![]() The epithelium of each process has two neuroepithelial layers:ġ. An outer, pigmented epithelium in contact with the stroma of the ciliary process (this layer represents a continuation of the retinal pigment epithelium) An inner, non-pigmented epithelium in contact with the posterior chamber (this layer represents a continuation of the retina)Ģ. Tight junctions between the non-pigmented cells form the blood–aqueous barrier. ![]() Each process has a central arteriole ending in a rich, highly fenestrated capillary network.Īqueous humour is formed via a combination of active secretion (70%–80%), ultrafiltration (20%), and diffusion (10%) as follows:ġ. Plasma from the fenestrated capillaries in the ciliary processes moves down a hydrostatic pressure gradient into the ciliary process stroma (ultrafiltration).Ģ. Plasma-derived ions are taken up across the basolateral surface of the outer pigmented epithelium and move to the non-pigmented cells via gap junctions. They are then transported into the intercellular clefts between the non-pigmented cells (active secretion). Carbonic anhydrase mediates the transport of bicarbonate, which in turn affects sodium ions.ģ. Active transport produces an osmotic gradient across the ciliary epithelium. Water follows ions into the intercellular spaces, allowing diffusion into the posterior chamber (diffusion). Aquaporin water channels aid the transport of fluid.Īfter secretion into the posterior chamber, aqueous passes around the lens equator and flows through the pupil into the anterior chamber, where it circulates because of convection currents derived from the temperature difference between the cornea and iris (see Figure 8.2). Some of the aqueous flows directly towards the cornea and then flows downwards in the anterior chamber. Diencephalon, Basal Ganglia, and Brain Ventricles In pigmentary dispersion, the pigment granules therefore deposit on the central and inferior cornea.Neuroanatomy for Speech-Language Pathology and Audiology 2nd Ed. In this chapter we will explore what sits above the brainstem and inside the brain-the diencephalon and surrounding structures. More specifically, we will learn about the thalamus, basal ganglia, and brain ventricles. ■ Survey disorders related to damage to the structures listed here ■ Discuss the role of cerebrospinal fluid ■ Survey the form and function of the basal ganglia ■ Learn about the four parts of the diencephalon We will also survey a few select disorders associated with these structures. ■ The learner will list the four parts of the diencephalon and briefly describe the function of each. ![]() ■ The learner will draw the basal ganglia and describe the function of these nuclei. ■ The learner will list the names of the four brain ventricles. ■ The learner will describe cerebrospinal fluid's composition and its function. INTERNAL CAPSULE BLOOD SUPPLY DRAWIT TO KNOW IT PDF.
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