Circulatory Flashcards
all animal cells must:
have enough O2 and nutrient
get rid of waste products
Why is there a need for circulatory system?
too big for diffusion
impermeable skin blocks diffusion
diffusion is too slow
what is transported in circulatory system?
water, respiratory gases, nutrients
waste products
blood clotting factors
hormones
antibodies
heat
simplest form of circulation
circulation through open body cavity (no organized system)
water currents bring nutrients and release waste
ex) sponges
open circulatory system
blood pumped by heart into open fluid space (animal body cavity - hemocoel)
blood + interstitial fluid = heamolymph
ex) many invertebrate animals
con of open circulatory system
low rate of oxygen transfer - not efficient
how insects transport O2
tracheole system (not circulatory)
functions of insect hemolymph
transports nutrients, hormones, waste, immune molecules
hydraulic skeleton
heat transfer
hydraulic skeleton
2 layers of body muscles put pressure on hemolymph to create body shape
hemolymph contains __
hemocyanin - metalloprotein with 2 copper atoms
hemocyanin
major O2 transporter in invertebrates
reversibly binds a single O2
not bound to blood cells
turns from colorless to blue when oxygenated
components of closed circulatory system
fluid
pump - to move fluid
vessels - to carry fluid between pump and body tissues
blood in a closed circulatory system:
never leaves the system
blood flow in closed circulatory system
in a continuous circuit of tubes
pros of closed circulatory system
blood reaches all cells - ideal for large animals
capillaries allow control of blood distribution
single circulation
higher blood pressure than open system
one loop, O2 used and replaced on same line
Ex) fish
parallel circulation
partially divided
simple double loop system (1 for giving O2, 1 for getting)
ex) amphibians
double circulation
completely divided
supports higher rate of cellular metabolism
complex double loop (1 to lungs, 1 to rest of body)
ex) birds & mammals
four chambers of mammalian heart
2 atria at top
2 ventricles at bottom
atrioventricular (AV) valves
valves between atria and ventricles
Semilunar (SL) valves
valves between ventricles and aorta/arteries
circuits of blood
pulmonary (right)
systemic (left)
function of valves in heart
regulate pressure
prevent backflow
neurogenic hearts
beat under control of nervous system
in some crustaceans
myogenic hearts
contractions are initiated within heart
heart contraction cycle
both atria
both ventricles (which contract bottom upwards)
during heart contraction cycle:
alternating periods of diastole and systole
diastole
low blood pressure
systole
high blood pressure
systolic pressure (when)
at contraction of ventricles
diastolic pressure (when)
between contractions of heart
auto-rhythmic fibers
network of special cardiac muscle fibers
source of electrical activity for heart
act as pacemaker
heart conduction pathway
special cardiac muscle cells, changes speed of conduction
myocardium
striated cardiac muscle
allows action potentials to spread to all cells
Plateau face
longer refractory period after action potential to prevent tetanus in heart
ECG
recording of heart electrical signals
graphed as series of waves during each heart beat
how many waves ECG waves in 1 contraction cycle
3
P wave > QRS complex > T wave
cardiac cycle
begins with onset of cardiac muscle contraction and ends with beginning of next contraction
bradycardia
low heart rate (under 60 bpm)
tachycardia
high heart rate (over 100 bpm)
Heart rate
number of heartbeats per unit of time
resting heart rate
heart rate while at rest, usually 75 bpm
stroke volume
volume of blood ejected by the ventricle during each contraction
cardiac output
stroke volume x heartrate
what controls heart rate
cardiovascular center of medulla oblongata (autonomic)
sensory inputs of heart
chemoreceptors (chemical changes in blood)
baroreceptors (blood pressure)
composition of blood
plasma, cellular portion (WBC), RBC
arteries
carry blood AWAY from heart
arterioles
branches of arteries that deliver blood to capillaries
capillaries
exchange material with interstitial fluid
venules
collect blood from capillaries
veins
carry blood TO heart
artery vs vein
narrower, thicker walls, not as elastic, higher pressure
skeletal pumping
veins squeeze and blood shoots in both directions, valve is closed to prevent backflow
respiratory pump
blood moves via negative pressure system from thoracic cavity to heart
features of capillary
walls are a single cells layer
very near body cells
most numerous vessel in body
lymphatic system
is a key component of immune system
what does lymphatic system do
collect excess interstitial fluid, now termed lymph
parts of lymphatic system
lymph, lymphatic vessels/tissues, lymph nodes, tonsils, spleen, thymus
lymphocytes
provide immune function in body
filter blood of microbes and pathogens
can produce antibodies
