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Internal respiration

Internal respiration is gas exchange that occurs at the level of body tissues ( [link] ). Similar to external respiration, internal respiration also occurs as simple diffusion due to a partial pressure gradient. However, the partial pressure gradients are opposite of those present at the respiratory membrane. The partial pressure of oxygen in tissues is low, about 40 mm Hg, because oxygen is continuously used for cellular respiration. In contrast, the partial pressure of oxygen in the blood is about 100 mm Hg. This creates a pressure gradient that causes oxygen to dissociate from hemoglobin, diffuse out of the blood, cross the interstitial space, and enter the tissue. Hemoglobin that has little oxygen bound to it loses much of its brightness, so that blood returning to the heart is more burgundy in color.

Considering that cellular respiration continuously produces carbon dioxide, the partial pressure of carbon dioxide is lower in the blood than it is in the tissue, causing carbon dioxide to diffuse out of the tissue, cross the interstitial fluid, and enter the blood. It is then carried back to the lungs either bound to hemoglobin, dissolved in plasma, or in a converted form. By the time blood returns to the heart, the partial pressure of oxygen has returned to about 40 mm Hg, and the partial pressure of carbon dioxide has returned to about 45 mm Hg. The blood is then pumped back to the lungs to be oxygenated once again during external respiration.

Internal respiration

This diagram details the pathway of internal respiration. The exchange of oxygen and carbon dioxide between a red blood cell and a tissue cell is shown.
Oxygen diffuses out of the capillary and into cells, whereas carbon dioxide diffuses out of cells and into the capillary.

Everyday connection

Hyperbaric chamber treatment

A type of device used in some areas of medicine that exploits the behavior of gases is hyperbaric chamber treatment. A hyperbaric chamber is a unit that can be sealed and expose a patient to either 100 percent oxygen with increased pressure or a mixture of gases that includes a higher concentration of oxygen than normal atmospheric air, also at a higher partial pressure than the atmosphere. There are two major types of chambers: monoplace and multiplace. Monoplace chambers are typically for one patient, and the staff tending to the patient observes the patient from outside of the chamber ( [link] ). Some facilities have special monoplace hyperbaric chambers that allow multiple patients to be treated at once, usually in a sitting or reclining position, to help ease feelings of isolation or claustrophobia. Multiplace chambers are large enough for multiple patients to be treated at one time, and the staff attending these patients is present inside the chamber. In a multiplace chamber, patients are often treated with air via a mask or hood, and the chamber is pressurized.

Hyperbaric chamber

This photo shows two hyperbaric chambers.
(credit: “komunews”/flickr.com)

Hyperbaric chamber treatment is based on the behavior of gases. As you recall, gases move from a region of higher partial pressure to a region of lower partial pressure. In a hyperbaric chamber, the atmospheric pressure is increased, causing a greater amount of oxygen than normal to diffuse into the bloodstream of the patient. Hyperbaric chamber therapy is used to treat a variety of medical problems, such as wound and graft healing, anaerobic bacterial infections, and carbon monoxide poisoning. Exposure to and poisoning by carbon monoxide is difficult to reverse, because hemoglobin’s affinity for carbon monoxide is much stronger than its affinity for oxygen, causing carbon monoxide to replace oxygen in the blood. Hyperbaric chamber therapy can treat carbon monoxide poisoning, because the increased atmospheric pressure causes more oxygen to diffuse into the bloodstream. At this increased pressure and increased concentration of oxygen, carbon monoxide is displaced from hemoglobin. Another example is the treatment of anaerobic bacterial infections, which are created by bacteria that cannot or prefer not to live in the presence of oxygen. An increase in blood and tissue levels of oxygen helps to kill the anaerobic bacteria that are responsible for the infection, as oxygen is toxic to anaerobic bacteria. For wounds and grafts, the chamber stimulates the healing process by increasing energy production needed for repair. Increasing oxygen transport allows cells to ramp up cellular respiration and thus ATP production, the energy needed to build new structures.

