The Biology Behind Behavior Flashcards
What are the fundamental building blocks of the nervous system?
Neurons and glial cells
Define neurons
Specialised cells that receive, conduct, and transmit electrochemical signals allowing for two way communication between the body and brain
What are dendrites?
Bushy fibers which receive information and conduct it towards the cell body
What is an axon?
Conducts information away from the dendrites to the muscles or glands or the dendrites of other neurons
What is a synapse?
The junction between adjacent neurons where chemical signals in the form of neurotransmitters, are transmitted across minuscule gaps
Do you dendrites receive or transmit information?
Signal receivers
Do you axons conduct or receive signals?
Conduct signals
What do Schwann cells do?
Produce myelin
What is myelin?
A lipid membrane surrounding the axon that helps increase signal transmission
In the central nervous system what are groups of cell body is called?
Nuclei
In the central nervous system why are groups of axons called?
Tracts
In the peripheral nervous system what are groups of cell body is called?
Ganglia
In the peripheral nervous system what are those of axons called?
Nerves
What are the three different types of neurons in the nervous system?
(1) Sensory neurons (afferent neurons)
(2) Motor neurons (efferent neurons)
(3) interneurons
What are sensory neurons?
Afferent nerve runs but send information from sensory receptors and body tissues towards the central nervous system for processing.
Why are motor neurons?
Efferent neurons that send information away from the central nervous system to glands and muscles
What are interneurons?
They send information between motor and sensory neurons, and are primarily located within the central nervous system
What are glial cells?
Provide protection and support for neurons, maintain homoeostasis, and form myelin
What is myelin? What cells form it?
A fatty insulation wrapping axons to increase the speed and efficiency of signal conduction. Formed by glial cells.
How does multiple sclerosis develop?
When the myelin sheet is damaged, nerve signals slow down and stop if this degeneration persists, caused by inflammation of an autoimmune response the disease develops
What are the symptoms of multiple sclerosis?
Loss of motor control, visual impairments, loss of coordination, slurred speech, and numbness and weakness in the limbs
What are the four main types of glia?
Oligodendrocytes, Schwann cells, microglia, and Astrocytes
What are Oligodendrocytes?
Wrap myelin extensions around the axons of neurons in the central nervous system
What is the purpose of Schwann cells?
Wrap myelin to one segment of a single neuron in the peripheral nervous system
Can Schwann cells and Oligodendrocytes direct axonal regeneration after damage?
Only Schwann cells can direct axonal re-generation after damage. (Located in the PNS)
What is the function of microglia?
They react to damage or disease as a macrophage would, they multiply, trigger inflammatorily responses and engulf cellular debris
What are astrocytes?
Astrocytes vary greatly in function, (1) Some astrocytes cover blood vessels throughout the brain and are in contact with the cell bodies of neurons. These astrocytes help regulate the passage or prevention of certain chemicals between the blood and central nervous system neurons
(2) other types of astrocytes have been shown to modulate neuronal activity, control the blood brain barrier, and to establish and sustain effective synopsis
What does neuronal function and communication depend on?
Membrane potential of each cell
What is membrane potential?
The difference in electrical charge between the exterior and interior of the cell that allows information to be passed from one area of the body to another
What does the internal fluid of an axon at rest mostly contain?
Negatively charged ions
What does the external fluid of an axon at rest usually contain
Mostly positively charged ions
What is the measurement of an axon at rest called? What is this value?
Resting potential, -70 mV
Is the resting potential of an axon considered to be polarised or non-polarised
Polarised
When a neuron fires, the selective permeability of the axon surface changes either to decrease or increase the resting membrane potential. When A net gain occurs what does the membrane potential become?
Depolarised
When a neuron fires, the selective permeability of the axon surface changes either to decrease or increase the resting membrane potential. When A net loss of positively charged ions occurs what does the membrane potential become?
Hyperpolized
When post synaptic depolarisations occur, does this increase or decrease the neurons chance of firing? What is this called?
