XI Chap 17 Breathing / Exchange of Gases Flashcards
___________ is used by organisms to indirectly break down simple molecules like glucose, amino acids, fatty acids, etc.
Oxygen
Respiration is commonly known as ___________
breathing
Exchange of ________ from the atmosphere with ________ produced by the cells is ___________
O2, CO2, breathing/respiration
Lower invertebrates like sponges, coelenterates, flatworms, etc. exchange O2 with CO2 through _____________
simple diffusion over their entire body surface
Earthworms use their _________ and insects have a ____________ to transport atmospheric air within the body.
moist cuticle, network of tracheal tubes
In branchial respiration specialized vascularised structures called _____ are used by aquatic arthropods and molluscs.
gills
In pulmonary respiration, vascularised bags called ______ are used by terrestrial forms.
lungs
Among vertebrates, _______ use gills whereas _______, _______, _______ and _______ respire through lungs
fishes;
amphibians, reptiles, birds and mammals
Amphibians like frogs can respire through their moist skin aka _____________ respiration
cutaneous
Nostrils leads to a __________ through the ________
nasal chamber, nasal passage
Nasal chamber opens into the ________
pharynx
Pharynx opens through the ______ region into the trachea
larynx
What is a larynx? aka?
Cartilaginous box which helps in sound production.
Aka sound box
Why is glottis covered with epiglottis during swallowing?
To prevent entry of food into larynx
What is trachea?
Straight tube extending up to the mid-thoracic cavity
Trachea divides at the level of the _______ thoracic vertebra into right and left ________
5th, primary bronchi
Each bronchi undergoes repeat divisions to form secondary and tertiary bronchi ending up in very thin terminal _________
bronchioles
The trachea, primary, secondary, tertiary bronchi and terminal bronchioles are supported by incomplete cartilaginous rings. T or F?
False, initial NOT terminal bronchioles (rest is correct)
What are alveoli?
Very thin, irregular-walled and vascularised bag-like structures at terminal bronchioles
The branching network of ________, _________ and _________ comprise the lungs
bronchi, bronchioles and alveoli
We have two lungs which are covered by a double-layered _______ with _________ between them
pleura, pleural fluid
What is the role of the pleural fluid?
Reduces friction on the lung surface
The outer pleural membrane is in close contact with the _________ whereas the inner pleural membrane is in contact with the _________
thoracic lining, lung surface
Where are the conducting and respiratory/exchange parts of the lung?
Conducting - external nostrils up to the terminal bronchioles
Respiratory/exchange - alveoli and their ducts
What are the roles of the conducting vs. respiratory/exchange parts of the lungs?
Conducting - transports atmospheric air to alveoli, clears it from foreign particles, humidifies and brings air to body temperature
Respiratory/exchange - site of actual diffusion of O2 and CO2 between blood and atmospheric air
Lungs are situated in the ______ chamber
thoracic
Thoracic chamber is anatomically an _________ chamber
air-tight
Position of the following wrt thoracic chamber? vertebral column diaphragm ribs sternum
vertebral column - dorsally
diaphragm - lower side
ribs - laterally
sternum - ventrally
Any change in the volume of the thoracic cavity will be reflected in the __________ cavity
lung (pulmonary)
We can directly alter pulmonary volume by injecting a tube through the thoracic cavity. T or F?
False, cannot directly alter pulmonary volume
Steps involved in respiration?
- Breathing or pulmonary ventilation
- Diffusion of gases across alveolar membrane
- Transport of gases by blood
- Diffusion of O2 and CO2 between blood and tissues
- Utilisation of O2 by cells for catabolic reactions => release of CO2
Breathing involves 2 stages:
inspiration - atmospheric air is drawn in
expiration - alveolar air is released out
Alveolar air is rich in ______ (CO2 or O2)
CO2
Movement of air into and out of the lungs is carried out by creating a pressure gradient. T or F?
True
Pressure within lungs less than atmospheric pressure => ______ [A] pressure in lungs => ______ [B}
Intra-pulmonary pressure is higher than atmospheric pressure => ______ [C} in lungs => ______ [D]
(positive / negative / inspiration / expiration)
negative
inspiration
positive
expiration
__________ and a specialized set of muscles ___________ between the ribs help in generation of pressure gradient for breathing.
Diaphragm, external and internal intercostals
Explain the process of inspiration
Contraction of diaphragm => increased volume of thoracic chamber in antero-posterior axis => contraction of external inter-costal muscles => lifts up ribs and sternum => increased volume of thoracic chamber in dorso-ventral axis => increase in pulmonary volume => decrease in intra-pulmonary pressure => forces air into the lungs
Explain the process of expiration
Relaxation of diaphragm and inter-costal muscles returns diaphragm and sternum to normal positions => reduce the thoracic volume => reduce pulmonary volume => increase in intra-pulmonary pressure => expulsion of air
We have the ability to increase the strength of inspiration and expiration with the help of additional muscles in abdomen. T or F?
