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116 Cards in this Set
- Front
- Back
Action Potential
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A brief change in the electrical charge across the plasma membrane of a nerve or muscle cell due to the movement of ions across the membrane. The mechanism by which impulses travel down neurons
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Axons
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Extension of a neuron that carries impulses away from the nerve cell body
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Cell Body
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Region of a nerve cell that includes the nucleus and most of the cytoplasm. Region from which axons and dendrites extend
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Central Nervous System (CNS)
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The brain and the spinal cord
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Dendrite
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Branching neuron extension that serves as a receptive or input region. Dendrites conduct potentials toward the cell body
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Meninges
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protective connective tissue covering of the central nervous system
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Myelin Sheath
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Fatty insulating sheath that surrounds axons of some nerve cells
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Nerve
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A bundle of neurons enclosed in a connective tissue sheath
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Neuron
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The basic unit of communication in the nervous system. Generate and conduct action potentials
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Sensory Neurons
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Detect and relay information to the central nervous system
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Motor Neurons
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Deliver signals to effectors (muscles, glands, organs) which carry out the response.
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Interneurons
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In Central Nervous System. Receive, integrate process, store and retrieve information.
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Neuroglia
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Cells that provide physical support and protection to neurons
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Schwann Cells
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In Peripheral Nervous System. Wind around axons to form myelin sheath, which helps propagate action potentials
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Oligodendrocytes
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Form myelin sheath around neurons in the Central Nervous System
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Astrocytes and Microglia
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Provide physical and nutritional support to neurons in the Central Nervous System.
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Neurotransmitter
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Chemical released by a neuron that may stimulate of inhibit other neurons or effector cells.
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Node of Ranvier
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Short unmyelinated gap between adjacent Schwann Cells where the surface of a neuron is exposed.
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Peripheral Nervous System
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Sensory and motor neurons that extend from spinal cord and brain to rest of body
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Somatic Nervous System
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control voluntary and involuntary motor functions
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Autonomic Nervous System
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Control involuntary functions like internal organs and glands
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Sympathetic Nervous System
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Promote responses that prepare body for stress or physical activity
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Parasympathetic Nervous System
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Promote general functions of body (“Housekeeping” functions).
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Reflex
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An involuntary, automatic response to a stimulus
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Refractory Period
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Period during which a neuron cannot generate a new action potential or can generate an action potential only with a strong stimulus
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Resting Potential
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Normal electrical charge difference across the plasma membrane of a cell. Is usually about 70 mV
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Synapse
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Functional junction or point of close contact between two neurons or between a neuron and an effector cell (e.g., a muscle cell).
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Adaptation
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A decline of the frequency of nerve impulses even when a receptor is stimulated continuously
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Cochlea
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Snail-shaped chamber in inner ear that houses the organ of Corti
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Cones
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Color vision photoreceptors in eye. 3 types, one each for red, green and blue light. Provide visual acuity, but are less sensitive than rods, so need more intense light
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Eye
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Organ of sight
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Choroid
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Layer of tissue between sclera and retina
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Ciliary Muscle
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Smooth muscle that controls shape of lens
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Cornea
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See-through window at front of eye
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Fovea
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Center of focus. Contains the highest concentration of photoreceptors in eye
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Iris
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The colored part of the eye
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Lens
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Clear disk that focuses light on retina
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Optic Disk
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Blind spot. Where axons exit eye
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Optic Nerve
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Sends sensory information from retina to brain
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Retina
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Light sensitive part of eye. Turns light signals into signals the brain can understand
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Four Layers of the Retina
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Pigmented Layer
Rods and Cones Bipolar Cells Ganglion Cells |
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Pigmented Layer
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captures stray light not captured by photoreceptors
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Rods and Cones
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photoreceptors
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Bipolar Cells
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Synapse with rods and cones. Pass their signal on to ganglion cells
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Ganglion Cells
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Nerves that transmit visual signals to brain. Exit via optic nerve
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Sclera
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The white of the eye. Outer layer that protects insides
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Otolith
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Hard crystals of bonelike material in inner ear. Contribute to sensing head position and movements
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Organ of Corti
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Hair cells and tectorial membrane of the inner ear. Converts pressure waves to nerve impulses.
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Rhodospin
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Photo pigment of rod cells
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Rods
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One of two types of photoreceptor in eye. Give black and white vision
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Semicircular Canals
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Fluid-filled bone tubes of the Vestibular apparatus of inner ear. Important for sensing rotational movements of head
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Sensory Receptors
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Respond to and convert stimuli to information that can be interpreted by brain. Several different types that respond to different forms of stimuli.
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Chemoreceptors
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respond to the presence of chemicals in the environment, like taste or smell receptors.
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Mechanoreceptors
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Respond to forms of mechanical energy, like sound waves, fluid pressure changes, touch, stretch, gravity
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Pain Receptors
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Respond to tissue damage or excessive pressure or temperature
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Photoreceptors
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Respond to light
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Thermoreceptors
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Respond to heat or cold
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Vestibule
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Part of inner ear that senses static position and acceleration/deceleration. Composed of utricle and saccule
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Acromegaly
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Results from overproduction of growth hormone in adulthood
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Diabetes
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Disease in which excess glucose accumulates in the blood
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Dwarfism
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Results from underproduction of Growth hormone during childhood
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Endocrine Gland
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Ductless gland that secretes one or more hormones into the bloodstream
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Feedback Mechanism
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Control of hormone secretion regulated by the hormone itself
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Negative Feedback
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An increase in hormone concentration triggers activities that inhibit further secretion.
