Respiration Flashcards
What is the primary medium of transport for O2 and CO2 in the body?
Blood
Blood transports gases, with 97% of O2 and 20-25% of CO2 carried by RBCs.
What percentage of O2 is carried in a dissolved state through plasma?
3%
The majority of O2 is transported by RBCs.
How is CO2 primarily transported in the blood?
As bicarbonate (70%)
CO2 is also carried by RBCs (20-25%) and in dissolved form (7%).
What is the role of haemoglobin in oxygen transport?
It binds O2 in a reversible manner to form oxyhemoglobin
Each haemoglobin molecule can carry a maximum of four O2 molecules.
What factors affect the binding of oxygen to haemoglobin?
Partial pressure of O2, partial pressure of CO2, hydrogen ion concentration, temperature
These factors can either promote or hinder the binding.
What is the shape of the curve obtained when plotting percentage saturation of haemoglobin with O2 against pO2?
Sigmoid curve
This curve is essential for studying the effects of different factors on O2 binding.
Where do conditions favor the formation of oxyhemoglobin?
In the alveoli
High pO2, low pCO2, low H+ concentration, and lower temperature are favorable.
Under normal physiological conditions, how much O2 can 100 ml of oxygenated blood deliver to the tissues?
Approximately 5 ml
This is an important measure of oxygen transport efficiency.
How is CO2 carried by haemoglobin?
As carbamino-haemoglobin (20-25%)
This binding is influenced by the partial pressure of CO2.
What happens to CO2 binding in high pCO2 and low pO2 conditions?
More binding of carbon dioxide occurs
This is typical in tissue environments.
What enzyme is present in high concentration in RBCs that facilitates the transport of CO2?
Carbonic anhydrase
This enzyme catalyzes the conversion between CO2 and bicarbonate.
What occurs at the tissue site where partial pressure of CO2 is high?
CO2 diffuses into blood and forms HCO3- and H+
This reaction is facilitated by carbonic anhydrase.
What is released at the alveolar site where pCO2 is low?
CO2
The reaction reverses, leading to the formation of CO2 and H2O.
How much CO2 does 100 ml of deoxygenated blood deliver to the alveoli?
Approximately 4 ml
This reflects the efficiency of CO2 transport from tissues to the lungs.
What do lower invertebrates like sponges and flatworms use for gas exchange?
Simple diffusion over their entire body surface
This method relies on the direct exchange of gases through the organism’s skin or body surface.
How do earthworms transport atmospheric air within their bodies?
Using their moist cuticle
The moist cuticle allows for gas exchange directly through the skin.
What structures do aquatic arthropods and mollusks use for respiration?
Gills (branchial respiration)
Gills are specialized organs that allow for the exchange of gases in water.
What type of respiration do terrestrial animals use?
Lungs (pulmonary respiration)
Lungs are adapted for gas exchange in air, allowing terrestrial animals to breathe efficiently.
Which respiratory structures are used by fishes?
Gills
Gills allow fishes to extract oxygen from water.
How do amphibians like frogs perform respiration?
Through their moist skin (cutaneous respiration)
This method of respiration allows amphibians to absorb oxygen directly through their skin.
What are the external openings of the human respiratory system called?
External nostrils
These nostrils lead into the nasal chamber and are the first part of the respiratory system.
What is the function of the larynx in the human respiratory system?
Sound production
The larynx is often referred to as the sound box due to its role in generating vocal sounds.
What prevents food from entering the larynx during swallowing?
Epiglottis
The epiglottis is a flap that covers the glottis during swallowing to protect the airway.
At what level does the trachea divide into the primary bronchi?
5th thoracic vertebra
This division is crucial for directing air into both lungs.
What type of support do the trachea and bronchi have?
Incomplete cartilaginous rings
These rings provide structural support while allowing flexibility.
What are the thin, vascularized structures at the end of terminal bronchioles called?
Alveoli
Alveoli are the sites of gas exchange in the lungs.
What covers the lungs and reduces friction during respiration?
Double layered pleura with pleural fluid
The pleural fluid acts as a lubricant to facilitate lung movement.
What is the primary function of the respiratory system?
Gas exchange
The respiratory system is responsible for the intake of oxygen and the expulsion of carbon dioxide.
Fill in the blank: The branching network of bronchi, bronchioles, and alveoli comprise the _______.
Lungs
The lungs are the main organs of the respiratory system.
