Chapter 3 Flashcards
(38 cards)
What is the function of an interneuron?
Associate sensory and motor activity within the central nervous system.
What is the function of a motor neuron?
Send signals from the brain and spinal cord to the muscles
What are the characteristics of a pyramidal neuron?
Found in the cortex, 2 sets of dendrites, a very long axon, and a pyramid shaped cell body.
What is the main difference between an interneuron and a motor and sensory neuron?
Interneurons are much more complex
What are the features of a Purkinje cell?
extremely branched dendrites, directs info from the cerebellum to the rest of the brain.
What are the features of a motor neuron?
Complex dendrites, long axons that connect to muscles. Located in the lower brainstem and spinal cord.
What are the features of sensory neurons and what are some examples?
Structurally, very simple; Bipolar neuron: found in the retina, conduct afferent info to the visual centres of the brain; Somatosensory neuron: afferent info into the spinal cord.
How is it that neurons talk to each other?
Each neuron receives thousands of excitatory and inhibitory signals every second. Neurons sum these signals and respond accordingly. From the simple “yes-no” language of neurons emerges enormous possibilities for behaviour. ie. Mostly excitatory input = ACTIVE, Mostly inhibitory input = NOT ACTIVE
What is the incoming signal to the neuron referred to as?
analog – graded signal (summation of input).
What is the outgoing signal of a neuron referred to as?
digital – on or off (binary).
What are glial cells and what are their functions?
Glia – support cells within the nervous system.
- Act as “nerve glue” (glia = glue), holding neurons in place.
- Supply nutrients to neurons.
- Act as insulation around axons.
- Remove pathogens and dead neurons.
What is an Ependymal cell?
Glial cell that makes and secretes cerebrospinal fluid (CSF).
What is hydrocephalus?
The resulting build up of pressure and swelling of the head; can happen if CSF is prevented from leaving the brain (usually due to a blockage in the fourth ventricle).
What are astrocytes?
Star shaped glial cells that are relatively symmetrical. Responsible for providing structural support for neurons, transporting substances between neurons and capillaries, scar tissue formation, sealing off a damaged area in the brain, promoting healing, and dilating blood vessels to provide more blood (and thus nutrients etc.) for active brain regions.
What is the blood brain barrier?
A protective barrier formed by astrocytes in combination with blood vessels. Prevents toxins etc. from entering the brain and also prevents useful substances from getting through (antibiotics
etc.).
What is the region of the brain that is not influence by the blood brain barrier and why?
Area postrema: serves as the bodies vomit reflex; checks the chemical constitution of the blood to see if there is anything toxic or harmful in it that needs to be ejected.
What are Microglia?
Glial cells that originate in the blood as offshoot of the immune system. After damage microglia invade the area, providing growth factors, and cleaning up the mess. The removal of debris occurs through phagocytosis.
What are Oligodendroglia cells?
Glial cell in the central nervous system that myelinates axons.
What are Schwann cells?
Glial cell in the peripheral nervous system that myelinates axons.
What is Myelin?
the glial coating that surrounds axons, providing insulation.
What is the function of a sensory neuron?
Bring information to the central nervous system
What is MS?
Central nervous system disorder that results from the loss of myelin around axons. Both sensory and motor pathways are affected and thus results in a huge number of symptoms, making it hard to diagnose. Repeated attacks of MS result in scar tissue formation.
What are some factors that can lead to MS?
Environmental factors: – Lack of Vitamin D (the further away from the equator you are…) – Smoking – Exposure to solvents and toxins – Diet – Etc. Genetic component – you are more likely to get it if someone in your family has it.
True or false, glial cells have axons and dendrites.
False
