Transport of Carbon Dioxide in the Blood
Carbon dioxide molecules are transported in the blood from body tissues to the lungs by one of three methods:Dissolve directly into the blood plasma.
Binding to hemoglobin.
Carried as a bicarbonate ion.
CO2 (5-10%), dissolved in the plasma, Carbon dioxide is transported in the plasma of the blood as dissolved CO2 molecules that aren't bound to anything else. Carbon dioxide has a much higher solubility than oxygen, which explains why a relatively greater amount of carbon dioxide is dissolved in the plasma compared to oxygen.
CO2 (30%) combines with hemoglobin to form Carbaminohemoglobin. While oxygen binds to the iron content in the heme of hemoglobin, carbon dioxide can bind to the amino acid chains on hemoglobin. Carbaminohemoglobin gives red blood cells a bluish color, which is one of the reasons why the veins that carry deoxygenated blood appear to be blue.
CO2(60-85%) combines with H2O to form carbonic acid (H2CO3), this reaction is catalyzed by the enzyme carbonic anhydrase (CA) which is found in RBC’s. Carbonic acid then dissociates to form bicarbonate ions (HCO3-) and hydrogen ions (H+). Bicarbonate ions release into the blood stream through protein channels in the RBCs wall then the CL- will enter to the RBCs for electrolytes equilibrium, this process called chloride shift.
CO2 + H2O → H2CO3 → H+ + HCO3–
This means that carbon dioxide reacts with water to form carbonic acid, which dissociates in solution to form hydrogen ions and bicarbonate ions.
The main implication of this process is that the pH of blood becomes a way of determining the amount of carbon dioxide in blood. This is because if carbon dioxide increases in the body, it will manifest as increased concentrations of bicarbonate and increased concentrations of hydrogen ions that reduce blood pH and make the blood more acidic.
Conversely, if carbon dioxide levels are reduced, there will be less bicarbonate and less hydrogen ions dissolved in the blood, so pH will increase and blood will become more basic. Bicarbonate ions act as a buffer for the pH of blood so that blood pH will be neutral as long as bicarbonate and hydrogen ions are balanced.
This connection explains how ventilation rate and blood chemistry are related, as hyperventilation will cause alkalosis, and hypoventilation will cause acidosis, due to the changes in carbon dioxide levels that they cause.
Bicarbonate is also carried in the fluids of tissues besides the blood vessels, especially in the duodenum and intestine, so problems in those organs can cause a respiratory system response.
In the pulmonary capillaries, the reverse occurs: bicarbonate ions enter the RBC and combine with H+ to form carbonic acid, which is broken down into CO2 and H2O, with CO2 diffusing out into alveoli.
Mammalian nervous system
The nervous system has two major parts:
The central nervous system (CNS) .
The peripheral nervous system (PNS).
The central system is the primary command center for the body, and is comprised of the brain and spinal cord. The peripheral nervous system consists of a network of nerves that connects the rest of the body to the CNS. The two systems work together to collect information from inside the body and from the environment outside it. The systems process the collected information and then dispatch instructions to the rest of the body, facilitating an appropriate response.
The central nervous system includes the brain and spinal cord. The brain is held in the cranial cavity of the skull and it consists of the cerebrum cerebellum, and the brain stem.
The brain is divided into many different sections, including the cerebrum and brain stem. These parts handle pieces of the brain’s overall workload, including storing and retrieving memory and making body movements smooth. Although the brain is the control center, its job would not be possible without the spinal cord, which is the major conduit for information traveling between brain and body.
Peripheral system nerves branch of nervous system outside of CNS. Each nerve is connected to a particular area of the organ or limbs and is responsible for communication to and from those regions.
The PNS can also be divided into components:
Motor neurons (efferent)
The somatic (spinal and cranial nerves).
Autonomic systems (sympathetic and parasympathetic nerves).
Sensory neurons (afferent)
The enteric nervous system (ENS)(second brain)
Nervous tissue, present in both the CNS and PNS, contains two basic types of cells: neurons and glial cells. A glial cell is one of a variety of cells that provide a framework of tissue that supports the neurons and their activities. The neuron is the more functionally important of the two, in terms of the communicative function of the nervous system.Function
The nervous system has three main functions:
Sensory input (sensation).
Integration of data .
motor output (response).
Sensory input is when the body gathers information or data, by way of neurons, glia and synapses. The neurons conduct impulses from sensory receptors to the brain and spinal cord. The data is then processed by way of integration of data, which occurs only in the brain. After the brain has processed the information, impulses are then conducted from the brain and spinal cord to muscles and glands, which is called motor output.