Nervous System Functions and Structure

The three types of neurons are sensory neurons, motor neurons, and interneurons. Sensory neurons transmit impulses from sensory receptors to the central nervous system. Motor neurons transmit impulses from the central nervous system to muscles and glands. Interneurons connect neurons within the central nervous system.

A nerve impulse is conducted along a nerve as an electrochemical signal. The signal travels as a wave of depolarization down the axon, caused by the movement of ions across the membrane. At the synapse, the impulse is transmitted from one neuron to another through the release of neurotransmitters, which bind to receptors on the postsynaptic neuron.

The three layers of meninges are dura mater, arachnoid mater, and pia mater. The dura mater is the outermost layer, providing protection and support. The arachnoid mater is the middle layer, containing cerebrospinal fluid. The pia mater is the innermost layer, adhering to the brain and spinal cord.

<p>The major parts of the brain include the cerebrum, cerebellum, brainstem, and diencephalon. The cerebral cortex is divided into four lobes: frontal, parietal, temporal, and occipital. The frontal lobe is responsible for higher cognitive functions, the parietal lobe processes sensory information, the temporal lobe processes auditory information, and the occipital lobe processes visual information.</p> Signup and view all the answers

<p>The nervous system receives sensory information from throughout the body, interprets it, and initiates responses that maintain homeostasis. For example, the nervous system controls the heart rate, blood pressure, and body temperature, all of which are crucial for maintaining a stable internal environment.</p> Signup and view all the answers

<p>Sodium-potassium pumps actively transport three sodium ions (Na+) out of the neuron for every two potassium ions (K+) pumped in. This creates an imbalance of ions across the plasma membrane, with more Na+ outside and more K+ inside the cell. This imbalance, along with the membrane's selective permeability to K+, results in a more negative charge inside the neuron, establishing the resting membrane potential.</p> Signup and view all the answers

<p>The three main types of neurons are motor neurons, sensory neurons, and interneurons. Motor neurons transmit signals from the central nervous system (CNS) to muscles, organs, and glands, causing contractions or secretions. Sensory neurons receive signals from sensory receptors and transmit them to the CNS. Interneurons connect neurons within the CNS, facilitating communication and processing of information.</p> Signup and view all the answers

<p>Motor neurons are typically multipolar, meaning they have a single axon and multiple dendrites. Sensory neurons, on the other hand, are usually unipolar, with a single process that acts as both axon and dendrite.</p> Signup and view all the answers

<p>The prefrontal area is involved in higher-level cognitive processes such as reasoning, planning, and decision-making. It integrates information from other association areas to perform these complex functions.</p> Signup and view all the answers

<p>The membrane of a neuron at rest is considered polarized because there is an uneven distribution of ions across its membrane. There is a higher concentration of positively charged ions (Na+) outside the neuron and a higher concentration of negatively charged ions (K+) inside the neuron. This creates a potential difference across the membrane, with the inside being more negative relative to the outside.</p> Signup and view all the answers

<p>An action potential is a rapid, short-lasting change in the membrane potential of a neuron. It is triggered by a sufficiently strong stimulus that depolarizes the membrane beyond a threshold. Voltage-gated sodium channels open first, allowing Na+ to rush into the neuron and further depolarize the membrane. This depolarization then triggers the opening of voltage-gated potassium channels, allowing K+ to flow out of the neuron, restoring the membrane potential to its resting state.</p> Signup and view all the answers

<p>Broca's area is crucial for speech production, specifically for controlling the muscles involved in articulation. Damage to Broca's area can result in difficulty speaking and forming words.</p> Signup and view all the answers

<p>Wernicke's area plays a key role in interpreting written and spoken language. It receives sensory input from other association areas and translates it into meaningful information.</p> Signup and view all the answers

<p>The generation of an action potential begins with a stimulus that depolarizes the membrane. If this depolarization reaches the threshold potential, voltage-gated sodium channels open, allowing Na+ to flow into the cell. This influx of Na+ further depolarizes the membrane, causing even more sodium channels to open, creating a positive feedback loop. As the membrane potential reaches its peak, sodium channels begin to close, and voltage-gated potassium channels open. This allows K+ to flow out of the cell, repolarizing the membrane. The membrane potential briefly undershoots the resting potential before returning to its resting state.</p> Signup and view all the answers

<p>The central white matter acts as a communication network within the brain. It contains tracts that carry signals between different sensory, motor, and association areas, as well as tracts connecting to other brain regions and the spinal cord.</p> Signup and view all the answers

<p>The resting membrane potential is the stable, negative electrical potential maintained by a neuron when it is not actively sending a signal. It is primarily maintained by the Na+/K+ pump and the membrane's permeability to K+. An action potential, on the other hand, is a rapid, short-lasting depolarization of the membrane that travels down the axon. It is triggered by a stimulus and involves the sequential opening of voltage-gated sodium and potassium channels.</p> Signup and view all the answers

<p>Interneurons connect neurons within the CNS, facilitating communication between different parts of the brain and spinal cord. They are involved in complex processes such as thinking, memory, learning, and language processing.</p> Signup and view all the answers

<p>Descending tracts carry motor signals from the primary motor area to the spinal cord, controlling voluntary movements. Ascending tracts relay sensory information from the peripheral nervous system to the primary somatosensory area, providing information about touch, temperature, and pain.</p> Signup and view all the answers

<p>The corpus callosum is a thick band of nerve fibers that connects the two cerebral hemispheres. It facilitates communication and coordination between the left and right hemispheres, allowing them to work together efficiently.</p> Signup and view all the answers

