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133 Cards in this Set
- Front
- Back
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What is the Central Nervous System? |
The body's coordinating centre for mechanical and chemical actions; made up of the brain and spinal cord. |
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What is the Peripheral Nervous System? |
All parts of the nervous system, excluding brain and spinal cord, that relay information between the central nervous system and other parts of the body. |
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What is a glial cell? |
Nonconducting cell important for structural support and metabolism of the nerve cells. |
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What is a neuron? |
A nerve cell that conducts nerve impulses. |
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What is a dendrite? |
Projection of the cytoplasm that carries impulses TOWARDS the cell body. |
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What is an axon? |
Extension of the cytoplasm that carries nerve impulses AWAY from the cell body. |
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What is the myelin sheath? |
Insulated covering over the axon of a nerve cell. |
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What is a Schwann cell? |
A special type of glial cell that produces the myelin sheath. |
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What are the Nodes of Ranvier? |
Regularly occurring gaps between sections of myelin sheath along the axon. |
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What is the neurilemma? |
The delicate membrane that surrounds the axon of some nerve cells. |
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What is the nervous system? |
An elaborate communication system that: 1. Gathers Data 2. Transmits 3. Interprets 4. Responds to information |
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Which two systems coordinate together to maintain homeostasis? |
The nervous and endocrine system. |
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How is the Nervous System organized? |
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What is the function of somatic nerves, and each division of the somatic nerves? |
Somatic nerves control the skeletal muscles, bones, and skin. Sensory somatic nerves relay information about the environment to the CNS. Motor somatic nerves initiate the appropriate response. |
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What is the function of autonomic nerves, and each division of the autonomic nerves? |
Autonomic nerves contain special motor skills that control your inner organs. The Sympathetic and Parasympathetic nervous system act as an "off and on" switch. |
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Which structural features do all neurons have? |
Dendrites, cell bodies, and axons. |
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What is/is the function of glial cells? |
They are nonconducting and offer structural support and metabolism of nerve cells. |
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What is/is the function of a neuron? |
Neurons are the functional units of the nervous system that function to process and transmit information. |
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What is/is the function of a dendrite? |
To receive information from the environment and neutrons and conduct nerve impulses TOWARDS the cell body. |
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What is/is the function of an axon? |
To conduct nerve impulses AWAY from the cell body. Neurons only have one axon that branches out, and carries nerve impulses to other neurons or effectors. Axons are very small. |
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What is/is the function of the Myelin Sheath? |
The Myelin Sheath covers the axon and acts as insulation to prevent the loss of charged ions from the nerve cell. It also keeps the electrical current strong - so it doesn't dissipate. It is a white fatty protein. |
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What is/is the function of Schwann Cells? |
The Schwann cells produce the Myelin Sheath. |
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What is the function of the Synaptic Knob (Axon Terminal)? |
The S.K passes nerve impulses to the next neuron/dendrite/effector. |
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What is saltatory conduction? |
S.C is when nerve impulses jump from one Node of Ranvier along a myelinated neuron, which speeds the movement of nerve impulses. |
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What factors allow neural impulses to move quicker? |
Myelinated neuron = faster nerve impulses due to saltatory conduction. Larger diameter = faster neural impulses. |
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What is/is the function of the Neurilemma? |
The Neurilemma is the outer membrane that surrounds all nerve fibres in the PNS. It surrounds axons and is formed by Schwann cells. The Neurilemma promotes regeneration of damaged axons. * not all myelinated cells have a neurilemma |
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What is white matter? What is grey matter? |
White matter are the nerves in the brain that have myelinated fibres. Has a neurilemma. Grey matter lacks a myelin sheath. Lacks the neurilemma. |
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What are the three types of neurons? |
Sensory neurons, interneurons, and motor neurons. |
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What is/is the function of sensory neurons (afferent)? What are the distinct physical features? |
Sensory neurons have have long dendrites and a short axon, and the cell bodies are located in the ganglia. Sensory neurons relay info (stimuli received from sensory receptors) to the CNS for processing. |
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What is/is the function of interneurons (association)? What are the distinct physical features? |
Interneurons have short dendrites and axons and only exist in the CNS. They integrate and interpret sensory information, and connect sensory neurons to the outgoing motor neurons. |
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What is/is the function of motor neurons (efferent)? What are the distinct physical features? |
Motor neurons have short dendrites and long axons. They rely information to the effectors - respond to the stimulus. Effectors = the muscle/organ/glands that produce responses. |
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What neuron is this? |
Motor neuron. |
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What neuron is this? |
Sensory neuron. |
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What neuron is this? |
Interneuron. |
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What is the sequence of the reflex arc? |
stimulus ---> sensory neuron ---> spine/interneurons ---> motor neurons ---> causes effector to contract |
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Why doesn't the stimulus travel to the brain in the reflex arc? |
Reflexes are involuntary and unconscious and stimuli do not travel to the brain because your body needs a quick response so the stimulus causes less damage. |
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What is an action potential? |
The voltage difference across a nerve cell membrane when the nerve is excited. |
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What is the resting potential? |
The voltage difference across a cell membrane when it is not transmitting a nerve impulse (usually negative). |
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What is facilitated diffusion?
