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74 Cards in this Set
- Front
- Back
Action Potential
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- Electrochemical impulses that send signals
- Localized area of depolarization - Wavelike motion - Can be caused by sodium influx (all other cells) or Calcium (heart) |
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Synaptic Transmission
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- Electric to chemical signal by release of neurotransmitter into the synaptic cleft
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Depolarization
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RMP = -70 mV
- Stimulus causes voltage gated sodium channels to open - ++++ charge increase in the cell until threshold potential reached - Goes up to +40 mV (where the AP happens) |
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Threshold potential
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-50 mV
- Must be reached in order for an action potential to occur - "ALL OR NONE". Either there is a reaction or there isn't. |
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Repolarization
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- Inside of the cell is positive because voltage gated sodium channels have been open (not for long though)
- Voltage gated potassium channels take time to open and diffuse out (efflux) - Overshoot RMP to go to -90 mV - Na/K ATPase brings back to RMP |
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Salatory Conduction
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- Axons of neurons wrapped on sheath of schwaan cells (PNS), oligodendrites in CNS
- Speeds up signal by forcing AP to jump from node to node - Na/K ATPase works less hard because of decreased area |
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Refractory Period (2)
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- There's a limit to how much a neuron can conduct and how soon after an AP it can conduct again
- Action Potential makes a neuron unresponsive for a short time - Absolute and Relative |
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Absolute Refractory
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- No matter how strong another action potential is, the neuron will NOT FIRE another action potential
- Inactivated voltage gated sodium channel until RMP reached again |
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Relative Refractory
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- Action Potential can be induced, but it has to be stronger than normal, immediately follows the absolute refractory period
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Acetylcholine
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- Neurotransmitter released for neuromuscular junctions, and pretty much responsible for everything everywhere
- When binding to a postsynaptic neuron, opens a sodium channel and depolarizes postsynapse |
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Acetylcholinesterase
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- Enzyme degrading remainder of AcH left in the cleft
- Getting rid of Ach will close sodium channels it opened to transmit the signal |
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Exciatory
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- Neurotransmitter starts AP/depolarization wave
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Inhibitory
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- Neurotransmitter induces hyperpolarization (more negative than RMP)
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Can a neurotransmitter be both exciatory and inhibitory?
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Yes! Depends entirely on the receptor!
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Can you control the rate of an action potential?
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Sure. Increase the stimulus (number of action potentials), and you increase the frequency at which they occur
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"Sensory" Neuron
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- Receives information
- Delegated by PNS, carried out by CNS |
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"Motor" Neuron
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- Carries info toward organs that can act on info it received from PNS/CNS
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Efferent Neuron
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- Carries information AWAY from CNS to INNERVATE effectors
- "Sensory" |
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Afferent Neuron
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- Carries information TOWARD the CNS
- "Motor" |
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Reflexes
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- Direct response, motor to sensor
- Occurs without conscious thought and often bypasses the CNS |
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General Organization of the Nervous System
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- Nervous System is separated into CNS and PNS
- CNS consists of brain, spinal cord - PNS consists of everything else, split into somatic and autonomic - Somatic is "voluntary", and autonomic is "involuntary". - Autonomic is split into parasympathetic and sympathetic. Holy CRAP! |
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Central Nervous System (CNS)
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- Brain, spinal cord
- Hindbrain (Medulla, Pons, Cerebellum) - Midbrain - Forebrain (Diencephalon, Telencephalon) |
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Cerebrospinal Fluid
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- Shock Absorption
- Nutrient and waste exchange - Coats entire brain and spinal cord |
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Spinal Cord is responsible for....
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- Simple reflexes
- Primitive processes - Central hub of nerves connecting to everything everywhere |
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Hindbrain (3)
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- Medulla
- Pons - Cerebellum |
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Medulla is responsible for...
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- Autonomic processes
- Blood pressure, respiratory rate, vomitting |
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Pons is responsible for...
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- Balance
- Antigravity posture |
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Cerebellum is responsible for...
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- Coordination and complex movements
- Balance, antigravity. - Damage this part and you get bad hand eye coordination |
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Midbrain
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- Relay for visual and auditory information
- Responsible for arousal (wakefulness) |
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Brainstem
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Medulla + Pons + Midbrain
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Forebrain
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- Diencephalon (thalamus, hypothalamus)
- Telencephalon (hemispheres) |
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Thalamus
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- Part of the forebrain and diencephalon
- Relay for somatic (conscious) thought |
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Hypothalamus
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- Part of the forebrain and diencephalon
- Controls homeostatic functions like temperature, sex drive, rage, hunger - Control center for endocrine system |
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Telencephalon
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- Consists of cerebreal hemispheres, basal nuclei, limbic, corpus callosum
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Cerebreal Hemispheres (Cortex)
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- Gray and white matter
- Outside of the brain is gray, inside is white - White is meylenated axons, while gray is TONS of somas - Responsible for intelligence, conversation, memory, all higher mind - Temporal (2), Occipital, frontal, parietal |
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Basal Nuclei
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Important in regulating body movement
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Corpus Callosum
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Collects left and right brain, if you separate this there is no communication and you can act as two separate entities.. hmm..
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Parts of the PNS
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- Everything else, remember?
