NERVOUS SYSTEM TEST Flashcards
What are the main parts of a neuron?
Cell body (soma), dendrites, axon, axon terminals
What is the function of the myelin sheath?
Insulates axon, protects from damage, increases conduction speed
What is the difference between white matter and gray matter?
White matter = myelinated axons, gray matter = unmyelinated axons + soma
What is resting membrane potential and how is it maintained?
-70mV. Maintained by Na+/K+ pump (3 Na+ out, 2 K+ in)
Describe the steps of an action potential.
- Resting potential (-70mV)
- Depolarization (-55mV to +30mV, Na+ in)
- Repolarization (K+ out)
- Hyperpolarization (-80mV, K+ channels slow to close)
- Refractory period (no new impulse)
- Na+/K+ pump restores resting potential
What is saltatory conduction and where does it occur?
Impulse jumps between nodes of Ranvier, occurs in myelinated axons
What are the steps of synaptic transmission?
- Nerve impulse reaches axon terminal
- Ca²⁺ enters, neurotransmitters released
- Neurotransmitter diffuses across synaptic cleft
- Binds to receptor, triggers action potential
- Neurotransmitter is removed or recycled
What are the main types of receptors and their functions?
- Thermoreceptors: Detect temperature changes
- Osmoreceptors: Detect blood water concentration
- Chemoreceptors: Detect CO₂ and pH changes
- Nociceptors: Detect pain, non-adaptive
What is the difference between afferent and efferent neurons?
Afferent (sensory) = into CNS, Efferent (motor) = out of CNS
Compare the autonomic and somatic nervous systems.
- Autonomic = Involuntary (organs, glands), uses 2-neuron chain
- Somatic = Voluntary (skeletal muscles), 1 neuron
Compare the sympathetic and parasympathetic nervous systems.
- Sympathetic = Fight or flight, short pre-ganglionic, uses noradrenaline
- Parasympathetic = Rest and digest, long pre-ganglionic, uses acetylcholine
What are the major parts of the brain and their functions?
- Cerebrum: Higher thinking, memory, voluntary movement
- Cerebellum: Coordination and balance
- Hypothalamus: Homeostasis (temp, hunger, hormones)
- Medulla oblongata: Breathing, heart rate, reflexes
How is the brain protected?
Skull, meninges (Dura, Arachnoid, Pia), cerebrospinal fluid, blood-brain barrier
What is a reflex arc and its pathway?
Fast, involuntary response bypassing cerebrum
1. Receptor → 2. Sensory neuron → 3. Interneuron → 4. Motor neuron → 5. Effector
