Science Olympiad: Anatomy and Physiology (The Nervous System)
Flashcard set for the 2017 Science Olympiad Anatomy and Physiology: The Nervous System
Terms in this set (94)
As the anterior portion of the brain, the cerebrum consists of the left and right hemispheres, and controls higher functions in the human body.
A part of the brain that controls body movement, coordination, and balance. It is located in the bottom end of the brain.
The posterior part of the brain that controls the "flow" of messages from the brain to the rest of the body. (Composed of the midbrain, pons, and medulla oblongata). Other basic functions include heart rate and respiration.
A cylindrical bundle of nerve fibers/tissues that is enclosed in the spine and connects nearly all parts of the body to the brain, which helps for the CNS. It controls numerous reflexes.
A part of the brain that controls vision, hearing, motor control, and alertness (sleep and awakeness). It is located in the brainstem, and is positioned above the pons and medulla.
A part of the brain that controls respiration, sleep, balance, taste, the bladder, and facial muscles. It is located in the brainstem, and is positioned below the midbrain.
A part of the brain that controls circulation, digestion, sneezing, and swallowing. It is located in the brainstem, and is positioned next to the pons.
A portion of the diencephalon (consists of the thalamus and hypothalamus) and included in the limbic system, the thalamus helps control motor functions, as well as receiving sensory information and relaying it to the appropriate sensory organs.
(Part of the limbic system)
A portion of the diencephalon (consists of the thalamus and the hypothalamus) and included in the limbic system, the hypothalamus helps maintain homeostasis (the "stability" of the body), as well as emotion, hunger and thirst, and controls the autonomic nervous system.
(Part of the limbic system and controls hormones.)
A bundle of axons which connect the two hemispheres of the brain.
A pea-sized structure located underneath the hypothalamus which releases hormones to the body and activates bodily functions.
(Part of the limbic system)
An almond shaped mass of grey mattered involved with the experiencing of emotions.
(Part of the limbic system)
The ridges on the floor of each lateral ventricle. It is thought to be the center of emotion, memory, thought, and the autonomic nervous system.
(Part of the limbic system)
A portion of the brain relating to the control of movement.
Left and Right Ventricles
Structures within the brain that contain cerebrospinal fluid (a clear fluid that helps cushion the brain and clear waste from the brain, also known as CSF).
Third and Fourth Ventricles
Structures of the brain that also contain cerebrospinal fluid, and serve the same function and work in junction with the left and right ventricles.
A portion of the brain associated with motor speech control and effective speaking.
A portion of the brain that is associated with the comprehension of speech.
(In mammals) helps produce milk to feed offspring.
Part of the limbic system, the fornix carries signals from the hippocampus to the mammillary bodies and then to the anterior nuclei of thalamus. It is involved in memory and recognition.
Produces CSF in the ventricles of the brain and consists of ependymal cells.
Bundles of neurons in the CNS.
Bundles of neurons in the PNS.
Receives sensory information and influences spatial orientation.
Detects and interprets visual images.
Interprets and recognizes auditory information.
Governs thought and emotion.
A small endocrine gland that produces melatonin, which regulates sleep.
Located at the back of the eye, optic nerves transfers information from the eye to the brain. The optic chiasma is the structure of the body in which two optic nerves form an X-shaped structure. It is formed at a point below the brain.
A ridge or fold between 2 clefts on the cerebral surface of the brain.
Controls most of the brain's neuronal cell bodies, and is involved in the control of muscles and sensory perception.
Composed of bundles of axons which connect grey matter together and carries nerve impulses between neurons.
Involved in planning and execution of voluntary movements. It consists of the primary motor cortex (which generates impulses down to the spinal cord and is a major component in this process), the premotor cortex (which prepares/plans movement and has some influence on spatial reasoning), and the supplementary motor cortex (which contributes to the control of movement).
The 3 membranes that envelop the skull, brain, and the spinal cord. They are (listed from uppermost to most bottom layer): the dura mater, the arachnoid, and the pia mater. CSF is found between the arachnoid and pia maters, and help cushion those areas.
Gyri and Sulci
Gyri are ridges on the brain's surface, while sulci are fissures. Sulci are found in between gyri.
Conducts impulses between hemispheres and form corpus callosum.
Conducts impulses in and out of the cerebral hemispheres.
Conducts impulses within the cerebral hemispheres.
Types of Neurons
Sensory neurons help transmit sensory information to the brain/spinal cord. Motor neurons release the neurotransmitter achetylcholine, which bind to postsynaptic receptors and result in muscle movement. Interneurons (the most abundant neuron) create neural circuits, and transmit impulses to other neurons. (There are 2 types of interneurons -- local, which have small axons and process little bits of information, and relay which have longer axons and perform complex functions.)
