Nervous System Flashcards
central nervous system
ONLY brain and spinal cord
peripheral nervous system
- everything else
– Sensory (afferent) neurons
– Efferent neurons: somatic motor and autonomic divisions
▪ Autonomic divided into sympathetic and parasympathetic branches
– Afferent neurons: sensory neurons
▪ Pain and senses - touching hot stove = afferent and taking it off = efferent
enteric nervous system
- only within the digestive system
- its own thing that can fxn on its own
– Network of neurons in the walls of the digestive tract
– Controlled by autonomic nervous system but is able to function autonomously
neurons carry what?
- electrical signals
- fxnal unit of the nervous system
neuron classification
– Structure – number of processes
▪ Multipolar (most common. neurons can go to so many other neurons), pseudounipolar, bipolar, anaxonic neurons
– Function
▪ Sensory (afferent) neurons, efferent neurons, and interneurons
- interneurons: inhibit action of another neuron
neuron structure
- cell body: integrating system. control center
- dendrites: receive incoming signals
- dendritic spines
- axons: carry outgoing signals
- axon hillock
anterior
ventral
posterior
dorsal
superior
postral, cephalic
inferior
caudal
what are nerves?
- axons bundled with connective tissue
– Sensory nerves, motor nerves, mixed nerves
ganglia and nucleus
- ganglia: cell body in PNS
- nucleus: CNS
- Ex: dorsal root ganglia=PNS
- something nucleus=CNS
fast axonal transport
- most organelles use this
– Moves organelles at rates of up to 400 mm/day
– Anterograde transport: from cell body to axon terminal (pos way)
– Retrograde transport: from axon terminal to cell body (neg way)
slow axonal transport
- think pain = v slow
– Moves material by axoplasmic (cytoplasmic) flow at 0.2–2.5 mm/day
schwann cells (PNS) and oligodendrocytes (CNS)
– Wrap around axon and form insulating myelin sheaths
▪ Nodes of Ranvier are gaps in insulation
- myelin sheaths: force action potential or message to go quicker
- oligodendrocytes: can connect to multiple neurones
satellite cells (PNS) - nonmyelinating schwann cells
– Ganglion outside of CNS (PNS) vs. nucleus inside CNS
plasticity
- reworking brain networks in response to day to day activities
affective behaviors
related to feeling and emotion
cognitive behaviors
related to thinking
the CNS is divided into what?
gray and white matter
gray matter
– Unmyelinated nerve cell bodies
– Clusters of cell bodies in the CNS are nuclei
– Dendrites
– Axon terminals
- cell body
white matter
– Myelinated axons
– Axon bundles connecting CNS regions are tracts
▪ Contain very few cell bodies
cerebrospinal fluid (CSF)
- brain just floats in this
- clear, no odor, no taste, cushion for the brain
- looks like water
- salty solution similar to plasma
- Produced by the choroid plexus in the ventricles
– Materials selectively moved from plasma to ventricles
– Water follows due to osmotic gradient - Surrounds entire brain
– Contained within subarachnoid space (between arachnoid membrane and pia mater)
– Flows from ventricles to subarachnoid space to return to plasma by villi - Function in physical and chemical protection
blood brain barrier
- highly regulated processes from astrocytes
- Highly selective permeability of brain capillaries
- Astrocytes foot processes promote tight junctions between endothelial cells
- Protects brain from toxic water soluble compounds and pathogens
- Small lipid-soluble molecules cross the blood-brain barrier