Intro to Nervous System
What are the two main parts of the nervous system?
Central Nervous System (CNS) and Peripheral Nervous System (PNS)
Which part of the brain controls balance and coordination?
Cerebellum
What are neurotransmitters, and what is their general role in the nervous system?
They are chemical messengers that transmit signals between neurons (or from neurons to muscles/glands), allowing communication and regulation of body functions.
What are the main parts of a typical neuron, and what is the function of each?
Dendrites receive signals, the cell body (soma) contains the nucleus and organelles, and the axon carries impulses to other neurons or effectors.
What are glial cells, and how do they differ from neurons?
Glial cells are non-neuronal support cells that maintain and protect neurons. Unlike neurons, they do not send electrical impulses but provide structural, nutritive, insulating, and immune-related support.
Which part of the nervous system controls voluntary movement?
Somatic Nervous System
What is the main function of the frontal lobe?
Decision-making, planning, voluntary movement, personality
Describe the difference between excitatory and inhibitory neurotransmitters. Give one example of each.
Excitatory neurotransmitters (e.g., glutamate) increase the likelihood of firing an action potential; inhibitory neurotransmitters (e.g., GABA) reduce the chance of firing.
What is resting potential in a neuron, and what is its typical voltage?
Resting potential is when the neuron is not firing; the inside is negatively charged relative to the outside, about -70 mV.
Name the main types of glial cells in the central nervous system (CNS).
Astrocytes, oligodendrocytes, microglia, and ependymal cells.
What is the main function of the peripheral nervous system?
To connect the CNS to limbs and organs
Which lobe of the brain is responsible for processing visual information?
The occipital lobe.
What is the main function of GABA, and what may happen if the body does not produce enough of it?
GABA calms neuronal activity and prevents overstimulation. A lack of GABA can cause anxiety, seizures, or sleep problems.
Describe what happens during depolarisation and repolarisation of a neuron membrane.
Depolarisation: sodium ions enter, making inside positive. Repolarisation: potassium ions exit, returning inside to negative.
What is the role of Schwann cells in the peripheral nervous system (PNS), and how do they differ from oligodendrocytes?
Schwann cells form myelin around PNS axons and aid in axon regeneration. Unlike oligodendrocytes (CNS), each Schwann cell myelinates only a single axon segment.
Differentiate between the somatic and autonomic nervous system.
Somatic controls voluntary actions, autonomic controls involuntary actions.
Which structure controls vital involuntary processes such as breathing, heart rate, and blood pressure?
The brain stem.
Summarise how norepinephrine and epinephrine affect the body during stress.
They trigger the "fight-or-flight" response: increase heart rate, blood pressure, energy, alertness, and focus.
What happens during hyperpolarisation, and why does it occur?
Hyperpolarisation is when the inside of the neuron becomes even more negative than at resting potential, usually because potassium channels stay open too long. It temporarily prevents the neuron from firing.
How do glial cells help during injury or infection in the nervous system?
Astrocytes form protective barriers, microglia engulf debris and pathogens, and Schwann cells guide axon regeneration in the PNS.
Explain the role of the sympathetic and parasympathetic systems in homeostasis.
Sympathetic prepares body for 'fight or flight'; parasympathetic for 'rest and digest'.
Which lobe is mainly responsible for hearing, memory, and language comprehension?
The temporal lobe.
Explain how the loss of dopamine-producing neurons affects movement in the body.
In Parkinson’s disease, dopamine loss disrupts motor circuits, causing tremors, stiffness, and slowed movement when ~60–80% of neurons in the substantia nigra are lost.
What is the refractory period, and why is it important for neuron function?
The refractory period is the short time after an action potential when a neuron cannot fire again (absolute and relative phases). It ensures impulses travel in one direction and separates each action potential as a distinct event.
Why is myelin important for efficient nervous system function, and what happens if it is damaged?
Myelin insulates axons and enables rapid signal transmission via saltatory conduction. Damage (e.g., in multiple sclerosis) slows or blocks impulses, causing motor, sensory, and coordination problems.