(BBB) the Nervous System Flashcards
week 2
The study of brain damage is called
Neuropsychology
EEG
Electroencephalography
Records electrical activity in the brain via electrodes attached to the scalp. EEG results show changes in brain activity that may be useful in diagnosing brain conditions, especially epilepsy and other conditions that cause seizures.
PET
Positron Emission Tomography
An imaging test of the brain, measures where activity happens, and how the brain and its tissues are working.
fMRI is preferable.
fMRI
Fuctional Magnetic Resonance Imaging
Measures the small changes in blood flow that occur with brain activity. It may be used to examine which parts of the brain are handling critical functions, evaluate the effects of stroke or other disease, or to guide brain treatment.
MEG
Magnetoencephalography
Measures the magnetic fields generated by electric currents in the brain to show where and when activity happens in the brain.
TMS
Transcranial Magnetic Stimulation
Can either be used as a measurement tool to assess cortical excitability or indirect estimates of neurochemical concentration, or as an intervention to increase or decrease the activity within a given region.
The Central Nervous System (CNS) and Peripheral Nervous System (PNS) are the two systems of the ..
.. Nervous system
The structure of the Peripheral nervous system includes 3 systems..
Autonomic Nervous System (ANS) - internal organs; heart, lungs.
Somatic Nervous System (SNS) - transmits sensations, produces movement.
Enteric Nervous System - controls the gut.
The Somatic Nervous System enables interactions between us and the environment.
Connects the brain to sensory organs to receive incoming information - afferent pathways.
Connects the brain to the muscles to produce movement - efferent pathways.
Afferent pathways
Conveys information from our senses into the brain. (Incoming)
Efferent pathways
Helping us react and producing movement. (Outgoing)
The SNS consists of 12 pairs of cranial nerves (in the brain) and 31 pairs of spinal nerves (in the spine).
There are sensory nerves (smell, vision, hearing/balance), motor nerves (eye movements, neck muscles, tongue), and sensory & motor nerves.
The Autonomic Nervous System regulates internal organs
“autonomous” - not nuch voluntary control
It has two parts:
Sympathetic nervous system - fight or flight: prepares the body for action, ie. increased heart rate and blood pressure, pupil dilation.
Parasympathetic nervous system - rest and digest: helps body relax, ie. decreased heart rate and blood pressure, stimulated digestion.
The Enteric Nervous system
Regulates digestion, helps control nutrient absorption and waste elimination.
sometimes categorized as part of the ANS but it functions largely independent of it.
Neurons, or neural cells, are the functional units or building blocks of the nervous system.
Interactions between neurons enable behaviour.
Neurons transmit information from one another through gaps called synapses.
The structure of the neuron
DENDRITES - these are the input zone. Receiving information from other neurons.
The dendrites are attached to the CELL BODY - this is the integration zone where all the information received is summed up.
The AXON conducts information via electrical activity (conduction zone) to the output zone or axon terminals. Axons are surrounded by a myelin sheath.
The AXON TERMINALS pass on information to other neurons; output zone.
Types of neurons
By function:
-Sensory. Carry information from the body to the spinal cord & brain.
-Motor. Carry information from the nervous system to the muscles and internal organs.
-Interneurons. Receive information from neurons and pass it on to other neurons.
By shape:
-Multipolar. Many dendrites, single axon.
-Bipolar. One dendrite, one axon.
-Unipolar. Single axon, branching in two directions.
Synapse
Information processing unit. Synapses connect neurons and help transmit information from one neuron to the next.
Synapse structure
Consists of the axon terminal of the sending neuron, the synaptic cleft (a small gap), and the dendrite or cell body of the recieving neuron.
Neurotransmitters have a key role in communicating information between neurons.
They are chemical messengers in the body. Their job is to transmit signals from nerve cells to target cells. These signals help regulate bodily functions ranging from heart rate to appetite.
There are different types of neurotransmitters, some mainly excitatory, some mainly inhibitory.
Neurotransmitters support different brain networks and their functions.
Acetylcholine (ACh): Cholinergic networks > attention, learning and memory.
Dopamine (DA): Dopaminergic networks > movement & motor control, reward & enforcement.
Serotonin (5-HT): Serotonergic networks > mood, sexual behaviour, anxiety.
Glial cells > support cells.
Astrocytes - nutrition; link between neurons and blood vessels, but, edema (swelling) when injured.
Microglia - clean-up crew; remove debris from damaged/dead cells, but, Alzheimer’s.
Olygodendrocytes - myelination in the central nervous system.
Schwann cells - myelination in the peripheral nervous system.
Myelin sheath thickness: speed of electrical conductance. (thicker > faster)