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The transport of substances across a cell membrane down a concentration gradient by a carrier in a membrane; does not use energy. |
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What is a gated ion channel? |
A pore in the cell membrane that allows ions to move in and out of the cell by opening and closing. |
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What is the sodium-potassium pump? |
A transporter in the cell membrane that moves potassium ions into the cytoplasm, while simultaneously removing sodium ions from the cytoplasm to the ECF. |
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What is active transport? |
The movement of substances across cell membranes that uses energy; often moves substances against a concentration gradient. |
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What is a polarized membrane? |
A membrane charged by unequal distribution of positively charged ions inside and outside the nerve cells. |
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What is depolarization? |
Diffusion of sodium ions into the nerve cell, resulting in a charge reversal. |
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What is repolarization? |
The process of restoring the original polarity of the nerve membrane. |
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What is hyperpolarization? |
The condition in which the inside of the nerve cell membrane has a greater negative charge than the resting membrane; caused by excessive diffusion of potassium ions out of the cell. |
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What is the refractory period? |
The recovery time required before a neuron can produce another action potential. |
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What is saltatory conduction? |
The generation of action potentials only at the Nodes of Ranvier in myelinated axons, resulting in rapid transmission of nerve impulses. |
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What is the threshold level? |
The minimum level of a stimulus required to produce a response. |
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What is the all-or-none response? |
A nerve or muscle fibre responds completely or not at all to a stimulus. |
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What is a synapse? |
A region between neurons, or between neurons and effectors; also known as the synaptic cleft. |
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What is a neurotransmitter? |
The chemical messenger released by the presynaptic neuron, that binds to receptors on the postsynaptic neuron. |
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What is the presynaptic neuron? |
The neuron that carries impulses to the synapse. |
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What is the postsynaptic neuron? |
The neuron that carries impulses away from the synapse. |
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What is summation? |
An effect produced by the accumulation of the neurotransmitters from two or more neurons. |
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What is acetylcholine? |
The neurotransmitter released from vesicles in the end plates of neurons, which makes the post synaptic membranes more permeable to Na+ ions. |
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What is cholinesterase? |
An enzyme which breaks down acetylcholine, that is released from the presynaptic membranes in the end plates of neurons shortly after acetylcholine. |
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What are nerve impulses? |
Electrochemical messages created by the movement of ions through the nerve cell membrane. |
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What are the values - in mV - of the resting potential and depolarized potential? |
Resting potential = -70mV Excited neuron = +40mV |
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Describe the resting potential/polarized state. |
There are more K+ ions inside the cell, and more Na+ ions outside the cell. The movement of K+ ions creates the electrical gradient - 2 K+ out and 3 Na+ in, as when K+ leaves the cell, the outside of the cell becomes positively charged. The charge of the plasma membrane of almost all cells is -70mV. Excess positive ions accumulate outside the membrane and excess negative ions accumulate inside the membrane. |
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Describe depolarization. |
During depolarization, the neuron receives a stimulus making the cell membrane more permeable to sodium than potassium. Sodium channels open and sodium ions rush inside the membrane through facilitated diffusion. The influx of positively charged Na+ ions causes a flip in charges - now the inside is positive, and outside is negative. The charge is now +40 mV. |
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Describe repolarization. |
During repolarization, due to the positively charged inside, the potassium channels open. K+ ions rush out via facilitated diffusion. Repolarization makes attempts at restoring the original polarity. |
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Describe hyperpolarization. |
After repolarization, the K+ channels close slowly, so even more positively charged ions escape. Now the inner membrane is even more negatively charged than the resting potential. |
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Describe the refractory period. |
After hyperpolarization, the sodium-potassium pumps transport Na+ ions out of the cell, and K+ ions into the cell. The time taken to return back to resting potential after depolarization is the refractory period. |
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Describe this image. |
