Ch.6: Respiratory System Flashcards
What is the major muscle for breathing?
Diaphragm (prime mover of respiration)
What muscles are involved in inspiration?
External Intercostals Muscles
What are the pressures involved in breathing?
Alveolar Pressure=Pressure inside the lungs.
Pleural Pressure=Pressure outside the lungs.
Transpulmonary Pressure=The difference between alveolar and pleural pressure, driving airflow in and out of the lungs.
How do the lungs work in terms of pressure?
Negative Pressure Type - Air is drawn into the lungs, not forced in.
What controls breathing?
CO2 Levels and its automatically controlled not autonomicly
What are the parts of the upper respiratory tract?
ose, Nasal Cavity, Nasopharynx, Oropharynx
What are the parts of the lower respiratory tract?
Laryngopharynx, Trachea, Bronchi, Bronchioles, Alveoli (air ducts/gas exchange)
What is the conducting zone?
nose, nasal cavit, nasopharynx, oropharynx, laryngopharynx, trachea, bronchial tree, bronchies, terminal bronchioles
What is the respiratory zone?
repiratory bronchioles, alveolar ducts, alveoli
What type of epithelium is found in the nasal cavity?
Pseudostratified Ciliated Columnar Epithelium
It helps trap dust and pathogens in the mucus.
What is the function of the epiglottis?
Covers the opening of the trachea during swallowing & Prevents food from entering the trachea.
What is the cardiac notch?
A depression in the left lung
left has 2 lobes, right has 3 lobes
What are the paranasal sinuses?
Frontal, Sphenoidal, Ethmoidal, Maxillary
They are air-filled cavities that help with sound resonance and lighten the skull.
What happens during sinusitis?
Inflammation of the sinuses, often caused by mucus buildup, leading to discomfort and voice changes.
What happens in the alveoli during gas exchange?
Oxygen is taken up into the bloodstream.
CO₂ is released into the air to be exhaled.
What structures have cartilaginous rings, and what is their function?
Trachea and bronchi have cartilaginous rings for structural support, preventing collapse.
Bronchioles do not have supporting rings and are narrow and collapsible, providing maximum resistance to airflow.
What are the functions of the paranasal sinuses?
Frontal, Sphenoidal, Ethmoidal, and Maxillary sinuses are air-filled spaces lined with mucus membranes.
Help with sound resonance by creating empty spaces.
Lighten the skull bones.
What happens during sinusitis?
Inflammation of the sinus membranes.
Fluid accumulation fills the sinuses, altering voice resonance and causing discomfort.
What is the function of the soft palate?
Separates the breathing and food passages.
Breathing continues continuously but stops momentarily when swallowing.
What happens to the epiglottis during swallowing?
The epiglottis momentarily blocks the trachea to prevent food from entering the airway.
What is the positional relationship between the trachea and esophagus?
Esophagus (food tube) is posterior (behind).
Trachea (airway) is anterior (in front).
What are the openings of the esophagus and trachea called?
Esophagus opening: Gullet
Trachea opening: Glottis
Where are the different sinuses located?
Frontal Sinus – In the frontal bone (forehead area).
Sphenoidal Sinus – Located toward the middle back of the skull.
Maxillary Sinus – Located in the maxilla (upper jaw).
What is the nasal cavity, and what structures line it?
Nasal cavity: Spaces where air passes through.
Lined by nasal conchae (thin, mucus-lined bones).
Function: Warms and humidifies air to match body temperature.
What are the three regions of the pharynx and their locations?
Nasopharynx: Behind the nose.
Oropharynx: Behind the mouth.
Laryngopharynx: Behind the larynx (voice box).
What tonsils are found in the pharynx, and what is their function?
Nasopharynx: Single (unpaired) pharyngeal tonsil.
Oropharynx: Paired palatine tonsils and lingual tonsils.
Function: Play a role in immunity by trapping pathogens.
What is the larynx, and what supports it?
