17 Nervous System

cranial nerves

12 pairs

Estimate how much caffeine you consume per day. What effects can you notice after consuming caffeine?

8 oz. - only to get rid of a headache

Amygdala

A limbic system structure involved in memory and emotion, particularly fear and aggression.

sodium-potassium pump

A special transport protein in the plasma membrane of animal cells that transports sodium out of the cell and potassium into the cell against their concentration gradients.

autonomic nervous system

A subdivision of the peripheral nervous system. Controls involuntary activity of visceral muscles and internal organs and glands.

How does the sodium-potassium pump move ions across the cell membrane?

Active transport is the energy-requiring process of pumping molecules and ions across membranes "uphill" - against a concentration gradient.

Define refractory period, saltatory conduction, and synaptic integration.

After the action potential passes one part of an axon, the sodium gates in that part are unable to open for a period of time, called the refractory period. This prevents action potentials from moving backward. A node of Ranvier is a gap between Schwann cells that make up the myelin sheath of an axon of a PNS neuron. Saltatory conduction is the "jumping" of action potentials as they spread from node to node. Synaptic integration is the summing up of all incoming excitatory and inhibitory messages by a neuron.

Effects of drugs can include prevention of neurotransmitter release. prevention of reuptake by the presynaptic membrane. blockages to a receptor. All of these are correct. None of these are correct.

All are correct

Do you believe that there should be any restrictions on selling, for example, an energy drink containing 500 mg of caffeine? If so, what should the minimum age be?

Arguments for or against this should recognize the large effects caffeine can have on human physiology, and the age of the population to which the marketing of the drinks is directed.

Explain why MS is an autoimmune disease.

Autoimmune diseases occur when the immune system attacks self-cells, tissues, or organs. In MS, the immune system attacks myelin, oligodendrocytes, and neurons.

Identify the four major parts of the brain and describe the general functions of each.

Cerebrum: receives sensory information, integrates it, and commands voluntary motor responses. Diencephalon has two parts: hypothalamus serves as a link between the nervous and endocrine system, maintaining homeostasis; thalamus receives sensory inputs except for smell. Cerebellum: processes information about body position and maintains posture and balance. Brain stem: acts as a relay between the cerebrum and spinal cord or cerebellum; regulates breathing through the pons; regulates vital functions through the medulla oblongata; receives and sends signals between the higher brain centers and the spinal cord.

Detail the specific modes of action of the drugs described in this section.

Cocaine prevents synaptic uptake of dopamine. Heroin binds to endorphin receptors. Methamphetamine results in high amounts of dopamine released in the brain. Bath Salts inhibit the reuptake of several neurotransmitters.

Ganglia

Collections of nerve cell bodies

hypothesize why, since illicit drugs affect activity of neurotransmitters, it might take increasing amounts of a drug to obtain the same effect over time.

Continued exposure to a drug over time might lead to compensatory responses at synaptic clefts that result in a decreased sensitivity to the drug.

Contrast cranial and spinal nerves.

Cranial nerves are the nerves that emerge directly from the brain (including the brainstem). In contrast, spinal nerves emerge from segments of the spinal cord.

stroke

Damage to the brain from interruption of its blood supply.

Explain how the changes in Na+ and K+ ion concentrations that occur during an action potential are associated with depolarization and repolarization.

During an action potential, the Na+ gates open and Na+ enters the cell, causing a depolarization. Then the Na+ gates close and the K+ gates open, causing repolarization (even a slight hyperpolarization).

synapse

Gap between neurons

Review the structure of gray matter and white matter, and describe where each is found in the CNS and the PNS.

Gray matter contains nonmyelinated nerve fibers; in white matter, the fibers are myelinated. The brain has gray matter on the surface and white matter in deeper tissue. That pattern is reversed in the spinal cord.

Discuss the following: One cause of bacterial meningitis, Haemophilus influenzae, can also be found in the throat (pharynx) of healthy people. What factors might determine when H. influenzae causes disease?

H. influenza can cause disease if the immune status of the carrier is compromised by fatigue, poor health, viral infection, lack of exercise, or risky behaviors.

MS affects the CNS only, not the PNS. What cells synthesize myelin in these two systems, and how might this help to explain why MS affects myelin in the CNS only?

In the PNS, Schwann cells wrap themselves around axons, forming myelin. In the CNS, oligodendrocytes, a type of neuroglial cell, form the myelin. With MS, oligodendrocytes are targeted by the immune system.

Summarize the major symptoms of Alzheimer disease and explain the age at which these symptoms may appear.

Major symptoms of AD include loss of short-term memory, progressing to an inability to carry out basic functions. These symptoms can begin before age 50, but usually not before 65.

Summarize the evidence from the mouse study that showed the role of glutamate in memory formation.

Mice that lack a glutamate receptor in their hippocampus were unable to learn to run mazes.

Describe the three parts of a neuron.

Most neurons contain dendrites, a cell body, and an axon.

Distinguish the cell types that form the myelin in the PNS versus the CNS.