A = depolarization B = repolarization C = hyperpolarization |
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Describe this image. |
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Draw and Label a synapse. |
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Explain what happens when you increase the intensity of stimuli above the threshold level. |
It will not generate an increased response because of the all-or-none response, as the intensity and speed of the nerve impulse stays the same. |
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Explain how you can can feel the difference between warm and hot. |
The stimulus of warm and hot is the same intensity, but the hot stimulus operates at a greater frequency. A greater frequency of neural impulses allows for an effect of greater intensity. The brain can differentiate between hot and warm simply because it can recognize differences in frequency. |
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Describe the process of synaptic transmission. |
The endplates of axons contain chemicals called neurotransmitters. When an impulse moves along an axon, neurotransmitters are released from the presynaptic neuron, and diffuse across the synapse creating a depolarization of the dendrites in the postsynaptic neuron when the neurotransmitters bind to receptors. |
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What is the function of neurotransmitters? |
Neurotransmitters alter membrane potentials of postsynaptic neurons |
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Describe the function and use of acetylcholine. |
Acetylcholine - an excitatory neurotransmitter found in the end plates of many nerve cells - opens Na+ channels on postsynaptic membranes, causing depolarization and an action potential. |
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What is wrong with a constant secretion of acetylcholine? How is this combatted? |
When Na+ channels are open, the membrane is in a constant state of depolarization. No recovery time means no next impulse. To combat this effect, the presynaptic membrane also releases cholinesterase, which destroys the acetylcholine. This allows the neurons to recover. |
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What is the role of inhibitory neurotransmitters? |
INT makes postsynaptic membranes more permeable to K+ ions. The rush of K+ causes K+ to diffuse out, which generates a greater number of positive ions relative to the inside. The cell membrane becomes hyperpolarized and inhibits any action potentials and prevents postsynaptic neurons from being active. *Norepinephrine and Acetylcholine can be inhibitory or excitatory. |
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Use an image to describe summation. |
Sometimes the sum of many neural impulses is needed to create an action potential. In the diagram, neither A or B alone could induce an A.P, but the sum of both excitatory neurons can induce an action potential. |
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Describe the causation and effect of Parkinson's and Alzheimers. |
Parkinson's causes involuntary muscle contraction due to inadequate levels of dopamine production. Alzheimer's is a deterioration of one's mental capacity and is caused by decreased production of acetylcholine. |
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Describe the movement of action potentials. |
Action potentials don't move, instead, many action potentials are generated one after the either causing a wave of depolarization. The first action potential generated causes depolarization, and the flow of positive ions from a depolarized area to resting membrane creates an electrical disturbance. This electrical stimulus causes sodium channels in the resting membrane to open, triggering an action potential next to the first one. This cycle repeats. |
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Explain norepinephrine's role as a neurotransmitter. |
Norepinephrine can either be an excitatory or inhibitory neurotransmitter that is secreted in both the CNS and PNS. It causes wakefulness. |
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What stops action potentials from going backwards? |
During the refractory period, cell membranes can't produce another action potential because it's hyper polarized. So, the new action potential can only be triggered @ the leading edge of the first depolarized area. |
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What is the meninges? |
The protective membranes that surround the brain and spinal cord. |
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What is cerebrospinal fluid? |
The cushioning liquid that circulates between the innermost and middle membranes of the brain and spinal cord; it provides a connection between neural and endocrine systems. |
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What is the cerebrum? |
The largest and most highly developed part of the human brain, which stores sensory information and initiates voluntary motor activities. |
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What is the cerebral cortex? |
The outer layer of the cerebral hemisphere. |
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What is the corpus callosum? |
The nerve tract that joins the two cerebral hemispheres. |
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What is the thalamus? |
The area of the brain that coordinates and interpretes sensory information, and directs it to the cerebrum. |
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What is the hypothalamus? |
The area of the brain that coordinates many nerve and hormone functions. |
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What is the olfactory bulb? |