Larynx is the voice box.
Supported by cartilage:
Paired cartilages: Arytenoid, Cuneiform, Corniculate.
Unpaired cartilages: Thyroid (largest, front of larynx), Cricoid, Epiglottis.
What structures are inside the larynx?
Vestibular folds: Superior, protective, no role in sound production.
Vocal folds (true vocal cords): Inferior, responsible for producing sound.
What determines pitch and loudness of the voice?
Pitch (frequency of sound waves): Measured in Hertz (Hz). aka number of waves
Loudness (amplitude of sound waves): Measured in decibels (dB) aka how high they are
What are the units for measuring loudness?
Bel (large unit).
Decibel (dB) is one-tenth of a Bel.
Normal conversation is 40-60 dB.
What is Broca’s area, and what is its function?
Brain region responsible for motor speech.
Helps in forming words and speaking.
What is the trachea, and what are its key features?
Length: 13 cm.
Supported by tracheal rings (cartilaginous rings that are incomplete on the backside).
Last ring forms the carina, which has nerves that trigger the coughing reflex.
How does the trachea divide, and what are the differences between the bronchi?
Divides into two primary bronchi (right and left).
Right bronchus: More vertical and wider.
Left bronchus: Narrower and more horizontal.
Each bronchus supplies a lung.
How do the bronchi continue to divide?
Primary bronchi → Secondary bronchi → Tertiary bronchi
Divides up to 20 times until reaching terminal bronchioles → respiratory bronchioles → alveolar ducts → alveolar sacs → alveoli.
What are alveoli, and what surrounds them?
Air sacs for gas exchange.
Surrounded by capillaries lined with simple squamous epithelium.
Diffusion distance between alveolus and blood vessels: 0.5 - 1 mm.
What are the two types of pneumocytes in the alveoli?
Type 1 pneumocytes: Gas exchange (simple squamous epithelium).
Type 2 pneumocytes: Secrete surfactant, a phospholipoprotein that reduces surface tension and prevents alveolar collapse.
What is the function of surfactant, and what happens if it is missing?
Reduces surface tension, allowing alveoli to expand and preventing collapse.
Without surfactant, lungs collapse (condition called atelectasis).
Surfactant production starts at 28 weeks of fetal development.
Premature babies lack surfactant and require artificial surfactant in a respirator until they produce their own.
How do alveoli maintain equal expansion?
Smaller alveoli have higher pressure and more surfactant, helping them expand.
Pores of Kohn allow air movement between alveoli, helping with collateral ventilation.
What happens in bronchodilation and bronchoconstriction?
Bronchodilation: Smooth muscles relax (caused by epinephrine or histamine).
Bronchoconstriction: Smooth muscles constrict (e.g., asthma, causing breathing difficulties).
What is a tracheotomy or tracheostomy?
A procedure to create an opening in the trachea to insert a breathing tube.
Done if someone stops breathing on their own.
How many alveoli are in the lungs, and what is their total surface area?
300 - 500 million alveoli.
Surface area of 50 - 75 m² for gas exchange.
What type of epithelium lines the trachea?
Pseudostratified ciliated columnar epithelium.
What is the relationship between the trachea and esophagus?
Trachea is anterior.
Esophagus is posterior.
Why are foreign objects more likely to enter the right bronchus?
Right bronchus is wider and more vertical.
Left bronchus is narrower and more horizontal due to the heart.
What happens when something enters the trachea?
Triggers the coughing reflex.
What surrounds the lungs?
Pleural cavity contains each lung.
Each lung is surrounded by two pleural membranes:
Visceral pleura (inner layer).
Parietal pleura (outer layer).
Pleural cavity contains 15 mL of fluid.
What is pleurisy?
Inflammation of the pleura, causing fluid buildup around the lungs.
What is pleural pressure, and how does it change during breathing?
Pleural pressure is always negative.
Becomes more negative during inspiration (-6).
Becomes less negative during expiration (-3).
