Term
| What is the nuclear envelope/membrane? |
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Definition
| A double phospholipid bilayer that wraps around the nucleus and contains nuclear pores |
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Term
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Definition
| Large holes perforated in the nuclear envelope/membrane that allow RNA to exit the nucleus after transcription, but prevent DNA from exiting the nucleus |
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Term
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Definition
| An area of the nucleus not separated by a membrane. rRNA is transcribed and the subunits of ribosomes are assembled in the nucleolus. |
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Term
| What are the three types of endocytosis? |
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Definition
Phagocytosis
Pinocytosis
Recepter mediated endocytotis |
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Term
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Definition
| Only a few cells are capable of phagocytosis. Proteins (usually antibodies or complement proteins) on the particulate matter bind to protein receptors (usually macrophages and neutrophils) on the cell membrane to signal the cell to begin phagocytosis. Once the particulate matter is engulfed, the membrane bound body is called a phagosome. |
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Term
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Definition
| Extracellular fluid is engulfed by small invaginations in the cell membrane. Most cells perform pinocytosis, and it is often a random occurence (nonselective) |
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Term
| Explain receptor mediated endocytosis |
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Definition
RME refers to the specific uptake of macromolecules (hormones and nutrients). The ligand binds to receptor proteins on the cell membrane, and is then moved to a clathrin coated pit, where the coated pit invaginates to form a coated vesicle.
The purpose of RME is to absorb the ligand, whereas in phagocytosis the ligand signals the cell to iniated phagocytosis and is not absorbed |
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Term
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Definition
| The reverse of endocytosis |
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Term
| Explain the basic compartments of the cell and how molecules are transported to and from these compartments |
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Definition
The cell can be divided into two sides: the cytosol and the ER lumen.
A substance must cross a membrane (via either passive/facilitated diffusion or active transport) to reach the cytosol.
A substance can reach the ER lumen via endocytosis without ever crossing a membrane |
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Term
| What are secretory vesicles? |
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Definition
| Vesicles from the Golgi that transport enzymes, growth factors, or extracellular matrix components out of the cell. They incorporate into the cell membrane after expelling their contents via endocytotis (thus supplying the membrane its integral proteins and lipids) |
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Term
| What happens to endocytotic vesicles after they enter the cell? |
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Definition
| They are sent to the Golgi for the recycling of the cell membrane |
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Term
| Describe the structure and function of Rough ER |
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Definition
Rough ER resembles flattened sacs and has ribosomes attached to it on its cytosol side
Rough ER synthesizes virtually all proteins not used in the cytosol, which are then pushed into the ER lumen and sent to the Golgi Apparatus |
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Term
| Describe the structure and function of the Golgi |
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Definition
Series of flattened, membrane bound sacs
Golgi modifies (by removing amino acids) and packages proteins for use in other parts of the cell and outside the cell |
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Term
| What are lysosomes and where do they come from? |
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Definition
Lysosomes contain hydrolytic enzymes that digest substances taken in via endocytosis
They come from the Golgi |
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Term
| Describe the structure and function of Smooth ER |
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Definition
Tubular
It is the site of lipid synthesis, including steroids, and helps detoxify some drugs |
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Term
| Structure and function of cytoskeleton? |
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Definition
Network of filaments (microtubules and microfiliaments) determining the structure and motility of the cell
Functions: anchor some membrane proteins and other cellular components; moves components within the cell; and moves the cell itself |
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Term
| Explain the difference between microtubules and microfilaments |
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Definition
Microtubules are larger and made of tubulin. They involved in flagella and cilia construction and the spindle apparatus
Microfilaments squeeze the membrane together in phagocytosis and cytokinesis, cytoplasmic streaming, and are also the contractile force in microvilli and muscle |
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Term
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Definition
The major portion of flagellum and cilium
It contains microtubules in a 9+2 arrangement, with the 9 outer pairs being held together by the protein "dynein" |
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Term
| In which two areas of the human body are cilia found? |
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Definition
| Only in the fallopian tubes and respiratory tract |
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Term
| Explain the differences between eukaryotic and prokaryotic flagella |
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Definition
Eukaryotic flagella: made from 9+2 microtubule configuration; flagella undergo whip-like action
Prokaryotic flagella: thin strand of protein flagellin; flagella rotate |
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Term
| Explain the difference between tight junctions, desmosomes, and gap junctions |
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Definition
Tight junctions: act as a fluid barrier around cells
Desmosomes: join two cells at a single point and attach directly to the cytoskeleton (similar to spot weld holding cells together)
Gap Junctions: small tunnels connecting cells, allowing for the exchange of small molecules |
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Term
| What is the endosymbiont theory? |
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Definition
| Theory stating mitochondria may have evolved from a symbiotic relationship between ancient prokaryotes and eukaryotes |
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Term
| What two things does every mitochondrian have distinct from the rest of the cell? |
