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61 Cards in this Set
- Front
- Back
Neuroglia
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Support neuron actions, can't propagate action potential
6 Types: (1-4 CNS, 5-6 PNS) 1) Astrocytes 2) Oligodendrocytes 3) Microglia 4) Ependymal cells 5) Schwann cells 6) Satellite cells |
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Astrocyte
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Provide blood-brain barrier in the CNS
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Oligodendrocytes
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Forms myelin sheaths on CNS axons
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Microglia
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Phagocytic neuroglia, removes debris in the CNS
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Ependymal cells
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Make cerebrospinal fluid in the CNS
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Schwann cells
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Forms myelin for Nodes of Ranvier in PNS nerves to increase conduction
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Satellite cells
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Structural support and regulation of material exchange in the PNS
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Clusters
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Ganglion (PNS cell body) + Nucleus (CNS cell body)
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Bundles
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Nerve (PNS axon) + Tract (CNS axon)
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White Matter
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Myelinated axons
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Gray Matter
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Neuronal cell bodies, dendrites, unmyelinated axons, axon terminals, neuroglia
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SNS vs. ANS
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ANS: Sensory receptors from stomach/lungs to CNS
SNS: Sensory receptors from head, body wall, limbs, vision, hearing, taste, smell ANS: Motor to skeletal muscle only, voluntary SNS: Motor to smooth & cardiac muscle & glands, involuntary |
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Resting Membrane Potential
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Due to the equal build-up of negative ions in cytosol and positively charged ions in ECF
Typical value = -70 mV Why: -K+ permeability 50-100x greater than Na+ at rest -Anions can't leave cell because they're attached to non-diffusable molecules |
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Graded Potential
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A small deviation from the membrane potential
Hyperpolarized = inside cell more negative Depolarized = inside cell more positive -Occurs w/ opening/closing of mechanical & ligand-gated channels in response to neurotransmitters/physical changes -Amplitude varies due to stimulus strength |
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Postsynaptic Potential
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Graded potential produced by a neurotransmitter binding to the postsynaptic neuron
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Receptor (Generator) Potential
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Graded Potential found in sensory receptors and neurons
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Subthreshold Stimulus
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Weak depolarization, doesn't reach membrane potential threshold, no action potential
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All-or-None Principle
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Action potential occurs completely or doesn't occur at all
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Propagation
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Mode of conduction in which the action potential maintains its strength as it travels along the membrane
Unidirectional: trigger zone --> axon terminal Continuous (slow) vs. Saltatory (fast) |
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Factors affecting Propagation Speed
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1) Amount of myelin
2) Axon diameter (greater SA, faster) 3) Temperature (higher, faster) |
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"A" Nerve Fiber
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- Largest axon diameter
- Myelinated - Brief absolute refractory period - Axons of sensory neurons (touch, pressure, position of joints, some thermal/pain sensors, motor neurons) |
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"B" Nerve Fiber
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- 2nd largest diameter
- Absolute refractory period > A fiber’s - Axons of sensory impulses from the viscera → brain/spinal cord - Axons of autonomic ganglia |
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"C" Nerve Fiber
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- Smallest axon dimater
- Unmyelinated (slowest) - Longest absolute refractory period - Axons of sensory neurons for pain, tough, pressure, heat, and cold |
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EPSP
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Excitatory postsynaptic potential
-Neurotransmitter causes depolarization, bringing the membrane closer to threshold -Makes cell more excitable, but does not usually initiate an action potential on its own |
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IPSP
