for final Flashcards
main parts of the central nervous system
the brain and spinal cord
role of the central nervous system
integrates/coordinates input and output; thoughts, emotions, memories
2 parts to the peripheral nervous system
sensory input and motor output
sensory input
input from sensory receptors responding to external stimuli, skin muscles and joints, internal organs
2 parts of motor output
somatic and autonomic nervous system
somatic nervous system
directs voluntary movement
autonomic nervous system
regulates involuntary bodily activities (heart rate and breathing)
autonomic nervous system branches off to:
parasympathetic nervous system and sympathetic nervous system
Parasympathetic nervous system
governs bodily activities during restful conditions (acetylcholine)
Sympathetic nervous system
prepares body for stressful or emergency situations (norepinephrine)
major cell types of the adult human CNS
- neurons
- Oligodendrocytes (CNS) and Schwann cells (PNS)
- Astrocytes
- Microglia
- Ependymal cells
** 2-5 can be classified together as “glial” cells**
Most abundant cell type in the adult human CNS?
Astrocytes
why are pain fibres not the fastest? (neurone)
because they do not have a reflex arc
reflex arc
the basic unit of a reflex, which involves neural pathways acting on an impulse before that impulse has reached the brain
What is the term(s) for a neurotransmitter specific to a given pre-synaptic neuron?
neurotransmitter
Insufficient levels of dopamine, serotonin and norepinephrine are associated with
depression
Lack of acetylcholine is associated with
Alzhiemer’s
Steps of a neurotransmitter
Step 1: impulse reaches the axon ending of the presynaptic membrane
Step 2: Synaptic vesicles release neurotransmitter into the synaptic cleft
OLIGODENDROCYTES
- produce myelin
- span multiple axons (each cell can support up to 30 myelin rolls)
- are found in the CNS
SCHWANN CELLS (PNS)
- produce myelin
- do not span multiple axons
- are found in the PNS
Astrocytes:
stellate (star-like) morphology
- Very important for communication
- More abundant than neurons
Microglia:
mobile macrophage-like immune cells
Ependymal cells:
line the ventricles to form a barrier; produces cerebrospinal fluid
what gets through the blood brain barrier?
- Mostly very small lipid soluble compounds (essential fatty acids)
- Caffeine/alcohol
= A problem when targeting drugs for the brain
how does glucose get through the blood brain barrier?
A specific glucose transporter (GLUT1 – not insulin sensitive)
Positron emission tomography (PET):
tracks glucose uptake (glucose tracer)
Functional magnetic resonance imaging (fMRI):
tracks blood flow – deoxyhemoglobin is paramagneticoIt
Networks are identified by
neurons using the same neurotransmitter
Norepinephrine network modulates:
attention, arousal, sleep-wake, learning, memory, pain, anxiety and mood
Psychostimulants:
methamphetamine, Ritalin (used by some college/university students as “smart drugs”), caffeine
Serotonin network (affected with mood modulates):
pain, sleep-wake cycle, emotion
Acetylcholine network modulates:
arousal, sleep-wake, learning, memory, sensory informationo
Alzheimer’s disease characterized in part by:
- Massive loss in cholinergic neurons (nerves that release acetylcholine)
- Low acetylcholine levelsoV
Various drugs available in Canada to treat Alzheimer’s symptoms are
cholinesterase (enzyme that rapidly breaks down Ach in the synapse) inhibitors
Controls the signal being continuously released (blocks the inhibitor so you are not breaking it down as fast)
Dopamine network modulates:
motor control, reward/pleasure centers
Dopamine agonists (stimulates; acts too similarly and mimics) used to increase health-span of individuals with:
Parkinson’s disease