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Definition
| It's own DNA (passed maternally) and ribosomes (55-60S) |
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Term
| Where is DNA located in a eukaryotic cell? |
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Definition
| Mostly in the nucleus, some in the mitochondria |
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Term
| How many membranes does the mitochondria have, and what are they composed of? |
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Definition
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Term
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Definition
| The invaginations of the inner mitochondrial membrane |
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Term
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Definition
| Cells that secrete fibrous proteins (collagen and elastin) that form the extracellular matrix |
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Term
| What is the extracellular matrix? |
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Definition
| A molecular network that holds tissue cells in place; it can a large part of the tissue (bone) or a small part; it can be liquid or solid |
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Term
| What are glycosaminoglycans? |
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Definition
| Polysaccharides with proteoglycans attached to them; they make up 90% of the extracellular matrix |
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Term
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Definition
1. Epithelial tissue
2. Muscle tissue
3. Connective tissue
4. Nervous tissue |
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Term
| Function of Epithelial Tissue |
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Definition
| Separates free body surfaces from their surroundings |
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Term
| Simple Epithlium vs. Stratified Epithelium |
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Definition
Simple: one layer thick
Stratified: two or more layers thick |
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Term
| 3 Molecules for Communication; Governing Systems; Distance Traveled |
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Definition
1. Neurotransmitters; nervous system; travel over short intercellular gaps
2. Local mediators; paracrine system; function in the immediate area around the cell from which they are released
3. Hormones; endocrine system; travel throughout the organism via blood stream |
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Term
| Neuronal Communication vs. Hormonal Communication |
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Definition
Neuronal: rapid, direct, specific
Hormonal: slow, spread throughout the body, affect many cells and tissues in many different ways |
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Term
| Structure & Facts about Neurons |
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Definition
Dendrites, Cell Body, Axon Hillock, Axon
They cannot divide; depends entirely on glucose and oxygen supplied via blood |
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Term
| Describe Resting Potential |
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Definition
| Na/K pump pumps three Na out of the cell and 2 K into the cell. This makes the inside increasingly negative (negative potential). As electrochemical gradient of Na becomes greater, more Na wants to come back into the cell. This rate increases until they both reach equilibrium. Same thing happens with K |
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Term
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Definition
| Voltage gated sodium channels change configuration when the voltage across the membrane is disturbed. As Na enters the cell through these channels, more channels open in positive feedback mechanism. Thus membrane changes polarity (inside is positive, outside negative) |
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Term
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Definition
| Voltage gated K channels open when majority of Na channels are (almost) closed. This causes inside of cell to become negative as K continues out of the cell (outside is positive) |
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Term
| Explain Hyperpolarization |
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Definition
The voltage gated K channels are less sensitive to voltage changes, so they take longer to close. They are so slow in closing that a small excess of K goes out of the cell, making the inside of the cell more negative than normal resting potential
Passive diffusion returns membrane to resting potential |
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Term
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Definition
| The minimum required stimulus to create an action potential; any stimulus greater than threshold stimulus creates the same size action potential |
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Term
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Definition
| Occurs when the threshold stimulus is reached very slowly - no action potential generated |
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Term
| Absolute Refractory Period |
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Definition
| Short period of time in which no stimulus will create another action potential |
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Term
| Relative Refractory Period |
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Definition
| Period of time during which only an abnormally large stimulus creates action potential |
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Term
| Slowest Part of Nervous System Cellular Communication |
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Definition
| Transmission of the signal from one cell to another via the synapse |
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Term
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Definition
| Uncommon; composed of gap junctions between cells; don't involve chemicals so transfer signal much faster than chemical synapses and in both directions |
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Term
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Definition
AKA motor end plate (when connecting neuron to muscle); unidirectional
Influx of Ca ions into presynaptic neuron causes neurotransmitter vesicles to be released via exocytotic process into synaptic cleft |
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Term
| 3 Ways Cells Prevent Neurotransmitters from Remaining in Synaptic Cleft after Post-synaptic stimulation |
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Definition
1. Neurontransmitter destroyed by enzyme in the matrix of the synaptic cleft and its parts are recycled by presynaptic cell
2. May be directly absorbed by presynaptic via active transport
3. Neurotransmitter may diffuse out of the synaptic cleft |
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Term
| Characteristics of Synapses & Neurotransmitters |
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Definition
A single synapse releases only one type of neurotransmitter and is designed to either inhibit or excite - but not both
A single synapse cannot change from inhibitory to excitatory, or vice versa
