Term
| Components of a circulatory system |
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Definition
1. circulating fluid
2. vascular system (network of tubes/vessels)
3. pump |
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Term
| Primary functions of a circulatory system |
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Definition
1. Transportation
allows for large, specialized surface areas to transport products; ex: intestines, lungs
three kinds of transportation: respiratory, nutritive, excretory
2. regulation
two kinds of regulation: hormonal (global impact), temperature (heat travels to maintain temperature)
3. protection
two kinds of protection: clotting, immune system (circulation of white blood cells) |
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Term
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Definition
system in which there is no distinction between circulatory fluid and extracellular fluid of body tissues
in anthropods, molluscs (huge diversity in design)
has low pressure
less efficient (wastes respiratory pigments)
no control over distribution
components: heart, arteries/vasculature, hemolymph, sinuses/ostia (where fluid enters vasculature) |
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Term
| closed circulatory system |
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Definition
system in which circulatory fluid (blood) is always enclosed within vessels that transport fluid to and away from the pump
in all vertebrates and some invertebrates
components: heart, arteries, capillaries, veins |
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Term
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Definition
| vessels moving away from heart |
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Term
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Definition
| site of exchange (from arteries to veins) |
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Term
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Definition
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Term
| heart and circulation of a fish |
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Definition
linear set up of heart
sinus venosus: collection chamber
atrium: collection chamber
ventricle: pumping chamber
conus arteriosus: pumping chamber |
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Term
| heart and circulation of terrestrial vertebrates |
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Definition
has subdivision of circulation
pulmonary: to the lungs (respiratory)
systemic: to the rest of the body |
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Term
| heart and circulation of amphibians |
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Definition
amphibians are pulmocutaneous: have gas exchange in respiratory system and in skin
components:
sinus venosus: bring blood from body into R atrium
**sub-divided atrium: 2 atria
systemic arch: out to body
L/R pulmocutaneous arteries: structures that separate blood flow
**conus arteriosus: helps to subdivide blood flow
ventricle: main pump, has folds in the walls that help direct blood flow |
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Term
| heart and circulation of reptiles |
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Definition
components:
**septum: blockage that routes oxygenated/deoxygenated blood to the correct artery
ventricle: main pump, folds in wall that direct blood flow
R/L aorta
R/L common pulmonary arteries
R/L pulmonary arteries |
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Term
| heart and circulation of mammals and birds |
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Definition
components:
sinus
2 atria
2 ventricles
pulmonary artery
aorta
veins |
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Term
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Definition
R atrium: receives blood from body
L atrium: receives blood from lungs
R ventricle: sends blood out to body
L ventricle: sends blood out to lungs
Tricuspid valve (R side) and Bicuspid valve (L side): valves between atrium and ventricle that prevent backflow of blood into atrium |
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Term
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Definition
muscle cells contract when depolarized
cells are electrically coupled (neighboring cells depolarize together)
waves of depolarization cause coordinated contraction of heart
Sequence of events:
1. mid-diastole: blood flows into atrium
2. atrial contraction: blood flows from atrium into ventricles
3. isometric ventricular contraction: pressure in ventricles because of blood flow in
4. ventricular ejection: valves pop open
5. isometric ventricular relaxation: valves close |
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Term
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Definition
cells located in the sinoatrial node that determine heart rate; can change heart rate by decreasing/increasing time between heart beats
neurogenic pacemakers: signal from CNS, still have neural input; causes heartbeat NOT heart rate
myogenic pacemakers: group of electrically-coupled muscle fibers that stimulate contraction, causes heartbeat based on activity of heart alone, **FASTEST one drives the system**
*Adenosine and Acetylcholine reduce starting voltage of pacemaker potential, which slows pacemaker potential and heart rate
*Norepinephrine accelerates pacemaker potential and heart rate |
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Term
| vertebrate heart muscle fibers |
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Definition
1. small muscle fibers: weak, don't contract well, autorhythmic (have own, rhythmic depolarization)
located in top of atrium
2. medium muscle fibers: bulk of heart fibers, contractile
located in walls of heart
3. large muscle fibers: don't contract, have rapid electrical conduction
located in bottom of atrium
small, medium, and large fibers work together to cause waves of contraction by pushing blood out through the ventricle |
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Term
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Definition
| cycle: rhythmic contraction (systole) and relaxation (diastole) of whole cardiac muscle mass system |
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Term
| cardiac pacemaker potential |
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Definition
steady depolarization after an action potential
pacemaker potentials don't have a resting potential
every time you go over the threshold, you get a heart beat
