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54 Cards in this Set
- Front
- Back
Receptor Mediated Endocytosis
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-Specific uptake of macromolecules such as hormones and nutrients
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Autolysis
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-Lysosomes rupture and release their contents into the cytosol killing the cell
-Useful in the formation of certain organs and tissues (EX: destruction of tissue btwn digits of a human fetus) |
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Smooth ER
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-Contains glucose 6-phosphatase, the enzyme used in the liver, intestinal epithelial cells, and renal tubule epithelial cells, to hydrolize glucose 6-phosphate to glucose (production of glucose from glycogen)
-Produces triglycerides -Cholesterol formation -Lipid formation on cytosol side of membrane -Important for detoxing |
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Where do lysosomes come from?
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They bud off from the golgi.
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Peroxisomes
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-Self-replicating vesicles that inactivate toxic substances (have water as a product) and produce/breakdown H2O2
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The cytoskeleton is made up of _______ and ________.
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microtubules and microfilaments
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Microtubles
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-Larger than microfilaments
-Made from a protein called tubulin, which may polymerize into long straight filaments -Makes up mitotic spindle, flagella and cilia |
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In humans, where are cilia usually found?
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In the fallopian tubes and the respiratory tract
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Axoneme
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-The major portion of each flagellum and cilium, which contains nine pairs of microtubules forming a circle around two lone microtubules (9+2 arrangement). The protein dynein makes the cross-bridges.
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Centrosome
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-A microtubule-organizing center (MTOC)
-microtubules grow away from these to their + ends |
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Centrioles
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-Function in the production of flagella and cilia, but are not necessary for microtubule production
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Microfilaments
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-Smaller than microtubules
-The polymerized protein actin forms a major component of these -Squeeze the membrane together in phagocytosis and cytokinesis -Contractile force in microvilli and muscle |
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Gap Junctions
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-Small tunnels connecting cells. They allow small molecules and ions to move btwn cells (EX: In cardiac muscle to provide spread of AP)
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T or F: Mitochondria have their own ribosomes
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True.
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Membrane of Mitochondria
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-Two phospholipid bilayers. The inner membrane invaginates to form cristae (electron transport chain). Btwn inner and outer membrane is the intermembrane space
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Fibroblasts
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-Secrete fibrous proteins such as elastin and collagen that form a molecular network that holds tissue cells in place --> extracellular matrix
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Extracellular Matrix
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-May provide structural support, help to determine the cell shape and motility, and affect cell growth
-Surrounds the cell and is formed by cell itself |
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Paracrine System
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-Local mediators are released by a variety of cells into the interstitial fluid and act on neighboring cells
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Local Mediators
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-May be proteins, other amino acid derivatives, or even fatty acids (EX: prostaglandins are fatty acid derivative local mediators that affect inflammation and smooth muscle contraction)
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Neuron
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-Functional unit of the nervous system
-Can't divide -Almost entirely dependent on glucose for energy; uses facilitated diffusion to move glucose into cytosol from blood -Has low stores of glycogen and oxygen, must rely on blood |
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T or F: The cytosol of the neuron is highly conductive
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True
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Resting Potential
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-Established by a balance between passive diffusion and Na+/K+ pump. A cell has a negative resting potential.
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Na+/K+ pump
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-Moves 3 Na+ out, 2 K+ in
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Electrical Synapses
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-Composed of gap junctions btwn cardiac muscle, visceral smooth muscle, etc.
-Transmit signals fast and in both directions |
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What happens if a neurotransmitter remains in the synaptic cleft?
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The cell may be stimulated over and over. To compensate, the neurotransmitter is destroyed/removed.
