Podcast
Questions and Answers
Which structure is responsible for coordinating movement and balance?
Which structure is responsible for coordinating movement and balance?
What role does the thalamus play in the brain?
What role does the thalamus play in the brain?
Which part of the brain is known for integrating and filtering information?
Which part of the brain is known for integrating and filtering information?
In which part of the brain does the major regulation of the autonomic nervous system occur?
In which part of the brain does the major regulation of the autonomic nervous system occur?
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What is indicative of a 'leaky' choroid plexus in the context of Multiple Sclerosis?
What is indicative of a 'leaky' choroid plexus in the context of Multiple Sclerosis?
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What is the primary function of the blood-brain barrier (BBB)?
What is the primary function of the blood-brain barrier (BBB)?
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Which cell types are involved in the composition of the blood-brain barrier?
Which cell types are involved in the composition of the blood-brain barrier?
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What role does cerebrospinal fluid (CSF) play in the central nervous system?
What role does cerebrospinal fluid (CSF) play in the central nervous system?
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What is produced by the choroid plexus system?
What is produced by the choroid plexus system?
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What can the analysis of cerebrospinal fluid (CSF) reveal?
What can the analysis of cerebrospinal fluid (CSF) reveal?
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Study Notes
Functional Organization and Neurotransmission in the Brain
- The brain is anatomically divided into six main regions.
- The brain contains an intricate ventricular system filled with cerebrospinal fluid.
- The lecture will cover gross development, functional subdivisions, topographical organization, and neuronal/neurotransmitter types in the cerebral cortex.
- The blood-brain barrier (BBB) is a selective transport system for molecules into the nervous system.
- It is a major obstacle for drug delivery into the nervous system.
- The BBB is negotiated by microglia and some immune cells, but only under specific disease conditions.
- The brain/CNS is surrounded by and contains fluid-filled cavities (ventricles, Lateral, 3rd, and 4th) and contains cerebrospinal fluid (CSF).
- CSF provides physical support, buoyancy, and nourishment to the brain/spinal cord.
- Approximately 500 ml of CSF is produced daily.
- CSF is produced by the choroid plexus system composed of ependymal cells.
- CSF content gives insight into the health status of the CNS.
- A sample of CSF is obtained through lumbar puncture.
- Detecting lymphocytes or bacteria in CSF can indicate infection or autoimmune disease like multiple sclerosis.
- High levels of transferrin in CSF can indicate a leaky choroid plexus.
- The brain develops from the disproportionate growth and flexure of the neural tube during embryonic development.
- The forebrain (cerebral cortex) becomes the largest part of the CNS, obscuring other parts of the brain.
Functional Subdivisions of the Brain
- Medulla oblongata: Major relay center, reticular formation (integration and filtering), involuntary functions (vital reflex center – eg, breathing, blood pressure, non-vital - swallowing, coughing, vomiting)
- Cerebellum: Coordination of movement and balance, integration of information from motor areas, muscles, joints, skin, eyes, ears, and viscera.
- Diencephalon: Thalamus (relay station, awareness/states of arousal), Hypothalamus (major homeostatic control center, regulation of autonomic nervous system and endocrine system, controls secretion of reproductive hormones, neural centers controlling behavior / appetite, thirst, sexual behavior, part of limbic system, circadian rhythm)
- Limbic System: Interconnecting group of structures, controls basic emotions (fear, anxiety, pleasure, anger), olfaction (smell), hippocampus (memory processing).
- Cerebrum: Consists of the cerebral cortex and sub-cortical nuclei (basal ganglia).
- Cerebral Cortex: Shell of grey matter, covering white matter (axonal tracts).
- Two hemispheres, not completely symmetrical or equivalent in function.
- Each hemisphere controls the contralateral side of the body, connected by the corpus callosum.
- Involved in higher functions (sensory analysis, motor coordination, language, and intellect).
- The cortex has different regions related to specific functions.
Topography and Cell Types in the Cerebral Cortex
- Corpus Callosum: Connects the two hemispheres.
- Brain has six laminae (I–VI).
- There are two major types of neurons: projection and interneurons.
- Almost all cortical neurons are generated during embryonic and early postnatal development.
Neurotransmitter Subtypes
- Glutamate: Major excitatory neurotransmitter in the CNS, synthesized through the Krebs cycle.
- Two major subtypes of glutamate receptors: Ionotropic (NMDA receptors) and Metabotropic receptors.
- GABA (and Glycine): Act by opening channels selective for chloride ions, causing hyperpolarization of the membrane potential (IPSP).
- Benzodiazepines are sedatives and modulate GABA effects (e.g., diazepam enhances chloride ion conductance).
Neurotransmitter-Related Diseases of the Central Nervous System
- Parkinson's disease: Dopamine deficiency in substantia nigra neurons – treated by supplying L-dopa or dopamine.
- Depression: Multifactorial causes, may respond to inhibiting serotonin (5HT) reuptake to increase endogenous levels of other neurotransmitters (e.g., norepinephrine and dopamine).
Role of Neurotransmission in Addiction
- Drugs like cocaine increase dendritic spine density, which results in sensitization of neurons due to changes in gene MEF2 regulations and other signaling pathways.
- Other drugs have differing effects on glutamate and GABA signaling.
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Description
Test your knowledge on the various structures of the brain and their functions. This quiz covers coordination of movement, sensory processing, and autonomic regulation. Ideal for students of neuroscience or anyone interested in brain anatomy.
