocal cords
- made from cartilages (tough, connective tissue)
- Space between vocal cords when normal breathing
How are you able to talk? Aka larynx
- The cartilage that supports vocal cords draw vocal cords together with different tensions for the various pitches of speech
- The tenser the cords, the higher the pitch
- Air moves over the cord and causes them to vibrate, producing voice
Explain the structure of the lower respiratory tract
- Trachea branches into two bronchi entering left and right lungs (cartilage rings keep them open)
- Bronchi subdivide into many bronchial tubes in each lung (cartilage ring)
- Bronchial tubes subdivide into many thin-walled bronchioles (No cartilage rings)
- All branching parts are lined with goblet cells and cilia to capture and sweep out foreign particles until they can be coughed, sneezed, or swallowed
- Each lung is divided into lobes (3 in right lung, 2 in left lung) that are divided into lobules (from each bronchiole)
- Each lung is surrounded by a thin double-layered pleural membrane (outer layer attached to inside of chest wall, inner layer to the lung) with fluid film
What is alveoli?
Cluster of tiny sacs at end of each bronchiole
How thick is the alveolar wall and capillaries surrounding the alveoli?
One cell thick
What are each alveolus surrounded by, and why is it there?
- surrounded by a network of tiny capillaries one cell layer thick
- site of gas exchange between air and blood
Which arteriole brings blood to capillaries, and which venule transports blood away
- pulmonary arteriole brings blood to capillaries
- pulmonary venule transports blood away
How is alveoli kept in position?
- elastic connective tissue keeps bronchioles and alveoli in a static position
What muscles control breathing?
- simultaneous movement of the diaphragm and intercostal (rib) muscles
What is the diaphragm?
- dome-shaped muscle separating thoracic and abdominal cavities
What is the process in inhalation? (7)
- Intercostal muscles and diaphragm contract
- Rib cage expands up and out, floor of chest cavity down
- Thoracic cavity volume is increased, decreasing air pressure in the cavity
- Wall of lungs are drawn outward and they expand
- Air pressure in lungs is now low
- Air moves from higher pressure outside the body towards the lower pressure inside the lungs
- Lungs are now filled with air
What is the process in exhalation? (5)
- Intercostal muscles and diaphragm relax and move up
Note:rib cage moves down and in - Volume of thoracic cavity reduces
- Volume of lungs decreases
- Air pressure in lungs increases
- Air moves out of the lungs from high-pressure to the lower pressure outside the body
What is tidal volume?
- volume of air inhaled and exhaled in a normal breathing movement when the body is at rest
What is inspiratory reserve volume?
- additional volume of air that can be taken into the lungs beyond a regular tidal inhalation
Ex. Taking a deep breath
What is expiratory reserve volume?
- additional volume of air that can be forced out of the lungs beyond a regular tidal exhalation
What is vital capacity?
- total lung volume capacity
tidal volume + inspiratory reserve volume + expiratory reserve volume
What is residual volume?
- amount of gas that remains in the lungs even after a full exhalation
- not used in gas exchange
- prevents collapse of lungs
Know that this is not the exact same stale air; it is constantly refreshed with every breath of air
Explain the process of external respiration. Note that it occurs in the lungs (6)
- Gas exchange (CO2 , O2) between alveoli and blood in capillaries by diffusion
- Inhaled air has a higher concentration of oxygen than blood in the capillaries, so oxygen diffuses into the blood
- Blood has a higher CO2 concentration, so CO2 diffuses into the alveoli
- Simple diffusion does occur, but about 30% of oxygen transfer is by facilitated diffusion
- Oxygenated blood is returned to the heart to be distributed to the body, and CO2 in the Alveoli is exhaled
What is the benefit of external respiration?
- Because diffusion occurs, the benefit is that no energy is needed to get oxygen to the blood
What is the process in internal respiration?
- Exchange of gases between blood and body tissues
- Blood has a higher concentration of oxygen than body tissues, so oxygen diffuses into the tissues (blood just came from lungs, lots of O2)
- Body tissues have higher CO2 concentration, so CO2 diffuses into the blood
- Blood (carrying CO2) is carried back to the heart and then the lungs for external respiration once more
How is oxygen transported throughout the body?
By hemoglobin
What is hemoglobin?
- oxygen-carrying molecule in red blood cells
- transport 99% of oxygen reaching cells (remaining 1% is dissolved in blood plasma)
- has an affinity for oxygen
- hemoglobin carrying oxygen is oxyhemoglobin
External respiration hemoglobin reaction
Hb + O2 -> HbO2
Hb is deoxyhemoglobin
HbO2 is oxyhemoglobin
Internal respiration hemoglobin reaction
HbO2 -> Hb + O2
How is carbon dioxide transported throughout the body?
- 23% carried by hemoglobin
- 7% in blood plasma
- 70% is dissolved in blood (red blood cells) as bicarbonate ion, HCO3-
Describe the process of bicarbonate ions
- CO2 reacts with H2O in blood to produce carbonic acid (H2CO3)
- carbonic acid dissociates to hydrogen ions (H+) and bicarbonate ions (HCO3-)
- reaction occurs in red blood cells
- H+ combine with hemoglobin and bicarbonate ions diffuse out of blood cells into plasma
- process reverse in lungs to produce CO2 to be exhaled
Bicarbonate ion in body cells reaction
CO2 + H2O —> H2CO3 —> H+ + HCO3-
First arrow: carbonic anhydrase
- H2CO3 is carbonic acid
- HCO3- bicarbonate ion
Bicarbonate ions in external respiration at the lungs reaction
H+ + HCO3- —> H2CO3 —> H2O + CO2
- H+ is held by hemoglobin
Second arrow is carbonic anhydrase
How is ventilation control?
- breathing is controlled by the respiratory center in the medulla oblongata of the brain
How does the medulla oblongata maintain homeostasis?
- Maintains homeostasis
- Controls amount of O2 and CO2 present in the body
What else does the medulla oblongata do?
- The impulses to the diaphragm and intercostal muscles cause inhalation as it sends messages to them
- refrain of impulses causes exhalation when medulla oblongata tells it to stop
What is the respiratory center sensitive to, and what does it cause?
- directly sensitive to CO2 and hydrogen ions in the blood
- more CO2 and H+ ions means increase in rate and depth of breathing
What happens if you have low oxygen levels?
- Chemo receptors in arteries are sensitive to oxygen levels and send impulses to respiratory centre to increase rate and depth of breathing if oxygen levels decrease