True
A healthy humans breathes how many times per minute?
12-16
Volume of air involved in breathing movements can be estimated by using a _________
spirometer
What is tidal volume (TV) ?
volume of air inspired/expired during a normal respiration ~500 ml
What is inspiratory reserve volume (IRV)?
Additional volume a person can FORCIBLY inspire ~2500-3000mL
What is expiratory reserve volume (IRV)?
Additional volume of air a person can FORCIBLY expire ~1000-1100 mL
What is residual volume (RV)?
Volume of air remaining in lungs even after a FORCIBLE expiration ~1100-1200mL
What are the pulmonary capacities used in clinical diagnosis?
IC, EC, FRC, VC, TLC
What is inspiratory capacity (IC)?
Total volume of air a person can inspire after a normal expiration
TV+IRV
What is expiratory capacity (EC)?
Total volume of air a person can expire after a normal expiration
TV+ERV
What is functional residual capacity (FRC)?
Volume of air that remains in lungs after normal expiration
ERV+RV
What is vital capacity (VC)?
Maximum volume of air a person can breathe in after a forced expirationOR can breathe out after a forced inhalation
TV + IRV + ERV
What is total lung capacity (TLC)?
Total volume of air accommodated in lungs at end of a forced inspiration
VC + residual volume => TV+ERV+IRV+RV
_________ are the primary sites of exchange of gases
Alveoli
Apart from alveoli, exchange of gases occur between _____ and ______
blood and tissues
O2 and CO2 are exchanged between blood and tissues by ____________ process.
simple diffusion
Factors that can affect rate of diffusion in exchange of gases?
- solubility of gases
2. thickness of membrane
What is partial pressure?
pressure contributed by an individual gas in a mixture of gases e.g. pO2, pCO2
What are the partial pressures of O2 and CO2 in atmosphere?
O2 - 159
CO2 - 0.3
What are the partial pressures of O2 at alveoli, deoxygenated blood, oxygenated blood and tissues?
Alveoli - 104
Oxygenated blood - 95
Deoxygenated blood - 40
Tissue - 40
What are the partial pressures of CO2 at alveoli, deoxygenated blood, oxygenated blood and tissues?
Alveoli - 40
Oxygenated blood - 40
Deoxygenated blood - 45
Tissue - 45
Concentration gradient for CO2 goes from tissues to …
blood to alveoli
Solubility of CO2 vs O2
Solubility of CO2 is 20-25 times higher
Owing to its solubility, amount of CO2 that can diffuse through the diffusion membrane per unit difference in partial pressure is much ______ (higher/lower) than O2
higher
Diffusion membrane is made up of 3 layers, they are:
- thin squamous epithelium of alveoli
- basement substance
- endothelium of alveolar capillaries
What is the basement substance?
thin basement membrane supporting the squamous epithelium and the basement membrane surrounding the single layer endothelial cells of capillaries
Total thickness of basement membrane substance is much less than _________
a millimetre
________ is the medium of transport for O2 and CO2
Blood
About ______ percent of O2 is transported by RBCs in the blood. Remaining?
97%
Remaining 3% is carried in dissolved state through plasma
____________ is a red-coloured iron containing pigment present in RBCs
Haemoglobin
O2 can bind with haemoglobin in a ____________ manner (reversible/irreversible) to form __________________
reversible, oxyhaemoglobin
Each haemoglobin molecule can carry a maximum of ______ molecules of O2
four
Binding of oxygen with haemoglobin is primarily related to partial pressure of ______
What are the other factors?
O2
Other factors - pCO2, hydrogen ion concentration, temperature
What is the oxygen dissociation curve?
A sigmoid curve
percentage saturation of haemoglobin with O2 is plotted against pO2
The oxygen dissociation curve useful in studying ______
the effect of factors like pCO2, H+ concentration, etc. on binding of O2 with haemoglobin
What are the factors in the alveoli that make it favourable for the formation of oxyhaemoglobin?
High pO2,
Low pCO2,
lesser H+ concentration,
lower temperature
What are the factors in the tissues that make it favourable for the dissociation of oxygen from oxyhaemoglobin?