Why does pleural pressure remain negative?
Parietal pleura is pulled outward by chest muscles.
Visceral pleura is pulled inward by lung elastic recoil.
These opposing forces create a constant negative pressure.
What is alveolar pressure, and how does it change during breathing?
Can be positive or negative.
under stan how this works
Negative during inspiration (-1 = 759 mmHg).
Positive during expiration (+1 = 761 mmHg).
What happens if the pleural cavity loses negative pressure?
Air enters the cavity, causing lung collapse (pneumothorax).
Only the injured lung collapses since pleural cavities are separate.
How do the lungs draw in air?
Negative pressure in the pleural cavity pulls air into the lungs (lungs are negative-pressure type).
What is the length of the trachea?
13 cm long.
What supports the trachea?
Tracheal rings (cartilage rings), which are incomplete on the backside.
What is the last tracheal ring called, and what does it do?
Carina – contains nerves that trigger the coughing reflex when something enters.
What does the trachea divide into?
Two primary bronchi (left and right bronchus), which also have cartilage rings.
how do the right and left bronchi differ?
Right bronchus is wider and more vertical.
Left bronchus is narrower and more horizontal due to the heart.
What do the primary bronchi branch into?
Secondary (lobar) bronchi
Tertiary (segmental) bronchi
Smaller branches (up to 20 times) → terminal bronchioles → respiratory bronchioles → alveolar ducts → alveolar sacs → alveolus.
What lines the alveoli?
Simple squamous epithelium (for gas exchange).
What is the diffusion distance for gases between alveoli and capillaries?
0.50 - 1 mm.
What are the two types of alveolar cells?
Type I pneumocytes: Simple squamous cells for gas exchange (passive diffusion down pressure gradient).
Type II pneumocytes: Large cells that produce surfactant.
What is the function of surfactant?
Reduces surface tension, prevents alveolar collapse, and allows expansion.
What connects alveoli to each other?
Pores of Kohn – allow collateral ventilation.
Why do bronchioles collapse easily?
They lack cartilage rings and are made of smooth muscle (1 mm in diameter).
What causes bronchodilation and bronchoconstriction?
Bronchodilation: Epinephrine or histamine (smooth muscle relaxes).
Bronchoconstriction: Asthma (smooth muscle contracts, making breathing difficult).
At what stage of fetal development does surfactant production begin?
28 weeks.
What happens if a baby is born prematurely before surfactant production?
Lungs collapse, leading to atelectasis.
How is respiratory distress in premature babies treated?
Placed in a ventilator and given artificial surfactant until they produce their own.
How many alveoli are in the lungs, and what is their surface area?
300-500 million alveoli, providing 50-75 m² of surface area.
What surrounds each lung?
Two pleural membranes:
Visceral pleura (inner).
Parietal pleura (outer).
Pleural cavity (space between them) contains 15 mL of fluid
What is pleurisy?
Inflammation of the pleura, causing fluid buildup.
Why is pleural pressure always negative?
these membranes are thin like paper
parietal pleura is pulled outward by chest muscles.
Visceral pleura is pulled inward by lung elastic recoil.
These opposing forces create a negative pressure.
What happens to pleural pressure during breathing?
Becomes more negative (-6) during inspiration.
Becomes less negative (-3) during expiration
What happens if the pleural cavity loses negative pressure?
Air enters, causing lung collapse (pneumothorax).
Does pneumothorax affect both lungs?
No, only the injured lung collapses since the pleural cavities are separate.
What type of pressure system do the lungs use to draw in air?
Negative pressure system (air is drawn in, not forced in).
What is alveolar pressure, and how does it change
Negative (-1 = 759 mmHg) → inspiration.
Positive (+1 = 761 mmHg) → expiration.
What determines pitch and loudness of sound in the vocal cords?
Pitch (frequency in Hertz): Number of sound waves per second.
