Neural System and Endocrine

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Biological Psychologists
Study the links between our biology and our behavior (everything you do has a physical basis)
Neuron
A nerve cell; the basic building block of the nervous system
Dendrites
A neurons often bushy, branching extensions that receive messages and conduct them towards the body
Axon
The neuron extension that passes messages through to its terminal branches to other neurons, muscles, or glands (can be very long)
Myelin Sheath
A fatty tissue layer segment ally encasing axons of some neurons, enabling vastly greater transmissions speed as neural impulses hop from one node to the next.
How does myelin affect a persons behavior?
As myelin is laid down until about 25 neural efficiency, judgement, and self control grow
Multiple Sclerosis
When myelin sheaths degenerate leading communications to muscles to slow and an eventual loss of muscle control
Glial Cells
Cells in the nervous system that support, nourish and protect neurons. They may also play a role in learning, thinking, and memory.
What does the glial or neuron ratio tell you?
The more complex the brain the higher the proportion of glia to neurons
Action Potential
A neural impulse; a brief electrical charge that travels down an axon
Threshold
The level of stimulation required to trigger a neural impulse
What is the resting potential of a neuron?
A positive outside/negative inside state
The fluid outside the neuron is mostly positively charged sodium ions
Inside there are negatively charged proteins and positively charged potassium ions
Depolarization
The change in charge when sodium ions attracted to the positive interior flood in the axon.
This causes the next section of axon channels to open and then the next like a line of falling dominoes producing an action potential.
Refractory Period
A brief resting pause that occurs after a neuron has fired; subsequent action potentials cannot occur until the axon returns to its resting state.
All-or-none response
A neuron's reaction of either firing (with a full-strength response) or not firing at all. While a strong stimulus can trigger more neurons to fire, the speed or strength of an action potential cannot be changed.
Synapse
The junction between an axon tip of the sending neuron and the dendrite or cell body of the receiving neuron
How did we discover that there was a synaptic gap?
Because it took an unexpectedly long time for impulses to travel a neural pathway
Neurotransmitters
Chemical messengers that cross synaptic gaps between neurons.
When released by the sending neuron, neurotransmitters traced across the synapse and bind to receptor sites on the receiving neuron, influencing an impulse.
Reuptake
The neurotransmitters re absorption by the sending neuron
Endorphins
"Morphine within" - natural, opiate like neurotransmitters link to pain control and pleasure
Acetylcholine
Enables muscle action, learning, and memory
Where is ACh used in the body and what happens when it is blocked?
It is the messenger at every junction between motor neurons and skeletal muscles, release of ACh at our muscle cell receptors causes muscles to contract.
If ACh is blocked (anesthesia and poison) muscles cannot contract and we are paralyzed.
Dopamine
Influences movement, learning, attention, and emotion
Serotonin
Affects mood, hunger, sleep, and arousal
Norepinephrine
Helps control alertness and arousal
GABA (gammaaminobutyric acid)
A major inhibitory transmitter
Glutamate
A major excitatory neurotransmitter
Agonist
A molecule that increase a neurotransmitters actions

Ways:
1) increasing the production or release of a neurotransmitter
2) some agonists similar in structure to a neurotransmitter can bind to receptors and mimic excitatory or inhibitory effects
3) blocking reuptake of the neurotransmitter
Antagonists
A molecule that inhibits or blocks a neurotransmitters action by blocking production or release.
What happens when we take Artifical opiates?
To maintain chemical balance the body may stop producing its own natural opiates, such that when the person stops taking the drug the person may be deprived of those opiates (making them feel uncomfortable)
Central Nervous System
The brain and the spinal chord
Peripheral Nervous System
The sensory and motor nervous that connect to the central nervous system and the rest of the body
Nerves
Bundled axons that form the neural cables connection the CNS with muscles, glands, and sense organs
Sensory Afferent Neurons
Neurons carrying incoming information from the sensory receptors to the brain and the spinal chord
Motor Efferent Neurons
Neurons carrying outgoing information from the brain and the spinal chord to the muscles and the glands
Interneurons
Neurons within the brain and the spinal chord; communicated internally and process information between the sensory inputs and motor outputs
Somatic Nervous System
The division of the peripheral nervous system that controls all of the body's skeletal muscles
Reflexes
A simple, automatic response to a sensory stimulus. A simple spinal reflex pathway maybe composed of a single sensory neuron and single motor neurons, but also often includes an interneuron. The reflex runs through your spinal chord and right back out, causing the reaction often before the information reaches the brain. Examples include a knee-jerk reaction and hand withdrawal upon touching a hot object
Autonomic Nervous System
The part of the peripheral nervous systems that controls the glands and muscles of the internal organs.
Sympathetic Nervous System
The division of the autonomic nervous system that ado uses the body and mobilizes its energy: accelerates heartbeat, inhibits digestion, stimulates glucose released, relates bladder, dilates pupils
How does the Autonomic Nervous System (sympathetic division) around the body?
The ANS stimulates the adrenal glands on top of the kidneys to release epinephrine and nonepinephrine which increase heart rate, blood pressure, and blood sugar
Parasympathetic Nervous System
The division of the autonomic nervous system that calms the body, conserving energy: contracts pupils, slows heartbeat, stimulates digestion, stimulates gallbladder, contracts bladder
Endocrine System
The body's slow chemical communication system, a set of glands that release hormones into the bloodstream
Hormones
Chemical messengers that are manufactured by the endocrine glands, which travel through the blood stream and affect certain tissues
How long do endocrine hormones last?
Endocrine messages tend to outlast the effects of neural messages, the hormones and feelings tend to linger for a whole
What are the organs of the endocrine system?
Hypothalamus, pituitary gland, thyroid gland, parathyroids, adrenal glands, pancreas, testes and ovaries
Pituary Gland
A pea-sized structure located in the core of the brain and controlled by the hypothalamus. It is the endocrine systems most influential gland secreting many hormones and influencing other glands.
Oxytocin
Stimulates uterine contractions associated with birthing, milk flow during nursing, and orgasm.
FSH (follicle stimulating hormone)
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Thyroxine
Hormones that stimulates metabolism and binds to all cells in the body
Insulin
Hormone that helps control blood glucose levels by stimulating the liver, muscle cells, and fat cells to take up glucose. If the body has enough glucose the liver takes up the glucose and stores it as glycogen
Glucagon
Signals the body to release glucose
Erythropoietin
Regulates the production of red blood cells
Calcitonin
Hormone that counteracts parathyroid hormone. It controls calcium levels in the blood by inhibiting osteoblast from breaking down bone.
Parathyroid Hormone
Hormone that increases the breakdown of bone and the release of calcium into the blood
Electroencephalogram (EEG)
An amplified recording of the waves of electrical activity that sweep across the brains surface, measured by electrodes placed in the scalp.
PET (positron emission tomography) Scan
A visual display of the brain activity that detects where a radioactive form of glucose goes and is being consumed, while a brag is performing a given task. Shows "hot spots"
How much glucose does the brain use?
The brain composes only 2 percent of our weight but consumes 20 percent of our caloric intake
(Idea: when we don't eat we can't think: because our brains aren't getting the energy we need?)
MRI (magnetic resonance imaging)
Technique that uses magnetic fields and radio waves to produce computer generated images of soft tissue displaying the brains anatomy
How can MRI scans be useful?
MRI scans can reveal structural abnormalities/differences in those suffering from mental illness or with different abilities.
(Schizophrenics tend to have enlarged ventricles. Musicians have enlarged left brains)
fMRI (functional MRI)
A technique for revealing blood flow and therefore activity by comparing successive MRI scans.
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