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IgG    is a major antibody of late primary responses and the main antibody of secondary responses in the blood. This is because class switching occurs during primary responses. IgG is a monomeric antibody that clears pathogens from the blood and can activate complement proteins (although not as well as IgM), taking advantage of its antibacterial activities. Furthermore, this class of antibody is the one that crosses the placenta to protect the developing fetus from disease exits the blood to the interstitial fluid to fight extracellular pathogens.

IgA    exists in two forms, a four-chain monomer in the blood and an eight-chain structure, or dimer, in exocrine gland secretions of the mucous membranes, including mucus, saliva, and tears. Thus, dimeric IgA is the only antibody to leave the interior of the body to protect body surfaces. IgA is also of importance to newborns, because this antibody is present in mother’s breast milk (colostrum), which serves to protect the infant from disease.

IgE    is usually associated with allergies and anaphylaxis. It is present in the lowest concentration in the blood, because its Fc region binds strongly to an IgE-specific Fc receptor on the surfaces of mast cells. IgE makes mast cell degranulation very specific, such that if a person is allergic to peanuts, there will be peanut-specific IgE bound to his or her mast cells. In this person, eating peanuts will cause the mast cells to degranulate, sometimes causing severe allergic reactions, including anaphylaxis, a severe, systemic allergic response that can cause death.

Clonal selection of b cells

Clonal selection and expansion work much the same way in B cells as in T cells. Only B cells with appropriate antigen specificity are selected for and expanded ( [link] ). Eventually, the plasma cells secrete antibodies with antigenic specificity identical to those that were on the surfaces of the selected B cells. Notice in the figure that both plasma cells and memory B cells are generated simultaneously.

Clonal selection of b cells

This flow chart shows how the clonal selection of B cells takes place. The left panel shows the primary response and the right panel shows the secondary response.
During a primary B cell immune response, both antibody-secreting plasma cells and memory B cells are produced. These memory cells lead to the differentiation of more plasma cells and memory B cells during secondary responses.

Primary versus secondary b cell responses

Primary and secondary responses as they relate to T cells were discussed earlier. This section will look at these responses with B cells and antibody production. Because antibodies are easily obtained from blood samples, they are easy to follow and graph ( [link] ). As you will see from the figure, the primary response to an antigen (representing a pathogen) is delayed by several days. This is the time it takes for the B cell clones to expand and differentiate into plasma cells. The level of antibody produced is low, but it is sufficient for immune protection. The second time a person encounters the same antigen, there is no time delay, and the amount of antibody made is much higher. Thus, the secondary antibody response overwhelms the pathogens quickly and, in most situations, no symptoms are felt. When a different antigen is used, another primary response is made with its low antibody levels and time delay.

Questions & Answers

why arteries deeper than veins?!
Cismaan Reply
arteries colour of blood is deeper than that of vein because its blood contains oxygen which is adhered to haemoglobin(a protein which gives the blood its red color) , while vein contains deoxygenated blood(blood without oxygen)
As we know, vein carries used blood to the heart. when we say used blood, we mean to say, blood that its content(oxygen and other nutrients) has been used up.
Arteries are deeper b'cuz they need to be protected.......If they are ruptured they cannot form clot and repair themselves.... Moreover, the pressure of blood is too high for the artery to form the clot and repair itself....... Hence, Arteries are deeper than veins........
Than u all. Special thanks too AMEL JEELANI.
You're welcome......
Thanks all
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.

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Source:  OpenStax, Anatomy & Physiology. OpenStax CNX. Feb 04, 2016 Download for free at http://legacy.cnx.org/content/col11496/1.8
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