The area of the brain that processes information about smell; there's one bulb in each hemisphere. |
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What is the cerebellum? |
The part of the hindbrain that controls limb movements, balance, and muscle tone. |
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What is the pons? |
The region of the brain that acts as a relay station by sending nerve messaged between the cerebellum and medulla. |
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What is the medulla oblongata? |
The region of the hindbrain that joins the spinal cord to the cerebellum; on elf the most important sites of autonomic nerve control. |
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What is/is the function of the brain? |
The brain is formed from a concentration of nerve tissue that acts as the coordinating centre of the nervous system. |
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What is/is the function of the meninges? |
The meninges is a tough three-layer membrane that protects the brain with the help of the skull. outer = dura mater middle = arachnoid mater inner = pia mater |
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What is/is the function of cerebrospinal fluid? |
The cerebrospinal fluid circulates between the inner and middle meninges later, and the central canal of the spinal cord. The fluid acts as a shock absorber and transport medium that carries nutrients to the brain cells and relays waste from the cells to blood. |
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What is/is the function of the spinal cord? |
The spinal cord carries sensory nerve messages from receptors to the brain, and relays motor nerve messages from the brain to effectors. |
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Which neurons coordinate with white and grey matter? |
white matter = sensory and motor neurons grey matter - interneurons |
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What is/is the function of the vertebral column? |
The vertebral column protects the spinal cord. |
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What is/is the function of the dorsal and ventral root? |
The dorsal root brings sensory information to the spinal cord. Sensory nerves enter the spinal cord through the dorsal root. The ventral root carries motor information from the spinal cord to effectors. Motor nerves leave through the ventral root. |
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What are the three parts of the brain? |
Forebrain, midbrain, and hindbrain. |
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Which parts of the brain are in the forebrain? |
Cerebrum (left and right hemisphere -->occipital, temporal, frontal, and parietal lobes), thalamus, hypothalamus, and olfactory bulbs. |
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What is/is the function of the cerebrum? |
It is the largest part of the forebrain, and is divided into a right and left hemisphere, and further divided into four lobes. It is the major coordinating centre where sensory and motor information originates. The surface of the cerebrum is composed of the cerebral cortex - which is composed of grey matter. |
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What is/is the function of the frontal lobe? |
The frontal love controls voluntary movement, intellectual activities, some memory, personality, and inhibition of bad behaviour. The motor cortex in the frontal lobe controls movement. Electricity is used to stimulate muscles. The greater number of nerve tracks means more movement. |
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What is/is the function of the temporal lobe? |
The temporal lobe deals with hearing, vision, memory, and interpretation of sensory information. |
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What is/is the function of the occipital lobe? |
The occipital lobe deals with vision. |
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What is/is the function of the parietal lobe? |
The parietal lobe deals with touch, temperature awareness, emotions, speech interpretation, pain, and links to memory. |
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What is/is the function of the right hemisphere of the cerebrum? |
Visual patterns, spatial awareness, art, creativity. |
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What is/is the function of the left hemisphere of the cerebrum? |
Verbal skills, logic, reasoning, order. |
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What is/is the function of the thalamus? |
The thalamus acts as the relay station that directs incoming sensory info to the cerebrum for interpretation. |
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What is/is the function of the corpus callosum? |
The corpus callosum allows for communication between the right and left hemisphere. |
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What is/is the function of the hypothalamus? |
The hypothalamus is a small part of the brain that maintains body equilibrium, connects to the pituitary gland (unites nervous and endocrine system), and regulates body responses (aka blood pressure, heart rate, temperature). |
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What is/is the function of the olfactory bulbs? |
To receive and interpret smell. |
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What is/is the function of the mid brain? |
The mid brain consists of four spheres of grey matter. It acts as a relay centre for eye and ear reflexes by relaying visual and auditory info between the forebrain and hypothalamus. Controls skeletal muscles. |
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Which parts of the brain are in the hind brain? |
Cerebellum, pons, and medulla oblongata. |
