Lect 2 nervous System Flashcards
Nervous system is separated in what categories
Central nervous system and peripheral nervous system
Peripheral nervous system is separated in what
Sensory division ( send information to the CNS)
Efferent division ( receive info from CNS and send to target cells via efferent neurons)
Explain the step when you have a signal ( what happens)
Signal - sensory receptors - sensory neurons - central nervous system - efferent neurons ( 2 types )
Automatic and somatic neurons. Automatic neurons is the involuntary part you have the sympathetic and the or the parasympathetic. And the somatic neurons you will have a skeletal muscle mouvement
Sensory receptors
Vision , hearing , balance, smell , skin and visceral organ
What are the types of sensory receptors that you find on the skin and in the visceral organ
Skin ( mechanoreceptors ( touch) , thermorécepteurs ( temperature ) and nocireceptors pain)
Visceral organs ( nocicepors - activate inflammation and tissue damage)
What are the 2 functions of the spinal cord
1) transmit signal t the brain or from the brain
2) reflex : react quick don’t need the Brain
What is the enteric nervous system
Neurons on the digestive tract
Controlled by the autonomic nervous system but it is able to function autonomously
What is the neuron structure
Cell body
Dendrites
Axons
Collaterals ( axons divide several time into branches)
Axon terminals
Varicosities ( enlarged regions along the axon)
What is the neuron structures
Multipolar , pseudounipolar, bipolar , anaxonic neurons
Explains the neurons structure
Multipolar , pseudounipolar , bipolar, anaxonic neurons
Multipolar - many dendrites and branched axons
Pseudounipolar- neurons have the cell body locate off one side of a long axon
Bipolar - single axon and a single dentrite
Anaxonic neurons - have numerous dendrites and lacks of an axon
What are the functions of neuron
Sensory , efferent and interneuron ( complex branching processes that allow them to communicate with other neurons )
What is the difference between a tract and a nerve
Tract : collection of nerve fibres CNS
Nerve : collection of nerve fibres PNS
What is the difference between fast axons transport and slow axonal transport
Fast axonal transport goes to 400mm/day it can do anterograde and retrograde transport
Slow oxo slow transport flows at 0.2-2.5 mm/day
What is a synapse
Region where an axon terminal meet its target
What is the difference between chemical and electrical synapses which one is faster
Chemical synapse : release a chemical
Electrical synapse: electrical current it is faster than chemical
What is growth cone
Ancon extension that will find their target
What is neurotrophic factors
Proteins that make the froth of neuron and make the neuron alive
What is the function of a glial cell
Communicate with neuron and provide important biochemical and structural support
Give examples of glial cells
Schwann cells , oligodendrocyte , satellite cells , atrocités , microglia, ependymal cells
Explain the Schwann cells and oligodendrocytes, and where are they found
They support and insulate axons ( makes myelin)
Schwann cells are found in PNS and oligodendrocytes are found in the CNS
Explain the satellite cells and where are they found
Supportive capsules around nerve cell bodies found in the PNS
Explain the role of astrocytes and where are they found
Found in CNS
Roles
1) take up and release chemical - neurotransmitter
2) help form blood brain barrier
3) provide substrates for ATO production
4) source of neural stem cells
Explain microglia and where are they found
Found in CNS and they make specialized immune cells
Explains ependymal cells
Source of neural stem cells , separated the fluid compartment of CNS
Can stem cells repair damage?
Regeneration is more likely in PNS than CNS because Schwann cells secrete neurotrophic factors that help the cells bodies alive and stimule rétro of the axon
What happens is a motor neuron is damage ? And a sensory neuron
Paralysis and loss of sensation
What is the difference between open channels and gated channels
Opens channels are always open and gated channels we can open and close
Give examples of open channels
Leak channels and pores
Give examples of gated channels
Chemically gated channels , voltage gated channels and mechanically gated channels ( response to physical force )
What are the 2 basic types of electrical signals
Graded potential and action potential
Explain grated potential
- variable strength that travels over short distance
- it can initiate Action potential of Depolarizing graded potential is strong enough
Describe action potential
Very brief large depolarization that travel for long distance through a neuron without losing strength
Which gates are open or close at this stages
1. Depolarization
2. Top
3. Repolarization
4. Hyperpolarization
- Depolarization - Na+ is open , goes in the cell
- Top - Na+ is closed
- Re polarisation - K+ opens goes out the cell
- Hyperpolarization k+ channel close
What are the 3 types of Gated channels control that controls ion permeability
1) mechanically gated ions channels
Open in response to physical force
2) chemically gated: ligand neurotransmitters
3) voltage gated : respond to changes in the cells membrane potential. Initiation and conduction of electrical signal
True or false
Threshold voltage varies from one channel to the other
True
Why do grated grated potential lose strength as they move through the cytoplasm
1) current leak : positive chantages leak out to the extracellular fluid and decrease depolarization
2) cytoplasmic resistance : resistance to the flow and so signal inside the cell decrease over distance
Tell if it is excitatory or inhibitory
- Depolarizing graded potential
- Hyperpolorizinf graded potential
1) excitatory
2) inhibitory ( makes the membrane further from the threshold)
A neuron may terminate where
Muscle, glande or a neuron
Give 3 types of cell junctions
Communicating junction, occluding junction and anchoring junction
Explain communicating junction
Cel to cell communication
Explain occluding junction
Block movement of material between cells and prevent substances going to the brain
Explain anchoring junction
Hold cells to one another and to the extracellular matrix and info can go from cell membrane to the cytoplasm
