Chapter 3 Part 1 Flashcards
Neurons:
Specialized cells that are the basic building blocks of the nervous system.
Dendrites:
They emerge from the cell body in branchlike fibres and are the receiving unites that collect messages and send them on to the cell body
Axon:
An extension from one side of the neuron cell body that conducts nerve impulses to other neurons, muscles, or glands.
Glial Cells:
Surround neurons and hold them in places, manufacture nutrient chemicals that neurons need, form the myelin sheath around axons, and absorb toxins and waste materials that might damage neurons.
Blood-brain barrier:
Prevents many substances, including a wide range of toxins, from entering the brain. The walls of the blood vessels within the brains contain smaller gaps and are covered by specialized glial cells.
Resting potential:
The electrical activity of neurons, the internal diffence of the sodium ions outside of a cell and the negatively charged protein ions inside the cell
Action potential:
A nerve impulse resulting from the depolarization of an axon’s cell membrane
Depolarization:
The shift from negative to positive voltage
All or none law:
The fact that an action potential is not proportional to the intensity of stimulation. A neuron either fires with max intensity or it does not fire at all.
Myelin Sheath:
A fatty, whitish insulation layer around axons and interrupted at regular intervals by the node of Ranvier.
Synapse:
the microscopic space between neurons over which the nerve impulse is biochemically transmitted
Neurotransmitters:
Chemical substances that carry messages cross the synapse to either excite other neurons or inhibit their firing
Multiple sclerosis:
neurological disorder characterized by demyelination of axons because immune system attacks myelin sheath
Five Step process of chemical communication between neurons
- Synthesis: chemical molc. are formed inside neuron
- Storage: Molc. stored in chambers called synaptic vesicales within axon terminal.
- Release: Molc. released into space between axon and membrane of receiving neuron
- Binding: Molc. cros synaptic space and attach to receptor sites
- Deactiviation.
Excitatory Neurotransmitter:
Depolarizes neurons’s membrane which increases likelihood of action potential.
Inhibitory neurotransmitter:
Hyper polarizes neuron’s membrane which decreases likelihood of action potential.
Glutmatic acid:
Excitatory neurotransmitter, involved in control of all behaviours, especially important in learning and memory
GABA (Gammaaminobutyric acid):
Inhibitory transmitter, important in anxiety and motor control. Destruction in Huntington’s disease produces tremors and loos of motor control, as well as personality changes.
Acetylcholine:
Excitatory at synapses involved in muscular movement and memory. Memory loss in Alzheimer’s disease (undersupply) or muscle contractions (oversupply)
Norepinephrine:
Involved in neural circuits controlling learning, memory, wakefulness, and eating. Depression (undersupply) or stress and panic disorders (oversupply)
Serotonin:
Involved in mood, sleep, eating, and arousal, may be important in pain and pleasure. Depression, sleeping, and eating disorders (undersupply)
Dopamine:
Involved in voluntary movement, emotional arousal, leaning, motivation, experiencing pleasure. Parkinson’s disease and depression (undersupply) Schizophrenia (oversupply)
Endorphins:
Inhibits transmission of pain impulses. Insensitivity to pain (oversupply) Pain hypersensitivity, immune problems (oversupply)
Three major types of neuron
- Sensory neurons: carry input messages from sense organs to the spinal cord and brain
- Motor neurons: transmit out impulses from the brain and spinal cord to the body’s muscles and organs
- Interneurons: Perform connective functions within the nervous system
Central nervous system:
consisting of all neurons in the brain and spinal cord
Peripheral nervous system
Composed of all the neurons that connect the central nervous system with the muscles, glands, and sensory receptors
Somatic nervous system: (Part of peripheral nervous system)
transmit messages from the eyes,ear, and other sensory receptors as well as motor neurons that send messages from brain and spinal cord to muscles.
Autonomic nervous system: (Part of peripheral nervous system)
controls glands and the smooth (involuntary) muscles of the hearts, blood vessels, and stomach + intestines
Sympathetic nervous system: (type of autonomic nervous system)
Speeds up bodily processes and mobilizing the body using an arousal function on the body’s internal organs.
Parasympathetic nervous system: (type of autonomic nervous system)
Slows down body processes and maintains or returns you to a state or rest.
Homeostasis:
The maintenance of biological equilibrium within the body
Spinal Cord
- most nerves enter/leave through spinal cord
- spinal reflexes do not involved brain
- central portion consists of grey, unmyelinated neurons
- outer portion consists of white myelinated neurons
Neuropsychological tests
tests used in clinical evaluations of people who may have suffered brain damage
Destruction and Stimulation Techniques
removing portions of the brain or stimulating specific areas using a mild electric current. These methods are useful when learning about the brain
Electroencephalogram (EEG)
Device used to record the simultaneous activity of many thousands of neurons through electrodes attached to the scalp. Some patterns correspond to wakefulness and sleep
CT scans - Computerized axial tomography
Uses X-ray technology to take pictures of narrow slices of brain, a computer then reconstructs the interior from many different angles
Positron emmission tomography (PET)
Measures brain activity, blood flow, metabolism, neurotransmitter activity. Gluscose, being a major nutrient in neurons, is injected as radioactive glucose. The energy emitted is measured by PET scan to shows active parts of the brain
Magnetic Resonance Imaging (MRI)
Combines CT and PET scans by creating images based on how atoms in living tissue respond to its magnetic pulse.
functional MRI
Produces pictures of blood flow in the brain less than a second apart enabling live feed of brain activity
