COPY: NEUROPHYSIOLOGY

The production of digestive enzymes is not a basic function of the nervous system. The nervous system's primary roles are to receive, process, and transmit information.

The nervous system is made up of two main types of cells: neurons and glial cells.

Glial cells provide structural and functional support to the nervous system. They help nourish neurons, protect them, and maintain the proper environment for nerve impulse transmission.

Neurons are responsible for the transmission of information throughout the nervous system. They receive, process, and transmit nerve impulses.

A neuron has a cell body (soma) and two types of extensions: dendrites and axons.

Dendrites are extensions of a neuron that receive impulses from other neurons or sensory receptors. They convey these impulses towards the cell body.

The axon is a long, slender extension of a neuron that conducts impulses away from the cell body towards other neurons, muscles, or glands.

Afferent nerves carry impulses towards the central nervous system (CNS). These impulses originate from sensory receptors.

Efferent nerves carry impulses away from the central nervous system (CNS) to target tissues like muscles or glands.

Cranial nerves and spinal nerves can carry both sensory and motor fibers, allowing for the transmission of both information and commands.

The somatic nervous system controls voluntary movements of skeletal muscles. It allows us to consciously choose how we move our body.

Somatic motor function refers to the voluntary movement of skeletal muscles. It is controlled by efferent impulses from the brain to the skeletal muscles.

Autonomic motor function is the control of involuntary movements of smooth muscle, cardiac muscle, and glands. This system operates automatically without conscious control.

The parasympathetic nervous system helps to conserve energy and restore body functions after a stressful situation. It's often referred to as the 'rest and digest' system.

The Na+/K+ pump actively transports sodium ions out of the cell and potassium ions into the cell. This maintains a negative charge inside the neuron, contributing to the resting membrane potential.

The resting membrane potential is the electrical difference in charges across the cell membrane of a neuron in a resting state. This is due to the unequal distribution of ions inside and outside the cell.

When a neuron 'fires,' it undergoes a rapid change in its membrane potential. Sodium ions rush into the cell (depolarization), followed by the outflow of potassium ions (repolarization). This produces a brief electrical impulse that travels down the axon.

The axon is responsible for transmitting information through the nervous system. It acts as the 'electrical cable' that carries the nerve impulse to the next cell.

Catecholamines (such as dopamine, norepinephrine, and epinephrine) are neurotransmitters that primarily have excitatory effects on neurons.

Acetylcholine is a neurotransmitter that counteracts the effects of the sympathetic nervous system (SNS). It's often referred to as the 'anti-stress' neurotransmitter.

Acetylcholine is a neurotransmitter that can have both excitatory and inhibitory effects depending on the specific neuron or target tissue it interacts with.

Neurotransmitters are chemical messengers that transmit signals between neurons or between neurons and target tissues. They play a crucial role in communication throughout the nervous system.

Sympathetic nerves emerge from the thoracic and lumbar regions of the spinal cord. These nerves are part of the sympathetic nervous system, which prepares the body for 'fight or flight' responses.

The parasympathetic and sympathetic nervous systems have opposite effects on organs and tissues. For example, the sympathetic system increases heart rate, while the parasympathetic system slows it down.

The central nervous system (CNS) is composed of the brain and spinal cord. It acts as the control center for the entire nervous system.

The peripheral nervous system (PNS) consists of all the nerves that extend away from the central nervous system (CNS) towards the periphery of the body. It connects the CNS to the rest of the body.

Somatic sensory function involves the transmission of sensory impulses from various receptors in the body (muscles, skin, eyes, ears) to the brain. It allows us to perceive the world around us.

During depolarization, sodium ions (Na+) diffuse into the cell. This influx of positive charge makes the inside of the neuron more positive, triggering the nerve impulse.

Repolarization occurs when sodium channels close and potassium channels open. This allows potassium ions (K+) to flow out of the cell, restoring the negative charge inside the neuron.

When the depolarization wave reaches the threshold, the neuron 'fires' and generates a nerve impulse. This is the point of no return—the signal will travel down the axon.

A neuron is refractory to new stimuli during the absolute refractory period (no new impulse can be generated) and the relative refractory period (a stronger stimulus is required to generate a new impulse). This ensures that the nerve impulse travels in one direction.

Saltatory conduction is the rapid rate of depolarization in myelinated axons. It occurs due to myelin sheath covering the axon, which prevents the electrical signal from leaking out. This speeds up the transmission of the nerve impulse.

Excitatory neurotransmitters stimulate neurons, increasing the likelihood that they will fire and transmit an impulse. They essentially 'push the gas pedal' on nerve activity.

The cerebellum plays a crucial role in coordinating movement and balance. It receives information from the sensory system and other parts of the brain to fine-tune motor commands.

The diencephalon serves as a passageway between the brainstem and cerebrum. It contains important structures like the thalamus and hypothalamus, which play key roles in sensory processing, hormone regulation, and other vital functions.

The brainstem is responsible for connecting the brain to the spinal cord. It also controls vital functions like breathing, heart rate, and blood pressure.

Drugs and/or diseases can have a variety of effects on the nervous system. They can stimulate, imitate, or inhibit the actions of neurotransmitters, leading to a wide range of symptoms or changes in behavior.

Autonomic motor function controls the involuntary movements of smooth muscle, cardiac muscle, and glands. This system maintains vital body functions that operate automatically.

The diencephalon contains several key structures including: the thalamus, which acts as a relay station for sensory information; the hypothalamus, which regulates temperature, hunger, thirst, and emotions; and the pituitary gland, the 'master gland' of the endocrine system.

The thalamus serves as a relay station for sensory impulses to the cerebrum. It receives information from sensory receptors and directs it to the appropriate areas of the cerebrum for processing.

The hypothalamus is the interface between the nervous and endocrine systems. It plays a crucial role in regulating temperature, hunger, thirst, sleep-wake cycles, and emotional responses.

The pituitary gland is the 'master gland' of the endocrine system. It secretes hormones that regulate the activity of other endocrine glands throughout the body.

The cerebellum plays a crucial role in fine-tuning and coordinating movements, ensuring that they are smooth and accurate. It receives sensory information from the body and from the brain to make adjustments to motor commands.

The cerebrum is the largest part of the brain and is responsible for higher-order functions such as receiving and interpreting sensory information, initiating voluntary movements, and carrying out complex cognitive tasks.

The cerebrum is involved in a wide range of cognitive functions, including language, memory, learning, problem-solving, emotional responses, and personality. It integrates neuronal activity associated with these complex behaviors.

Many of the cranial nerves, which connect the brain to the rest of the body, originate from the brainstem. These nerves control vital functions like breathing, heart rate, and facial movements.

Excitatory neurotransmitters, such as norepinephrine, dopamine, and epinephrine, stimulate neurons, increasing the likelihood that they will fire and transmit an impulse. They act as 'accelerators' for nerve activity.

Inhibitory neurotransmitters, such as GABA and glycine, decrease the likelihood that neurons will fire. They act as 'brakes' on nerve activity.

A presynaptic neuron releases a chemical neurotransmitter into the synaptic cleft. This neurotransmitter then binds to receptors on the postsynaptic neuron, either stimulating or inhibiting its activity.