Chapter review

The behavior of gases can be explained by the principles of Dalton’s law and Henry’s law, both of which describe aspects of gas exchange. Dalton’s law states that each specific gas in a mixture of gases exerts force (its partial pressure) independently of the other gases in the mixture. Henry’s law states that the amount of a specific gas that dissolves in a liquid is a function of its partial pressure. The greater the partial pressure of a gas, the more of that gas will dissolve in a liquid, as the gas moves toward equilibrium. Gas molecules move down a pressure gradient; in other words, gas moves from a region of high pressure to a region of low pressure. The partial pressure of oxygen is high in the alveoli and low in the blood of the pulmonary capillaries. As a result, oxygen diffuses across the respiratory membrane from the alveoli into the blood. In contrast, the partial pressure of carbon dioxide is high in the pulmonary capillaries and low in the alveoli. Therefore, carbon dioxide diffuses across the respiratory membrane from the blood into the alveoli. The amount of oxygen and carbon dioxide that diffuses across the respiratory membrane is similar.

Ventilation is the process that moves air into and out of the alveoli, and perfusion affects the flow of blood in the capillaries. Both are important in gas exchange, as ventilation must be sufficient to create a high partial pressure of oxygen in the alveoli. If ventilation is insufficient and the partial pressure of oxygen drops in the alveolar air, the capillary is constricted and blood flow is redirected to alveoli with sufficient ventilation. External respiration refers to gas exchange that occurs in the alveoli, whereas internal respiration refers to gas exchange that occurs in the tissue. Both are driven by partial pressure differences.

Questions & Answers

describe the location of the macula densa and explain its role in the regulation of renin secretion and in tubuglomerular feedback
mwamba Reply
its located near the vascular pole of the glomurelus also regulate blood pressure and the filtration rate of glomurelus
Describe two early induced responses and what pathogens they affect
olivia Reply
what are pathogens
pathogens are disease-causing agents/organisms
pathogen are the causative of disease
thank you sister
What are organelles
The are little organs found in cells of living things... Eg gogi apparatus
what is anatomy
Linda Reply
is the study of the structures of the body and how they relates to each other
Anatomy is the study of the structures of body parts and how they relates to each other
is the study of the structure of the body and how they relates to each other
what are the difference between Pacinian corpuscle and cutaneous vascular plexus?
thivya Reply
what are membranous epithelial tissues
Naa Reply
they are the lining and covering epithelial tissues which cover body surfaces and line cavities... they're grouped into simple and stratified according to the number of layers and squamous, cuboidal and columnar according to their shape
what is an acina
acina is known to be the basic functional unit of the lungs .(singular:- acinus) this is where the alveoli(the gaseous exchange site) is found...
what happens to the unfertilized egg
the study of tissues is called
Scandy Reply
microscopic or histology anatomy
What specific types of biological macromolecules do living things require and why?
Marieland Reply
what is partial pressure?
Tariq Reply
it is the pressure exerted by mixture of gases...
What is the Important of studying anatomy and philosophy
Michael Reply
because to know the mechanisms of our body
to discover the regional structural of human body based on physically and also biochemically.
how many region do we have in human body
nsofor Reply
head thorax abdomen and many kind of...
what is principal ponatine nucleas
Human body can be divided into different regions on the basis of: 1. Systems: e.g. digestive system, respiratory system, excretory system etc.. 2. Parts: e.g. head, thorax, neck, upper limbs, lower limbs etc..
we have 9 region in d human body
what is systematic anatomy?
nsofor Reply
it is the anatomy or study of a certain body system for example the digestive system. or respiratory system.
It is a group of structure that work together to perform a unique function..
describe the division of anatomy and physiology
Vissa Reply
the what and the how
anatomy is the structure. physiology is the function.
what is homeostasis?
the balance if everything in your body
is the tendency of the body to maintain the internal environment
It is the ability of systems and living organisms to adjust its internal environment
how does a saggital plane look like and a frontal plane
susan Reply
saggital plane divides left and right.. frontal plane divides front and back.. I'm trying to upload a picture but idk how.
tnx sis
The sagittal plane is a vertical plane that divides the body into left and right anteriorly whilst the frontal plane divides the body into the posterior(back) and anterior(front) parts. They're all perpendicular to the transverse plane.
what is a neurones?
Angella Reply
how many systems are there in human
It is a cell that specialized to conduct nerve impulse
why arteries deeper than veins?!
Cismaan Reply

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