Comprehensive Nervous System and Brain Function Review EVERYTHINg

What are the 3 main functions of the nervous system?

Sensory input, integration, and motor output.

What is sensory input?

Detection of changes inside or outside the body and transmission of that information to the CNS.

What is integration?

Processing and interpreting sensory information, primarily in the CNS.

What is motor output?

Commands sent from the CNS to muscles or glands.

What structures make up the CNS?

Brain and spinal cord.

What structures make up the PNS?

Cranial nerves, spinal nerves, and ganglia; everything outside the brain and spinal cord.

What does the afferent division do?

Carries sensory information toward the CNS.

What does the efferent division do?

Carries motor commands away from the CNS.

What does the somatic nervous system control?

Skeletal muscles and voluntary movement.

What does the autonomic nervous system control?

Smooth muscle, cardiac muscle, and glands; primarily involuntary functions.

What does the sympathetic nervous system do?

Produces the fight-or-flight response; increases heart rate, dilates pupils, increases breathing, and inhibits digestion.

What does the parasympathetic nervous system do?

Produces the rest-and-digest response; decreases heart rate and promotes digestion.

What is the functional unit of the nervous system?

The neuron.

What do dendrites do?

Receive incoming signals from other neurons or sensory receptors.

What is the soma?

The neuron's cell body; contains the nucleus and organelles and integrates incoming signals.

What does the axon do?

Carries electrical impulses away from the cell body.

What is the myelin sheath?

An insulating covering around many axons that increases the speed of nerve impulse conduction.

What are Nodes of Ranvier?

Gaps between sections of myelin where action potentials are regenerated.

What do axon terminals do?

Release neurotransmitters into the synapse.

What is saltatory conduction?

Rapid propagation of an action potential from node to node along a myelinated axon.

Which glial cell forms myelin in the CNS?

Oligodendrocytes.

Which glial cell forms myelin in the PNS?

Schwann cells.

What do astrocytes do?

Support neurons, help maintain the blood-brain barrier, and regulate the extracellular environment.

What do microglia do?

Act as immune cells of the CNS and remove damaged cells and pathogens by phagocytosis.

What do ependymal cells do?

Line the ventricles and help produce/circulate cerebrospinal fluid.

What do satellite cells do?

Support neuron cell bodies in PNS ganglia.

What is the resting membrane potential of a typical neuron?

Approximately -70 mV.

What does the sodium-potassium pump do?

Uses ATP to move 3 Na+ out of the neuron and 2 K+ into the neuron.

What happens during depolarization?

Sodium channels open and Na+ rapidly enters the neuron, making the membrane potential more positive.

What happens during repolarization?

Potassium channels open and K+ leaves the neuron, making the membrane potential more negative.

What is hyperpolarization?

A brief period when the membrane becomes more negative than its resting potential after repolarization.

Which ion enters during depolarization?

Sodium (Na+).

Which ion leaves during repolarization?

Potassium (K+).

What is an action potential?

A rapid electrical change in a neuron's membrane that propagates along the axon.

What is a synapse?

The junction where a neuron communicates with another neuron, muscle, or gland.

What happens when an action potential reaches an axon terminal?

Calcium enters the terminal, causing synaptic vesicles to release neurotransmitter into the synaptic cleft.

What is a synaptic cleft?

The tiny gap between communicating cells at a chemical synapse.

What is acetylcholine (ACh)?

A neurotransmitter involved in skeletal muscle contraction and parasympathetic signaling.

What is dopamine?

A neurotransmitter involved in reward, motivation, movement, and other functions.

What is serotonin?

A neurotransmitter involved in mood, sleep, appetite, and other functions.

What is norepinephrine?

A neurotransmitter involved in alertness and sympathetic nervous system responses.

What is epinephrine?

A hormone and neurotransmitter involved in the fight-or-flight response.

What is GABA?

The main inhibitory neurotransmitter in the CNS.

What is glutamate?

The main excitatory neurotransmitter in the CNS.

What are endorphins?

Natural chemicals involved in pain relief and other functions.

What is the cerebrum?

The largest part of the brain; responsible for conscious thought, memory, sensation, and voluntary movement.

What does the frontal lobe control?

Planning, judgment, personality, voluntary movement, and speech production.

What does the parietal lobe control?

Somatic sensation such as touch, pressure, pain, temperature, and spatial awareness.

What does the temporal lobe control?

Hearing, memory, and language comprehension.

What does the occipital lobe control?

Vision.

Where is the primary motor cortex?

In the frontal lobe, specifically the precentral gyrus.

Where is the primary somatosensory cortex?