High pCO2,
Low pO2,
Higher H+ concentration,
higher temperature
O2 gets bounds to haemoglobin at the __________ and gets dissociated at the _________
choose: tissues, plasma membrane, lung surface
lung surface, tissues
Every 100ml of oxygenated blood can deliver around _____ml of O2 to the tissues under normal physiological conditions
5ml
Every 100ml of deoxygenated blood can deliver around _____ml of CO2 to the alveoli under normal physiological conditions
4ml
CO2 is carried by haemoglobin as ________________ about _____ percent
carbamino-haemoglobin (20-25 per cent)
Binding of CO2 to haemoglobin is related to the partial pressure of _____
CO2
pO2 is a major factor which could affect the binding of CO2 to haemoglobin. T or F?
True
RBCs contain a very high concentration of the enzyme ____________ and minute quantities of the same is present in __________
carbonic anhydrase, plasma
What is the reaction that captures the transport of carbon dioxide?
CO2 + H2O <==Carbonic anhydrase==> H2CO3 <==Carbonic anhydrase==> HCO3- + H+
At the tissue site partial pressure of CO2 is high due to __________ (anabolism / catabolism)
catabolism
CO2 diffuses into the blood (RBCs and plasma) and forms _____ and ____
HCO3- and H+
At the alveolar site where pCO2 is low, reaction proceeds in the opposite direction leading to the formation of ______ from _____
CO2 and H20 from H+ and HCO3- ions
Human beings do not have the ability to maintain and moderate the respiratory rhythm through the neural system. T or F?
False, they do have the ability
A specialized centre in the medulla region of the brain called __________ the responsible for regulation of respiration
respiratory rhythm centre
Other than the respiratory rhythm centre, what are the regions/factors that can regulate respiration?
- pneumotaxic centre
- chemosensitive area adjacent to the rhythm centre
- receptors associated with aortic arch and carotid artery
Role of oxygen in regulation of respiratory rhythm is quite insignificant. T or F?
True
Pneumotaxic centre is present in the _______ region of the brain and reduces the duration of ____________ (inspiration / expiration / respiration)
pons region, inspiration
The chemosensitive area adjacent to the rhythm centre is highly sensitive to ______ and ______
CO2 and Hydrogen ions
Increase in CO2 and/or hydrogen ions activates the _________ and causes these substances to be ________ (increased further, eliminated, or neither)
chemosensitive area adjacent to the rhythm centre,
eliminated
Receptors associated with aortic arch and carotid artery can also recognize changes in ____ and _____ concentration
CO2 and H+
Asthma is difficulty in breathing causing _________ due to inflammation of __________ and __________
wheezing, bronchi and bronchioles
Amphysema is a chronic disorder in which ….
alveoli walls are damaged due to which respiratory surface is decreased
One of the major causes of amphysema is _________
cigarette smoking
In industries like grinding or stone breaking, disproportionate amounts of _____ is produced that the defense mechanisms of body cannot cope with.
Dust
Long exposure to dust can give rise to __________ leading to ______________ and causing serious lung damage.
inflammation, fibrosis (proliferation of fibrous tissues)
Which groups live in water, have no specific respiratory organs and respire through diffusion? (4)
Porifera
Coelenterata
Ctenophora
Platyhelminthes
Animals having cellular, tissue and organ levels of organisation do not have any specific respiratory organs. T or F?
True
__________ and __________ groups of organisms show cutaneous respiration
Annelida
Amphibians
Annelida have many blood capillaries below the skin that aid in cutaneous respiration. T or F?
True
Aquatic arthropoda respire through _________ or ________
Gills
Book gills
Terrestrial arthropoda respire through ___________ system
Tracheal
____________ respire through book lungs
Scorpions and spiders
All mollusca respire through gills. T or F?
False, mostly through gills
______________ have a water vascular system wherein they respire through ____________
Echinoderms,
tube feet
Balanoglosses respire through _________
Gills
Prawns respire through ____________
Gills or book gills
Respiratory structures in amphibians? (4)
Gills
Lungs
Skin
Bucco-pharangeal cavity
What is unique about Aves respiratory organs?
Lungs with air sacs
Mechanisms of breathing vary among different groups of animals depending mainly on their _________ and __________
habitats
levels of organisation
Nostrils are aka internal nares. T or F?
False, external nares.
Internal nares are inside nasal chamber/cavity
What are the 3 steps in human respiration - name and brief description?
- External respiration - gaseous exchange between atmosphere and lungs
- Internal respiration - between lungs and blood
- Cellular respiration - between blood and tissues (glucose oxidation)
Nasal cavity is divided into how many parts? What are they called?
2
Nasal vestibule
Middle-posterior part
______________ is the anterior part of the nasal cavity
Nasal vestibule
Nasal vestibule contains turbinal bones that create long passage for air. T or F?
False, contains hair particles that trap dust
________ part of nasal cavity is also called bony part and contains __________ bones
Middle-posterior, turbinal
What is the function of turbinal bones?
Create long spiral passage so that air is brought to body temperature