Central Nervous System (CNS)
The complex of nervous tissues/fibers that controls the body. It is composed of the brain and the spinal cord.
Peripheral Nervous System (PNS)
The nervous system outside of the brain and spinal cord (nerve cells etc).
Autonomic Nervous System (ANS)
A portion of the brain that controls involuntary processes of the body (breathing, heartbeat, digestion etc); it consists of the parasympathetic nervous system and the sympathetic nervous system.
Sympathetic Nervous System
A part of the ANS that controls and activates the "flight or fight" response.
Parasympathetic Nervous System
A part of the ANS that controls and maintains homeostasis, as well as rest and digestion.
Somatic Nervous System
A part of the brain that is part of the PNS which controls voluntary skeletal and muscular movements.
An encephalographic waveform that are associated with normal consciousness and heightened alertness, logic, and reasoning. (12-40 Hz)
Present when a person is relaxed. (8-12 Hz)
An EEG waveform that is present in deep meditation or light sleep. (4-8 Hz)
EEG waveform shown in deep sleep. (0-4 Hz)
EEG involved in higher processing skills and cognitive functions. Important for learning new things. (40-100 Hz)
A cell that transmits nerve impulses (located in the PNS)
Physiology of a neuron (Dendrite)
Receives electrical messages from other neurons.
Physiology of a neuron (Soma aka Cell Body)
A part of a neuron that contains the nucleus and connects to the dendrites. It brings information to the cell and the axon, which transmits the information to other cells.
Physiology of a neuron (Nucleus)
Contains genetic material (chromosomes) that include information for cellular development and proteins necessary for cellular maintenance and survival.
Physiology of a neuron (Axon)
Sends information to other cells.
Physiology of a neuron (Myelin Sheath)
A fatty white substance that covers the axon. Its function is to protect the axon and enhance the transmission of impulses.
Physiology of a neuron (Node of Ranvier)
Gaps in between the myelin sheath. They allow impulses to quickly propagate inside the axon.
A mixture of proteins and phospholipids that creates the whitish substance around the nerve fibers in a neuron. They help increase the speed at which nerve impulses are conducted.
Physiology of a neuron (Axon Terminal Button)
A structure at the end of a neuron that helps transmit a neurotransmitter from one neuron to another.
Chemical messengers that carry signals to other parts of the human body.
Ionic basis of cellular membrane potential (resting potential)
When a neuron is not sending a signal, the inside of the neuron is negative relative to the outside. At rest, K+ ions can cross the membrane easily while the Na+ cannot as easily. The sodium-potassium pump removes 3 sodium ions for every 2 potassium ions it lets in. When all forces balance out, the voltage between the inside and outside of the neuron are measured -- this is called resting potential. (Usually -70 mV; more sodium ions outside than potassium ions inside.)
Action potential: Generation
Action potential occurs when a neuron sends information down the axon, away from the cell body. Such stimulus causes the resting potential to move towards 0 mV, and when the depolarization reaches about -55 mV the neuron will fire an action potential. The "all or none" principle states that the neuron will not fire as long as this threshold is not met. Action potentials are caused when different ions cross the neuron membrane. A stimulus causes the sodium channels to open because of the concentration gradient, allowing the neuron to become more positive and depolarize. The plateau at which the sodium concentration is highest is usually around 30-40 mV. When the potassium channels open, however, the depolarization is reversed, and slowly go back to -70 mV. Usually, the action potential goes past -70 mV because the potassium channels stay open a little too long. Gradually the potential returns to resting potential.
Action potential: Propagation
Impulses are carried from one axon to another neuron through synapses and neurotransmitters. Positive ions outside of the neuron flood into it, changing the inside from negative to positive. It moves down the axon.
From the axon to the dendrite
For communication to occur between two neurons, an electric impulse must be conducted from the axon to a synaptic terminal, where neurotransmitters are stored and released. At the terminal, the impulse will trigger the neurotransmitters to be released (they are stored in vesicles). These neurotransmitters then travel across the synaptic cleft (a junction between two neurons) and bind to receptors located on the postsynaptic neuron in order for the effect to be performed. This changes the postsynaptic neuron's excitability. Picture applies for both parts.
From the axon to the dendrite (continued)
Whether the postsynaptic cell will fire and the impulse be continued is determined by the number of events of postsynaptic activity. The impulse is conducted through the neurons in this fashion. Excess neurotransmitters are broken down by enzymes. This enzyme is called acetylcholinesterase. Picture applies for both parts.
