Week 5 Neurons And Nervous System Flashcards
What was the first animal to arose from protist ancestor?
Choanoflagellates
What are the main benefits of multicellularity
→ lower surface areas to volume ratio affects flux in an out
→efficiency through divisor of labour via cell specialization
What does division of labour mean?
Cell specialization: cell divides up The responsibilities for survival amongst each other
Describe cell specialization in tissues and organs
Regions/faces can become dedicated to specific functions
What are the three models of cellular specialization
- Aggregation of “like” cells
- Division of responsibilities
- Dedicated functions
In intercellular connections what is the impact of a cell wall?
→resist cell volume changes
→can grow but not easily move
How does 1 genome have different cells?
Embryonic stem cells are omnipotent, become any type of cell
→individual cell can differentiate turning on/off suites of genes to express specific phenotype
What is a metamer?
Repeating subunits that appear in embryonic development
What is a tagma?
A collection of segments in embryonic development that permit formation of complex structures
What is cephalization?
Collection of tagmata that enables sensory and nervous processes to be concentrated toward the anterior
What are the animal evolution trends
-increase in size
- increase in complexity
- increase in specialization and regionalization
How do non-animal organisms more?
-cytoskeleton reorganization
- flagella and cilia
-osmotic pressure
What do neurons and myocytes have in common?
They are both post-mitotic cells which means they no longer divide
→not prone to cancer but also cannot repair themselves
Why do neurons have a complex cytoskeletal network?
- Structurally polarize
- have microtublules
- require constant movement
What does na-k-ATPase do?
Permits recovery of a resting membrane potential enabling the excitable cells to repeat action potentials
Can NKA be found in plants
No! Only in animals, plants vs h-atpase
How does activation of myocytes in skeletal muscle happen?
A neuron triggers an action potential that causes an increase in cast
How does activation of a cardiac muscle happen?
Myocyte communicates AP directly to another magocyte to cause increase in calcium
How does activation of smooth muscle happen?
Changes activation state with input from neurons, hormones and may or may not change calcium levels
Is contraction, shortening
No, the cell doesn’t necessarily contract as in get shorter
What do protein specific toxins do?
→ligand binds a protein, altering its behaviour
→ affects the functions of specific cells, typically neurons
→ affects physiological systems
How do organisms that make toxin avoid poisoning themselves?
→ Insensitive targets ( host differs in shape or lacks target centirly)
→avoidance (host maybe vulnerable to the toxin but its held in a diff compartments )
What are the proteins that regulate the process of neuronal function called?
Gene products - evolve to suit organisms structure/function
If a toxin activates/inactivales a neuromuscular protein, what happens?
Toxins can open channels, block it, change kinetics and effects may be reversible or not
What does tetrodotoxin do?
Binds to sodium voltage gated channels, locking them closed
What are muscarinic receptor toxins?
G-protein coupled receptors mat bind to acetylcholine
What is atropine?
An antagonist of Ac H at muscarine receptors
What is snake venom?
→ cocktails of many toxins, some act on specific proteins and some alter enzyme activity
→ metalloprotinases have enzymes that breakdown extracellular matrix (hemorrhages)
→ phospholipase are enzymes that attack phospholipids (inflamation)
Define sensory neuron
Transmit info about external stimuli
Define inter neuron
Neurons in the brain that receive/ process info
Define motor neurons
Transmit signals to muscle cells
What is the concentration of sodium and potassium in a cell
Cells have a high concentration of potassium inside and a low concentration of sodium outside
→ this causes a membrane potential ( - 70/-90)
What is the typical concentration of potassium
- 90 mv
What is the typical concentration of sodium?
+62mv
What does the myelin sheath do?
Produced by oligodendrocytes and Schwann cells and allows for faster conduction and insulation around an axon
Define saltatory conduction
Rapid transmission of nerve impulse along a axon
What is post-synaptic potentials?
Receiving signals (NT) from pre-synaptic neurons
Define excitatory post-synaptic potential
Change in membrane potential that brings the post synaptic closer to threshold
Define inhibitory post-synaptic potential
Change in membrane potential that hyperpolarizes
Define temporal summation
Time →2 ap occurring at single synapse in rapid succession
Define spacial summation
Amount → diff synapses at same neuron
How do neurons terminate?
Neurotransmitters bind to a metabotropic receptor that regulates ion channels
What does acetylcholine do?
Essential to muscle contraction, allows motor neurons to synapse with muscles
What does glutamate do?
Binds to many ligand channels → memory
What are neuropetides?
Short chains of amino that operate via metabotropic receptors
→ endorphins: natural analgesics/decreases pain perception
What does nitric oxide do?
Synthesizes on demand
→defused into target cell
What does carbon monoxide do?
Regulates release of hypothalamic hormones
Where is short term memory stored?
Hippocampus
Where does short term memory get stored?
Cerebral cortex
What is enteric division?
The myenteric plexus and controls Gi movements, the submucosal plexus controls Gi secretions/ blood flow
What happens in parasympathetic efferent pathway?
Slows heart, rest/digest
What does the sympathetic pathway do?
Increases heart rate and contractile function.
→ fight or flight
Define plasticity
Ability to change both synaptic connections and functional properties of neurons in response to stimui
What is the purpose of the CNS and PNS
Integrate information and trigger events that ensure homeostasis as well as enable animals to respond to situations
Define gila
Cells of the nervous system that support/regulate/ augment functions of nerves
