The Human Nervous System

Nervous System Functions

Collects, processes, and responds to stimuli.

Peripheral Nervous System

Includes sensory and motor systems, and consists of cranial nerves, spinal nerves, and ganglia.

Central Nervous System (CNS)

Integrates, processes, and coordinates information; consists of the brain and spinal cord.

Neuroglial Cells

Supportive cells in the nervous system that fill spaces, provide a structural framework, produce myelin, and can divide.

Oligodendrocytes

Type of neuroglial cell that provides myelin sheath around CNS axons.

Astrocytes

Supportive cells that transport nutrients, regulate ions, and form scar tissue in the CNS.

Ependymal Cells

Cells that line the membranes covering the spinal cord and brain.

Myelination

The process of forming a myelin sheath around axons, which increases impulse speed.

Neuron Structure

Composed of the cell body, dendrites, axon, telodendria, and axon terminals.

Action Potential

An all-or-nothing event that occurs when a neuron reaches threshold potential; involves depolarization followed by repolarization.

Neurotransmitters

Chemical messengers released from synaptic vesicles that diffuse across the synaptic cleft.

Meninges

Layered membranes that protect the brain and spinal cord; includes dura mater, arachnoid mater, and pia mater.

Cerebrum

The largest part of the brain responsible for sensory/motor functions and higher mental processes.

Thalamus

Sensory relay station of the brain that processes sensory information.

Hypothalamus

Regulates hunger, thirst, body temperature, and hormone secretion; maintains homeostasis.

Limbic System

Involved in emotions, motivations, memory, particularly survival-related functions.

Cerebellum

Coordinates voluntary muscular movements, posture, and balance.

Cranial Nerves

Twelve pairs of nerves that originate in the brain stem and control various sensory and motor functions.

Autonomic Nervous System

Regulates involuntary body functions; includes sympathetic and parasympathetic divisions.

Sympathetic Nervous System

Part of the autonomic system that prepares the body for 'fight or flight' responses.

Parasympathetic Nervous System

Part of the autonomic system that promotes 'rest and digest' functions.

Brain Stem

Part of the brain connecting the brain and spinal cord, responsible for vital life functions like breathing and heart rate.

Cerebral Cortex

Outer layer of the brain involved in higher brain functions, such as thought, perception, and decision-making.

Corpus Callosum

Bundle of nerve fibers connecting the left and right hemispheres of the brain, allowing communication between them.

Spinal Cord

The cylindrical bundle of nerve fibers encased in the vertebral column, serving as the main pathway for information between the brain and the peripheral nervous system.

Somatic Nervous System

Part of the peripheral nervous system responsible for voluntary movements and communication between the brain and skeletal muscles.

Sensory Nerves

Nerves that carry sensory information from the body to the central nervous system.

Motor Nerves

Nerves that transmit signals from the central nervous system to muscles to produce movement.

Reflex Arc

The neural pathway that controls a reflex action, involving sensory neurons, interneurons, and motor neurons without direct involvement of the brain.

Nervous System

The _ is crucial for maintaining homeostasis as it collects sensory information, processes it to interpret the environment, and coordinates appropriate responses to stimuli.

Peripheral Nervous System

The _____ includes all the nerves outside the brain and spinal cord, composed of sensory neurons that transmit signals to the CNS and motor neurons that carry signals from the CNS to the rest of the body.

Central Nervous System (CNS)

The ____ is the control center of the body, integrating sensory data and directing responses; it consists of the brain, responsible for conscious thought and decision-making, and the spinal cord, which facilitates reflex actions and communication with the body.

Neuroglial Cells

_____ provide support and protection for neurons; they maintain the homeostasis of the extracellular fluid, form myelin, and act as the scaffolding for the nervous system.

Oligodendrocytes

_ are specialized neuroglial cells in the CNS that wrap around axons to form the protective myelin sheath, which enhances the speed of electrical impulses.

Astrocytes

_ are star-shaped glial cells in the CNS; they support the blood-brain barrier, regulate blood flow, and provide nutrients to neurons, also contributing to the repair of the central nervous system after injury.

Ependymal Cells

____ are ciliated cells that line the ventricles of the brain and the central canal of the spinal cord, helping in the production and circulation of cerebrospinal fluid (CSF).

Myelination

____ refers to the process by which glial cells produce the myelin sheath around neural axons, insulating them to increase the speed of electrical impulses and improve communication between neurons.

Neuron Structure

A neuron consists of a cell body containing the nucleus, dendrites that receive signals, an axon that transmits signals away from the cell body, and axon terminals that release neurotransmitters to communicate with other neurons.

Action Potential

An ____ is a rapid rise and fall in voltage across a neuron's membrane, triggered when a neuron reaches a certain threshold, resulting in the depolarization and repolarization phases that send signals down the axon.

Neurotransmitters

_ are chemical messengers synthesized in neurons and released into the synaptic cleft; they bind to receptors on the postsynaptic neuron, influencing whether it will generate an action potential.