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Positive Feedback
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An increase in concentration of a hormone triggers activities that stimulate further secretion.
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Gigantism
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Result of growth hormone overproduction in childhood
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Hormone
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A chemical messenger molecule secreted by an endocrine gland or cell into the bloodstream. Has effects on specific target cells.
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Steroid Hormones
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Derived from cholesterol. Diffuse across membrane and bind to receptors in cell nucleus to affect gene expression
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Nonsteroid (peptide) Hormones
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Proteins. Bind to receptors on cell surface to trigger reactions inside cell.
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Hypothalamus
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Region of brain that regulates body’s internal environment by releasing factors that affect the secretion of pituitary hormones
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Ketoacidosis
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formation of ketones from the breakdown of fats. In some diabetics. Can interfere with normal brain function
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Neuroendocrine Reflex
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A nervous system stimulus is responsible for the secretion of a hormone
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Pituitary Gland
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Pea-sized gland located just below hypothalamus. Secretes eight different hormones under control of hypothalamus.
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Ion Concentrations at resting potential
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Potassium (K+ )Concentration inside the neuron is higher than outside
Sodium (Na+ )Concentration inside the neuron is lower than outside |
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Repolarization
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Once peak is reached, Na+ gates close and K+ gates open, K+ follows it’s gradient out of cell, and the membrane potential is restored in that region
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Depolarization
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Inside negative relative to outside, Electrical disturbance stimulates trigger zone of membrane, Gated Na+ channels open and Na+ starts to flood into cell down their concentration and electrical gradient
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Acetylcholine
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neuromuscular junctions
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Serotonin
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Governs sleeping, sensory perception, temperature regulation and emotional states – acts on brain cells
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Norepinephrine
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affects brain regions concerned with emotions, autonomic nervous system
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Dopamine
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brain regions dealing with emotions
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GABA
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inhibitory signal in brain
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Multiple Sclerosis
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A condition in which nerve fibers lose their myelin – autoimmune response to protein in myelin sheath
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Somatic Nerves
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Motor functions – skeletal muscle, tendons, skin
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Autonomic Nerves
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Visceral functions – internal organs and glands
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Functions of the Spinal Cord
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Expressway for signals between brain and peripheral nerves
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Gray Matter
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Cell bodies, dendrites, unmyelinated axons, glia
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White Matter
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Axons with myelin sheaths (fatty) – run in tracts along spinal cord
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Meninges
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Protective connective tissue over CNS
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Medulla Oblongata
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respiration, circulation. Integrates motor functions and some complex reflexes (coughing, vomiting, sneezing)
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Cerebellum
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controls motor skills and posture
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Pons
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controls signals between cerebellum and integrating centers. Aids in regulating respiration
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Cerebrum
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Integrates sensory input and some motor responses
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Thalamus
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Sorts sensory input and relays to cerebrum
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Hypothalamus
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control center for the internal environment, governs behavior related to internal organ function – e.g., thirst or hunger
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Parts of the Forebrain
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Hypothalamus
Thalamus Cerebrum |
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MIdbrain
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Coordinates reflex responses to sight and sounds – relays signals to forebrain
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Cerebral Cortex
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outer layer of the cerebrum
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Function of the Right Side of Cerebrum
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Controls nonverbal skills like music, visual interpretations
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Function of the Left Side of Cerebrum
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Deals with math, speech and analytical skills
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Limbic System
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Involved in emotions, basic behaviors (hunger, thirst, sexual desire) and short-term memory
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Receptors That Adapt
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Light touch, pressure, and smell
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Receptors That Do Not Adapt
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Pain, joint, and muscle monitoring receptors
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Somatic Sensations
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temperature, touch, pressure, vibration, pain, awareness of body movements and position
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Five Basic Taste Qualities
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Sweet, Sour, Bitter, Salty and Umami
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Olfactory hairs
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in mucus layer contain chemoreceptors that bind odorant molecules dissolved in mucus – send signal to brain
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Examples of Steroid Hormones
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Estrogens, progestins, androgens (such as testosterone), cortisol, aldosterone
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Examples of Nonsteroid Hormones
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Glucagon, ADH, oxytocin, TRH, insulin, somatotropin, prolactin, FSH, LH, TSH
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Posterior Pituitary Gland
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stores and secretes hormones that were synthesized in the hypothalamus
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Anterior Pituitary Gland
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produces and secretes its own hormones
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Releasers
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stimulate target cells in Anterior Lobe
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Inhibitors
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slow secretion from target cells in Anterior Lobe
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Cortisol
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promotes breakdown of fats, proteins for energy – helps raise blood glucose levels
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Oxytocin
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stimulates and enhances labor contractions
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Insulin
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secreted by Beta cells of pancreas. Stimulates glucose uptake
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Glucagon
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secreted by Alpha cells of pancreas. Raises blood level of glucose by causing liver cells to convert amino acids and glycogen to glucose
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Diabetes Mellitus
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Disease in which excess glucose accumulates in blood, then urine due to insulin deficiency
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