When light enters the eye through the pupil , it strikes photoreceptor cells in the retina called rods and cones. Rod cells are responsible for peripheral vision and night vision, while cone cells react to brighter light, color and fine details. When light hits its corresponding rod or cone, the cell activates, firing a nerve impulse through the optic nerve — the middle man between the eye and the brain.
This is eyesight. All of this happens within the tiniest fraction of a second, allowing us to perceive the world in essentially real time.
The human brain is an incredibly complex web of neurons and synapses. And the more we understand about its mind-boggling ability to process and make sense of random collections of light, the more we can appreciate the equally complex world around us. Talk to an eye doctor near you to schedule an appointment.
This receives sensory input for touch and body position. The Occipital lobe is the portion of the cerebral cortex lying at the back of the head. This area receives information from the visual fields and is associated with vision processing. The forth lobe, the temporal lobe, is the portion of the cerebral cortex laying roughly above the ears.
The size of the stroke may be correlated to the severity of the impairments. For instance, a massive stroke in the right hemisphere might lead to paralysis on the left side of the body instead of hemiparesis.
Functions of the cerebrum include: initiation of movement, coordination of movement, temperature, touch, vision, hearing, speech and language, judgment, reasoning, problem solving, emotions, and learning. Functions of this area include: movement of the eyes and mouth, relaying sensory messages , hunger, respirations, consciousness, cardiac function, body temperature, involuntary muscle movements, sneezing, coughing, vomiting, and swallowing. Its function is to coordinate voluntary muscle movements and to maintain posture, balance, and equilibrium.
After a right hemisphere stroke, some patients may have difficulty recognizing faces a condition known as prosopagnosia. Many suspect that the inability to recognize faces is linked to damage to the fusiform gyrus , which resides in the right hemisphere of the brain.
Damage in this region may cause right-sided survivors difficulty in recognizing family members faces, which can be distressing to loved ones. The brain can be divided into three basic units: the forebrain, the midbrain and the hindbrain.
These areas are: Occipital lobe, Temporal lobe, Parietal lobe, Frontal lobe. Occipital lobe :; This is found in the back of the brain. It is responsible for our vision. Temporal lobe : The temporal lobes are found on either side of the brain and just above the ears.
The temporal lobes are responsible for hearing , memory, meaning, and language. They also play a role in emotion and learning. The temporal lobes are concerned with interpreting and processing auditory stimuli.
Parietal lobe : The parietal lobes are found behind the frontal lobes, above the temporal lobes, and at the top back of the brain. They are connected with the processing of nerve impulses related to the senses, such as touch, pain, taste, pressure, and temperature. They also have language functions. Frontal lobe :It is concerned with emotions, reasoning, planning, movement, and parts of speech. It is also involved in purposeful acts such as creativity, judgment, and problem solving, and planning.
The brain is made up of two types of cells: neurons and glial cells, also known as neuroglia or glia. The neuron is responsible for sending and receiving nerve impulses or signals. Glial cells are non-neuronal cells that provide support and nutrition, maintain homeostasis, form myelin and facilitate signal transmission in the nervous system. In the human brain, glial cells outnumber neurons by about 50 to one. Glial cells are the most common cells found in primary brain tumors. When a person is diagnosed with a brain tumor, a biopsy may be done, in which tissue is removed from the tumor for identification purposes by a pathologist.
Pathologists identify the type of cells that are present in this brain tissue, and brain tumors are named based on this association. The type of brain tumor and cells involved impact patient prognosis and treatment. There are some specialty MRI exams that require certain restrictions. You will be provided detailed preparations instructions by Johns Hopkins Medical Imaging when you schedule your exam.
A locker will be provided for you to use. Please remove allpiercings and leave all jewelry and valuables at home. You must lie perfectly still for quality images. Due to the loudnoise of the MRI machine, earplugs are required and will be provided. ALLERGY : If you have had an allergic reaction to contrast that required medicaltreatment, contact your ordering physician to obtain the recommendedprescription.
You will likely take this by mouth 24, 12 and two hours priorto examination. Please note that you will needsome else to drive you home. Based on your medical condition, your health care provider may requireother specific preparation. In recent decades, there has been an explosion of research into language processing in the brain. Its now generally accepted that the control of speech is part of a complex network in the brain.
The formation of speech requires many different processes, from putting thoughts into words, forming a comprehensible sentence, and then actually making the mouth move to make the correct sounds. We already mentioned that there is not one single part of the brain that is responsible for learning or memory, so there is not a single region responsible for memory loss either. The frontal and temporal lobes, the limbic system, and parts of the brain stem that control alertness are all involved in memory and learning.
So, if any of these parts get damaged, a person can suffer memory loss or amnesia.
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