Module 2, Lecture 3: Organismal Neurophysiology Flashcards
Do all animals have neurons?
- No
- Sponges, porifera, and others don’t have neurons
What are neurons?
Nerve cells that transmit electrical and chemical signals in the nervous system
Pufferfish - Tetrodotoxin
-Toxin that blocks Na channels, preventing transmission of action potentials
Poisonous Hemlock - Piperidine alkaloids
- Blocks acetylcholine receptors
- Paralyzes motor nerve endings, leading to respiratory failure
Clostridium botulinum - Botulinum toxin
- Blocks release of acetylcholine at neuromuscular junctions
- Paralyzes muscles, leading to respiratory failure
- Most poisonous known substance
5 normal functions of a neuron
- Neurotransmitters are synthesized and stored into the vesicles
- Nerve impulse
- Depolarization causes voltage-gated Ca2+ channel opening and Ca2+ enters into the axon terminal
- Neurotransmitters released into the synaptic space via exocytosis
- Neurotransmitter binds to the receptor molecules and opens ligand-gated ion channel
Normal function - Voltage-gated Na+ channels, Closed
At the resting potential the channel is closed
Normal function - Voltage-gated Na+ channels, Open
In response to a nerve impulse, the gate opens and Na+ enters the cell
Normal function - Voltage-gated Na+ channels, Inactivated
For a brief period following activation, the channel doesn’t open in response to a new signal
Piperidine Alkaloids
Block post-synaptic neurotransmitter receptors, preventing communication among neurons
Botulinum Toxin
Prevents presynaptic neurotransmitter release, blocking communication between neurons and muscles
Cognitive abilities
brain function associated with focus, processing of info, use of logic and reason, memory, planning, communication, and comprehension
Proximate hypothesis
explains how a trait or behavior occurs, focusing on mechanisms like genetics, physiology, and environmental influences
Ultimate hypothesis
explains why a trait or behavior exists, focusing on evolutionary advantages and survival benefits
