Nervous System Flashcards
What are the major divisions of the nervous system?
CNS PNS - SNS + ANS = ANS - SNS + PNS
What do afferent and efferent nerves do?
ANS = efferent motor signals from CNS to internal organs / afferent sensory signals from internal organs to CNS. SNS = efferent motor signals from CNS to skeletal muscles, afferent- sensory signals from skin etc to CNS
What are two types of efferent nerves and how do they compare?
Sympathetic and parasympathetic. Sympathetic mobilise energy, react to threats, synapse onto 2nd stage neurons at a distance. PS is opposite.
What are the meninges and what do they do?
Three protective membranes for the brain. Dura, arachnoid (plus sub) and pia mater. Cushion brain from physical damage.
Where is CSP found, where is it made and what does it do?
What is the choriod plexus?
Found in central canal that goes down spinal cord, made in choriod plexus, protects CNS by cushioning the brain. Fills spinal cord, 4 ventricles of brain and subarachnoid space. Excess flows from sub arach to dural sinuses.
Choriod plexus is network of capillaries protruding from the pia mater into the ventricles of the brain.
What is the blood brain barrier and what is its function?
Semipermeable layer, highly selective. It forms a barrier between the brain and the blood. Cell walls wedged tight, prevent large molecules from crossing. Protects from unwanted pathogens, molecules and toxins in blood.
What is the soma?
Cell body, contains major internal features of neuron, where metabolic processes take place.
What do axons and axon hillocks do?
Carry nerves impulses and connect cell body to axon.
What is a cell membrane ?
Lipid bilayer, imbedded with proteins to help neuron perform. Channel proteins provide passage, signal proteins send signal to inside of neuron.
What do dendrites do?
Receive signals from other neurons.
What are nodes of ranvier?
What is myelin?
Gas between neurons myelin.
A fat protective layer covering around axons.
What are axon buttons?
End of axons, release chemical signals into synapses to transmit impulses between neurons.
What are neurotransmitters?
Chemical messengers that relay messages between neurons. Stored in synaptic vesicles before release at synapse.
Name internal cell features and their role.
Ribosomes = synthesis protein, located on endoplasmic reticulum.
Endoplasmic reticulum - highly folded structure, smooth section synthesises fat, rough section (ribosomes) see above.
Cytoplasm = thick fluid inside cell.
Microtubules - transport cell material
Golgi complex- packs molecules
Mitochondria - generate energy through aerobic processes.
What are differences between neurons?
Multipolar interneuron, only in single brain area and integrate rather than transmit.
Bipolar, unipolar and multipolar all transmit. Multipolar is most numerous neuron.
