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32 Cards in this Set
- Front
- Back
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Ion Channel Receptors
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Salty= Na ions
Sour= H ions |
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G-Protein Coupled Receptors
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*Neurotransmitter release without depolarization
Sweet,Bitter,Umami |
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Functions of muscles
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1) Movement
2) Stability 3) Communication 4) Control of body openings & passages 5) Heat production |
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Properties of muscles
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-Excitability
-Conductivity -Contractility -Extensibility -Elasticity *Excitability & Conductivity are shared between neurons and muscle cells |
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Types of Muscle cells
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1) Skeletal: voluntary, striated, multinucleate,atttached to bone,skin or fascia
2) Cardiac: involuntary,striated,mononucleate,authorhythmic(can self regulate beat),typically smaller and HIGHLY BRANCHED 3) Smooth: involuntary, non-striated, mononucleate, hair follicles, walls of hollow organs 3) Smooth |
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Sarcomere
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-"contractile unit" of muscles
-organization of protein |
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Sarcoplasm
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- the cytoplasm of a muscle cell
-contain: myofibrils,myoglobin, glycogen *when you increase the size of your muscles, you are adding more myofibrils in the muscle cell. |
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Myofibrils
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bundles of 3 types of myofilaments that make up the sarcomere:
1) thick filaments--> myosin protein 2) thin filaments--> actin protein 3) elastic filaments--> titan protein |
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Thick/Thin Filaments
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THICK:
-myosin protein -binds and hydrolyzes ATP THIN: -actin proteins -each actin has an active site that can bind to the head of myosin protein -tropomyosin is a protein that blocks the active site on the actin from the myosin head in the relaxed muscle. -troponin binds tropomyosin and calcium to all the active site to be exposed. *Thin/Thick filaments DO NOT change shape |
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Muscle Contraction
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1) Excitation: communication between neuron and muscle cell
2) Excitation-Contraction Coupling: conversion of action potential in muscle cell to activation of protein in the sarcomere 3) Contraction: muscles develop tension and may shorten/ sliding filament theory 4) Relaxation: return to resting |
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Muscle Contraction:
Purpose/Major Events |
1) Excitation:
Purpose- communication between neuron and muscle cell Events- release of ACh in synapse. ACh binds to receptors to create EPP. Start of action potential 2)Excitation-contraction coupling: Purpose- Activation of proteins in sarcomere Events: Sodium voltage-gated channels in T-tubules open. Calcium channels of SR open and Ca diffuses in sarcoplasm and binds to troponin. Tropomyosin exposes the active sites on actin. 3) Contraction: Purpose- Interaction of proteins in sarcomere. Creation of tension and shortening Events- Hydrolysis of ATP by myosin. Myosin head is activated. creation of cross bridges. Release ADP+P causing head to flex. and new ATP causes the head to release. 4) Relaxation: Purpose- return to resting Events- No ACh. AChE breaks down ACh in synapse. no EPP. Ca actively transported to SR. Tropomyosin masks active sites. No cross bridges |
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Types of Junctions
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1) Mechanical:
-Desmosomes- cell adhesion proteins - Allows muscle cells to pull on eachother without damaging membrane 2) Electrical: "gap junctions" - connexons: non-specific, leaky ion channels - allows Na to diffuse between cells during depolarization - propagation of signal |
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Functions of the Heart's Fibrous "Skeleton"
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1) provides structural support for the heart
2) Gives the muscle cells something to pull against 3) Electrical insulator, helps regulate beating of the heart |
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Chambers of the Heart
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Two atria (right and left):
-thin walled muscle -recieve blood going toward heart from the body and lungs -pumps blood to ventricles Two ventricles (right and left): -Thick- walled muscle - Recieves blood from atria - pumps blood to lungs and body |
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Mechanism of a heart beat
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-Cells of the SA node triggers action potential
-action potential moves through the two atria causing contraction (atria systole) - action potential depolarizes the cells of the AV node (ventribular systole) - action potential propagated down the bundle of His - action potential propagated thoughout the ventricles, causing contraction |
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ECG waves
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P- wave: atrial depolarization (atria systole-contraction)- started by SA node
QRS complex: ventricular depolarization, atria repolarization T-wave: ventricular repolarization |
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Purkinje fibers
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-spread throughout ventricles
- coordinate contraction of ventricles -ventricles contract from bottom upwards because of the direcions of the bundles |
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Stages of the Cardiac cycle
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Phase 1: Quiescent Period
Phase 2: Atrial Systole Phase 3: Isovolumetric contraction- FIRST heart sound Phase 4: Ventricular ejection Phase 5: Isovolumetric Relaxation-SECOND heart sound |
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Cardiac Output
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-the amt of blood pumped by one ventricle in one minute
-CO= Heart rate x Stroke volume - CO increases during exercise |
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Cardioacceleratory Center
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-increase heart rate
-sympathetic nervous system - neuron secretes norepinephrine (NE) - Adrenergic receptors on cells of SA node bind NE - cause an increase rate of action potentials of SA node. |
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Cardioinhibitory Center
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- Decrease heart rate
- Parasympathetic nervous system - neuron secretes ACh - Cholinergic receptors bind ACh - allows K to leave the cell--> hyperolarizing reaction (moves cells away from threshold- takes longer for action potential to occur) - rate of action potentional decrease |
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Normal heart rate
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70 beats/minute
*without nervous control, the heart could beat about 100 beats/minute |
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Normal flow of blood
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-Heart-> artery->arteriole->capillary
-Capillary->venule->vein->back to heart |
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Pulmonary system
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-from heart to lungs and then lungs to heart
- functions in GAS exchange (drop off carbon dioxide and pick up oxygen) - capillaries in lungs |
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Systemic system
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- from heart to rest of the body after getting oxygen
- capillaries in all body systems |
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Arteries vs. Veins
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Arteries: under more pressure than veins- amount of muscle and collagen is higher due to more pressure (allows them to stretch)
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3 layers of tissue in vessels
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1) Tunica intima: innermost layer, endothelium is a selectively permeable barrier
2) Tunica media: middle layer, usually thickest , smooth muscle controls VASOCONSTRICTION and VASODILATION 3) Tunica externa: outtermost layer, consists of loose connective tissue, ANCHORS vessel to its surroundings (stabilizing role) |
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Capillary beds
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- site of exchange of materials
-relies on diffusion - flow of blood controlled by sphincters - only about 1/4 of capillaries are open at once because if all were open, BP would be too low. (ex: getting a sunburn) |
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Veins
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-carry blood BACK to the heart (typically deoxygenated blood)
- Thin walls, with less muscle and elastic - under low pressure compared to arteries - contain valves that prevent backflow |
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Varicose veins
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- when blood pools in veins of lower limbs
- causes veins to stretch more than usual- the stretching seperates the valves - valves cant completely close causing more pooling - seen in people who stand or sit for too long because there is no muscle contraction - Hemorrhoids are varicose veins in anal canal -painful surgery |
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Blood Pressure
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-the forces that the blood exerts against a vessel wall
- Systolic pressure: peak pressure during ventricle contraction -Diastolic pressure: peak presure during ventricle relaxation -Healthy BP: (age 20-30) 120/75 -Disease State BP: 140/90 |
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What Affects BP?
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1) Cardiac Output: higher output-> higher pressure
2) Blood Volume: more blood in same volume= higher pressure, less blood in same volume= lower pressure- mainly controlled by kidneys and hormones 3) Resistance of blood flow in vessels: vessel diameter can change (vasomotion)- Atherosclerosis: deposition of cholesterol and fat deposits in arteries--> decreases vessel diameter--> higher pressure- affects afterload stroke volume |
