Wk5 Flashcards
Neurons
Generate electricity and create nerve impulses and release chemicals that facilitate communication.
Glial cells
Are the support of neurons, they; hold neurons in place, manufacture nutrient chemicals and absorb toxins and waste.
3 steps in the activation of nerve impulses
- neuron has resting electric potential
- action potential occurs when neuron is stimulated
- original iconic balance is restored; neuron is at rest again
Absolute refractory period
neuron cannot fire again until it regains its natural negative polarisation
All-or-none law
action potentials occur at a uniform and maximum potential or they do not occur at all
Action potential threshold
Change needed to fire is 250 milivolts
Graded potentials
any change to resting potential that doesn’t reach the threshold.
4 steps of neuron communication
- synthesis - transmitter molecules are formed
- storage - transmitter molecules are stored in the axon terminals
- Release - action potential in one neuron triggers the release of those transmitter molecules across the gap
- Binding - transmitter molecules bind themselves to receptor sites which are large protein molecules embedded in the receiving neurons cell membrane.
What are the 2 types of neurotransmitters?
Excitatory - cause the action potential to fire
Inhibitory - prevent the neuron from firing
3 types of neurons
Sensory neurons - carry messages from the sense organs to the spinal cord and brain
Motor neurons - transmit impulses from the brain and spinal cord to the muscles and organs
Interneurons - perform connective or associate functions
Excitatory neurons
Cause the action potential to fire
Inhibitory neurons
Prevent the neuron from firing
Sensory neurons
Carry messages from the sense organs to the spinal cord and brain - outside-in.
Motor neurons
Transmit impulses from the brain and spinal cord to the muscles and organs - inside-out.
Interneurons
Perform connective functions
Acetylcholine
Learning and memory. Disorders - Alzheimer’s (under), paralysis (under), convulsions (over).
noradrenalin
Excitatory - Controls learning, memory, wakefulness and eating. Disorders - Depression (under), stress and panic (over)
Serotonin
Inhibitory - Mood, sleep, eating and arousal - underlies pleasure and pain. Disorders - Depression, sleep and eating disorders (under) and OCD (over).
Dopamine
Excitatory - voluntary movement, emotional arousal, learning, memory and experiences of pleasure/pain. Disorders - Parkinsons and depression (under) and schizophrenia (over)
GABA
Inhibitory
Endorphins
Mood and pain. Disorders - Insensitivity to pain (over) Pain hypersensitivity (under)
Dendrites
Branch like extensions of the neuron that receive inputs from other cells.
Cell body
Includes the nucleus that contains the genetic material of the cell and is considered the brains of the operation.
Axon
Long extension from the cell body (up to 1mtre) that transmits information to other neurons.
Myelin sheath
coat of cells composed primarily of fats that help transmit information to other neurons. Insulates axon from chemical and physical stimuli that might interfere with nerve impulses. They also dramatically increase the speed of transmission.
White matter
From the myelinated axons
Grey matter
Cell bodies, dendrites and unmyelinated sheaths
Terminal buttons
At the end of the axon sending signals from a neuron to adjacent cell.
Synaptic cleft
Space between two cells
Synapses
Connections between neurons
Resting potential
When a neuron is not firing and electrical charge is 70 milivolts. Membrane is polarised - inside has a negative change and outside has a positive charge.
Graded potential
Change in cells voltage is passed down dendrites and cell body.
When a neuron is stimulated it can reduce the membranes polarisation and make it more likely to fire or increase polarisation and make it less likely to fire. Graded potentials strength diminishes as it moves along the cell membrane and they are cumulative or additive - If 2 potentials at each end are the same they cancel eachother out.
Action potential
The firing of the neuron - Rapidly spreads down the length of the axon to the terminal buttons and has an all-or-none quality.
Neurotransmitter release
Action potential causes terminal buttons to release neurotransmitters into the synaptic cleft.
Glutamate
Excitatory - Learning
Peripheral nervous system
Contains all the neural structures that lie outside of the brain and spinal cord.
