Choroid Fissure
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The tela choroidea (or tela chorioidea) is a region of
meningeal In anatomy, the meninges (; meninx ; ) are the three membranes that envelop the brain and spinal cord. In mammals, the meninges are the dura mater, the arachnoid mater, and the pia mater. Cerebrospinal fluid is located in the subarachnoid spa ...
pia mater Pia mater ( or ),Entry "pia mater"
in
ependyma The ependyma is the thin neuroepithelial ( simple columnar ciliated epithelium) lining of the ventricular system of the brain and the central canal of the spinal cord. The ependyma is one of the four types of neuroglia in the central nervous s ...
, and gives rise to the
choroid plexus The choroid plexus, or plica choroidea, is a plexus of cells that arises from the tela choroidea in each of the ventricles of the brain. Regions of the choroid plexus produce and secrete most of the cerebrospinal fluid (CSF) of the central ...
in each of the
brain The brain is an organ (biology), organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It consists of nervous tissue and is typically located in the head (cephalization), usually near organs for ...
’s four ventricles. ''Tela'' is Latin for ''woven'' and is used to describe a web-like membrane or layer. The tela choroidea is a very thin part of the loose connective tissue of pia mater overlying and closely adhering to the ependyma. It has a rich blood supply. The ependyma and
vascular Vascular can refer to: * blood vessels, the vascular system in animals * vascular tissue Vascular tissue is a complex transporting tissue, formed of more than one cell type, found in vascular plants. The primary components of vascular tissue ...
pia mater – the tela choroidea, form regions of minute projections known as a choroid plexus that projects into each ventricle. The choroid plexus produces most of the
cerebrospinal fluid Cerebrospinal fluid (CSF) is a clear, colorless Extracellular fluid#Transcellular fluid, transcellular body fluid found within the meninges, meningeal tissue that surrounds the vertebrate brain and spinal cord, and in the ventricular system, ven ...
of the
central nervous system The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain, spinal cord and retina. The CNS is so named because the brain integrates the received information and coordinates and influences the activity o ...
that circulates through the ventricles of the brain, the
central canal The central canal (also known as spinal foramen or ependymal canal) is the cerebrospinal fluid-filled space that runs through the spinal cord. The central canal lies below and is connected to the ventricular system of the brain, from which it r ...
of the
spinal cord The spinal cord is a long, thin, tubular structure made up of nervous tissue that extends from the medulla oblongata in the lower brainstem to the lumbar region of the vertebral column (backbone) of vertebrate animals. The center of the spinal c ...
, and the subarachnoid space. The tela choroidea in the ventricles forms from different parts of the
roof plate The alar plate (or alar lamina) is a neural structure in the embryonic nervous system, part of the dorsal side of the neural tube, that involves the communication of general somatic and general visceral sensory impulses. The caudal part later ...
in the development of the embryo.


