The
blood-testis barrier (abbreviated as BTB) is a physical barrier between the
blood vesselThe blood vessels are the part of the circulatory system that transport blood throughout the body. There are three major types of blood vessels: the arteries, which carry the blood away from the heart, the capillaries, which enable the actual exchange of water and chemicals between the blood and...
s and the seminiferous tubules of the animal
testesThe testicle is the male generative gland in animals.The etymology of the word is based on Roman law...
.
The barrier is formed by tight connections between the
Sertoli cellA Sertoli cell is a 'nurse' cell of the testes that is part of a seminiferous tubule.It is activated by follicle-stimulating hormone and has FSH-receptor on its membranes.-Functions:...
s, which are sustentacular cells (supporting cells) of the
seminiferous tubulesSeminiferous tubules are located in the testicles, and are the specific location of meiosis, and the subsequent creation of gametes, namely spermatozoa....
, and nourish the
spermatogoniaA spermatogonium is an intermediary male gametogonium in the production of spermatozoa.There are three subtypes:...
.
The barrier avoids passage of
cytotoxicCytotoxicity is the quality of being toxic to cells. Examples of toxic agents are a chemical substance, an immune cell or some types of venom .-Cell physiology:...
agents (bodies or substances that are
toxicToxicity is the degree to which a substance is able to damage an exposed organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a substructure of the organism, such as a cell or an organ , such as the liver...
to
cellThe cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of an organism that is classified as living, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos...
s) into the seminiferous tubules.
The blood-testes barrier can be damaged by trauma to the testes (including torsion or impact), by surgery or as a result of
vasectomyVasectomy is a minor surgical procedure wherein the vasa deferentia of a man are severed, and then tied or sealed in a manner such to prevent sperm from entering the seminal stream .-Types:...
.
The
blood-testis barrier (abbreviated as BTB) is a physical barrier between the
blood vesselThe blood vessels are the part of the circulatory system that transport blood throughout the body. There are three major types of blood vessels: the arteries, which carry the blood away from the heart, the capillaries, which enable the actual exchange of water and chemicals between the blood and...
s and the seminiferous tubules of the animal
testesThe testicle is the male generative gland in animals.The etymology of the word is based on Roman law...
.
The barrier is formed by tight connections between the
Sertoli cellA Sertoli cell is a 'nurse' cell of the testes that is part of a seminiferous tubule.It is activated by follicle-stimulating hormone and has FSH-receptor on its membranes.-Functions:...
s, which are sustentacular cells (supporting cells) of the
seminiferous tubulesSeminiferous tubules are located in the testicles, and are the specific location of meiosis, and the subsequent creation of gametes, namely spermatozoa....
, and nourish the
spermatogoniaA spermatogonium is an intermediary male gametogonium in the production of spermatozoa.There are three subtypes:...
.
The barrier avoids passage of
cytotoxicCytotoxicity is the quality of being toxic to cells. Examples of toxic agents are a chemical substance, an immune cell or some types of venom .-Cell physiology:...
agents (bodies or substances that are
toxicToxicity is the degree to which a substance is able to damage an exposed organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a substructure of the organism, such as a cell or an organ , such as the liver...
to
cellThe cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of an organism that is classified as living, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos...
s) into the seminiferous tubules.
Autoimmune response
The blood-testes barrier can be damaged by trauma to the testes (including torsion or impact), by surgery or as a result of
vasectomyVasectomy is a minor surgical procedure wherein the vasa deferentia of a man are severed, and then tied or sealed in a manner such to prevent sperm from entering the seminal stream .-Types:...
. When the blood-testes barrier is breached, and sperm enters the bloodstream, the
immune systemAn immune system is a system of biological structures and processes within an organism that protects against disease by identifying and killing pathogens and tumour cells. It detects a wide variety of agents, from viruses to parasitic worms, and needs to distinguish them from the organism's own...
mounts an autoimmune response against the sperm. The anti-sperm
antibodiesAntibodies are gamma globulin proteins that are found in blood or other bodily fluids of vertebrates, and are used by the immune system to identify and neutralize foreign objects, such as bacteria and viruses...
generated by the immune system can bind to various
antigenicAn antigen is a substance that prompts the generation of antibodies and can cause an immune response. "Self" antigens are usually tolerated by the immune system; whereas "Non-self" antigens are identified as intruders and attacked by the immune system...
sites on the surface of the sperm. If they bind to the head, the sperm may be less able to fertilize an
eggAn ovum is a haploid female reproductive cell or gamete. Both animals and embryophytes have ova. The term ovule is used for the young ovum of an animal, as well as the plant structure that carries the female gametophyte and egg cell and develops into a seed after fertilization...
, and if they bind to the tail, the motility of the sperm can be reduced.
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