Myelin is formed by Schwann cells in the PNS, and by oligodendroglial cells in the CNS.

right hemisphere of brain

Nonverbal, visual, spatial, Intuitive

medulla oblongata

Part of the brainstem that controls vital life-sustaining functions such as heartbeat, breathing, blood pressure, and digestion.

somatic system

Part of the nervous system that controls voluntary muscles.

Alzheimer's disease

Progressive degeneration of the brain that ultimately results in dementia.

What is the function of myelin? What specific type of neurological process will be affected if myelin is damaged?

Protection and insulation of nerves; nerve conduction will be disrupted.

Discuss why two forms of memory are needed by the body.

Short-term memory is useful in managing operations within the present by holding a thought in mind. Long-term memory involves semantic and episodic memory as well as skill memory. It allows recall of the past and use of that information to shape future actions.

The nervous system interacts with which other body systems?

Skeletal system cardiovascular system muscular system endocrine system lymphatic system respiratory system digestive system reproductive system urinary system integumentary system

Briefly, how would you define what sleep is?

Sleep is a period of inactivity involving a suspension of consciousness, lack of responsiveness, and changes in brain wave activity. It is essential to health.

Of the several ideas presented here regarding the purpose of sleep, which one makes the most sense to you?

Sleep is a time for the brain to organize, and integrate through new connections, the information accumulated during the day. It is also a time for housekeeping functions performed by supportive cells in the brain.

Describe the interaction of the CNS and PNS.

The CNS is composed of the spinal cord and the brain. The PNS, which lies outside of the CNS, is composed of nerves and ganglia. Sensory fibers send information to the CNS and motor fibers conduct information away from the CNS to tissues and organs. Ganglia are areas of nerves that are collections of cell bodies.

sympathetic division

The branch of the autonomic nervous system that mobilizes the body's resources for emergencies.

Do you agree that the necessity of sleep for mammals and birds is one of the biggest mysteries in biology? Why do you think that the answer has eluded scientists for so long?

The difficulty in measuring the processes and actions of sleep contribute to the mystery.

Summarize the role of the major structure of the limbic system in memory.

The hippocampus within the limbic system is involved in learning and memory. It communicates with the prefrontal area of the brain in these functions.

Summarize the features of the autonomic system that are different from the somatic system.

The main difference between the somatic and autonomic systems is in what target tissues are effectors. Somatic responses are solely based on skeletal muscle contraction. The autonomic system, however, targets cardiac and smooth muscle, as well as glandular tissue.

Provide the neurological explanation for the following: You eat a big lunch, then go for a jog, during which your stomach starts to ache.

The neurological explanation for a stomachache after jogging might be that your brain directed more activity to the sympathetic system, and less to the parasympathetic. This could decrease peristalsis and direct blood away from the digestive system, leading to some discomfort.

grey matter

The portions of the central nervous system that are abundant in cell bodies of neurons rather than axons. Unmyelinated.

Describe the activity of the sodium-potassium pump present in neurons.

The sodium-potassium pumps in neurons are always transporting Na+ to the outside, and K+ to the inside of the cell.

Summarize the functions of the spinal cord.

The spinal cord is structured so that the brain can communicate with the peripheral nerves. This communication involves sensory and motor functions.

What are the major components of nervous tissue?

The three main components of the central nervous system are the brain, spinal cord, and neurons.

Identify the three classes of neurons, and describe their relationship to each other.

Three classes of neurons are sensory neurons, which take messages to the CNS; interneurons, which sum up messages from sensory neurons and other interneurons and communicate with motor neurons; and motor neurons, which take messages away from the CNS to effector organs, muscles, or glands.

Explain how the nerve impulse is transmitted across a synapse.

Transmission across a synapse from one neuron to another occurs when an action potential causes a neurotransmitter to be released at the presynaptic membrane. The neurotransmitter diffuses across a synaptic cleft and binds to a receptor in the postsynaptic membrane. An action potential may begin in the postsynaptic membrane if the concentration of incoming Na+ reaches threshold.

Describe the specific functions of Broca's and Wernicke's areas.

Wernicke's area is involved in the comprehension of speech; Broca's area is involved in the actual motor function of speech.

Explain why, if you touch a hot stove, you usually withdraw your hand before feeling the pain.

When you touch a hot stove, your hand withdraws before you feel the pain because the nerve pathway for a reflex arc travels directly through the spinal cord, without input from the brain.

Would MS cause more of a problem with the white matter or gray matter of the brain?

White matter, which contains myelinated axons, is disrupted by MS.

white matter

Whitish nervous tissue of the CNS consisting of neurons and their myelin sheaths.

Distinguish between Alzheimer disease and Parkinson disease.