<p>The basal nuclei are clusters of gray matter deep within the cerebrum. They are involved in the selection and integration of voluntary movements, helping to refine and coordinate motor activity.</p> Signup and view all the answers

<p>The basal nuclei play a role in procedural learning, which involves the acquisition of skills and habits through practice. They contribute to the formation of motor memories and the automation of learned movements.</p> Signup and view all the answers

<p>A stronger than normal stimulus initiates a second action potential in a neuron.</p> Signup and view all the answers

<p>Depolarization in adjacent regions occurs due to opposite charges attracting, creating a local current.</p> Signup and view all the answers

<p>Continuous conduction is the propagation of action potentials in unmyelinated axons, moving region to region.</p> Signup and view all the answers

<p>Saltatory conduction is when an action potential jumps over myelinated portions of the axon from node to node.</p> Signup and view all the answers

<p>A synapse consists of the presynaptic membrane, postsynaptic membrane, and the synaptic cleft.</p> Signup and view all the answers

<p>Neurotransmitters are molecules that carry information across a synapse.</p> Signup and view all the answers

<p>The arrival of an action potential at the axon terminal opens calcium voltage-gated channels, allowing Ca2+ to enter.</p> Signup and view all the answers

<p>Once an action potential reaches the axon terminal, it triggers the opening of calcium channels and subsequent neurotransmitter release.</p> Signup and view all the answers

<p>Norepinephrine (NE)</p> Signup and view all the answers

<p>Reflexes</p> Signup and view all the answers

<p>Sympathetic division ('Fight or Flight') and Parasympathetic division ('Rest and Digest')</p> Signup and view all the answers

<p>They help maintain homeostasis.</p> Signup and view all the answers

<p>It slows the heart rate.</p> Signup and view all the answers

<p>Down syndrome</p> Signup and view all the answers

<p>Acetylcholine (ACh)</p> Signup and view all the answers

<p>Neurofibrillary tangles and accumulation of amyloid plaques.</p> Signup and view all the answers

<p>The reflex arc is the pathway of information flow that includes sensory receptors, sensory neurons, interneurons, motor neurons, and effectors to produce a response.</p> Signup and view all the answers

<p>The cerebrum is responsible for voluntary motor responses.</p> Signup and view all the answers

<p>The longitudinal fissure divides the left and right cerebral hemispheres.</p> Signup and view all the answers

<p>The primary motor area is located in the frontal lobe, anterior to the central sulcus.</p> Signup and view all the answers

<p>Gyri are ridges on the brain's surface, while sulci are shallow grooves that separate these ridges.</p> Signup and view all the answers

<p>The primary taste area is located in the insula.</p> Signup and view all the answers

<p>The primary visual area receives information from our eyes and is located in the occipital lobe.</p> Signup and view all the answers

<p>The cortical homunculus represents the physical mapping of the body in the primary motor and sensory cortices.</p> Signup and view all the answers

<p>Association areas connect the sensory and motor regions of the cortex to facilitate complex processing.</p> Signup and view all the answers

<p>The temporal lobe is primarily involved in auditory processing.</p> Signup and view all the answers

Neurons are nerve cells with a cell body, dendrites, and an axon that transmit impulses.

There are three types of neurons: sensory, motor, and interneurons, each serving specific roles.

The meninges are three protective layers (dura mater, arachnoid, pia mater) covering the brain and spinal cord.

CSF is the fluid surrounding the brain and spinal cord, providing cushioning and nutrient transport.

A reflex arc is a neural pathway that controls a reflex action without involving the brain.

A rapid change in membrane potential that initiates a nerve impulse.

The process where the membrane potential becomes less negative, moving towards zero.

A current generated by opposite charges attracting, causing depolarization in adjacent regions.

Propagation of action potentials in unmyelinated axons, moving slowly from region to region.

Propagation of action potentials in myelinated axons, where impulses jump between nodes.

The small swelling at the tip of a branched axon that releases neurotransmitters.

The gap between two neurons where information transfer occurs.

Chemical messengers that transmit signals across the synapse.

Nerve cells that carry impulses from the CNS to muscles, organs, or glands.

Nerve cells that transmit impulses from sensory receptors to the CNS; mostly unipolar.

Neurons in the CNS that interconnect and process information; typically multipolar.

The voltage difference across a neuron's membrane when it is not transmitting signals, with more Na+ outside and K+ inside.

A protein that moves 3 Na+ ions out of the cell and 2 K+ ions in, creating an ion imbalance that contributes to resting potential.

Protein channels in the neuron's membrane that open or close in response to changes in voltage, crucial for action potentials.

The state of a neuron's membrane when it maintains a difference in charge, with more positive ions outside and more negative inside at rest.

Involuntary responses to stimuli, using a reflex arc.

The largest brain part, responsible for voluntary actions and higher thinking.

Coordinates movement and balance; ensures smooth motion.

Outer gray matter layer; involved in sensation and movement.

Representation of body areas in the motor and sensory cortices.

Located in occipital lobe; processes visual information.

Located in temporal lobe; processes auditory information from ears.

A type of muscle attached to bones, enabling movement.

Reflexes that involve the brain in their response.

Reflexes that involve only the spinal cord.

Part of the nervous system that controls involuntary actions and regulates internal organs.

Part of ANS that prepares the body for 'fight or flight' responses.

Part of ANS that promotes 'rest and digest' activities.

Reflexes that help maintain homeostasis in internal organs.

Regions that interpret data and coordinate responses.

Brain region for reasoning and planning.

Area involved in speech production.

Responsible for understanding language.

Tracts that connect sensory, motor, and association areas.

Structure joining the two cerebral hemispheres.

Masses of gray matter for voluntary movement control.

Inhibitory neurotransmitter in basal nuclei.