Loudness (amplitude): Determined by the strength of sound waves. In decibels (dB), which is one-tenth of a Bel. (40-69 db is a normal convo)
What are the two types of vocal folds?
Vestibular folds (superior, protective, no role in sound).
Vocal folds (inferior, true vocal cords, produce sound).
What part of the brain controls motor speech?
Broca’s area.
What is a tracheostomy or tracheotomy?
A procedure where a hole is made in the trachea to insert a breathing tube if someone stops breathing.
What is normal breathing called, and what is forced breathing?
Normal breathing is called quiet breathing or eupnea.
Forced breathing occurs after exercise or exertion.
What muscles are involved in normal inspiration?
Diaphragm and external intercostal muscles aid in normal inspiration.
Diaphragm:
Relaxed: Dome-shaped (expiration).
External intercostal muscles:
Contracted: Raise the ribcage (inspiration).
Relaxed: Lower the ribcage (expiration).
What is the difference between normal and forced breathing?
Normal breathing (eupnea): Involves diaphragm and external intercostal muscles.
Forced breathing: Additional muscles are needed for more effort like neck and abdomin
What is the mechanics of inspiration and expiration?
Inspiration: Active process, requires muscle contraction.
Expiration: Passive process, occurs due to elastic recoil of the lungs.
Mechanics: Diaphragm and external intercostal muscles relax.
What happens to alveolar pressure during inspiration and expiration?
Inspiration:
Alveolar pressure drops to -1 mmHg (759) as the chest cavity expands.
Expiration:
Alveolar pressure rises to +1 mmHg (761), pushing air out of the lungs.
How long does a single breath take, and how many breaths occur per minute?
A single breath takes about 5 seconds.
Normal breathing rate is 12–16 breaths per minute.
What happens to pleural pressure during breathing?
At -3 mmHg (757), no action occurs.
At -6 mmHg (754), inspiration occurs.
Pleural pressure returns to -3 mmHg during expiration, and air flows out of the lungs.
What is transpulmonary pressure and its role in lung expansion?
Transpulmonary pressure is responsible for the expansion or distention of the lungs.
which is equal to:
(alveolar pressure) - (pleural pressure)
Example: Inspiration: (-1) - (-6) = 5
Example: Expiration: (+1) - (-3) = 4
Transpulmonary pressure is always positive, preventing lung collapse, and ensures air is always in the lungs.
What nerves supply the diaphragm and intercostal muscles?
The diaphragm is supplied by the phrenic nerve.
Intercostal muscles are supplied by spinal nerves.
What muscles are involved in forced breathing?
Forced inspiration requires muscles in the NECK:
Sternocleidomastoids
Scalenes
Pectoralis minor
Erector spinae
Forced expiration requires ABDOMINAL MUSCLES:
Rectus abdominis
Internal intercostals
External oblique
Transversus thoracis
Serratus posterior inferior
What is tidal volume (TV), and how much air does it involve?
Tidal volume (TV) is the amount of air that moves in and out of the lungs with each breath.
Normal TV is about 500 ml.
What are the lung volumes and capacities?
Inspiratory reserve volume (IRV): 3100 ml (air intake after normal inspiration).
Expiratory reserve volume (ERV): 1200 ml (air exhaled after normal expiration).
Residual volume (RV): Air always present in the lungs.
Inspiratory capacity (IC): TV + IRV = 3600 ml.
Functional residual capacity (FRC): ERV + RV = 2400 ml.
Vital capacity (VC): TV + IRV + ERV = 4800 ml.
Total lung capacity (TLC): IC + FRC = 6000 ml.
What is minute ventilation rate (minute volume), and how is it calculated?
Minute ventilation rate (minute volume) is the total volume of air moved in and out of the lungs per minute.
Formula: TV x rate of breathing
Example: 500 ml x 12 breaths/min = 6000 ml/min.
What is alveolar ventilation rate, and how is it calculated?
Alveolar ventilation rate is the volume of air that reaches the alveoli for gas exchange.