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Second Messenger System
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-When neurotransmitter attaches, the receptor may activate another molecule inside the cell to make changes (EX: prolonged changes like memory involve this)
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G-Proteins
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-Commonly initiate second messenger systems. Usually attached to the receptor protein. When receptor is stimulated, the a-subunit of the G-Protein breaks off and may activate: more ion channels, a second messenger (cAMP or cGMP), enzymes, or gene transcription
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T or F: The chemical synapse is the fastest step in the transfer of a nervous signal
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False: It is the slowest step
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Support Cells
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-In the brain, outnumber neurons
-Capable of cell division -Schwann cells and oligodendrocytes make myelin |
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Myelin
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-Wraps around axons, increases the rate at which an axon can transmit signals (signal jumps from one node of Ranvier to the next)
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White Matter
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Myelinated axons appear white
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Gray Matter
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Neuronal cell bodies appear gray
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Sensory Neurons (afferent)
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-Receive signals from a receptor cell that interacts with its environment. It then transfers this signal to other neurons
-Located dorsally in body -99% of sensory input is discarded by the brain |
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Interneurons
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-Transfer signals from neuron to neuron. 90% of neurons in the human body are interneurons
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Motor Neurons (efferent)
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-Carry signals to a muscle or gland called the effector
-Located ventrally in body |
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Central Nervous System (CNS)
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-Consists of the interneurons and support tissue within the brain and spinal cord
-Function is to integrate nervous signals between sensory and motor neurons |
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Peripheral Nervous System (PNS)
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-Handles the sensory and motor functions of the nervous system
-Divided into the somatic (voluntary) and autonomic nervous systems (involuntary) |
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Somatic Nervous System
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-Designed to respond to external environment (voluntary)
-Contains sensory and motor neurons, the motor neurons innervate skeletal muscle -Synapse directly on their effectors and use ACH |
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Autonomic Nervous System
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-The sensory portion receives signals from organs inside ventral body cavity (involuntary)
-Innervates smooth muscle, cardiac muscle, and glands -Motor portion subdivided into sympathetic and parasympathetic |
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Sympathetic
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Part of ANS, which is part of PNS: "Flight or Fight"
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Parasympathetic
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Part of ANS, which is part of PNS: "Rest or Digest"
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Acetylcholine
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-The neurotransmitter used by all preganglionic neurons in the ANS and by postganglionic neurons in the parasympathetic system
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Epinephrine/Norepinephrine in the nervous system
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-The neurotransmitter used by the postganglionic neurons of the sympathetic nervous system
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The Spinal Cord
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-Acts mainly as a conduit for nerves to reach the brain, but it controls walking reflexes, leg stiffening, and limb withdrawal from pain
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The Lower Brain
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-Consists of the medulla, hypothalamus, thalamus, cerebellum, and basal ganglia.
-Integrates subconcious activities such as the respiratory system, arterial pressure, salivation, emotions, and reaction to pain and pleasure. |
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The Higher Brain (cortical brain)
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-Consists of the cerebrum or cerebral cortex (incapable of functioning without the lower brain)
-Acts to store memories and process thoughts. |
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Sensory Receptors
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-Distinguish between different stimuli
-Transduce physical stimulus to neural signals |
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Cornea
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-Where light first strikes (and bends) onto the eye
-Nonvascular and made of collagen |
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Lens
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-Acts as a converging lens
-Flattening the eye by relaxing the ciliary muscles make the lens less powerful (moves focal point away from lens) |
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Retina
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-Covers the inside of the back of the eye.
-Contains light sensitive cells called rods and cones (only cones make out colors) -Vitamin A is a precursor to all the pigments in rods and cones |
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Iris
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-Colored portion of the eye that creates the opening called the pupil.
-In the dark, the sympathetic nervous system contracts the iris, dilating the pupil. |
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The Three Parts of the Ear
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1) outer ear
2) middle ear 3) inner ear |
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Cochlea
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-Part of the inner ear. Allows the sound pressure to be detected by the hair cells of the organ of Corti, and transduced into neural signals.
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Semicircular Canals
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-Inside the inner ear.
-They are responsible for balance, and detect movement in all directions. |