Week 2 - Mechanics of the Nervous System Flashcards
(26 cards)
What are the two main parts of the nervous system?
Central Nervous System (CNS) and Peripheral Nervous System (PNS).
What does the CNS consist of?
Brain and spinal cord.
What are the functions of the spinal cord?
Reflex coordination, sensory/motor conduit, brain-body communication.
What does the PNS connect?
CNS to limbs and organs via cranial and spinal nerves.
What are the two main divisions of the PNS?
Somatic Nervous System and Autonomic Nervous System.
What are the three subdivisions of the Autonomic Nervous System?
Sympathetic, Parasympathetic, and Enteric Nervous Systems.
What is the role of the Enteric Nervous System?
Controls digestion, swallowing, enzyme release, blood flow for nutrient absorption.
What is the Gut-Brain Axis?
Interaction between gut microbiota, immune system, and CNS via vagus nerve and circulation.
What are the three main types of neurons?
Sensory neurons, motor neurons, and interneurons.
What is the function of interneurons?
Integrate sensory input and relay signals to motor neurons.
What forces move ions across membranes?
Diffusion (concentration gradient) and electrostatic pressure (charge).
What is the resting membrane potential?
−70 mV; inside of the neuron is negatively charged.
What is the role of the sodium-potassium pump?
Pumps 3 Na+ out and 2 K+ in to maintain ion gradients.
What triggers an action potential?
Depolarisation reaching threshold (~−55 mV).
What are the phases of an action potential?
Depolarisation, repolarisation, hyperpolarisation.
What does the ‘all-or-nothing’ law refer to?
An AP only occurs if the threshold is reached; size is constant.
How is signal strength coded?
By frequency of APs (rate law), not amplitude.
What ensures unidirectional AP movement?
The refractory period.
What is synaptic transmission?
Neurotransmitters released to excite, inhibit, or modulate postsynaptic neurons.
What is acetylcholine responsible for?
Excitatory; muscle contraction, memory, heart rate, sleep.
What does serotonin regulate?
Mood, sleep, libido, anxiety, pain; imbalance linked to disorders like SAD, anxiety.
What is dopamine involved in?
Reward, motivation, focus, mood; linked to Parkinson’s, ADHD, schizophrenia.
What is the role of epinephrine and norepinephrine?
Fight-or-flight response: increases HR, BP, attention.
What are endorphins responsible for?
Pain relief, mood elevation; low levels linked to headaches, fibromyalgia.