Formula: (TV - dead space) x rate of breathing (how many times you breathed)
Example: If dead space is 150 ml, and TV is 500 ml, the effective air for gas exchange is reduced.
What is transpulmonary pressure?
It is the difference between alveolar pressure and pleural pressure that is responsible for the expansion of the lungs.
What does positive transpulmonary pressure prevent?
It prevents lung collapse, ensuring some air is always present in the lungs.
What is forced vital capacity (FVC) and FEV1?
Forced vital capacity (FVC): Volume of air exhaled after a deep breath.
FEV1 (Forced Expiratory Volume in 1 second): Volume of air exhaled in the first second of forced expiration.
The FEV1/FVC ratio should be 80% in normal individuals.
Example: 400 ml / 500 ml = 80%.
What does a low FEV1/FVC ratio indicate?
A ratio less than 80% suggests obstructive lung diseases, such as:
Asthma
Emphysema
A normal ratio with reduced air flow suggests restrictive lung diseases (lungs loos eleasticity so they have to cough the air out, such as:
Lung fibrosis
Pulmonary edema (when fluid builds up in the lungs due to the high blood pressue)
Tuberculosis
What is Dalton’s Law and what does it explain?
Dalton’s Law explains the partial pressures of gases in a mixture.
Each gas exerts its own pressure independently of other gases in the mixture. The total pressure of a mixture is the sum of the partial pressures of individual gases.
What does Boyle’s Law describe?
Boyle’s Law describes the relationship between pressure and volume of a gas.
If a gas is compressed, its pressure increases; if the gas is expanded, its pressure decreases.
What is Henry’s Law and how does it relate to gas solubility?
Henry’s Law states that the solubility of gases in a liquid is proportional to the partial pressure of that gas.
CO2 is highly soluble, while oxygen is 24 times less soluble. Nitrogen is the least soluble.
Example: When a diver ascends too quickly, dissolved gases like nitrogen, which were absorbed at high pressures, form bubbles that are painful in the joints called Bends, causing diver’s sickness (or decompression sickness).
What does Haldane’s Law explain?
Haldane’s Law explains that hemoglobin has a higher affinity for CO2 when it is not bound to oxygen (deoxygenated hemoglobin).
When hemoglobin is carrying oxygen, it has a lower affinity for CO2, reducing the amount of carbon dioxide it can bind.
What does Bohr’s Law describe?
Bohr’s Law explains how pH (acidity) affects oxygen transport.
When the pH is acidic, the affinity of hemoglobin for oxygen decreases, and oxygen is more easily released to tissues.
What are the partial pressures of gases in air at sea level?
Nitrogen (N2): 79% of the air, partial pressure = 600 mmHg
Oxygen (O2): 21% of the air, partial pressure = 160 mmHg (Po2)
Carbon Dioxide (CO2): 0.04% of the air, partial pressure = 0.03 mmHg (Pco2)
Total atmospheric pressure = 760 mmHg
What are the partial pressures of gases in the lungs?
in the lungs, oxygen is more and in tissues, CO2 is higher than oxygen
Nitrogen (N2): 570 mmHg
Oxygen (O2): 104 mmHg (Po2)
Carbon Dioxide (CO2): 40 mmHg (Pco2)
Water Vapor: 45 mmHg
What are the partial pressures of gases in tissues?
Oxygen (Po2) in tissues = 40 mmHg
Carbon Dioxide (Pco2) in tissues = 46 mmHg
How does altitude affect air pressure and gas percentages?
At high altitude, the total atmospheric pressure falls, but the percentage of gases (N2, O2, CO2) remains the same.
How is oxygen transported in the blood?
Oxygen Loading (In the Lungs):
In the alveoli of the lungs, partial pressure of oxygen (Po2) is 104 mmHg.
The venous blood entering the lungs has a lower Po2 of 40 mmHg.
Oxygen from the alveoli moves into the blood, and hemoglobin binds with oxygen to form oxyhemoglobin (HbO2).
