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Theme 3 animals - Coggle Diagram
Theme 3 animals
cardiovascular systems
main parts
heart
blood vessels
blood
system type
open
most invertebrates
heart(s) that pump blood/hemolymph through a section of artery & smaller vessels
hemolymph
blood + lymphatic system
artery = carries blood away from heart
nutrients + hormones
blood/hemolymph empties into hemocoel
direct contact with tissue
no endothelial lining in vessels or hemocoel
closed
heart(s) pumps blood throughout body in closed vessels
heart
muscular pump that generates pressure to move blood around body
ranges from single chamber (ventricle) to 4
four chambers
2 atria + 2 ventricles
birds & mammals
keeps oxygen poor blood separate from oxygen rich blood
resistance in systemic circuit > pulmonary circuit
work done by left ventricle pumping to systemic is 5-7x greater
left ventricle more muscular
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valves
prevent backflow of blood
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atrioventricular valves (AV)
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semilunar valves
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cardiac cycle
systole
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diastole
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both atria contract simultaneously
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ventricle = chamber that pumps blood out of the heart
various forms of 3 chambers
amphibians
2 atria + 1 ventricle
vessels lined with endothelium
even capillaries of mammals
blood never leaves blood vessels
vertebrates & cephalopod molluscs
cardiac rhythm
control of cardiac muscle contraction
requires no input from CNS in all animals
most cells are not innervated
regulated by spontaneous depolarization of specialized cardiac muscle cells in most animals
myogenic pacemakers
signal travel down conducting system
automated
inherent rhythmicity
each cell can contract and perpetuate signal
action potential
causes calciium to enter sarcoplasm
triggers SR to release calcium
contracts by sliding filament mechanism
regulated by spontaneous depolarization of specialized cardiac muscle cells
myogenic pacemaker
adjacent cardica muscle cells transmit action potential
insulation of nonconductive tissues lies between each chamber of the heart
conducting system
Sinoatrial (SA) node
myogenic pacemaker
membrane voltage begins at -60mV
gradually deploarizes to -40mV threshold
repolarize via opening of voltage gated potassium channels
depolarizes spontaneously to threshold
caused by Na+ flowing through channel opens when hyperolarized (HCN channel)
at threshold Votage-gated Ca2+ channels open
create upstroke
create contraction
setting intrinsic heart rate
pace is set by the timing of depolarization & repolarization
located in right atrium
action potential from SA node spread at rate of 0.8 - 1m/sec
time delay occurs as action potential pass through AV node
has slow conduction of 0.03 - 0.05 m/sec
slowing permits atria to contract first and then ventricles
ectopic pacemakers
other tissues in heart spontaneously active
slower than SA node
stimulated to produce APs by SA node before spontaneously depolarize to threshold
if APs from SA node are prevented from reaching these, they will generate pacemaker potentials
action potential spread through gap junctions
reach other atria
both atria contract simultaneously
AV node
connects to AV bundle
splits into 2 down the septum of heart
toward inferior end branches into Perkinje fibers
aka subendocardial conducting network
in wall of ventricles
makes both ventricles contract at same time
speed 5m/sec
ventricular contraction begins 0.1 - 0.2 sec after contraction of atria
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aka bundle of His
cardiac muscle tissue
aka myocardium
also includes some connective tissue
cardiac muscle cells
striated
caused by sacromere
overlapping
actin
thin
myosin -thick
bound by z-disc
short branching
one or two nuclei
parralel fibers often connected
intercalated discs
junction between cardiac muscle cells
gap juctions
conduct action potentials
allow action potential to travel through
intermembrane proteins
facia adherens
anchor adjacent cells together
found at intercalated discs
sacroplasmic reticulum
membrane web in cell
small tubes that contain calcium ions
storage structure
T-tubule
let's calcium reach all of sarcromere
blood vessels
3 major types
arteries
carry blood away froom the heart
arterioles
smallest blood arteries
low permeability because of multiple layers of tissues
capillaries
smallest blood vessels
typically 1 red blood cell passes at a time
venules
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receive blood from capillaries
smallest veins
deliver all necessary stuff to tissues
only tunica intima
one layer of enothelial cells
extensisve surface area for exchanges
gases
water
ions
metabolites
hormones
continuous capillaries
complete layer of endothelial cells
joined by tight junctions
desmosomes
allow passage of small molecules
least permeable
intercellular clefts
gaps of unjoined membraines
pericytes
help control permeability
most organs have this kind of capillary
fenestrated capillaries
endothelial cells joined by tigth junctions
desmosomes
fenestrae
pores in endothelium
highly permeable to water solutes and small peptides
organs of high rates of exchange
intestines
glomeruli of kidneys
endocrine glands
discontinuous capillaries
large fenestration
wide open intercellular clefts
fewer tight junctions
most permeable
organs
liver
old blood cells recycled
spleen
bone marrow
new blood cells made
capillary permeation
direct diffusion acros endothelial cell membranes
through
intercellular celft
fenestrae
cytoplasmic vesciles
capillary bed
network of capillaries in tissue
between arteriol and venule
typical mammalian capillary
1mm long
8-10 um diameter
most cells are <_ 3 cell widths from a capillary
precapillary sphincters
regulate the flow of blood to tissues
ring of smooth muscle
gas exchange across capillaries
affected by
difference in partial pressure of gas
between capillary & tissue
area of capillary available for exchange
distance for exchange
Krogh's diffusion constant (K)
product of gas's
diffusion coeffcient
solubilitiy in tissue
value specific to each type of gas
Krogh cylinder
cylindrical unit of tissue supplies by a single capillary
radius of Krogh cylinder depends on capillary density
PO2 decreases from arterial end to venous end of Krogh cylinder
PO2 decreases in tissue farther out from capillary in a cylinder
Bohr shift
increase CO2 twoards venous end of capillary
resulting in decrease pH
reduces hemoglobin affinity for O2
causing rightward shift in O2 equilibrium curve
increase PO2 in blood
facilitated diffusion
myoglobin
iron-containing organelle of muscle fibers
O2 binding
transports OS from muscle cell membrane to mitochondira
lower density of mitochondira near core of musce fiber
veins
carry blood toward the heart
walls
tunica intima
innermost tunic
endothelium
simple squamous epithelium
elastic fibbers in internal elastic membrane provides elasticity
tunica media
middle tunic
sheets of smooth muscle & elastic fibers
thicker in arteries
thinner in veins
controls blood vessel diameter
tunica externa
outermost tunic
composed of fibrous connective tissue
for larger vessels have vasa vasorum
capillaries feeding the layers of cells around these vessels
elasticity
vasoconstriction
contraciton of smooth muscles in tunica media
decrease lumen diameter
increases resistance
decreases blood flow
vasodilation
relaxation of smooth muscles
increases lumen diameter
decreases resistance
increases blood flow
elastin
in large arteries allows them to expand during systole and recoil during diastole
recoil reduces with age
one of causes of high blood pressure
in tunica intima
type of protein
compliance
change in volume for a given change in pressure
