Special senses [ EYE] These are organs in the body that performs specialised functions. They contain sensory receptors which receives sensory impulses and pass them to the appropriate centers in the brain for interpretation. ➡️ Types of Sensory Receptors - based on the type of stimuli they detect: 1. Mechanoreceptors - pressure receptors, stretch receptors, and specialized mechanoreceptors involved in movement and balance. 2. Thermoreceptors - skin and viscera, respond to both external and internal temperature. 3. Pain receptors - stimulated by lack of O2, chemicals released from damaged cells and inflammatory cells. 4. Chemoreceptors - detect changes in levels of O2, CO2, and H+ ions (pH) as well as chemicals that stimulate taste and smell receptors 5. Photoreceptors - stimulated by light ➡️ Distribution of Receptors in the body: Special Senses • mediated by relatively complex sense organs of the head, innervated by cranial ...
The ventricular system is a set of communicating cavities within the brain. These structures are responsible for the production, transport and removal of cerebrospinal fluid, which bathes the central nervous system. FUNCTIONS OF CEREBROSPINAL FLUID Cerebrospinal fluid is an ultrafiltrate of plasma that surrounds the brain and spinal cord. It serves three main functions : ➡️ Protection : acts as a cushion for the brain, limiting neural damage in cranial injuries. ➡️Buoyancy : by being immersed in CSF, the net weight of the brain is reduced to approximately 25 grams. This prevents excessive pressure on the base of the brain. ➡️Chemical stability : the CSF creates an environment to allow for proper functioning of the brain, e.g. maintaining low extracellular K+ for synaptic transmission. VENTRICLES OF THE BRAIN The ventricles are structures that produce cerebrospinal fluid, and transport it around the cranial cavity. They are lined by ependymal cells, which fo...
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