In the parietal lobe, specifically the postcentral gyrus.

Where is the primary auditory cortex?

In the temporal lobe.

Where is the primary visual cortex?

In the occipital lobe.

What is Broca's area?

A region involved primarily in speech production, usually in the dominant frontal lobe.

What is Wernicke's area?

A region involved primarily in language comprehension, usually in the dominant temporal/parietal region.

What does the cerebellum control?

Balance, coordination, fine motor movement, muscle tone, and motor learning.

What are symptoms of cerebellar damage?

Ataxia, poor coordination, balance problems, and intention tremors.

What is the brainstem?

The midbrain, pons, and medulla oblongata.

What does the midbrain control?

Visual and auditory reflexes, eye movements, and aspects of motor control.

What does the pons do?

Acts as a relay between brain regions and helps regulate breathing and sleep.

What does the medulla oblongata control?

Vital autonomic functions including heart rate, blood pressure, breathing, swallowing, coughing, and vomiting.

What is the thalamus?

A major sensory relay station that routes most sensory information to the cerebral cortex.

Which major sense bypasses the thalamus as its initial sensory relay?

Smell (olfaction).

What does the hypothalamus control?

Homeostasis, body temperature, hunger, thirst, circadian rhythms, autonomic function, and endocrine regulation.

What is the hippocampus responsible for?

Formation of new long-term memories.

What happens with hippocampal damage?

Impaired ability to form new long-term memories.

What does the amygdala do?

Processes emotions, especially fear, emotional learning, and threat-related responses.

How many pairs of cranial nerves are there?

12 pairs.

What is Cranial Nerve I?

Olfactory nerve; smell.

What is Cranial Nerve II?

Optic nerve; vision.

What is Cranial Nerve III?

Oculomotor nerve; most eye movements, eyelid elevation, and pupil constriction.

What is Cranial Nerve IV?

Trochlear nerve; controls the superior oblique eye muscle.

What is Cranial Nerve V?

Trigeminal nerve; facial sensation and muscles of mastication.

What is Cranial Nerve VI?

Abducens nerve; controls the lateral rectus muscle and abducts the eye.

What is Cranial Nerve VII?

Facial nerve; facial expression, taste from anterior two-thirds of tongue, and tear/saliva production.

What is Cranial Nerve VIII?

Vestibulocochlear nerve; hearing and balance.

What is Cranial Nerve IX?

Glossopharyngeal nerve; taste from posterior one-third of tongue and swallowing.

What is Cranial Nerve X?

Vagus nerve; parasympathetic control of thoracic and abdominal organs, swallowing, and voice.

What is Cranial Nerve XI?

Accessory nerve; controls sternocleidomastoid and trapezius muscles.

What is Cranial Nerve XII?

Hypoglossal nerve; controls tongue movement.

Which cranial nerve is responsible for smell?

Cranial Nerve I, olfactory.

Which cranial nerve is responsible for vision?

Cranial Nerve II, optic.

Which cranial nerve controls most eye movements?

Cranial Nerve III, oculomotor.

Which cranial nerve controls facial sensation and chewing?

Cranial Nerve V, trigeminal.

Which cranial nerve controls facial expression?

Cranial Nerve VII, facial.

Which cranial nerve controls hearing and balance?

Cranial Nerve VIII, vestibulocochlear.

Which cranial nerve is the longest?

Cranial Nerve X, vagus.

Which cranial nerve provides most parasympathetic innervation to thoracic and abdominal organs?

Cranial Nerve X, vagus.

Which cranial nerve controls tongue movement?

Cranial Nerve XII, hypoglossal.

What is the mnemonic for cranial nerve names?

Oh Oh Oh To Touch And Feel Very Good Velvet, Ah Heaven.

What is the general cranial nerve sensory/motor mnemonic?

Some Say Marry Money, But My Brother Says Big Brains Matter More.

What does gray matter primarily contain?

Neuron cell bodies, dendrites, and unmyelinated portions of axons.

What does white matter primarily contain?

Myelinated axons.

What is a reflex arc?

The neural pathway responsible for a reflex response.

What is the correct reflex arc sequence?

Receptor → sensory/afferent neuron → integration center → motor/efferent neuron → effector.

What is a monosynaptic reflex?

A reflex involving one synapse between the sensory and motor neuron.

What is an example of a monosynaptic reflex?

The patellar or knee-jerk reflex.

What is a polysynaptic reflex?

A reflex involving multiple synapses, usually including interneurons.

What is an example of a polysynaptic reflex?

The withdrawal reflex from a painful stimulus.