Carbon Dioxide Exchange (In the Lungs):
The venous blood also carries high levels of carbon dioxide (Pco2 = 46 mmHg), while in the lungs, Pco2 is 40 mmHg.
CO2 moves from the blood into the lungs, while O2 is taken up by the blood.
Arterial Blood:
After this exchange, the arterial blood that exits the lungs has a Po2 = 104 mmHg and a Pco2 = 40 mmHg.
This blood then travels to the tissues.
Oxygen Unloading (In the Tissues):
In the tissues, the Po2 is lower (around 40 mmHg) and the Pco2 is higher (around 46 mmHg).
Hemoglobin (HbO2) releases its bound oxygen (O2) to the tissues, and CO2 from the tissues moves into the blood.
Return to the Lungs:
Cycle Continues:
The blood circulates between the lungs and tissues, constantly picking up oxygen and releasing carbon dioxide.
What are Bends
happen when a diver ascends too quickly, causing dissolved nitrogen in the blood to form bubbles and joint pain
Nitrogen narcosis
condition that affects divers when they breathe compressed air at deep depths and causes them to be semiconcious
What is lung compliance?
The ability of the lungs to expand and recoil efficiently when air enters and exits.
What happens when lung compliance is too high?
The lungs expand too much but don’t generate enough pressure, leading to obstructive lung disease.
aka lungs can expand easily (they are too stretchy), but they lack the ability to generate enough pressure
What happens when lung compliance is too low?
High pressure is needed to expand the lungs, but the volume is insufficient, leading to restrictive lung disease.
aka lungs are stiff and non-compliant. This means that it takes more effort (higher pressure) to stretch the lungs and fill them with air.
What happens when lung elasticity is lost?
The lungs fill with air but cannot recoil properly, causing air to remain trapped. This leads to coughing.
What does SCUBA stand for, and why is helium used instead of nitrogen?
Self-Contained Underwater Breathing Apparatus. Helium replaces nitrogen to prevent bends/diver’s sickness /dysbarism but makes the diver feel cold.
What is the total atmospheric pressure at sea level?
760 mmHg
How does gas exchange occur in the lungs?
Gases move from high pressure to low pressure by simple diffusion (passive transport, no ATP required).
What happens when oxyhemoglobin (HbO₂) unloads oxygen in the tissues?
Hemoglobin releases oxygen and binds to CO₂, forming carbaminohemoglobin (HbCO₂).
How is CO₂ transported back to the lungs?
HbCO₂ releases CO₂ into the lungs, separating back into hemoglobin (Hb) and carbon dioxide (CO₂), allowing hemoglobin to pick up oxygen again.
What happens to atmospheric pressure and oxygen partial pressure at high altitudes?
The total/atmospheric pressure falls, which decreases the partial pressure of oxygen (Po₂), but the percent of oxygen remains unchanged.
How much oxygen can 1 gram of hemoglobin carry?
1 gram of hemoglobin can carry 1.33 ml of oxygen.
How much oxygen can 15 grams of hemoglobin carry per 100 ml of blood at 100% saturation?
15 grams of hemoglobin can transport 20 ml of oxygen per 100 ml of blood.
What is the oxygen carrying capacity of the blood?
The oxygen carrying capacity is 20 ml of oxygen per 100 ml of blood at 100% saturation.
How much oxygen is released to tissues at rest?
At rest, 5 ml (25%) of oxygen is released to tissues.
How much oxygen is needed per minute by tissues?
Tissues need 250 ml of oxygen per minute, so the body requires 500 ml (5 liters) of oxygen per minute.
What is the oxygen equilibrium curve also known as?
The oxygen equilibrium curve is also known as the oxyhemoglobin dissociation curve.
How does exercise affect oxygen unloading in muscles?
During exercise, muscles unload 80% of oxygen, which is why more oxygen is needed during physical activity.
What factors affect the oxyhemoglobin dissociation curve?
