Review questions: CNS Anatomy 1. Compare the structure and function of the 3 layers of meninges. Dura Mater: Encloses dural sinuses, collects blood from brain and drains into jugular vein. 2 layers – periosteal – attaches to cranial bones. and meningeal – continues around spinal cord. Arachnoid mater: Has villi which extend into the sub-arachnoid space. Large blood vessels located in sub-arachnoid space. Attaches to pia mater with villi. Pia mater: Attached tightly to brain, going into each fold. Thin layer filled with tiny blood vessels. Held to brain with astrocytes. 2. Describe how the sensation of being touched is dealt with in the 3 functional areas of the cerebral cortex. Sensory areas: Conscious awareness. Interprets things such as visual and auditory stimulus (size, shape, pitch, rhythm etc) but will not identify or associate those stimuli with actual objects or things. Association areas: Analyses sensory information, reasons and makes decision about reaction. Motor areas: Initiate voluntary muscle movement after decision made in the association areas. In terms of touch, the sensory areas register touch, pressure and location on homunculus. Association areas decide what the touch might be and how to respond. Motor areas respond. 3. Explain what is meant by the term “the emotional brain”. The Limbic System controls moods, attitude, motivation, appetite, libido, memory etc. Located in the central area of the brain. 4. Define proprioception. In which part of the brain is it processed? Proprioceptors are located in skeletal muscles (eg: golgi tendon organs), tendons, joints, ligaments and connective tissue that tell the brain where the body is in time and space. Proprioception is processed by the cerebellum. 5. Describe the locations and functions of the 3 areas of the brain stem. Midbrain: Top of stem below diencephalon, descending motor pathways. Reflex centre for head and eyes. Pain suppression Pons (bridge): Is the middle bump in the brain stem. Connects spinal cord and brain. Co-operates with medulla to regulate breathing. Medulla oblongata: Most inferior section of brain stem. Decussation of pyramids – crossover of tracts between the 2 hemispheres. Relay for hypothalamus: cardiac, BP, respiration etc.