The nervous system Flashcards
subdivisions of the nervous system
central nervous system (CNS)
peripheral nervous system (PNS)
what does the CNS consist of?
brain
spinal cord
(encased in bone and not plastic)
what does the PNS consist of?
everything outside the spinal cord and skull
(plastic)
subdivisions of the PNS
sensory (afferent) and motor (efferent) divisions
subdivisions of motor division
autonomic nervous system
somatic nervous system
subdivisions of ANS
sympathetic
parasympathetic
role of somatic nervous system
controls voluntary movement
peripheral nerves exit spinal cord and connect to muscles and stimulation of these nerves cause muscle contraction
role of autonomic nervous system
controls involuntary movements e.g. lungs and heart
has two components: sympathetic and parasympathetic
role of sensory system
takes information from the senses
5 basic senses but also vestibular and proprioreceptive systems
what are the 2 basic cells of the nervous system?
neurones
glial cells
what are neurones?
electrically excitable cells that communicate with other cells via synapses
how does information travel through a neurone?
through action potentials
1. signal arrives at dendrites
2. if charge reaches threshold, action potential travels down axon
3.information coded by rate of firing
how does information pass between neurones
through chemicals
1. AP causes calcium to enter axon terminals
2. synaptic vesicles containing neurotransmitters bind to cell membrane and release this into synaptic cleft
3. neurotransmitter binds to dendrites of next neurone
4. if neurotransmitter is inhibitory then charge of receiving neurone is lowered and if excitatory charge is increased
5. if charge passes the threshold, the next neurone will fire an AP
what are glial cells
non-neuronal cells that maintain homeostasis
provide support and protection for neurones
5 major types of glial cells
Schwann cell
oligodendrocyte
astrocyte
microglial cell
ependymal cell
astrocyte
regulate chemicals around neurones e.g. neurotransmitter uptake nod ion conc
regulate blood flow around the brain
repair areas of the nervous system forming glial scars
maintain the blood-brain barrier
oligodendrocyte
form myelin sheath in CNS
each oligodendrocyte can myelinated up to 50 axons
Schwann cells
form myelin sheath in PNS
assist in regeneration and regrowth of axons
microglia
immune system for the brain
scavenge CNS for plaques, damaged cells and infectious agents
ependymal cells
make up ependyma membranes
ependyma membranes are thin linings of central canal of the spinal cord and ventricles
produce cerebrospinal fluid
what is white matter made of
myelin sheaths (made of fats and proteins)
what is grey matter made of
cell bodies and neurones
what is the basic layout of the brain from bottom to top
spinal cord
medulla
pons
cerebellum
midbrain
thalamus
basal ganglia
cerebral cortex
brainstem
sits on top of spinal cord
made up of medulla, pons and cerebellum
medulla
lower half of brainstem
controls cardiac, respiration and reflexes (basic motor functions)
pons
contains nuclei and relays signals from forebrain to cerebellum
primarily deals with: sleep, respiration, swallowing, bladder control, hearing, taste, eye movements, posture, facial expressions
cerebellum
maintenance of balance and posture
coordination of movements
motor learning
midbrain
made up of tactum and substantia nigra
tactum
controls orientation of head and neck
superior colliculus- vision
inferior colliculus- sound
substantia nigra
associated with sleep and wake cycles
alertness
temperature regulation
diancephalon
made up of thalamus and hypothalamus
thalamus
takes information from periphery and passes it to the cortex
hypothalamus
responsible for hormones and metabolic control
telencephalon
made up of basal ganglia and cerebral cortex
basal ganglia
series of interconnected nuclei
responsible for: movement regulation, skill learning, habit formation, reward systems, selection of appropriate behaviours
cerebral cortex
key roles in movement, attention, perception, awareness, thought, memory, language, consciousness
contains 6 highly folded layers
