CHAPTER 7

Functions of the Nervous System Collects sensory input, processes information (integration), and produces a motor output.

Central Nervous System (CNS) Consists of the brain and spinal cord; processes and integrates information.

Peripheral Nervous System (PNS) Includes all nerves outside the CNS; connects the CNS to the body.

Sensory (Afferent) Division Carries sensory information from receptors to the CNS.

Motor (Efferent) Division Carries commands from the CNS to muscles and glands.

Somatic Nervous System Controls voluntary movements of skeletal muscles.

Autonomic Nervous System Controls involuntary functions, such as heart rate and digestion.

Sympathetic Nervous System Activates "fight or flight" response during stress.

Parasympathetic Nervous System Activates "rest and digest" functions to maintain homeostasis.

Neurons Basic unit of the nervous system; transmits electrical signals.

Neuroglia (Glial Cells) Support neurons by providing nutrients, protection, and insulation.

Dendrites Receive signals from other neurons and transmit them to the cell body.

Axon Conducts nerve impulses away from the cell body.

Myelin Sheath Insulating layer around axons that speeds up nerve impulses.

Nodes of Ranvier Gaps in the myelin sheath that facilitate rapid conduction of nerve impulses.

Synapse Junction between two neurons where neurotransmitters transmit signals.

Neurotransmitters Chemical messengers that transmit signals across synapses.

Action Potential Electrical signal that travels along a neuron’s axon.

Depolarization Neuron's membrane potential becomes more positive as sodium (Na+) enters.

Repolarization Neuron restores its resting state by pumping potassium (K+) out.

Sodium-Potassium Pump Restores ion balance after an action potential using ATP.

Reflex Arc The direct pathway of a reflex, including sensory neuron, interneuron, and motor neuron.

Sensory (Afferent) Neurons Carry impulses from sensory receptors to the CNS.

Motor (Efferent) Neurons Transmit impulses from the CNS to muscles or glands.

Interneurons (Association Neurons) Located in the CNS; connect sensory and motor neurons.

Cerebrum Largest part of the brain responsible for voluntary actions and higher thinking.

Frontal Lobe Controls voluntary movements, reasoning, and problem-solving.

Parietal Lobe Processes touch, temperature, and pain sensations.

Occipital Lobe Responsible for processing visual information.

Temporal Lobe Processes hearing and smell; involved in memory.

Diencephalon Includes the thalamus, hypothalamus, and epithalamus; controls many autonomic functions.

Thalamus Relay station for sensory impulses to the cerebral cortex.

Hypothalamus Regulates body temperature, hunger, thirst, and emotions.

Epithalamus Contains the pineal gland; involved in sleep-wake cycles.

Brainstem Includes the midbrain, pons, and medulla oblongata; controls basic survival functions.

Midbrain Controls visual and auditory reflexes.

Pons Helps regulate breathing and communication between brain regions.

Medulla Oblongata Regulates heart rate, blood pressure, and respiration.

Cerebellum Coordinates movement and balance.

Meninges Protective membranes surrounding the brain and spinal cord.

Cerebrospinal Fluid (CSF) Fluid that cushions and protects the CNS.

Blood-Brain Barrier Protects the brain by preventing harmful substances from entering.

Cranial Nerves 12 pairs of nerves that originate from the brain, controlling sensory and motor functions.

Spinal Nerves 31 pairs of nerves that originate from the spinal cord.