<< Chapter < Page Chapter >> Page >

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

what is anatomy
philemon Reply
what is anatomy in terms of medicine
Describe early studies into the working of human body.
Tonny Reply
please guys help me to answer this question; Define the two divisions of the skeleton ?
Jonathan Reply
two example of appendicular skeleton
upper limb ;eg humerus n lower limb;eg tibia
write notes on the level of organizations of the body .citing examples for each level
Kaddijatou Reply
Jonathan Nyakpaab
what is pathology
Ericka Reply
1 What is Nasogastric Tube 2 what is the difference between Nasogastric Aspiration and Nasogastric Feeling
You measure a patient’s blood pressure at 130/85. Calculate the patient’s pulse pressure and mean arterial pressure. Determine whether each pressure is low, normal, or high.
normal blood pressure 120/80
what are nocciceptors
1 Its a flexible tube of plastic that pass through the nose, down to the eausophagus, and into the stomach, used to add or remove substances in the stomach.
2 Nasogastric aspiration is process of draining stomach contents via a tube and Nasogastric feeding is a process of giving food liquid through nasogastric tube
andile sir what is meant by clonoscopy
colonoscpopy is an exam use to detect abnormalities in the small intestine or the colon
What is the skin
Astony Reply
What is physiology?
Njaleny Reply
it is the study of the structure of the human body and its reationship
Physiology is the function of a living organism.
It is the study of human body and how it works.
if physiology is the function of a living organism.What method is keep for living organism.
what are Nocciceptors
Nocciceptors are pain receptor
Or is a sensory neutron that responds to damage
It is d entrance to the uterus
Umunna Reply
It is a small sensitive part of female sex organ which is found above d entrance to the vagina
A small hole in d skin which contains d root of a hair
A thin membrane which covers d entrance to the vagina in young girls
Is a gland that produces milk in women and other female mammals
A repeated process in which a woman's uterus gets ready for pregnancy which ends in a period if she does not get pregnant
hi sir
why should one consider studying neuroanatomy to physiology?
so in summary describe the level of structural complexity within the body
Freda Reply
how can we describe briefly the levels of organization
what is blood clotting
Yahya Reply
Tiny bits in your blood called platelets get "turned on" by triggers released when a blood vessel is damaged. They stick to the walls in the area and each other, changing shape to form a plug that fills in the broken part to stop blood from leaking out. When activated, platelets also release chemic
what is a cell membrane?
lameck Reply
the cell membrane also called the plasma membrane regulates the transport materials entering and existing the cell.
what's gonna happen if your body doesn't produce enough white blood cells?
how is speech controlled by the nervous system?
Joseph Reply
The broca's area
what does the HCG
chemical level cellular level tissue level organ level organ system level organism
Chidera Reply
Yes Yes because they can perform more than one activity in the body
the functional and structural unit of the body
A group of 2 or more tissue that come together to perform a specific function
A group of organs that work together to perform a specific function or meet the physiological needs of the body
It's the highest level of organization
2 or more cells coming together to perform a specific function
Skeletal muscles can be tetanized but not cardiac muscle.Discuss
Okeke Reply

Get Jobilize Job Search Mobile App in your pocket Now!

Get it on Google Play

Source:  OpenStax, Anatomy & Physiology. OpenStax CNX. Feb 04, 2016 Download for free at http://legacy.cnx.org/content/col11496/1.8
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Anatomy & Physiology' conversation and receive update notifications?