- Cranial Nerves, Spinal Nerves, examples: vagus nerve, all somatic motor neurons, Adrenal Medulla - Parasympathetic and Sympathetic |
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Somatic Nervous System
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VOLUNTARY control of things like skeletal muscles
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Autonomic Nervous System
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INVOLUNTARY control of things like smooth muscle (heart, valves), glands
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Vagus Nerve
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- Example of a cranial nerve that directly innervates the heart
- Decreases heart rate, can increase GI activity in parasympathetic response |
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Sympathetic Nervous System
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- "Fight or Flight"
- Use energy - Preganglions are in thoracocolumbar, that makes sense, right? - Short axons, use nonepinephrine |
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All somatic motor neurons do ... (3)
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- Innervate skeletal muscles
- Use ACH as their neurotransmitter - Cell bodies are in brain stem or spinal cord |
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Parasympathetic Nervous System
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- "Rest and Digest"
- Store energy - Long axons, use ACH - Preganglions are in craniosacular area, this makes sense right? |
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Hormone
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- Secreted into bloodstream
- Effect is distant |
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Endocrine Gland
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- DUCTLESS gland
- Secretes into bloodstream |
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Exocrine Gland
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- Duct gland
- Secrets product into environment by way of gastrointestinal lumen or outside (skin) |
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Hormone Receptor
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Tissue specific, ligand specific binding site
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Peptide Hormones
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- Synthesized in ER, modified in Golgi (like everything else)
- Hydrophobic, large - Cannot cross plasma membrane and rely on second messenger system - Purpose is that they modify activity of existing enzymes - Rapid effect, duration brief, STORED (always around) |
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Steroid Hormones
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- Hydrophobic, small
- Synthesized from cholesterol in smooth ER and can diffuse through the plasma membrane - If they AREN'T NEEDED, they WONT BE MADE - Carried by other proteins because they can't dissolve in blood plasma - Slow (because they have to be transcribed), but longer lasting |
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How do we regulate hormone production?
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- Dictated by physiological need, signals from brain
- Feedback inhibition - Hypothalamus (PNS) secretes releasing and inhibitory factors where the target is the anterior pituitary gland, which controls hormone production |
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What is the central command unit of the Endocrine System?
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The HYPOTHALAMUS!
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What is the first lieutenant of the Endocrine System?
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The ANTERIOR PITUITARY!
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Anterior Pituitary's Job
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- Secreting factors that affect activity of another thing (tells the glands to produce milk, tells the thyroid to release TH)
- Regulated by hypothalamus |
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Portal System
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- Connection of two capillary beds through veins without having to go through the heart
- Best example is the portal system used in the pituitary gland that connects the anterior pituitary and the hypothalamus and allows regulation of the other |
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Anterior Pituitary Hormones (6)
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- F (FSH)
- L (LH) - A (ACTH) - T (TSH) - P (Prolactin) - H (HGH) |
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Posterior Pituitary Hormones (2)
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- Vasopressin/ADH
- Oxytocin |
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Prolactin
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- Initiate mammary gland and milk production
- Inputs stimulate hypothalamus to stimulate Anterior Pit |
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TSH
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- Increases hormone synthesis in the thyroid
- Stimulates release of TH (T3/T4) |
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ACTH
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- Increases growth and secretory activity of the Adrenal Cortex (kidneys!), especially cortisol
- Circadian rhythm stimulation, stress stimulation |
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LH
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- Acts on the ovarian follicle
- Induces ovulation and maintains the corpus luteum |
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FSH
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- Development of the ovarian follicle
- Stimulates secretion progesterone |
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Vasopressin/ADH
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- Responsible for water retention in the kidney
- Increases permeability of collecting duct of kidney (Always Diggin' Holes) - Can also lead to HTN |
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Oxytocin
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- Decreases breast milk production
- Causes uterus contractions |
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Thyroid Produces... (1!)
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TH (T3/T4)
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TH (T3/T4)
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- In children: responsible for physical and mental development
- In adult: controls temperature and metabolic rate (hypo people are fat) |
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Adrenal Medulla Produces.... (2)
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- Epinephrine
- Norepinephrine |
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Epinephrine/Norephinephrine
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- Stress hormone (Sympathetic)
- Released into blood stream through ductless glands - Increases HR, contracts blood vessels, dilates air passages - Same thing, different receptors basically. |
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Adrenal Cortex Produces... (3)
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- Cortisol
- Aldosterone - Sex Steroids |
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Cortisol
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- Longterm stress/anxiety response
- Anterior Pituitary (ACTH) response - Increases protein catabolism, increase blood sugar, suppress immune system (decrease inflammation) |
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Aldosterone
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- Increases reabsorption of sodium and water, secretion of potassium
- Effect: increases blood volume, increase blood pressure - Acts on Distal Tubules, Collecting Ducts of Kidney |
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Pancreas Produces (2)
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- Insulin
- Glycogen |
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Insulin
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- Made by Beta Cells in Pancreas in response to high blood sugar
- After a meal, - Decrease blood glucose, increase glycogen and fat storage - Glycolysis |
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Glucagon
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- Made by Alpha Cells of Pancrease when blood glucose is low (between meals and exercise)
- Increase blood glucose, decrease glycogen and fat storage - Tells the liver "crap, release the stuff we've stored!" - Gluconeogenesis |