It increases the neurons chances of firing, this is called excitatory post synaptic potentials (EPSPs)
When post synaptic hyperolarization occur, does this increase or decrease the neurons chance of firing? What is this called?
Decrease the neurons chances of firing, inhibitory post synaptic potentials
What type of responses are EPSPs and IPSP? What does this term mean?
Graded responses, their answer to this are proportional to the intensity of the original signals that create them (strong signals generate large postsynaptic potentials, and weak signals generate small post synaptic potentials)
What must the neuron do since it receives hundreds of thousands of signals? In what two ways does it do this?
It must integrate the incoming EPSP and IPSP signals into one signal. This occurs both spatially and temporally.
What is spatial summation
Adds incoming EPSP or IPSP signals that are received simultaneously on different parts of the receptive membrane to account for many areas of input.
What is temporal summation?
Occurs when high-frequency post synaptic potential overlap with one another and Sammy to create a more intense signal
In temporal summation, where does summation occur?
The axon hillcock–The base of the cell body that connects to the axon
What is a threshold level? What is its value?
If the sum of excited Tori signals and inhibitory signals exceeds and minima intensity sufficient to depolarise the membrane past it’s threshold level (usually about -55mV) this generates an action potential
Once an action potential is triggered what occurs?
Adjacent Axson all statements causing more and more action potential is to fire is triggering the next action potential
Are action potentials graded responses?
No, increasing depolarisation past it’s threshold will not increase the intensity of the neural impulse
What type of responses are action potentials?
All or none responses; they occur either fully or not at all
Increasing the intensity of the stimulus or number of stimuli will not change the intensity of the response
What are chemical messengers called? when do they release?
Neurotransmitters; they are released into the synaptic left between neurons when an action potential reaches the axon terminal
Where are neurotransmitters located before release into the synaptic cleft?
Each neuron prepackages the appropriate neurotransmitter into vesicles the cluster near the pre-synaptic membrane is rich in voltage activated calcium channels
When do you voltage activated calcium channels open? What does this allow?
Voltage activated calcium channels open when stimulated by action potentials. This causes an influx of calcium ions into the axons terminal button, causing synaptic vesicles to fuse with the presynaptic membrane is followed by the subsequent release of neurotransmitters into the cleft period neurotransmitter molecules bind to post synaptic receptors and excite (generate EPSPs) or inhibit (generate IPSPs) the post synaptic neurons ability to fire. Then excess neurotransmitters are reabsorbed.
What is reuptake?
When the presynaptic neuron reabsorbs excess neurotransmitters
What are the two types of neurotransmitters?
Small molecule neurotransmitters and large molecule neurotransmitters
What are the four types of small molecule neurotransmitters
Acetylcholine, amino acids, monoamines, and unconventional neurotransmitters
What is the name of the large molecule neurotransmitters
Neuropeptides
What is the function of Acetylcholine?
Muscle stimulation, learning and memory
What are the behavioural and physical mail functions associated with ACh?
Motor control loss and dementia and all is Eimers disease characterised by the deterioration aCh producing an hour on this
What is the function of glutamate
It has a major role in mediating excitatory signals; involved in cognition, memory, and learning
What is associated with behavioural and physical now functions of glutamate?
Imbalance associate with memory loss in all timers disease; oversupply associated with Maranda and D crease in motor control in ALS patients
What is the function of GABA?
It plays a major role in mediating inhibitory signals; involved in motor control and vision
What behavioural and physical malfunctions are associated with GABA?
Deficiency associated with seizures, tremors, and anxiety
What is the function of norepinephrine?
Major role in controlling alertness and arousal; increases heart rate
What behavioural and physical now functions are associated with norepinephrine
Imbalance associated with mood disorders, manic depression
What is the function of dopamine?
Major role in award motivated behaviour; influences attention, emotion, and movement
What is associated with behavioural and physical malfunctions of dopamine?
