NEUROLOGICAL NOTES

• Meninges


  Serves to protect and act as a cushion. It also contributes to the blood brain barrier.
• Epidural space


  Located between the dura mater (the outermost layer of the meninges). It contains fat, connective tissue, blood vessels, and the epidural venous plexus.
• Dura mater


  Outermost layer. Composed of tough, fibrous connective tissue. Provides a protective barrier and contains blood vessels, nerves, and the venous sinuses, which drain blood from the brain.

  
• Subdural space


  Located between the dura mater and the arachnoid mater (two of the layers of the meninges). It contains a thin layer of fluid called the subdural space or subdural fluid.
• Arachnoid mater


  The middle layer of the meninges, located between the dura mater and the pia mater. Composed of thin, web-like connective tissue. Forms the subarachnoid space, which is filled with cerebrospinal fluid (CSF) and contains blood vessels.

  
• Pia mater


  The innermost layer of the meninges, located directly adjacent to the surface of the brain and spinal cord. Composed of thin, delicate connective tissue. Contains blood vessels that supply nutrients to the underlying neural tissue.

  
• Phrenic nerve


  Originates from the cervical spine (C3-C5) and innervates the diaphragm, which is the primary muscle involved in respiration.

  
• Intracranial pressure (ICP)


  Pressure inside the cranial vaults, dependent on 3 volumes: CSF (10%), blood (10%), brain tissue (80%).
• The brain is wrinkly for efficient organization and the need to maximize surface area within the limited space of the skull. This wrinkled structure is known as the cerebral cortex, which is the outermost layer of the brain responsible for higher cognitive functions such as thinking, memory, perception, and language.

  
• What can change the brain component?

  • Environmental stimuli
  • Learning
  • Exercise
  • Nutrition
  • Stress
• What can change the blood component?

  • Nutrition
  • Hydration
  • Medication
  • Hormonal changes
  • Disease and disorders
• Cerebrospinal fluid (CSF)


  Clear, colorless fluid that surrounds the brain and spinal cord, providing cushioning, support, and protection to these delicate structures.

  
• What can change the CSF component?

  • Disease
  • Injury
  • Medication
• Peripheral Nervous System


  Sensory neurons (afferent): Somatic and visceral sensory ganglia, Cranial nerve ganglia, Autonomic: PNS (far from spine) & SNS (close to spine). Motor neurons (efferent).

  
• Central Nervous System


  Brain and spinal cord, protected by skull, vertebrae and meninges. Meninges: Dura, arachnoid, pia. Spaces: Epidural, subdural, subarachnoid (CSF is here). ICP: blood, CSF, brain.

  
• Neurons


  Dendrite – cell body – axon (myelin) – synapse. Sensory: afferent bring information to the CNS. Motor: afferent bring information away from the CNS.
• Dermatomes from C-spine, thoracic, lumbar and sacral connect the CNS to the PNS.

  
• Macular degeneration


  A progressive eye disease affecting the macula, the central part of the retina responsible for sharp, central vision.
• Cataracts


  Clouding of the lens of the eye, leading to blurred or impaired vision, typically associated with aging.
• Diabetic retinopathy


  A complication of diabetes affecting the blood vessels in the retina, leading to vision impairment and potential blindness if left untreated.
• Glaucoma


  A group of eye conditions characterized by damage to the optic nerve, often associated with elevated intraocular pressure.
• Refractive errors


  Vision problems caused by abnormalities in the shape of the eye, resulting in blurred or distorted vision.
• Age-related Macular degeneration (AMD)


  • Leading cause of vision loss, affects >50yrs, Incurable, Loss of central vision
• Cataracts


  • Everyone will develop it with age, gradually and without pain, Blurs all vision
• Diabetic retinopathy


  • Leading cause of vision loss <50yrs, Uncontrolled diabetes, Severe vision loss/blindness
• Glaucoma


  • Second most common cause of vision loss >65, Visual field loss, decreased acuity, halo, or blindness
• Refractive errors


  • Myopia- nearsighted, Hyperopia- farsighted, Presbyopia- difficulty reading small print
• Conductive Hearing Loss


  Inefficient sound waves outer to inner ear, Ear canal blockage- cold, allergy, infection
• Sensorineural Hearing Loss


  Auditory center damage (pathway to medulla), Central cortex pathway damage, TBI, tumor, heredity
• Otitis media


  Eardrum and middle ear damage, Infection, Can lead to permanent hearing loss
• Osteosclerosis


  Hereditary, Ossicle hardening, Causes tinnitus
• Sensorineural Hearing Loss


  Cochlea or nerve damage, Causes- excess noise, meds, virus
• Cerumen Accumulation


  Wax build-up that can harden, Common in elderly
• Presbycusis


  Low-pitched sounds are heard better, Muffled hearing, Age related hearing loss
• Meniere's Disease


  Inner ear disease, Fluid in the ears, Can cause tinnitus, hearing loss, and vertigo.
• Xerostomia


  Dry mouth – decreases saliva and thicker, Causes: medications, cancer, and aging, Risks: food aversions, decreasing calorie intake
• Olfaction decreases with age due to reduced sensory neurons and bulb cells, affecting sensitivity to odors and taste discrimination.
• In Older persons, changes to the nervous system

  • Decrease in nerve cells
  • Myelin sheath degeneration
  • Decreased neurotransmitters
  • Decreased conduction rate
• Neurological Deficit


  Abnormality or impairment in the structure or function of the nervous system.

  
• Neuropathy


  Condition characterized by damage or dysfunction of the peripheral nerves.