Types of Neuroglial Cells: Astrocyte (CNS)
Help form the blood-brain barrier, supply nutrients to neurons, and help regulate the extra cellular chemical environment most notably, removing potassium ions, in order to keep the concentration gradient. These are the most numerous of the CNS glial cells. (The blood-brain barrier is a "wall" that prevents certain chemicals/materials from entering the brain/spinal cord)
Types of Neuroglial Cells: Oligodendrocyte (CNS)
These are similar to Schwann cells, but in the CNS. Like Schwann cells, they provide myelination to axons. However, they are able to myelinate many axons around they instead of just one. (Myelin is a whitish substance that protects the axon of a neuron and increases the speed at which impulses travel within it.)
Types of Neuroglial Cells: Microglia (CNS)
They protect the neurons from bacteria and viruses through phagocytosis. These are the least numerous of the CNS glial cells, and they help clean up debris within the brain. (Phagocytosis is the ingestion of bacteria or other materials by phagocytes.)
Types of Neuroglial Cells: Ependymal Cells (CNS)
Also called ependymocytes, these line the walls of the ventricles and produce cerebrospinal fluid. They also have cilia that they beat in order to move CSF. Also, they make up the blood CSF barrier. Lastly, they also are believed to be neuronal stem cells.
Types of Neuroglial Cells: Schwann Cells (PNS)
These cells myelinate PNS axons. All cells -- even the unmyelinated ones -- in the PNS are surrounded by Schwann cells. When myelinating, Schwann cells can only surround one axon. However, they can surround many unmyelinated axons at once. They also undergo a small amount of phagocytotic activity, as they clear debris.
Types of Neuroglial Cells: Satellite Cells (PNS)
These cells are similar to astrocytes in that they regulate the extracellular chemical environment. They are different in that this is their only main job.
Physiology of the Spinal Cord
The spinal cord is divided into 31 pairs of nerves, making 62 nerves composed of sensory and motor neurons. The nerves are named off of where they leave the spine. They are divided into 5 groups, cervical, thoracic, lumbar, sacral, and coccygeal.
Physiology of the Spinal Cord: Cervical Nerves
Provide movement and sensation for the head, neck, diaphragm, upper limbs, and the back.
Physiology of the Spinal Cord: Thoracic Nerves
Responsible for sending information to the brain, spine, abdomen, and torso. Such signals include pain receptors and muscle movement.
Physiology of the Spinal Cord: Lumbar Nerves
Provides movement and sensation for the muscles from the abdomen to the gluteus maximus (buttocks).
Physiology of the Spinal Cord: Sacral Nerves
Provides movement and sensation for the hip, thigh, leg, and foot (the lower body).
Stages of Sleep: Stage 1
This is a light sleep; a person can be awakened easily. The eyes move slowly and muscle activity decreases. He/she may have slight muscle contractions during this period, and may feel like he/she is falling.
Stages of Sleep: Stage 2
Eye movement stops and brain waves become slower, with occasional bursts of brain waves.
Stages of Sleep: Stage 3
Extremely slow brain waves (delta) are mixed with occasional faster waves (theta). Stages 3 and 4 are known as deep sleep. It is very difficult to wake someone up during these two periods.
Stages of Sleep: Stage 4
Delta waves are produced almost exclusively. Stages 3 and 4 are known as deep sleep. There are no muscle/eye movements, and this is when people may start experiencing nightmares, sleepwalking, or bedwetting. *Note: In 2008 the US banned the usage of Stage 4 sleep, and combined it with Stage 3 sleep since the descriptions of these two stages are almost similar.
Stages of Sleep: REM Sleep
During this period, breathing becomes more rapid and eyes jerk randomly. The limbs become temporarily paralyzed, and blood pressure rises. If a person is woken during REM sleep, he/she is most likely to remember their dreams.
Physiology of the PNS
Nerves and ganglia (a cluster of nerve cells) not located in the CNS form two systems: afferent (sensory) and efferent (motor control) nervous systems. The efferent nervous system is then furthermore split into the ANS and the Somatic Nervous System. (Refer to other flashcards for definitions.) Afferent pathways conduct impulses to the CNS while efferent pathways conduct impulses to the effector (the gland that responds.)
Nervous System Disorder: Epilepsy
A disorder that causes people to have unprovoked or unexpected seizures. A person is considered to have epilepsy once he or she has gone through this two times or more. Epilepsy has a varying amount of physical and mental incapacitations depending on the severity of the seizures. Causes of epilepsy include the deprivation of oxygen when the fetus was inside the maternal organism, a brain infection, head or brain injury, strokes, tumors, and/or Alzheimer's Disease.
Nervous System Disorder: Alzheimer's Disease
A disease that occurs usually to people 65 and over, this disease is progressive. It attacks the neurons of the nervous system, and results in loss of memory, thinking and language skills, and changes in behavior.
Nervous System Disorder: Parkinson's Disease
A chronic and progressive disorder that causes the malfunction and death of neurons. Results of this include tremors, slow movement, rigidness of the body, and impaired balance and coordination. Caused by a loss of dopamine. Most commonly appears in people 50-60.