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Inhibitory postsynaptic potential
-Neurotransmitter causes hyperpolarization -More difficult to produce an action potential b/c membrane potential is farther away (more negative) from the stimulus threshold |
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Ionotropic Receptors
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The binding sites and ion channels are on the SAME protein
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Metabotropic Receptors
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Ion channels are on a different protein than the binding site
ex. G-protein: coupled to the receptor, directly opens/closes the ion channel or indirectly opens it via secondary messengers |
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3 Methods of Neurotransmitter Removal
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1. Diffuses away from the synaptic cleft, out of reach of the receptor
2. Enzymatic degradation (eg. ACh-esterase breaks down ACh in the synaptic cleft) 3. Uptake into cells |
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Spatial Summation
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Simultaneous PSP summation by stimuli from different locations on the membrane on the postsynaptic neuron
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Temporal Summation
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Summation of multiple PSPs by stimuli from the same location of postsynaptic membrane at different times (increased firing frequency)
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Excitatory CNS Neurotransmitters
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-ACh
-Glutamate -Aspartate |
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Inhibitory CNS Neurotransmitters
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-GABA
-Glycine |
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Differences between Action Potentials & Postsynaptic Potentials
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1) Nature of signal (excitatory/inhibitory)
2) Propagation distance (graded = short) 3) Signal strength (maintaining it) 4) Signal amplitude (greatest @ formation site) 5) Refractory period (graded = none) |
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Properties of Blood
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- Fluid connective tissue
- Total volume ~ 4-6L - 55% Plasma, 45% formed elements - Formed Elements: RBC, WBC, Platelets - Plasma: 91.5% H2O, 8.5% proteins & solutes (albumin, globulin, fibrinogen, electrolytes, nutrients etc) |
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Hematocrit
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Percentage of total blood volume occupied by red blood cells
Female Avg: 42% (38-46) Male Avg: 47% (40-54) |
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Erythropoiesis
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RBC formation; occurs in red bone marrow
-Stimulated by hypoxia, which stimulates EPO release from kidneys *aka Hemopoiesis* |
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Leukocytes (WBCs)
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Nucleated cells that combat infection & inflammation, no Hb
2 Types: 1) Granulocytes (Neutrophils, eosinophils, basophils) 2) Agranulocytes (Lymphocytes, monocytes) *Live for only a few hours to a few days Neutrophils + Monocytes = phagocytosis Eosinophils = combat histamine effects & parasitic worms Basophils = inflammatory response in allergic rxns Lymphocytes = destroy foreign invaders |
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Platelets (Thrombocytes)
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Disc-shaped cell fragments w/o nucleis that help stop blood loss from damaged blood vessels by forming a platelet plug
Production stimulated by Thrombopoietin Life span of 5-9 days |
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Hemostasis
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The stoppage of bleeding, prevents hemorrhages
3 Mechanisms: 1) Vascular spasm (smooth muscle contracts) 2) Platelet plug formation (platelets clump around damage) 3) Coagulation |
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3 Phases of Blood Clotting
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1) Formation of prothrombinase (activator)
2) Conversion of prothrombin to thrombin 3) Conversion of soluble fibrinogen to insoluble fibrin Extrinsic & intrinsic pathways initiate prothrombokinase formation |
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Blood Types
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Antigen = Agglutinogens (on RBCs)
Antibodies = Agglutinins (in Plasma) AB = universal recipient, no antibodies in plasma O = universal donor, no antigens on RBCs Rh System: Have antigen = RH+ No antigen = Rh- |
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3 Different Capillaries
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1) Continuous (diffuse gases; found in brain/lungs/smooth & skeletal muscle/connective tissue)
2) Fenustrated (pores for pinocytosis; found in kidneys/ SI/endocrine glands) 3) Sinusoid (large cell gaps for protein diffusion; found in liver/spleen/anterior pituitary/parathyroid gland) |
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Capillary Exchange
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- Substances enter/leave capillaries by simple diffusion, vesicular transport, filtration, absorption
- H2O & dissolved substances movement dependent on HYDROSTATIC & OSMOTIC pressures |
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Net Filtration Pressure (NFP) [Starling's Law of the Capillaries]