there is an offset in time between atrial contraction and ventricular contraction
atrial depolarization, ventricular depolarization, then ventricular repolarization |
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Term
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Definition
contractile properties of heart muscles adapt to changing conditions
if a heart fills with greater volume of blood, it will contract with greater force
filling pressure: volume of fluid into heart; increased volume causes increased filling pressure
stroke volume: blood ejection from heart ventricles; increased contraction causes increased stroke volume
stroke volume/filling pressure: when heart has pumped out all the blood it can, system is killed; the positive relationship has a limit |
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Term
| factors affecting end-diastolic volume |
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Definition
end-diastolic volume: volume of blood in ventricle at end of filling phase
-distensibility of ventricle (ability of fivers to stretch)
-thickness of walls of ventricle: if they are too thick, the walls cannot stretch to fill
-strength of arterial contraction
-venus filling pressure (amount of blood from venus system)
-filling time (increased time causes increased fluid) |
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Term
| factors affecting end-systolic volume |
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Definition
end-systolic volume: volume of blood in ventricle at end of contraction
-force of ventricular contraction
-how much arterial backpressure there is |
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Term
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Definition
determined by pressure and resistance
pressure: force/area; pumping of heart is source of pressure in system (increased pressure causes increased flow)
resistance: how much we are fighting flow in system due to friction with the walls of vessels and within fluid layers; impacted by viscosity (blood is 3-4x more viscous than water, plasma is less viscous than blood)
boundary layer: thickness of walls of vessel; as diameter of vessel changes so does resistance
turbulent blood flow: unsteady flow can be caused by physical obstructions of viscocity
Q=(P1-P2)/R
highest resistance in circulatory system: capillaries (smaller vessels so more obstructions)
highest pressure in circulatory system: arteries |
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Term
| 4 primary functions of arterial system |
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Definition
1. act as a conduit (delivery system)
2. damp oscillations in pressure and flow; smooth out flow
3. act as a pressure reservoir for forcing blood back into the small-diameter arterioles
4. control distribution of blood via structure constriction of terminal branches of arterial tree |
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Term
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Definition
pressure oscillations: expanding and contracting (elasticity) of arteries
arteries closer to heart have more elasticity than arteries further from the heart
larger pressure oscillations in arterial system, want smaller oscillations in capillaries and veins
less resistance means a smoother blood flow
ventricle is source of oscillations
aorta needs elasticity to reduce turbulence flow, because without elasticity it wouldn't recapture energy and blood would just be sucked back in |
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Term
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Definition
primary function is to return blood to heart
also largely functions as a reservoir/storage (stores 50% of blood volume)
vein is more floppy
-allows for continuity of flow, valves in vein are there so gravity doesn't pull down blood, muscles aid by squeezing
-countercurrent warms veins from arteries (endothermic)
-fat cells around blood vessels prevent loss of heat
increased venous return causes increased stroke volume which causes increased cardiac output |
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Term
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Definition
| expansion that helps fluid return by pulling blood from head and neck |
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Term
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Definition
primary function is to bring circulating fluid and nutrients through system into contact with tissues; extensive network
form and function:
-different cells have different kinds of transfers
-necessary for metabolism, plasma/fluid transfer, uptake into circulation
pressure and flow:
1. physical pressure: blood pressure pushes fluid out
2. colloid osmotic pressure: many mores pull fluid in (arterial-away, venous-in)
continuous capillaries: narrow and thing, many vesicles, small cleft, diffuse, move through endothermic cells, most common and least permeable
ex: muscles, neuronal, lungs, connective tissue, exocrine, glands
fenestrated capillaries: no longer have narrow clefts so pores are relatively permeable, less vesicles
ex: intestines, endocrine glands, renal glomerulus
sinusoidal capillaries: has big holes, most permeable, no vesicles, rare
ex: liver, bone marrow, spleen, lymph nodes, adrenal cortex |
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Term
| factors that affect blood flow in capillaries |
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Definition
-arteries changing diameter and flow rate
-precapillary sphincter (muscle cell contracts/dilates)
hyperemia: increased blood flow to tissue
ischemia: decreased blood flow to tissue
systemic: neutral blood flow
local control: myogenic response leads to excess fluid, causes increased stretching and contracting of artery to maintain its diameter
-chemical triggers: local chemicals either cause vasodilation or vasoconstriction
vasodilation: dilation of vessels increases blood flow
vasoconstriction: constriction of vessels, decreases blood flow
CO2: increases oxygen uptake
NO: inflammatory chemical, produced/released by vascular endothelium (causes smooth muscle to relax)
endothelin: vasoconstrictors released in response to stretch of vessels
prostacyclin: released by vascular endothelium, causes vasodilation and decreased clotting |
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Term
| factors that affect blood pressure |
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Definition
-heart rate
-stroke volume
-resistance |
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