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Central Nervous System (CNS)

Consists of the brain and spinal cord.

Peripheral Nervous System (PNS)

All nerves outside the central nervous system (CNS).

Sensory Division (Afferent)

Carries information to the CNS from receptors.

Motor Division (Efferent)

Sends commands from the CNS to effectors like muscles and glands.

Neurons

Nerve cells that send signals.

Dendrites

Branch-like extensions of a neuron that receive signals from other neurons.

Axon

The long, slender projection of a neuron that conducts electrical impulses away from the neuron's cell body.

Glial Cells

Support and protect neurons.

Myelin Sheath

Insulates axons and speeds up signal transmission.

Nodes of Ranvier

Gaps in the myelin sheath that allow for saltatory conduction.

Action Potential

Large, all-or-nothing electrical signal transmitted along an axon.

Resting Potential

The membrane potential of a neuron at rest, typically about -70mV.

Threshold Potential

The critical level of membrane potential that must be reached to initiate an action potential, typically around -55mV.

Synapse

The junction between two neurons for communication.

Neurotransmitter

Chemical that transmits signals across the synapse.

Autonomic Nervous System (ANS)

Regulates involuntary functions and is divided into sympathetic and parasympathetic.

Sympathetic Nervous System

Part of ANS that controls 'fight or flight' responses.

Parasympathetic Nervous System

Part of ANS that controls 'rest and digest' functions.

Reflex Arc

A neural pathway that controls a reflex action.

Hippocampus

Brain structure involved in long-term memory formation.

Cerebellum

Coordinates movement and balance; also helps with motor learning and fine-tuning movement.

Motor Unit

A motor neuron and all the muscle fibers it controls.

Calcium Ions (Ca²⁺)

Trigger contraction by exposing binding sites on actin.

Brain Lateralization

The specialization of certain functions in either the left or right hemisphere of the brain.

Left Hemisphere

Responsible for language, logic, math, and analytical thinking.

Contraction of muscles step 1

Nerve Impulse: Action potential travels down motor neuron, triggering the release of acetylcholine (ACh) into the neuromuscular junction.

Muscle contraction step two

Calcium Release: Action potential travels down T-tubules signaling sarcoplasmic reticulum to release Ca²⁺ ions.

Muscle contraction step three

Binding Sites Exposed: Ca²⁺ binds to troponin, moving tropomyosin away from myosin-binding sites on actin.

Muscle contraction step four

Cross-Bridge Cycling: Myosin heads bind to actin, powering the power stroke.

Muscle contraction step five

Relaxation: Ca²⁺ is pumped back into the SR when stimulation stops.

Cerebrum/Cerebral Cortex

Responsible for thinking, perception, movement, and memory.

Frontal Lobe

Involved in decision making, planning, and language production.

Prefrontal Cortex

Involved in personality, reasoning, and social behavior.

Parietal Lobe

Processes touch, pressure, temperature, pain, and spatial awareness.

Temporal Lobe

Involved in hearing, language comprehension, and memory storage.

Amygdala

Processes emotions such as fear and anger.

Thalamus

Acts as a relay station for sensory information.

Hypothalamus

Controls homeostasis and links the nervous system to the endocrine system.

Subcortical Nuclei (e.g., basal ganglia)

Clusters of neurons beneath the cortex that help regulate movement and emotions.

Brain Stem

Controls basic life functions.

Midbrain

Involved in eye movement and visual/auditory reflexes.

Pons

Serves as a bridge between the cerebrum and cerebellum.

Medulla Oblongata

Regulates heart rate, breathing, and blood pressure.

Right Hemisphere

Associated with creativity and spatial awareness.

Alzheimer's disease

A neurological disorder characterized by the degeneration of neurons, leading to memory loss.

Parkinson's disease

A neurological disorder caused by dopamine loss, resulting in tremors and movement issues.

Somatic Nervous System (SNS)

Part of the motor division of the PNS, controlling voluntary movements.

Enteric Nervous System (ENS)

Controls the gastrointestinal system and can operate independently of the CNS.