Nervous System Disorder: Multiple Sclerosis (MS)
A chronic disabling disease that attacks the CNS, most commonly myelin. When myelin is distorted, nerve impulses are destroyed or interrupted, resulting in the numbness of the limbs (mild) up to paralysis and loss of vision (severe). Symptoms also include tremors, anxiety, heat intolerance, overactive reflexes, and the abnormality of taste. Other symptoms include slurred speech and mood swings. Autoimmunity causes this, as well as genetic disorders and environmental factors. MS most commonly occurs in Caucasians.
Nervous System Disorder: Cerebral Palsy
A disorder that affects muscle tone, movement, and motor skills; usually caused by prenatal brain damage or during first 3-5 years of a child's life. The brain damage may lead to other health issues including vision, hearing, speech problems, and learning disabilities. There are three types: spastic cerebral palsy (stiffness and movement difficulties), athetoid cerebral palsy (involuntary and uncontrolled movements), and ataxic cerebral palsy (disturbed sense of balance and depth perception). Causes include hypoxia (low oxygen levels in the fetus), a maternal infection during pregnancy, and trauma/damage to the fetal brain.
Nervous System Disorder: Shingles (Herpes Zoster)
Caused by varicella (the virus that causes chickenpox), shingles is a rash that usually occurs where skin cells connect with the spinal cord. Can be treated with medications such as Acyclovir, Valacyclovir, and Famciclovir.
Nervous System Disorder: Glaucoma
Glaucoma is a group of diseases that can damage the eye's optic nerve and result in vision loss and blindness. While glaucoma can strike anyone, the risk is much greater for people 40 and over. The most common type of glaucoma is called open-angle glaucoma. In the normal eye, the clear fluid leaves the anterior chamber at the open angle where the cornea and iris meet. When fluid reaches the angle, it flows through a spongy meshwork, like a drain, and leaves the eye. Sometimes, when the fluid reaches the angle, it passes too slowly through the meshwork drain, causing the pressure inside the eye to build. If the pressure damages the optic nerve, open-angle glaucoma -- and vision loss -- may result. Eye drops/pills and surgery can help cure this malady.
Nervous System Disorder: Pink Eye (Conjunctivitis)
Pink eye (conjunctivitis) is an inflammation or infection of the transparent membrane (conjunctiva) that lines your eyelid and covers the white part of your eyeball. When small blood vessels in the conjunctiva become inflamed, they're more visible. This is what causes the whites of your eyes to appear reddish or pink. Pink eye is commonly caused by a bacterial or viral infection, an allergic reaction, or, in babies, an incompletely opened tear duct.
Effects of Alcohol on the Nervous System
Alcohol is a central nervous system depressant. It acts at many sites, including the reticular formation, spinal cord, cerebellum and cerebral cortex, and on many neurotransmitter systems. It gets into the bloodstream easily, and in low doses it creates relaxation, impairs concentration, and impairs coordination and focus. In medium doses it slurs speech, causes fatigue, and alters emotions. In high doses, it induces vomiting, breathing difficulties, unconsciousness, and comas. Slows down nervous system.
Effects of Caffeine on the Nervous System
Caffeine is an alkaloid which acts as a stimulant drug. Caffeine causes the user to have high alertness and attention. When overused, though, the user builds up a tolerance to it. Suppresses melatonin and increases adrenaline.
Effects of Nicotine on the Nervous System
Nicotine is an alkaloid which constitutes about 0.6-3% of tobacco plants. As well as being a chemical, which, when contained in plants, resists animal consumption, it is also a stimulant for mammals. About 1 milligram is contained in the average cigarette, and it is responsible for the addiction to smoking. When nicotine enters the body, it quickly enters the bloodstream. When it binds to receptors in the central nervous system, they "turn up the volume" on neurotransmitters. Nicotine may increase heart rate, increase respiration, and constrict blood vessels. Decreases the amount of neurotransmitters released, and user builds up a tolerance to it.
Effects of Marijuana on the Nervous System
Marijuana comes from a plant called "cannabis sativa"; the chemical in the plant that produces the altered states of consciousness is called "delta-9 tetrahydrocannabinol" or "THC". THC acts on cannabinoid receptors, which are found on neurons in many places in the brain. These areas are involved in memory (hippocampus), concentration (cerebral cortex), perception (sensory portions of the cerebral cortex), and movement (cerebellum, substantia nigra, globus pallidus). In low-medium doses, marijuana causes relaxation, reduces coordination, reduces blood pressure, induces sleepiness, disrupts attention, and creates an altered sense of time and space. In high doses, marijuana induces hallucinations, creates delusions, impairs memory, and provokes disorientation. Literally suppresses learning and limbic system (emotion and memory).