Overview of the Nervous System and Its Functions

Innervate

To supply nerves to a body part.

Neurons

Basic building blocks of the nervous system.

Dendrite

Conducts messages towards the cell body.

Axon

Conducts messages away from the cell body.

Synapse

Gap where neurotransmitters transmit signals.

Myelin Sheath

Insulates nerve fibers to speed up impulses.

Node of Ranvier

Gaps in myelin sheath for faster transmission.

Cell Body

Contains nucleus; maintains neuron functions.

Motor Neuron

Connects to muscles or glands; signals movement.

Sensory Neuron

Transmits signals from sensory receptors to CNS.

Interneuron

Connects neurons within the CNS; processes information.

Synaptic Transmission

Chemical transmission of impulses across a synapse.

Neurotransmitter

Chemical messengers transmitting signals between neurons.

Acetylcholine

Neurotransmitter involved in muscle activation.

Noradrenalin

Neurotransmitter affecting arousal and alertness.

Serotonin

Regulates mood and emotional states.

Dopamine

Influences pleasure, motivation, and reward.

Enzymatic Breakdown

Process of degrading neurotransmitters in synapse.

Acetylcholinesterase

Enzyme breaking down acetylcholine in synapse.

Reflex Arc

Pathway for reflex actions involving sensory and motor neurons.

Action Potential

Electrical impulse traveling along a neuron.

Synaptic Cleft

Space between pre and post-synaptic neurons.

Presynaptic Membrane

Membrane of neuron releasing neurotransmitters.

Postsynaptic Membrane

Membrane of neuron receiving neurotransmitters.

Reflex Action

Automatic response to stimulus, bypassing brain.

Effector

Muscle or gland that responds to a stimulus.

Depolarization

Change in membrane potential, sodium influx.

Threshold Potential

Minimum stimulus required to trigger action potential.

Saltatory Conduction

Impulse jumps between nodes of Ranvier.

Central Nervous System (CNS)

Brain and spinal cord, information processing center.

Peripheral Nervous System (PNS)

Nerves outside CNS, connects to limbs and organs.

Somatic Nervous System

Controls voluntary movements and external senses.

Autonomic Nervous System

Regulates involuntary body functions automatically.

Sympathetic System

Prepares body for 'fight or flight' response.

Parasympathetic System

Restores body to calm state, conserves energy.

Ion Channels

Proteins that allow ions to cross membranes.

Voltage-Gated Channels

Open in response to membrane potential changes.

CNS Protection

Encased in bone and meninges for safety.

Cardiac Activity Regulation

Controlled by autonomic nervous system involuntarily.

Myelinated Axons

Axons covered with myelin for faster conduction.

Impulse Speed

Myelinated axons conduct impulses up to 200 m/s.

Receptor

Detects stimulus and initiates response.

Preganglionic Neuron

Longer than postganglionic in parasympathetic system.

Postganglionic Neuron

Shorter than preganglionic in parasympathetic system.

Central Nervous System

Includes brain and spinal cord.

Peripheral Nervous System

Nerves outside the central nervous system.

Adrenal Gland

Produces hormones for stress response.

Adrenalin

Hormone that triggers fight or flight response.

Medulla Oblongata

Controls unconscious bodily functions.

Cerebrum

Responsible for consciousness and information processing.

Thalamus

Sorting center for sensory impulses to cerebrum.

Cerebellum

Coordinates balance and muscle movements.

Hypothalamus

Regulates homeostasis and links nervous systems.

Corpus Callosum

Connects left and right cerebral hemispheres.

Pituitary Gland

Master gland controlling endocrine functions.

Sympathetic Impulses

Increase heart rate and blood flow.

Homeostasis

Maintaining stable internal body conditions.

Proprioception

Awareness of body position in space.

Cortex

Outer layer of the cerebrum.

Sensory Impulses

Messages sent to the brain for processing.

Posterior Pituitary

Stores hormones made in the hypothalamus for release.

Anterior Pituitary

Produces hormones stimulated by hypothalamic releasing factors.

ADH (Antidiuretic Hormone)

Regulates water reabsorption in kidneys.

Oxytocin

Stimulates uterine contractions and milk production.

Growth Hormone (GH)

Stimulates growth and cell reproduction.

Prolactin (PRL)

Stimulates milk production in mammary glands.

FSH (Follicle Stimulating Hormone)

Stimulates growth of ovarian follicles and sperm production.

LH (Luteinizing Hormone)

Triggers ovulation and testosterone production.

Thyroid Stimulating Hormone (TSH)

Stimulates thyroid gland to produce thyroid hormones.

Adrenocorticotropic Hormone (ACTH)

Stimulates adrenal cortex to produce cortisol.

Negative Feedback System

Regulates hormone levels by inhibiting further secretion.

Neurosecretory Cells

Produce hormones like ADH and oxytocin in hypothalamus.

Portal System

Blood vessel system connecting hypothalamus and anterior pituitary.

Releasing Factors

Hormones from hypothalamus that stimulate anterior pituitary.

Inhibiting Factors

Hormones that suppress anterior pituitary hormone release.

Nerve Impulse

Signal transmitted along a neuron via action potentials.

Resting Potential

Stable membrane potential of a neuron at rest.

Refractory Period

Time after action potential when neuron cannot fire.