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What are the differences between open and closed circulatory systems in
animals, and what are the advantages of closed systems? ANSW ✔✔ Both
systems have three basic components: A circulatory fluid (blood or
hemolymph), a set of tubes (blood vessels), a muscular pump (the heart)
Open Circulatory System
There is no distinction between blood and interstitial fluid, called hemolymph.
Insects, other arthropods, and most molluscs have open systems.
Closed Circulatory System
Blood is confined to vessels and is distinct from the interstitial fluid. They are
more efficient at transporting circulatory fluids to tissues and cells because of
the internal pressure that moves the blood at a much faster rate. Humans and
other vertebrates have a closed circulatory system, often called the
cardiovascular system. The three main types of blood vessels are arteries and
capillaries.
Distinguish arteries, veins and capillaries, both in terms of their unique
anatomical features and functions. ANSW ✔✔ Arteries branch into arterioles
and carry blood to
capillaries.Arteries and veins have endothelium and connective tissue. Arteries
have thicker walls than veins to accommodate the high pressure of blood
pumped
from the heart. Networks of capillaries called capillary beds are the sites of
chemical exchange
between the blood and interstitial fluid. Venules converge into veins and
return blood from capillaries to
the heart. Veins have thinner walls so that blood flows back to the heart
mainly as a result of muscle action
,Which blood vessels contribute most to blood pressure? Which contain
smooth muscle? Which contain valves? ANSW ✔✔ The blood vessels
contributing most to blood pressure is arteries, they have thicker muscular
walls. Veins have muscles in the walls, but are thinner and are less compliant
with large diameter (might be a storage for vein). The arterials are small, so
diameter difference creates more pressure + we have a lot of arterials
compared to major arteries.
Understand the purpose (and advantages) of a double circulation ("2 pump"
circulatory system). ANSW ✔✔ Amphibians, reptiles, and mammals have
double circulation. Oxygen-poor and oxygen-rich blood are pumped separately
from the right and left sides of the heart. Higher blood pressure is maintained.
There is a greater flow of blood to the tissues. It also gives the ability to create
more pressure to pump blood around the whole body system.
the left side of the heart pumps and receives only oxygen-rich blood, while the
right side receives and pumps only oxygen-poor blood
Be able to describe all the events (steps) that occur during a cardiac cycle for
mammals. This includes movement of blood through the heart, lungs and
other tissues, as well as the opening and closing of all heart valves, and the
signals arising from the SA and AV nodes. ANSW ✔✔ Right ventricle with
deoxygenated blood passes through 2) pulmonary arteries that transport into
3) capillaries of both lungs that oxygenates blood and then get transported by
4) pulmonary veins that pass through the left atrium into 5) Left ventricle
which carries the blood out through the 6) Aorta that sends blood to 7)
Capillaries of head and forelimbs) and 8) capillaries of abdominal organs and
hind limbs. The deoxygenated blood from 7) capillaries of head and forelimbs
gets sent back around through the 9)superior vena cava, while 8) capillaries of
abdominal organs and hind limbs use the 10) inferior vena cava and both then
meet at the 11) right atrium and back into the Right ventricle.
Sinoatrial (SA) node- or pacemaker, sets the rate and timing at which cardiac
muscle cells contract.
, Atrioventricular (AV) node- impulses from the SA travel to the AV node. At the
AV node, the impulses are delayed and then travel to the Purkinje fibers that
make the ventricles contract.
How does hypertension develop, and how is it detrimental to health long-
term? ANSW ✔✔ One physical way humans can develop hypertension is by
being overweight. If the amount of fat in your body is above normal, then the
heart will need to compensate by pumping blood faster through the body
because of the narrower blood vessels. When blood is pumping faster than
normal, it can increase the chances that a clot forms inside the blood vessels
blocking blood flow. A second way humans can physically develop
hypertension is by high amounts of stress. The autonomic nervous system
raises blood pressure and heart rate when under stress. This will put the heart
under even more stress to work harder than normal to pump blood through
the body. Some long-term consequences of elevated hypertension would be
stroke, heart attack, or death if untreated.
Be familiar with the 3 physical conditions that can optimize rate of diffusion of
a gas across a membrane (conceptualized in Fick's Law of Diffusion), and
understand ways that animal respiratory systems have evolved in order to
maximize the exchange of O2 and CO2 across their membranes. ANSW ✔✔ 3
Physical conditions to optimize rate of diffusion.
1. Distance - A physical condition that can optimize the rate of diffusion of a
gas across a membrane would be by decreasing the distance over which
diffusion occurs. We can relate this to Fick's diffusion law because of its inverse
relationship to distance. If we decrease the distance (or thickness) of the
membrane, then we increase the rate at which gas diffuse across the
membrane.
2. Surface Area- A physical condition that can optimize the rate of diffusion of a
gas across a membrane would be by increasing surface area. If the surface area
increases, then there would more particles ready to diffuse and also more area
for diffusion to take place. This can relate to Fick's law of diffusion because it
states its proportionality to surface area; If surface area increases, then rate of
diffusion also increases.