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What is/is the function of the cerebellum? |
The cerebellum is the largest section of the hind brain and controls limb movement, balance, and muscle tone. It receives information from proprioceptors for balance maintenance, and also controls excitatory and inhibitory nerve impulses for movement. |
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What is/is the function of the Pons? |
The pons is a bridge that passes information between regions of the cerebellum, or between the cerebellum and medulla. |
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What is/is the function of the medulla oblongata? |
Right below the Pons, the medulla controls involuntary muscle action by acting as the coordinating centre for the autonomic nervous system. It is the connection between the PNS and CNS. |
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Why does caffein and other drugs have such quick and drastic effects on the brain? |
Lipid based molecules move across the lipid bilayer of the brain via capillary cells, so lipid soluble materials have rapid effects on brain function. |
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What is the sympathetic nervous system? |
The nerve cells of the autonomic nervous system that prepares the body for stress. |
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What is the parasympathetic nervous system? |
The nerve cells of the autonomic nervous system that returns the body to normal resting levels after adjustments to stress. |
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Label all parts of the brain. |
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Label each lobe. |
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What is the vagus nerve? |
A major cranial nerve that is part of the parasympathetic nervous system. |
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What are the two division of the PNS? |
1. Sensory - somatic 2. Autonomic nervous system Both are composed of sensory receptors. They run from stimulus receptors --> CNS, then motor neurons from CNS --> effectors. |
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What is/is the function of the sensory somatic nervous system? |
Sensory-somatic nerves respond to external stimuli and sends this information via sensory neurons to the CNS. The CNS then initiates a response via motor neurons. All conscious awareness of surroundings + our actions to cope with these are controlled through the somatic system. |
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What is/is the function of of the autonomic nervous system? |
The autonomic nervous system responds to internal stimuli and sends this information via sensory neurons to the CNS. The CNS then regulates your internal environment. The ANS controls involuntary action, smooth and cardiac muscles, and your internal organs. Ex. breathing + bloody oxygen levels |
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What is/is the function of cranial nerves? |
Cranial nerves within the somatic system control vision, hearing, balance, taste/smell, face/tongue movement, and head/neck muscles. |
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How do the somatic and autonomic system differ anatomically? |
The ANS uses two groups of motor neurons to stimulate effectors. |
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What are the two groups of motor neurons used by the ANS, and what role do they play? |
1. Preganglionic nerves - run from the CNS ---> ganglion ---> connect with the second group. 2. Postganglionic nerves - runs to the target effector. |
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What are the two antagonistic units of the ANS? |
The sympathetic and parasympathetic nervous systems. |
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What is/is the function of the sympathetic nervous system? |
The sympathetic nervous system prepares the body for stress. It has short preganglionic nerves that release acetylcholine, and long postgalionic nerves that release norepinephrine (excitatory, actives muscles). |
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What is/is the function of the parasympathetic nervous system? |
The parasympathetic nervous system reverses the effect of the SNS by restoring the body back to normal after stress. It has long pre ganglionic nerves that release acetylcholine, and short postganglionic nerves that release acetylcholine and nitric oxide. An important cranial nerve of the PSNS is the vagus nerve, which supplies the heart, bronchi, liver, pancreas and digestive tract. |
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What is the effect of the sympathetic nervous system on the heart, digestive system, liver, eyes, bladder, skin, adrenal gland, and muscles? |
Increase heart rate, release of glucose in liver, and blood flow to skin and muscles. Decrease peristalsis in the digestive tract. Pupils dilate, sphincters relax in bladder, and epinephrine is released from the adrenal gland. |
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What is the effect of the parasympathetic nervous system on the heart, digestive system, liver, eyes, bladder, skin, adrenal gland, and muscles? |
Increase in peristalsis in the digestive tract. Decrease in heart rate and blood flow to the skin and muscles. Glucose is stored in the liver, pupils constrict, sphincters contract in the bladder, and there is no effect on the adrenal gland. |
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What triggers the movement of vesicles to the plasma membrane during synaptic transmission? |
When an action potential reaches an axon endplate, Calcium ions enter the endplate to facilitate the movement of vesicles to the plasma membrane. |
