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CIRCULATION
•Circulatory systems
–Material transport
•Gases
•Nutrients
•Waste
•Hormones
•Antibodies
–Composition
•Propulsive organ
–Chambers
»Atria
»Ventricle
»valves
•Arterial system
•Capillaries
•Venous system
–Movements
•Heart contraction
•Elastic recoil of arteries
•BV squeeze by body moves
•Peristaltic contraction of smooth muscle
–Types
•Open (Invertebrates)
•Closed
–Verts and cephalopods
–Heart
–High artery BP
–Increase O2 rapidly
»Squid rapid movement
–Permits ultrafiltration
»Important in kidneys
»Necessitates lymphatic System
–Vertebrate divided heart
»Different pressures in systemic and pulmonary
–Systemic (body)
–Pulmonary (respiration)
–Blood pressure
•High
–Rapid transit times
–Rapid BF changes in caps
–Needs lymphatic system
HEARTS
•Divided vs undivided
•Form leads to function
•Where blood needs to go
•Undivided
–lungfish, amphibs, reptiles, bird embryos and fetal mammals
–Undivided ventricle
»Mixing of p and s
»Mechanisms exist for shunts
»Move blood from P to S
–variation in flow ratio
–pressure must be same
Divided
•Divided
–Birds and mammals
–(-) output of heart same, regardless of requirement
»P=S
–(+) input into systems at dif pressures
»Prevent pooling in lungs
–water breathing fish
•Serial for resp and systemic
•three contractile chambers
•first through gills
–high pressure
–ionic regulation
–gas transfer
–Air breathing fish
•Evolved many times
–Gill collapse
–Mouth, SwimB, or skin
•Arapaima
–Gills reduced, 1/5 O2 uptake
–Vascularized swimbladder
–Fish can drown
–Obligate air breather
•Channa argus Division of ventral aorta
–Reduction of posterior gill arches
–Deox blood directed to via ant gills to ABO
•Protopterus
–Lungs and pulmonary circulation
–Cardiac septa
–Blood bypass during lung operation
–Estivation
–Amphibians
•Heart
–Separated atria
–Single ventricle
–Deox leaves first and enters lung
–Oxy blood from skin and lungs sent to body
–During nonbreathing, can shunt blood to body
•Non crocs
–Turtles and snakes
–bradychardia
•Crocodilian reptiles
–Completely divided ventricle
–Separation of systemic and pulmonary
–Can shunt PS
–Mammals and birds
•Four chambers
•Valves
•Embryos
–mammals
»PS
»Ductus arterious
»Foramen ovale
–birds
•Myocardial cells
–Similar to skel
•Gap junctions
•Ca++ uptake and release
•subtypes
–SA and AV nodes (small)
»autorhythmic
»Weakly contractile
»Slow e conduction
–Inner ventricular (largest)
»Weakly contractile
»Fast electrical conduction
–Intermediate size
»Widespread
»Strongly contractile
Electrical activity of the heart
http://library.med.utah.edu/kw/pharm
•Rhythmic contraction
–Systole
–Diastole (relax)
–Each cell AP
•Membrane junctions spread I
–Pacemaker
•Neurogenic (inverts)
•Myogenic (verts, some inverts)
•Cells lack stable resting potential
•Undergo steady depolarization
–Pace maker potential
–All or none
–Heart beat
»Faster depolar, faster heart beat
–Cardiac APs
•Prolonged repolarization
–High [Ca++]
–Delay in K+ conductance
•Repolar delayed during plateau phase
•Refracted state
–Summation not possible
•Results in prolonged contraction
–Transmission of excitation
•SA node origin
–Gap junctions
–Concentric current spread
–0.8 m/s
•AV node
–Only conductive connection between A & V
•Small junctional fibers
–0.05 m/s
•Nodal fibers (0.1 m/s)→transitional fibers→Bundle of His (4-5 m/s)
•Purkinje fibers
•Conducted to ventricle muscle fibers at 0.5m/s
•End result
–Synchronous contractions of A then V
–A precedes V
–Allow time for blood movement
•ECG
•PQRST complex
Pharmacology
•Autonomous ns
–Regulates visceral function wo conscious control
•Sympathetic
–Active
•parasympathetic
–Relaxed or sleeping
•Two systems act continuously and in opposition
•Ach
–parasympathetic
–+ AP interval in pacemaker
–Reduces velocity through AV node
–Decrease heart rate
•Epinephrine
–sympathetic
–+ rate of myocardial contractions
–+ force of contractions
–+ speed of conduction
Blood pressure
•Arterial system
–Transmural
•In and out a x bv wall
•Systolic pressure
–Maximal arterial pressure
•Diastolic pressure
–Minimum arterial pressure
•Pressure pulse
–Mm of Hg
–S/d, 120/80
•Gravity and body position on BP
–Stand up
•Changes
•Increase in lower limbs
–Gravity
•No absolute effect on P
•Increase P cause expansion of BV
•Cause pooling
•Giraffe
–Vaso constrict and dilation
–Kidneys
•Aquatic animals
•Venous distribution
–soldiers
–Astronauts
•Cardiovascular response to extreme conditions
–Exercise
–Diving