week 4 Flashcards
what are the 2 parts of the nervous system
- Centeral nervous system (CNS), contains brain and spinal cord
Peripheral nervous system (PNS)
what is in the automatic nervous system
- Parasympathetic: unconcious/ involuntary
Sympathetic: concious/ voluntary
what are the cells of the nervous system
neuron / glial
draw or describe a neuron
Neuron: cell body (soma) which contains nucleus// around ccell body coming off is the dendrites which receive info and pass info along to the //axon (long log looking thing) // at the start of the axon is called axon hillock// at end of axon is the axon terminal which transmites neurotransmitters to other cells// the axon terminal contains visciles which conatins the neruorntransmitter around axon is myelin
what is multi polar neuron
a nureon that has lots of axon terminals and it present in:
motornurons
Interneurons
what is a bipolar nueron (sensory)
is very rare which is only found in the eye and in the ear
what is the last neutron
Pseudo-unipolar sensory neuron
what is Neuroglia
specialized cells found only in close association with neurons, don’t participate directly in information transfer.
Oligodendrocyte (CNS)
makes myolin for serveral axon at the same time
Schwann (PNS)
does one myolin one at a time but does faster thus most effiecent then the oligodendrocyte and more resistent to injury
Astrocytes (CNS)
provide nutrients and support for neuron in homostatis regulates synaptic connections and readts to injury (star shape)
Microstrecite (PNS)
provide nutrients and support for neuron
Microglia (CNS)
get pathogen and take into cell to eat it away via phagocytosis (immune cell to protect the brain)
Epenymal
provinding lining in the ventricles and are involved in production of Cerebro-spinal Fluid (CSF)
what helps in resisting membrane potential
1)Anions in cell
2) number of leak channels of potassium and sodium
3) Active pump to move K+ and Na+ (2 K+ into cell & 3Na+ out thus lose one + charge each time)
what is action potential
Normal potential=-70mV
Ligand gated channel needs a ligand to attach to receptor to open the door
- Ligand gated channel for Na+ opens at -55mV and closes at 30mV Ligand gated channel for K+ open 30mV closes -80mV so this decreases the postive charge inside the axon
what is depolarisation
The voltage gated sodium (Na+) channels in the neuronal membrane open and sodium flows into the cell, bringing positive electrical charge and so increasing membrane potential. This phase is called DEPOLARISATION.
what is repolarisation
When the membrane reaches a certain potential (around +30 to 40 mV), the voltage gated potassium (K+) channels open which leads to the exit of K+ ions out of the cell (so the membrane potential will decrease). This phase is called REPOLARISATION.
what is hyperpolarisation
Since the voltage gated potassium channels take time to close, K+ ions continue to leave the neuron, which causes the membrane potential to drop below the RMP (-70 mV) until it reaches around -90 mV.
what are the 2 types of synapses
Electrical: gap junction
chemical
what is an Electrical: gap junction synapse
Very fast connection present mainly in brain and heart
what is a chemical synapse
most common ones in mammals. Examples of chemical synapse locations include;
* Connection between Neuron- Neurons
* Neuromuscular junction: synapse between neuron and muscle
* Neuroglandular junction: synapse between neuron and gland
what are the 3 chemical synapses essential components
- Pre-synaptic neuron with neurotransmitter housed in the pre-synaptic neuron in vesicles
- Post-synaptic neuron with neurotransmitter binding sites
- Cleft or gap with enzymes to degrade left over of neurotransmitters (such as Acetylcholinesterase degrading Acetylcholine)
how do neurotransmitters insynapse get out
1) Enzymes
2) Reuptake
3) Diffusion away