diseases. It has been observed in many neurodegenerative diseases such as Alzheimer’s disease and Parkinson’s disease. Axon degeneration does not necessarily have to involve the typical apoptotic pathway regardless of the morphological similarities to cells undergoing apoptosis. Yang et al. focused on axonal death in traumatic injury because it has been shown to be independent of the necroptotic pathway. This was discovered since treatment with necroptosis inhibitors did not protect axons. To reiterate
The specific topic being addressed by the members of this group is: Describe the molecules responsible for regulating the human circadian clock and how they affect metabolism in the human body. Be sure to address how the circadian rhythms are governed, the signaling mechanisms used, and specific metabolic pathways. Note you do not need to discuss each step in the metabolic pathway (e.g. you don’t need to describe all ten steps of glycolysis if that’s a pathway that is affected,) but you should identify
Each day, when the sun rises and sets, mammals and plants alike conform together with a celestial rhythm that instructs the activities of the day. The human body, along with nearly all other mammals, endogenously oscillates on a rhythm that coincides with these daily activities. However, when mammals are placed in an environment void of nearly all outside influences, also known as zeitgebers, these rhythms continue to run at specified intervals. Thus, the endogenous rhythm must be governed by an
represents the retinal region of greatest visual acuity . The fovea has the highest density of cone photoreceptors .The long axons of the foveal cones form Henle’s layer. The central 500 mm of the fovea contains no retinal capillaries (the foveal avascular zone [FAZ]), making the fovea dependent on blood supply from the choriocapillaries.( Curcio CA,1990) The ora serrata delineates the anterior termination of the sensory retina. Cellular organization of the retina:
nerve cells that compares stimulation of the other cones, and calculates whether the light that approaches the cones could
the cells within the brain contain an area known as the receptive field and is the point in which light enters hits the cell of a receptor (Kalat, 2013). This part of the visual system relies on sensory information, such as light, to either excite or inhibit the cells within the center portion of the receptive field. One of the most significant processes of transmitting information from the visual field is through primary cells of the visual receptors, which include the retinal ganglion cells. In
nents, opsin and all-trans retinal. When this happens, retinal gets reduced to retinol and transported to the pigment epithelium. There the retinol gets converted back into 11-cis retinal for the cycle to begin again. The phototransduction cascade converts light into electrical signals in the rod and cone cells, and in the photosensitive ganglion cells of the retina of the eye. This biological cycle converts photons into electrical signals in the retina. Rod photoreceptors in vertebrates are responsible
structures, which begins in the retina. When light enters the eye and hits the photoreceptors (rods and cones) located in the retina, the retinal ganglion cells are activated. The retinal ganglion cells are organized in the retina and then are sent to the optic nerve, which is located at the back of the eye. The optic nerve transports the signals from the retinal ganglion cells to the lateral geniculate nucleus (also abbreviated as the LGN). The thalamus is the structure that houses the lateral geniculate
chemical process that releases energy. In order to detect varying levels of light, “photopigments consist of 11-cis-retinal (a derivative of vitamin A) bound to proteins called opsins, which modify the photopigments’ sensitivity to different wavelengths of light. Light converts 11-cis-retinal to all-trans-retinal, thus releasing energy that activates second messengers within the cell” (Kalat, 2013, p. 159). The photopigments are responsible for initiating the first steps of communication within visual
on the same ganglion cells, the cell only responds to the appropriate receptor based on the amount of illumination coming into the eye. (Purves et al., 2001). The placement of both the rods and cones on the ganglion cells allows for many of the differences between the two receptors. “The pathway from rods to ganglion cells involve a distinct class of bipolar cells (called rod bipolar) that, unlike cone bipolar cells, does not contact retinal ganglion cells. Instead, rod bipolar cells synapse with