The oxyhemoglobin dissociation curve is affected by pH (DH), CO₂ levels, and temperature.
What happens if carbon monoxide (CO) is present in the blood?
Hemoglobin has 200 times more affinity for carbon monoxide (CO) than for CO₂, so it will bind with CO, forming carboxyhemoglobin (HbCO). which is toxic
What is carboxyhemoglobin (HbCO)?
Carboxyhemoglobin (HbCO) is the compound formed when hemoglobin binds with carbon monoxide (CO) instead of oxygen.
What should you do if someone has carbon monoxide poisoning?
You should place the person in a hyperbaric chamber, where the pressure of oxygen is very high, almost pure oxygen.
How does a hyperbaric chamber treat carbon monoxide poisoning
In a hyperbaric chamber, the high oxygen pressure causes oxygen to displace CO from hemoglobin, turning HbCO into HbO₂ (oxygenated hemoglobin), releasing the carbon monoxide.
What does a shift to the left in the oxyhemoglobin dissociation curve indicate?
A left shift means low CO₂, the pH is alkaline, and hemoglobin has a higher affinity for oxygen, meaning oxygen away from tissue
What does a shift to the right in the oxyhemoglobin dissociation curve indicate?
A right shift means high CO₂, the pH is acidic, and hemoglobin has a lower affinity for oxygen, making it more likely to release oxygen to tissues.en going to the tissue
Why does a shift to the right in the curve occur during exercise?
During exercise, CO₂ levels rise, the pH becomes more acidic, and oxygen is more readily released to tissues or muscles that need it.
How does temperature affect the oxyhemoglobin dissociation curve?
If temperature increases, the curve shifts right, meaning more oxygen is released. If temperature decreases, the curve shifts left, meaning less oxygen is released.
What is the primary method of carbon dioxide transport in the blood?
70% of carbon dioxide is transported as bicarbonate.
What happens when carbon dioxide combines with water in plasma?
When CO₂ combines with water in plasma, it forms carbonic acid (7%), which then dissociates into H⁺ ions and bicarbonate. This reaction occurs when Pco₂ is high (in tissues).
What is the role of carbonic anhydrase in red blood cells?
Carbonic anhydrase is an enzyme that catalyzes the formation of carbonic acid when CO₂ enters red blood cells. This helps convert CO₂ into bicarbonate for transport.
What is the chloride shift in red blood cells?
The chloride shift occurs when bicarbonate ions (HCO₃⁻) move out of red blood cells in exchange for chloride ions (Cl⁻) coming into the cells.
aka keep the balance of charges in red blood cells (RBCs) when CO₂ is being carried in the blood.
How does carbon dioxide interact with hemoglobin in tissues?
In tissues, CO₂ binds with hemoglobin to form carbaminohemoglobin (HbCO₂). This occurs due to high Pco₂.
What is acid hemoglobin and how does it form?
Acid hemoglobin forms when hemoglobin combines with H⁺ ions in red blood cells, creating HbH (acidic form of hemoglobin), which occurs in tissues where CO₂ is high.
What happens to carbon dioxide in plasma as blood moves from tissues to lungs?
In the lungs, plasma gives out CO₂. The carbonic acid formed in tissues dissociates into H₂O and CO₂ (which is released into the air due to low Pco₂ in the lungs).
How does hemoglobin interact with oxygen in the lungs?
In the lungs, acid hemoglobin (HbH) picks up oxygen and becomes oxyhemoglobin (HbO₂). H⁺ ions are released during this process.
What happens to bicarbonate ions (HCO₃⁻) in the lungs?
In the lungs, bicarbonate (HCO₃⁻) comes back into red blood cells, while chloride ions (Cl⁻) exit into the plasma. This helps maintain ion balance.
How does sodium bicarbonate form and what happens to it in the lungs?
Sodium bicarbonate (NaHCO₃) formed in tissues gives rise to sodium chloride (NaCl). In the lungs, bicarbonate (HCO₃⁻) goes back into red blood cells.