Undersupply associated with tremors in muscle rigidity in Parkinson’s disease; oversupply associated with schizophrenia and impulsive behaviour
What is the function of seratonin?
Major role in the regulation of mood, appetite, arousal, and sleep
What is associated with behavioural and physical now functions of serotonin?
Undersupply associated with depression, sleep problems, and compulsive behaviour
What is the function of nitrous oxide?
Involved in redox signalling; relaxes gastrointestinal smooth-muscle; vasodilator
What behavioural and physical malfunctions are associated with nitrous oxide?
Deficiency associated with depressed mood and impulsive behaviour
What is the function of endorphins?
Pain and stress inhibitors
What behavioural and physical malfunctions are associated with endorphins?
Undersupply associated with hyper sensitivity to pain and depression; oversupply associated with in sensitivity to pain and addictive behaviour
Where is acetylcholine present?
It is present at every junction between motor neurons and skeletal muscles
What does ACh uptake by muscle cells causes the muscles to do?
Contract
When ACh transmission is blocked what occurs?
Muscle contraction occurs resulting in paralysis
When ACh is released into the central nervous system what role does it play
Plays a role in learning and memory
What type of neurotransmitter is ACh?
Small molecule neurotransmitters
What type of neurotransmitter are amino acid’s?
Small molecule neurotransmitter
What type of neurotransmitter are Monoamines?
Small molecule neurotransmitters
What type of neurotransmitter is unconventional neurotransmitters?
Small molecule neurotransmitters
What type of neurotransmitter are neuropeptides?
Large molecule neurotransmitters
Which neurotransmitter comprises the majority of fast acting neurotransmitters found in the nervous system?
Amino acid neurotransmitters
What are the four primary amino acid neurotransmitters?
Aspartate, glutamate, glycine, and gamma aminobutyric acid (GABA)
What is the major excitatory neurotransmitter in the CNS?
Glutamate
What is the major inhibitory neurotransmitter in the CNS?
GABA (modified derivative of glutamate)
What are the four monoamine neurotransmitters?
Dopamine, epinephrine, norepinephrine and serotonin
What are the four monoamine neurotransmitters synthesised from?
Single amino acids and is slightly larger than an amino acid neurotransmitter
What are the two types of monoamine neurotransmitters?
Catchecholamines and indolamines
What amino acid synthesises dopamine?
Tyrosine
What amino acid synthesises epinephrine ?
Tyrosine
What amino acid synthesises norepinephrine ?
Tyrosine
What group of monoamine neurotransmitters are synthesised by tyrosine? What neurotransmitters do these include?
Catchecholamines; dopamine, epinephrine, and norepinephrine
What are neurons called that release epinephrine?
Adrenergic
What are neurotransmitters called that release norepinephrine?
Noradrenergic
What neurotransmitters make up the monoamine neurotransmitter group indolamine? Which amino acid is this synthesised from?
Serotonin; tryptophan
What are the unconventional neurotransmitters? What are two examples of subclasses of these organisms?
The unconventional neurotransmitters act along different pathways and are a group of misfits; soluble gas neurotransmitters and endocannabinoids
What neurotransmitters does the subclass soluble gas neurotransmitters include?
Carbon monoxide and nitric oxide
What is the unique value of soluble gas neurotransmitters?
Due to their high lipid solubility, these neurotransmitters readily pass through cellular membranes and quickly stimulate a second messenger before being deactivated
Where are most neurotransmitters released in a cell?
Axon terminal
Where are endocannabinoids generally released from in a cell?
Dendrites of a cell; not the axon
What is the function of endocannabinoids?
Affect presynaptic neurons and inhibit or reduce synaptic transmission
What behavioural effects do endocannabinoids produce?
Role in long term memory interference, stress and anxiety suppression, regulation of motivation and pleasure associated with feeding behaviour
What are the five categories of large molecule neurotransmitters?
Pituitary peptides, hypothalamic peptides, brain gut peptides, opioid peptides, and miscellaneous peptides
How are neuropeptides used?