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*Filtration Pressures- (Net Filtration @ Arteriole end)*
BHP (Blood Hydrostatic Pressure) 35 mmHg IFOP (Interstitial Fluid Osmotic Pressure) 1 mmHg *Absorption Pressures- (Net Absorption @ Venule end)* BCOP (Blood Colloid Osmotic Pressure) 26 mmHg IFHP (Interstitial Fluid Hydrostatic Pressure) 0 mmHg NFP = (BHP + IFOP) - (BCOP + IFHP) |
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Cardiac Output (CO)
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Amount of blood ejected per minute by either ventricle
CO (mL/min) = SV (mL/beat) x HR (bpm) CO = MAP (Mean Arterial Pressure) / R (Total Resistance) |
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Benefits of Aerobic Exercise
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- ↑ CO, contractility, SV
- ↓ rHR, BP |
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Control of Blood Pressure & Blood Flow
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1) CV Center in MO reg. HR, contractility, vasomotor tone (input from baro&chemoreceptors, output along cardioaccelerator/vagus(X) nerves)
2) Hormones (Epi/Norepi, ADH, angiotensin II) reg. BP & flow 3) Autoregulation from local adjustments to flow to match needs of tissue |
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Heart Rate
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Normal Resting = 70-80 bpm
Tachycardia = > 100 bpm Bradycardia = < 60 bpm |
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Systemic Blood Circulation
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L. Atrium --(bicuspid valve)--> L. Ventricle --(aortic valve)--> Aorta --> Arterioles --> Capillaries --> Venules --> Veins --> Inferior/Superior Vena Cava/Coronary Sinus --> R. Atrium
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Pulmonary Blood Circulation
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R. Atrium --(tricuspid valve)--> R. Ventricle --(pulmonary valve)--> Pulmonary artery --> Arteries of lungs --> capillaries of lungs --> pulmonary veins --> L. Atrium
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Cardiac Cycle
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1) Atrial Depolarization (P-Wave)
2) Atrial Systole (Contract) [PQ Interval] 3) Ventricular Depolarization (QRS Complex) 4) Ventricular Systole (Contract) [ST Segment] 5) Ventricular Repolarization (T-Wave) 6) Ventricular Diastole (Relax) Takes ~0.8 sec ST segment can indicate risk of heart attack |
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Cardiac Conduction System (Pacemaker Potential)
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1) SA Node
2) Atrioventricular (AV) Node 3) AV bundle (Bundle of His) 4) R/L bundle branches 5) Purkinje fibers |
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Factors Affecting Stroke Volume
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To Increase SV:
↑ Preload (EDV) - More venous return back to heart ↑ Contractility - ↑ temp, more catech., glucagon, thyroid hormones ↓ Afterload (ESV) - vasoconstriction in periphery |
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Frank-Starling Law
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Greater Preload (EDV) will increase force of contraction (SV)
w/ Training, increase in sympathetic tone = greater direct relationship bet. EDV & SV |
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Heart Rate Reserve (HRR)
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HRR = HRmax - RHR
Heart's ability to increase CO independent of SV during exercise *Indication of CV fitness level |
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3 Processes of Respiration
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1) Pulmonary Ventilation (Breathing)
- Inspiration/Inhalation (Active) - Expiration/Exhalation (Passive) 2) External (Pulmonary) Respiration - Exchange bet. alveoli & pulmonary capillaries (CO2 --> O2 blood) 3) Internal (Tissue) Respiration - Exchange bet. systemic capillaries & tissue cells (O2 --> CO2 blood) |
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Factors Influencing Rate of Airflow
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1) Alternating pressure differences
2) Alveolar surface tension 3) Lung compliance 4) Airway resistance |
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Control of Respiration
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Respiratory Center:
- Rhythmicity Area (MO) --> sets rhythm of respiration - Pneumotaxic & Apneustic Areas (Pons) --> coordinates transition bet. inhale/exhale Central (Pons) & peripheral (Aorta + carotid arch) Chemoreceptors increase ventilation when pCO2 levels rise above 40mmHg *CO2 drives respiration to greater extent than pO2) |
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Oxygen Uptake (VO2)
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VO2 = CO x avO2-diff
avO2-diff -- a measure of how much O2 is extracted by the tissues Product gives the rate at which O2 is consumed by body tissues *At rest: VO2 (ml/kg/min) = 3.5 *Maximal (relative) = 40.5 |
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Factors Influencing VO2max
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1) Cardiac Output - stronger heart, more O2 it can deliver
2) Oxygen delivery 3) Rate of ventilation/expiration (Lung diffusion) 4) Blood O2 carrying capacity 5) Muscle metabolism |
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Bone Composition
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25% Water
25% Organic Matrix - Osteogenic cells, osteoblasts, osteocytes, osteoclasts 50% Inorganic Matrix - Ca Phosphate* and Ca Carbonate* - Fluoride - Sodium - Potassium |