Meninges

The ____ are three protective membranes — dura mater, arachnoid mater, and pia mater — that shield the brain and spinal cord from injury, facilitate the flow of cerebrospinal fluid, and provide a supportive framework.

Cerebrum

The ____ is the largest region of the brain, divided into left and right hemispheres, and is responsible for higher cognitive functions, voluntary movement, sensory processing, and emotional regulation.

Thalamus

The ____ acts as a sensory relay station, receiving sensory signals from the body and sending them to appropriate areas of the cerebral cortex for processing, playing a critical role in sensory perception.

Hypothalamus

Located below the thalamus, the ____ regulates various autonomic functions including hunger, thirst, body temperature, sleep cycles, and hormone release, maintaining the body's internal balance.

Limbic System

The ____ encompasses structures such as the hippocampus and amygdala, and is essential for emotion regulation, memory formation, and linking memories with emotions, particularly significant for survival.

Cerebellum

The ____ is responsible for fine-tuning movements, maintaining posture and balance, and coordinating voluntary movements by analyzing sensory input and adjusting motor output.

Cranial Nerves

The twelve pairs of ____ emerge from the brainstem and are responsible for a variety of functions, including sensory and motor functions like facial expressions, taste, and eye movement.

Autonomic Nervous System

The ____ regulates involuntary body functions, such as heart rate, digestion, and respiration, and consists of the sympathetic and parasympathetic systems.

Sympathetic Nervous System

The _ prepares the body for 'fight or flight' responses by increasing heart rate, dilating airways, and redirecting blood flow to essential muscles during perceived threats.

Parasympathetic Nervous System

The ____ promotes 'rest and digest' activities, slowing heart rate, enhancing digestive processes, and conserving energy during restful states.

Brain Stem

The _____ connects the brain to the spinal cord and regulates vital life functions such as heart rate, blood pressure, and respiratory rhythm, comprising the midbrain, pons, and medulla oblongata.

Cerebral Cortex

The ____ is the outer layer of the cerebrum, involved in numerous high-level functions including sensory perception, memory, reasoning, and decision-making, divided into lobes with specialized roles.

Corpus Callosum

The ____ is a large bundle of nerve fibers that connects the left and right hemispheres of the brain, facilitating communication and coordination between them for integrated brain function.

Spinal Cord

The ____ is the long bundle of nerve tissue encased within the vertebral column, acting as a main pathway for information traveling between the brain and peripheral nervous system; it also mediates reflex actions.

Somatic Nervous System

The _____ is a component of the peripheral nervous system that controls voluntary movements by transmitting motor commands from the CNS to skeletal muscles.

Sensory Nerves

____ are responsible for carrying sensory information from the peripheral body to the central nervous system, enabling the perception of touch, pain, temperature, and other sensations.

Motor Nerves

____ carry signals from the central nervous system to the muscles, facilitating voluntary movements by instructing muscle contractions.

Reflex Arc

A ____ is a neural pathway that mediates reflex actions, consisting of sensory neurons, interneurons, and motor neurons, allowing for quick responses without direct involvement of the brain.

A patient was in a motor vehicle accident and hit their head on the dash board.  They are confused and have slurred speech.  What lobe of the brain has been affected?

Frontal

A stroke deep in the brain results in a patient having an impaired ability to remember new things that they learn.  What specific area of the brain has been affected?

Amygdaloid body (amygdala)

A child fell out of a chair and hit the back of their head.  They are complaining about having a headache and blurred vision.  Which lobe the brain has been affected?

Occipital

A patient presents with abnormal hormonal levels and elevated body temperature.  They also complain of being unusually thirsty.   What specific area of the brain do you suspect has been affected?

Hypothalamus

A 77-year-old woman was cooking in the kitchen when she collapsed onto the floor. Her daughter called an ambulance and the woman was taken to the emergency room. She had suffered a stroke, and slowly regained consciousness over the next two days. However, when she woke up, she was unable to answer questions but did understand them because she was still able to write down her thoughts.  What specific area of the brain has been affected? (Choose all options that apply.)

Left, frontal lobe, brocas area

A patient has trouble with their balance and coordination.  What specific area of the brain is most likely to have been affected?

Cerebellum

dura mater

outermost covering of the brain, composed of tough fibrous connective tissue, its outer layer forms the periosteum of the skull

arachnoid mater

middle meningeal layer, like a cobweb structure

arachnoid villi

structure that return cerebral spinal fluid to the venous blood in the dural sinuses

pia mater

innermost covering of the brain, delicate and vascular

A gunshot wound to the head instantly results in death as breathing stopped.  What specific area of the brain has been affected?

Medulla oblongata

A 61-year-old business executive with a long history of high blood pressure collapsed while jogging over the lunch hour. His jogging mate quickly contacted a police officer who helped carry the man to a hospital just down the road. At the hospital, an MRI was performed that revealed a blockage of a cerebral artery and ischemic changes to the portion of the brain supplied by that artery. With quick medical attention, the man was stabilized, and he slowly improved over the next three weeks. Loss of sensation of the right leg and foot did persist, however.  What specific area of the brain has been affected (include the side)? 

Parietal, Left