They are used for neuronal Communication just as they are used for hormonal communication
What is the difference between the release of neuropeptides and peptide hormones?
Neuropeptides are released from neuronal cells in signal to other neighbouring neurons; peptide hormones are released from neuroendocrine cells and travel through the blood various receptors in the body
Do neuropeptides have local or distant communication?
Local
Do peptide hormones have local or distant communication?
Distant
What are endorphins?
(Endogenous morphine) Neuropeptide transmitters released in response to pain and intense exercise, helps explain why eating spicy food and working out make someone feel good afterwards
What do endorphins mimic?
Morphine
What are agonists?
Molecules that are structurally similar enough to certain neurotransmitters to allow them to bind to the same receptors and elicit a similar response
What are antagonists?
Molecules that also bind to the same receptors but instead block the neurotransmitters function
What are the two divisions of the nervous system?
Peripheral nervous system and central nervous system
What is the central nervous system?
Consists of the brain and spinal cord and is responsible for making decisions
What is the peripheral nervous system?
Consists of sensory and motor near on that connect the central nervous system to the rest of the body and is responsible for reflexes, gathering information, transmitting this information to the CNS, and then transmitting CNS Decisions throughout the body
What are the two divisions of the peripheral nervous system?
Somatic nervous system
Autonomic nervous system
What is the somatic nervous system?
It interacts with the external environment and enables us to control our skeletal muscles voluntarily
What is the autonomic nervous system?
It regulates our internal environment, such as our glands and smooth muscles, autonomously (on its own) and therefore is considered to be involuntary
What are the two divisions of the autonomic nervous system?
Sympathetic and parasympathetic nervous systems
What is the sympathetic nervous system?
It arouses the body under stressful conditions and uses energy resources to do so; releases epinephrine and norepinephrine to create a flight or fight response
Which division of the nervous system creates a fight or flight response?
Sympathetic nervous system
What is the parasympathetic nervous system?
It re-gains control when the stress or condition passes and acts to conserve energy and bring the body back to homoeostasis
Why are the two divisions of the central nervous system?
The brain and spinal cord
What covers the brain and spinal cord?
Three layers of connective-tissue called the meninges and Cerebrospinal fluid (CSF)
Why are the three layers of the meninges?
(Exterior) dura mater, arachnoid membrane, and pia mater (internal)
What is cerebrospinal fluid?
It is found in between the arachnoid membrane and the pia mater, it supports and cushions the brain and spinal cord to provide added protection against trauma and aid in the circulation of nutrients to the brain
What is the spinal cord?
It is a bundle of nerve fivers connected to the brain
What two types of matter are in the spinal cord? Which is the inner layer and which is the outer layer?
Grey matter (inner) and white matter (outer)
What is grey matter?
That in a portion of the spinal-cord composed of cell bodies and unmyelinated interneurons
What is white-matter?
The outer portion of the spinal-cord composed of myelinated axons
What is the function of the spinal cord?
The spinal-cord transmit sensory information from the body to the brain and transmits motor information from the brain to the body
Where are afferent nerve tracts found? What did they do?
There found on the backside of the spinal cord. They carry sensory information to the brain
What are efferent nerve tracts? Where are they found?
Efferents nerve tracts are found on the ventral side of the spinal-cord. They carry motor function information to the skeletal muscles via the somatic nervous system or smooth muscles by the autonomic nervous system
Which organs are involved with the somatic nervous system?
Skin and skeletal muscles
Which organs are involved with the autonomic nervous system?
Smooth muscles
Where do you afferent nerve tracts enter the spinal cord?
Dorsal horn
Where do you efferent nerve tracts enter the spinal cord?
Ventral horn
The vertebrate embryo contains a fluid filled neural tube with three distinct swelling is that eventually develop into?
Forebrain, midbrain, and hindbrain
What does the forebrain differentiate into?
Telencephalon and diencephalon