With Parkinson's disease, the dopamine-releasing neurons in the brain degenerate. With lower levels of dopamine, motor control decreases, and involuntary tremors and muscular rigidity develop.

neurons

a nerve cell; the basic building block of the nervous system

Hippocampus

a neural center located in the limbic system; helps process explicit memories for storage

Hypothalamus

a neural structure lying below the thalamus; directs eating, drinking, body temperature; helps govern the endocrine system via the pituitary gland, and is linked to emotion

Dendrites

a neuron's bushy, branching extensions that receive messages and conduct impulses toward the cell body

refractory period

a period of inactivity after a neuron has fired

parasympathetic nervous system

a set of nerves that helps the body return to a normal resting state

Dementia

a slowly progressive decline in mental abilities, including memory, thinking, and judgment, that is often accompanied by personality changes

Which of the following does not act as a stimulant to the CNS? cocaine methamphetamine ecstasy alcohol

alcohol

Which of the following is correct regarding the autonomic nervous system? It uses both cranial and spinal nerves. It is divided into sympathetic and parasympathetic divisions. Most organs under ANS control are under dual innervation—that is, by both sympathetic and parasympathetic divisions. Major responsibilities are regulation and repair of cardiac muscle, smooth muscles, organs, and glands. All of these are correct.

all are correct

association areas

areas of the cerebral cortex that are not involved in primary motor or sensory functions; rather, they are involved in higher mental functions such as learning, remembering, thinking, and speaking

Guillain-Barre syndrome

ascending muscle weakness

Which of the following neuron parts receive(s) signals from sensory receptors of other neurons? cell body axon dendrites Both a and c are correct.

both cell body and dendrites

central nervous system

brain and spinal cord

Action Potential (AP)

buildup of electrical current in the neuron

sensory neurons

carry impulses from the sense organs to the spinal cord and brain

nerve fibers

carry messages to and from the brain

Memories are stored in the sensory association areas of the

cerebral cortex.

Cerrebellum

coordinates skeletal muscle movements. receives sensory input from the joints and muscles. receives motor output from the cerebral cortex.

myelin sheath

covers the axon of some neurons and helps speed neural impulses

Multiple Sclerosis (MS)

degenerative disease characterized by sclerotic patches along the brain and spinal cord

myasthenia gravis

descending musle weakness

amyotrophic lateral sclerosis (ALS)

disease with muscular weakness and atrophy due to degeneration of motor neurons of spinal cord; commonly called Lou Gehrig disease

A stroke results from

hemorrhage in the brain or a blockage of a blood vessel in the brain.

The regulation of the information that is to be relayed to memory is the function of the

hippocampus

This part of the brain forms the link between the nervous system and the endocrine system.

hypothalamus

prions

infectious protein particles that do not have a genome

Meningitis

inflammation of the meninges of the brain and spinal cord

A node of Ranvier (myelin sheath gap)

is a bare region of axonal membrane in myelinated axons only.

Cerebrum

largest part of the brain

When the action potential begins, sodium gates open, allowing Na+ to cross the membrane. This causes the charge on the inside of the neuron to become

more positive

Which of these correctly describes the distribution of ions on either side of an axon when it is not conducting a nerve signal? more sodium ions (Na+) outside and more potassium ions (K+) inside more K+ outside and more Na+ inside charged protein outside and Na+ and K inside Na+ and K+ outside and water only inside chloride ions (Cl−) outside and K+ and Na+ inside

more sodium ions (Na+) outside and more potassium ions (K+) inside

Neuroglia

nerve glue

limbic system

neural system located below the cerebral hemispheres; associated with emotions and drives

nervous system 2 types of cells

neurons and neuroglia

motor neurons

neurons that carry outgoing information from the brain and spinal cord to the muscles and glands

Interneurons

neurons within the brain and spinal cord that communicate internally and intervene between the sensory inputs and motor outputs

The neuroglia cells that form myelin sheaths in the CNS are called

oligodendrocytes.

Repolarization of an axon during an action potential is produced by

outward diffusion of K+.

Transmission of the nerve signal across a synapse is accomplished by the

release of a neurotransmitter by an axon.

Which of the following cerebral areas is not correctly matched with its function? occipital lobe—vision parietal lobe—somatosensory area temporal lobe—primary motor area frontal lobe—Broca's motor speech area

temporal lobe—primary motor area

nervous system

the body's speedy, electrochemical communication network, consisting of all the nerve cells of the peripheral and central nervous systems

Axon

the extension of a neuron, ending in branching terminal fibers, through which messages pass to other neurons or to muscles or glands

cerebrospinal fluid

the fluid in and around the brain and spinal cord

saltatory conduction

the jumping of action potentials from node to node

peripheral nervous system

the sensory and motor neurons that connect the central nervous system to the rest of the body

Parkinson's disease

this ailment, whose symptoms includes tremors and later difficulty walking, is caused by inability to produce dopamine

Meninges

three protective membranes that surround the brain and spinal cord

left hemisphere of brain

verbal, logical, analytical, rational

Would you agree that manufacturers should be required to display the caffeine content of soft drinks and energy drinks on the label? Why or why not?

yes. Because caffeine is a drug it should be reported, just like other ingredients are listed in the Nutrition Facts labels of foods.