Some neurotransmitters are capable of inhibition or excitation depending on the type of receptor in the postsynaptic membrane |
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Term
| Two Mechanisms by which Post-Synaptic Membrane Receptors Act after Stimulation |
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Definition
1) May act as ion channels themselves
2) Act via second messenger system using a G-protein |
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Term
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Definition
1. Activates separate specific ion channels
2. Activates second messenger (i.e. cyclic AMP or cyclic GMP)
3. Activate intracellular enzymes
4. Activate gene transcription |
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Term
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Definition
| Neural support cells capable of cellular division |
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Term
| 5 Functions of Neuroglia/Glial Cells |
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Definition
1. Phagocytize microbes and cellular debris in CNS
2. Line the space containing the cerbrospinal fluid
3. Support Ganglia
4. Give physical support to neurons and help maintain the mineral and nutrient balance in the interstitial space
5. Produce myelin sheaths (oligodendrocytes produce in CNS; Schwann Cells in PNS) |
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Term
| Myelinated Axons in Vertebrates vs. Invertebrates |
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Definition
| Only vertebrates have myelinated axons |
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Term
| White Matter vs. Gray Matter |
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Definition
White: myelinated axons
Gray: Rest of neuron |
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Term
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Definition
| The tiny gaps between myelin on axons |
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Term
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Definition
| Action potential jumps from node of Ranvier to node of Ranvier |
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Term
| 3 Types of Neurons & Their Functions |
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Definition
1. Sensory (Afferent) Neurons - receive signals from receptor cell that interacts with its environment; transmits signal to other neuron (99% of sensory input discarded by brain)
2. Interneuron - transmits signals from neuron to neuron (90% of neurons are interneurons)
3. Motor (Efferent) Neurons - carry signal to muscle or gland (called effector) |
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Term
| Position of Afferent & Efferent Neurons Relative to Spinal Cord |
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Definition
| Afferent (Sensory) - located dorsally of SC (back) Efferent (Motor) - located ventrally of SC (front) |
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Term
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Definition
CNS: Brain & Spinal Cord; function is to integrate nervous signals between sensory and motor neurons
PNS: Everything else; handles sensory and motor functions of the nervous system; further divided into Somatic and Autonomic |
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Term
| Somatic Nervous System vs. Autonomic Nervous System |
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Definition
Somatic: voluntary; function is to respond to external environment; includes sensory and motor neurons; synapse directly on effectors and use acetylcholine as neurotransmitter
ANS: involuntary, further divided into Sympathetic (fight or flight) and Parasympathetic (rest and digest) |
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Term
| Neurons Using Acetylcholine Neurontransmitter |
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Definition
| All Somatic Nervous System neurons; preganglionic neurons in ANS and postganglionic neurons in Parasympathetic System |
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Term
| Neurons Using Epinephrine or Norepinephrine Neurotransmitter |
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Definition
| Postganglionic neurons in Sympathetic Nervous System |
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Term
| Controls Autonomic Pathways |
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Definition
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Term
| Parts & Functions of Lower Brain |
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Definition
Medulla, Pons, Hypothalamus, Thalamus, Cerebellum, Basal Ganglia
(No specific order)
Integrates subconscious activities (respiratory system, arterial pressure, salivation, emotions, reaction to pain/pleasure) |
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Term
| Parts & Function of Higher Brain |
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Definition
Cerebrum (or cerebral cortex)
Incapable of functioning without lower brain
Stores memory and processes thoughts |
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Term
| 5 Types of Sensory Receptors & Their Functions |
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Definition
1. Mechanoreceptors - touch
2. Thermoreceptors - temperature changes
3. Nociceptors - pain
4. Electromagnetic receptors - light
5. Chemoreceptors - taste, smell, blood chemistry
All receptors tranduce physical stimuli to neural signals |
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Term
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Definition
Controls shape of lens
Contraction -> lens becomes more sphere-like; brings focal point closer to lens
Relax -> Lens flattens, becomes less powerful; focal point moves away from lens |
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Term
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Definition
Located in retina (back of inside of eye)
Require vitamin A
Rods cannot distinguish between colors, cones can |
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Term
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Definition
Colored part of eye, controls pupil
Dark environment -> Sympathetic nervous system contracts iris -> pupil dilates to allow more light to enter
Bright environment -> Parasympathetic system contracts circular muscles of iris -> constricts pupil, screening out light |
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Term
| Order Sound Waves Flow through Ear |
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Definition
Auricle/Pinna (outside ear)
Tympanic membrane (outer ear)
Malleus/Incus/Stapes (middle ear) - three small bones changing force
Cochlea (inner ear) |
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Term
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Definition
| Located in inner ear and contains hair cells made of stereocilia that detect movement of vestibular membrane caused by sound waves in cochlea |
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Term
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Definition
| Located in inner ear, responsible for balance |
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Term
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Definition
Olfactory - sense of smell
Gustatory - sense of taste |
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Term
| 4 Primary Taste Sensations |
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Definition
| Bitter, Sour, Sweet, Salty |
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