Structure

In the
lateral ventricles The lateral ventricles are the two largest ventricles of the brain and contain cerebrospinal fluid. Each cerebral hemisphere contains a lateral ventricle, known as the left or right lateral ventricle, respectively. Each lateral ventricle resemb ...
, the tela choroidea–a double-layered fold of
pia mater Pia mater ( or ),Entry "pia mater"
in
ependyma The ependyma is the thin neuroepithelial ( simple columnar ciliated epithelium) lining of the ventricular system of the brain and the central canal of the spinal cord. The ependyma is one of the four types of neuroglia in the central nervous s ...
, produces the choroid fissure (sometimes also called the choroidal fissure but this is different from the
choroidal fissure The choroid is the middle, vascular coat of the eye which resides between the sclera and the retina. Early in development the choroidal fissure is a groove that extends along the ventral aspect of the optic stalk. In effect, it is a continuation ...
of the optic stalk). The choroid fissure is C-shaped, runs between the fornix and the
thalamus The thalamus (: thalami; from Greek language, Greek Wikt:θάλαμος, θάλαμος, "chamber") is a large mass of gray matter on the lateral wall of the third ventricle forming the wikt:dorsal, dorsal part of the diencephalon (a division of ...
in the body of the ventricle, and between the
stria terminalis The stria terminalis (or terminal stria) is a structure in the brain consisting of a band of fibers running along the lateral margin of the ventricular surface of the thalamus. Serving as a major output pathway of the amygdala, the stria termina ...
and hippocampal fimbria in the inferior horn, and is the location of the attachment of the margins of the
choroid plexus The choroid plexus, or plica choroidea, is a plexus of cells that arises from the tela choroidea in each of the ventricles of the brain. Regions of the choroid plexus produce and secrete most of the cerebrospinal fluid (CSF) of the central ...
. In the choroid fissure of the lateral ventricles, the tela choroidea is a lateral extension of the tela choroidea from the
third ventricle The third ventricle is one of the four connected cerebral ventricles of the ventricular system within the mammalian brain. It is a slit-like cavity formed in the diencephalon between the two thalami, in the midline between the right and lef ...
. In the
third ventricle The third ventricle is one of the four connected cerebral ventricles of the ventricular system within the mammalian brain. It is a slit-like cavity formed in the diencephalon between the two thalami, in the midline between the right and lef ...
, the tela choroidea forms the roof of the ventricle. Two vascular fringes from the lower fold invaginate the roof and form the choroid plexus. The tela choroidea of the fourth ventricle (also known as the ''triangular lamella'') is a double layer of pia mater and ependyma, between the
cerebellum The cerebellum (: cerebella or cerebellums; Latin for 'little brain') is a major feature of the hindbrain of all vertebrates. Although usually smaller than the cerebrum, in some animals such as the mormyrid fishes it may be as large as it or eve ...
and the lower part of the roof of the fourth ventricle. The two layers are continuous with each other in front, and are mostly adherent throughout. The anterior layer of the fold, contains vascular fringes which make up the choroid plexus. The anterior layer is continuous inferiorly with the pia mater on the
inferior cerebellar peduncle The inferior cerebellar peduncle is formed by fibers of the restiform body that join with fibers from the much smaller juxtarestiform body. The inferior cerebellar peduncle is the smallest of the three cerebellar peduncles. The upper part of t ...
s and the closed part of the
medulla oblongata The medulla oblongata or simply medulla is a long stem-like structure which makes up the lower part of the brainstem. It is anterior and partially inferior to the cerebellum. It is a cone-shaped neuronal mass responsible for autonomic (involun ...
. The ''posterior layer'' covers the antero-inferior surface of the cerebellum.
Cilia The cilium (: cilia; ; in Medieval Latin and in anatomy, ''cilium'') is a short hair-like membrane protrusion from many types of eukaryotic cell. (Cilia are absent in bacteria and archaea.) The cilium has the shape of a slender threadlike proj ...
on the
ependymal cell The ependyma is the thin neuroepithelial ( simple columnar ciliated epithelium) lining of the ventricular system of the brain and the central canal of the spinal cord. The ependyma is one of the four types of neuroglia in the central nervous sys ...
s move to circulate the cerebrospinal fluid. These cilia are unusually multiple
primary cilia The cilium (: cilia; ; in Medieval Latin and in anatomy, ''cilium'') is a short hair-like membrane protrusion from many types of eukaryotic cell. (Cilia are absent in bacteria and archaea.) The cilium has the shape of a slender threadlike pr ...
.>


Blood supply

The blood supply of these plexuses is from the
posterior inferior cerebellar artery The posterior inferior cerebellar artery (PICA) is the largest branch of the vertebral artery. It is one of the three main arteries that supply blood to the cerebellum, a part of the brain. Blockage of the posterior inferior cerebellar artery can ...
. The lateral ventricles also contains the right and left
internal cerebral veins The internal cerebral veins are two veins included in the group of deep cerebral veins that drain the deep parts of the hemispheres; each internal cerebral vein is formed near the interventricular foramina by the union of the superior thalamos ...
(which drain the choroid plexuses) at its roof (the two veins unite to form the great cerebral vein). The arteries carrying blood into the choroid plexuses are: # the
anterior choroidal artery The anterior choroidal artery is a bilaterally paired artery of the brain. It is typically a branch of the internal carotid artery which supplies the choroid plexus of lateral ventricle and third ventricle as well as numerous structures of the br ...
(branch from the internal carotid). # the
posterior choroidal artery The posterior cerebral artery (PCA) is one of a pair of cerebral arteries that supply oxygenated blood to the occipital lobe, as well as the medial and inferior aspects of the temporal lobe of the human brain. The two arteries originate from the d ...
(branch from the posterior cerebral artery). Medial posterior choroidal branches run forward beneath the splenium of the corpus callosum, and supply the tela chorioidea of the third ventricle and the choroid plexus.


See also

* Choroidal fissure cyst


References

{{Authority control Meninges