How does carbonic acid (H₂CO₃) dissociate in the lungs?
In the lungs, H⁺ ions combine with bicarbonate (HCO₃⁻) to form carbonic acid (H₂CO₃), which dissociates into H₂O and CO₂. This reaction is catalyzed by the enzyme carbonic anhydrase.
What is the Bohr effect?
The Bohr effect is when acidity (from lactic acid) lowers hemoglobin’s affinity for oxygen, enhancing oxygen unloading to muscles.
How do hemoglobin (normal, muscle, fetal) types differ in oxygen binding?
Normal hemoglobin: 4 units, binds oxygen at normal pressure.
Muscle hemoglobin (myoglobin): 1 unit, binds oxygen at lower pressure.
Fetal hemoglobin: Binds oxygen at even lower pressure, allowing efficient oxygen transfer from the mother.
How is breathing controlled?
Breathing is both automatic & voluntary.
What does the pneumotaxic center do?
It controls rate & depth of breathing and ensures a smooth transition between inhalation and exhalation.
What does the apneustic center do?
It prolongs inspiration, allowing more air intake into the lungs.
What is the Hering-Breuer reflex?
A reflex that prevents lung overinflation by using stretch receptors.
What is the role of the dorsal respiratory group (DRG)?
It controls quiet breathing, which mainly involves the diaphragm (via the phrenic nerve) and external intercostal muscles (via spinal nerves).
What is the role of the ventral respiratory group (VRG)?
It controls forced breathing, using neck and abdominal muscles.
What affects breathing more: CO₂ or O₂?
CO₂ affects breathing more than oxygen.
What are the two types of chemoreceptors that regulate breathing?
Central chemoreceptors: Located in the brain, detect CO₂ levels in blood & CSF.
High CO₂ → faster breathing
Low CO₂ → slower breathing
Peripheral chemoreceptors: Located in the aortic & carotid bodies, detect acidity from CO₂ & lactic acid.
Activated if Po₂ < 60 mmHg
What are the different types of breathing patterns?
Eupnea: Normal breathing
Apnea: No breathing
Hyperpnea: Deep breathing
Bradypnea: Slow breathing
Tachypnea: Fast breathing
Dyspnea: Difficulty breathing (air hunger)
What do hypercapnia, hypocapnia, hypoxia, hypoxemia, and anoxia mean?
Hypercapnia: High CO₂ in blood
Hypocapnia: Low CO₂ in blood
Hypoxia: Low oxygen in air
Hypoxemia: Low oxygen in blood
Anoxia: No oxygen in blood
Why do we yawn?
Yawning spreads surfactant, which helps expand the alveoli for better lung function.
Eupnea
Normal breathing
Apnea
No breathing
Hyperpnea:
Deep breathing
Bradypnea
Slow breathing
Tachypnea
Fast breathing
Dyspnea
Difficulty breathing (air hunger)
when is oxygen and carbon more, in lungs or tissues
in the lungs, oxygen is more and in tissues, CO2 is higher than oxygen
What does hemoglobin do in the lungs and tissues?
Hemoglobin picks up oxygen in the lungs and carries it to the tissues. In the tissues, it picks up carbon dioxide and takes it back to the lungs to be exhaled.
h ions function
In the blood, hydrogen ions (H⁺) bond with bicarbonate ions (HCO₃⁻) to form carbonic acid (H₂CO₃):
and can make acid hemoglobin in tissues where co2 is high
How is CO₂ transported in the blood and expelled from the body?
In tissues, CO₂ enters red blood cells and combines with water to form bicarbonate (HCO₃⁻).
Chloride ions (Cl⁻) move into the red blood cells (chloride shift) to balance the charge.
In the lungs, bicarbonate moves back into the red blood cells, combining with hydrogen (H⁺) to form CO₂.
CO₂ is then expelled when you exhale.
