Functional Neuroanatomy The Cells and Structures of the Nervous system - Aidan Helfant's Digital Garden

What are the four zones of a neuron? ::: Input zone, integration zone, conduction zone, and output zone. ![[Pasted image 20220824082918.png]]  ### Types of Neurons What are the four most common types of neurons? 1. ==Multipolar neurons== have many dendrites and a single axon, and they are the most common type of neuron 2. ==Bipolar neurons== have a single dendrite at one end of the cell and a single axon at the other end. This type of neuron is especially common in sensory systems, such as vision. 3. ==Unipolar neurons== (also called monopolar) have a single extension (or process), usually thought of as an axon, that branches in two directions after leaving the cell body. One end is the input zone with branches like dendrites; the other, the output zone. Such cells transmit touch information from the body into the spinal cord. 4. Pseudounipolar neurons. ![[Pasted image 20220829090023.png]]  What are the four types of glial cells? :: astrocytes, microglial cells, oligodendrocytyes, and Schwann cells.  Oligodendrocytyes, and Schwann cells peform the process of ==[[Myelination]]== on neurons.  A simple, functional description of the autonomic nervous system is that the ==sympathetic== division prepares the body for action, whereas the ==parasympathetic== division relaxes the body.  Aggregates of neurons inside the brain are known as ==ganglia.==  ==White matter== is composed primarily of ==myelin-sheathed== axons where as ==gray matter== is composed primarily of ==cell-bodies.== It can be said that gray matter is where the actual processing of information is done where as white matter provides the communication between different areas of gray matter and between gray matter and the rest of the body.  White matter is white because of the ==fat== that surrounds it.  The central nervous system (CNS) consists primarily of the ==spinal cord and the brain==. The peripheral nervous system consists of nerves throughout the body. ### Regional specializations of function The ==cerebral cortex== covers the outer surface of the brain.  The cortex consists of ==six== layers. The ==basal ganglia== are structures deep in the front half of the brain made up of ==gray matter== and intimately involved in ==motor control.==  The ==limbic system== structures are mainly in the back half of the brain and includes the ==hippocampus, thalamus, and the hypothalamus, and the amygdala== The system is especially important for learning, emotion, and memory.  The substantia nigra, also located in the midbrain, is the main source of neurons containing the neurotransmitter ==dopamine.== ![[Pasted image 20220829091332.png]] The ==medulla== majorly controls both ==heart rate== and ==respiration.== ![[Pasted image 20220829092954.png]] The three meningeal layers, from outer to inner, are: the ==dura mater== (meaning “tough mother”), the ==arachnoid layer== (meaning “spiderweb-like”) and the ==pia mater== (meaning &ldquotender mother”). Of these, it is the ==arachnoid layer== filled with cerebrospinal fluid (CSF). CSF is produced by a highly vascular tissue named the choroid plexus, which is found in the ==ventricular== system of the brain. ![[Pasted image 20220829091109.png]] ==Astrocytes== are a subtype of glial cells in the central nervous system that regulate blood flow, transfer mitochondria to cells, and supply the building blocks of neurotransmitters.  The blood-brain barrier is the result of ==astrocytes== and an unusually tight fit between the endothelial cells that make up the walls of capillaries in the brain. This property prevents ==large molecules== from diffusing out of the bloodstream and into the brain. ![[Pasted image 20220829085307.png]]  What are the three ventricles in the brain? :: lateral ventricle, third ventricle, and fourth ventricle.  ### Imaging Technologies of the Brain X rays of the brain are largely uninformative because of the brain’s uniform ==density==.  The term “CT” stands for computerized ==computerized tomography==. CTs are created using X-ray energy detecting slight differences in ==texture.==  The term “PET” is short for ==positron emission tomography==. PET scans reveal regional variation in brain activity associated with specific tasks.  fMRI scans provide a powerful means of imaging brain ==activity== but are slower than some other forms of scanning.  ==Transcranial magnetic stimulation (TMS)== uses focal magnetic currents to briefly stimulate the cortex of alert normal subjects without any invasive procedures. This procedure can produce ==transient== changes in behavior.  ==Dyadic fMRI== scans allow researchers to image two brains of people exposed to the same stimulus. This is allowing for the more recent field of [[Social neuroscience]] to open up. In a few studies, participants exposed to the same social stimulation had different activation in their brains suggesting we respond differently to social situations.