Human Nervous System Flashcards
What are the two important parts of the nervous system?
Peripheral Nervous System (PNS) and Central Nervous System (CNS)
The PNS controls voluntary and involuntary actions, while the CNS processes sensory information.
What is the primary function of the Central Nervous System (CNS)?
Information synthesizing
The CNS regulates organ function, high-level thought, and purposeful body movement.
What does the Peripheral Nervous System (PNS) control?
Volitional (somatic) and non-volitional (autonomic) behaviours
It uses cranial and spinal nerves to carry signals necessary for survival.
What are the two divisions of the autonomic nervous system?
Sympathetic and parasympathetic divisions
The sympathetic division prepares the body for stress, while the parasympathetic division restores routine functions.
What is the role of the sympathetic nervous system?
Prepares the body for stress-related activities
It triggers the fight-or-flight response in fear-inducing situations.
What is the role of the parasympathetic nervous system?
Restores and calms down physiological responses
It maintains homeostasis and routine operations.
What are the main components of the Central Nervous System?
Brain, brainstem, and spinal cord
Each component performs various tasks crucial for body function.
What is the largest part of the Central Nervous System?
The brain
It is responsible for sensation, perception, thinking, awareness, emotions, and planning.
What is the function of the limbic system?
Regulates emotions
It includes structures such as the hippocampus and amygdala.
What are the four major parts of a neuron?
Dendrites, cell body (soma), axon, terminal boutons
Each part plays a crucial role in information transmission.
What is an action potential?
An all-or-nothing event that occurs when a neuron fires an impulse signal
It involves a change in the charge of the cell’s membrane.
What must a neuron reach to initiate an action potential?
Threshold of excitation
This is the change in membrane potential that excites the neuron.
What are EPSP and IPSP?
Excitatory postsynaptic potential and inhibitory postsynaptic potential
EPSP causes depolarization, while IPSP causes hyperpolarization of the neuron’s membrane.
What is the function of the cerebellum?
Coordinates actions without conscious awareness
It plays a key role in motor movement coordination and balance.
What does the brainstem oversee?
Basic life support functions such as breathing, digestion, and heartbeat
It operates without conscious effort.
What type of neurons carry information from the CNS to the muscles?
Efferent neurons
Efferent means ‘moving away from’.
What type of neurons carry sensory information to the CNS?
Afferent neurons
Afferent means ‘moving toward’.
Fill in the blank: The ________ is a layer of fatty tissue surrounding the axon of a neuron.
myelin sheath
It helps to insulate the neuron and allows for faster transmission of electrical signals.
What is the corpus callosum?
A thick bundle of axons connecting the two cerebral hemispheres
It facilitates communication between the left and right sides of the brain.
True or False: The left side of the brain controls sensory and motor functions of the left side of the body.
False
The brain is contralateral; the left side controls the right side of the body and vice versa.
What is the function of the medulla oblongata?
Processes breathing, digestion, heart and blood vessel function
It is part of the brainstem.
What is the refractory period in neurons?
A time during which a neuron is incapable of firing because the excitable membrane must return to a resting state.
What are the two subsets of the refractory period?
- Absolute refractory period (ARP)
- Relative refractory period (RRP)
What happens during the absolute refractory period (ARP)?
The neuron cannot send a new impulse because sodium channels are inactive.
What is the relative refractory period (RRP)?
A period following the ARP when a neuron can respond to a stimulus but requires a stronger than normal stimulus.
What is the synaptic cleft?
A small space between adjacent neurons that allows nerve impulses to pass from one neuron to another.
What are neurotransmitters?
Chemicals that relay signals across synapses between neurons.
What role do neurotransmitters play at the synapse?
They are released when the action potential reaches the end of the axon and travel across the synaptic space to bind to receptors on neighboring neurons.
What happens if neurotransmitters are not accepted by receptor sites?
They must be removed from the synapse to allow for the next potential stimulation of the neuron.
What is the action potential?
A transient all-or-nothing transmission of impulse conducted down the axon when the membrane potential reaches the threshold of excitation.
What does the axon do?
Sends information to another neuron or to muscles and glands.
How do electrical signals travel down the axon?
Through changes in the electrical charge of the axon, jumping from node to node.
What is the resting membrane potential?
A state where the interior of the neuron contains a greater number of negatively charged ions than the area outside the cell.
What is the function of acetylcholine (ACh)?
Stimulates muscle contractions and regulates memory, sleeping, and dreaming.
What psychological condition is associated with a deficiency of acetylcholine?
Alzheimer’s disease.
What is dopamine involved in?
Movement, motivation, and emotion; it produces feelings of pleasure.
What is associated with low levels of serotonin?
Seasonal depression.
What is the main function of GABA (gamma-aminobutyric acid)?
It is the major inhibitory neurotransmitter in the brain.
What does an agonist drug do?
Mimics the effects of a neurotransmitter.
What is an antagonist drug?
A drug that reduces or inhibits the normal effects of a neurotransmitter.
Fill in the blank: The _______ is the part of the peripheral nervous system that controls involuntary functions.
autonomic nervous system
What is the main role of the somatic nervous system?
Controls conscious and voluntary activities.
What is the corpus callosum?
The nerve fibre that connects the left and right hemispheres of the brain.
What is the difference between EPSP and IPSP?
- EPSP: depolarizing current that makes the membrane potential more positive
- IPSP: hyperpolarizing current that makes the membrane potential more negative
What is the significance of the Node of Ranvier?
It allows the electrical charge to jump from segment to segment along the axon.
What happens during neurotransmitter reuptake?
Neurotransmitters in the synapse are reabsorbed into the transmitting terminal buttons.
What are endorphins known for?
Natural pain relievers related to compounds found in opium, morphine, and heroin.
What effect does excess glutamate have?
Can cause overstimulation, migraines, and seizures.
What does a neuron respond to?
A very intense stimulation.
What is the resting membrane potential?
A state in which the interior of the neuron contains a greater number of negatively charged ions than the area outside the cell.
What is the function of the retina?
It is a cell layer in the back of the eye containing photoreceptors.
What is the soma in a neuron?
The cell body of a neuron that contains the nucleus and genetic information and directs protein synthesis.
What does the somatic nervous system control?
Conscious and voluntary activities and serves as a relay of sensory and motor information to and from the central nervous system.
What is the spinal cord?
A section of the central nervous system that connects the brain and the brainstem to all major nerves in the body.
What is the role of the sympathetic nervous system?
It prepares the body for stress-related activities.
What is a synapse?
A process whereby neurons use electrical and chemical messages to communicate with each other at the synaptic cleft.
What is the synaptic (gap) cleft?
The small space between the presynaptic terminal button of one neuron and the postsynaptic dendrite of another adjacent neuron.
What part of the brain is involved in auditory and olfactory processing?
Temporal lobe.