Input functions - sense what is going on inside and outside the body.
Output functions - enable response
Input functions
Sense what is going on inside and outside the body
Output functions
Enable response
Somatic nervous system
Allows us to sense and respond to our environment
Autonomic nervous system
Basic life functions - sense the body’s internal functions and controls glands and smooth muscles that form the heart, blood vessels, and lining of the stomach and intestines.
Sympathetic nervous system
activation or arousal (fight or flight)
Parasympathetic nervous system
Slows down the body, maintains equilibrium.
Hindbrain
Lowest and most primitive part of the brain.
Brain stem - supports vital life functions.
Medulla - heart rate and respiration, blood pressure and vomiting
Pons - carries nerve impulses between higher and lower levels of the nervous system and regulates sleep
Cerebellum - muscular movement coordination, learning and memory.
Brain stem
Supports vital life functions
Medulla
Heart rate, respiration, blood pressure and vomiting
Pons
Carries nerve impulses between higher and lower levels of the nervous system and regulates sleep
Cerebellum
Muscular movement coordination, learning and memory.
Midbrain
contains clusters of sensory and motor neurons
Reticular formation - alerts higher centres of the brain that messages are coming.
Tectum - structures involved in vision and hearing.
Tegmentum - Serves a variety of functions, mostly to do with movement.
Reticular formation
Alerts higher centres of the brain that messages are coming.
Forebrain
Most evolutionary advanced part of the brain.
Cerebrum - Major structure consisting of 2 hemispheres
Thalamus - switchboard that organises inputs from sensory organs and routes them to the appropriate areas
Hypothalamus - Motivation and emotion, sexual behaviour, temperature regulation, eating, drinking and aggression.
Limbic system - amygdala and hippocampus
Cerebral cortex - outermost layer
Cerebrum
Major structure consisting of 2 hemispheres
Thalamus
Switchboard that organises inputs from sensory organs and routes them to the appropriate area.
Hypothalamus
Motivation and emotion, sexual behaviour, temperature regulation, eating, drinking and aggression.
Tectum
Includes structures involved in vision and hearing
Tegmentum
Midbrain - variety of functions, mostly to do with movement.
Limbic system
Set of structures with diverse functions involving emotions, motivation, learning and memory - amygdala and hippocampus
Cerebral cortex
unmyelinated cells that form the outer layer. Fissures mark the 4 lobes - frontal, parietal, temporal and occipital.
Amygdala
Involved in many emotional processes - learning and remembering emotionally significant events. Fear detector
Hippocampus
Storing new information in memory.
Basal ganglia
Set of structures including the putamen and caudate nucleus that are involved in a wide array of functions, especially movement and judgements that require minimal conscious thought.
Corpus callosum
Thick band of axons connecting the two hemispheres
Motor cortex
controls 600+ muscles for voluntary body movement
Sensory cortex
receives sensory input from sensory receptors
Wernicke’s area
Speech understanding, located in the temporal lobe
Broca’s area
Speech formation, located in the frontal lobe
Association cortex
Located across the brain. Important in language, perception and thought
Agnosia
Inability to identify familiar objects
Hemispheric lateralisation
relatively greater localisation of a function in one hemisphere or the other.
Left hemisphere
Verbal activities, speech, math and logic. More active when you’re feeling positive emotions
Right hemisphere
spatial relations, faces, mental imagery, music, art. More active when you’re feeling negative emotions.
Occipital lobe
Located at the rear - specialised for vision.
Parietal lobe
Infront of occipital lobe. Involved in touch, detecting movement, locating objects and experiencing ones own body.
Somatosensory cortex
Different areas receive different info from different body parts.
Frontal lobe
Movement, attention, planning, social skills, abstract thinking, memory and some aspects of personality.
Temporal lobe
Lower portion - Important in hearing and language
Neuroplasticity
The ability for neurons to change in structure and function
Neurogenesis
Production of new neurons in the nervous system
Neural stem cells
immature uncommitted cells that can mature any type of neuron or glial cell
