A8- Circulation and The Heart Flashcards
Function of circulatory system
It transports many essential materials around the body including…
Oxygen from the respiratory system
Nutrients from the digestive system
Hormones from the endocrine system
Chemicals and cells from the immune
system (e.g. T-cells, B-cells, macrophages)
Metabolic wastes from the cells to the
lungs and kidneys
Thermal energy
A circulatory system allows for… (2 answers)
oxygen and nutrients to be delivered to every cell in the body
also allowed for wastes in the these cells to be removed from the body
a true circulatory system has 3 key features:
A fluid that transports or circulates materials throughout the body
A network of tubes in which the fluid circulates
A pump that pushes the fluid through the tubes
3 types of circulatory systems:
none, opened, closed
No circulatory system
Not all living things have a circulatory system, just like not all living things have a digestive or respiratory system
Unicellular organisms, like some bacteria, algae and fungi, can function without a circulatory system because they directly exchange gases with the environment
Some simple multicellular organisms do not either, but instead depend on an internal body cavity lining covered in flagella to circulate fluid through the body (recall: flagella are microscopic hair like structures that help with locomotion)
Open circulatory system
In an open circulatory system, the circulating fluid is pumped into a connected system of body cavities, often called sinuses
These openings bathe the cells directly in the hemolymph, a mixture of blood and tissue fluid
The contraction of one or more hearts forces the hemolymph around the body
Most invertebrates, like snails and insects, have this type of system
hemolymph
a mixture of blood and tissue
fl uid that is the circulating fl uid in an open
circulatory system
Why are open circulatory systems ineffective?
relatively inefficient method of circulation because the hemolymph is under low pressure and circulates slowly
- however, is practical for many animals with low metabolic rates which therefore have lower oxygen and energy demands
In a closed circulatory system, the fluid, often blood, is contained within…
a network of tubes called blood vessels
The blood and tissue fluid (recall- the interstitial fluid) are always ____ in closed circulatory systems
The blood and tissue fluid (recall- the interstitial fluid) are always separate
All vertebrates and some complex invertebrates have a
closed system
Closed circulatory systems may include one of…
5 versions of an increasingly complex “heart” structure depending on their evolution
Aortic Arch:
which are enlarged blood vessels that work like hearts to pump blood through the system (found in earthworms)
Two Chambered Heart:
this structure is commonly found in fish
atrium
a chamber of the heart that
receives blood from the body
ventricle
a chamber of the heart that
pumps blood to the body
septum
a wall of tissue that divides a
body cavity or structure into smaller parts;
for example, the ventricle of a mammal’s
heart is divided into two cavities by
a septum
pulmonary circuit
the part of the
circulatory system that delivers blood to
the lungs
systemic circuit
the part of the
circulatory system that delivers blood
around the body
Three Chambered Heart:
this structure is commonly found in amphibians
Four Chambered Heart:
This structure is found in reptiles, mammals, and birds (which may or may not have a septum)
humans have an example of a…
complex closed circulatory system, called a two-circuit circulatory system
in humans closed circulatory system the circulation of blood to the lungs (pulmonary circuit) is separate…
from the circulation of blood to the rest of the body (systemic circuit)
This is possible because of our four chambered heart
Humans and mammals have a dual circulation
FALSE
- They have a figure eight circulation
figure eight
- blood goes from 1 heart pump to the luns
- back to the second heart pump which sends it to the body and then back to the first pump
Where is the heart found?
found in the middle of your chest, directly under your breastbone, is the center of your circulatory system
What recives blood from the top of your heart?
You have two atria, which receive blood from your body at the top of the heart
What receives blood from your atria at the bottom of the heart
You have two ventricles, which receive blood from your atria at the bottom of the heart
TRUE IR FALSE: Artia walls are much thicker and muscular then the ventircular walls
FALSE
The ventricular walls are much thicker and more muscular than the atria
-This is because the ventricles have to pump blood a much longer distance
Why does the artia walls have less msucle then the ventircular walls?
Because the atria do not have to pump blood far there is less muscle required (blood in atria must only be pumped into ventricles)
STEPS TO CIRCULATION
Blood enters your right atrium from one of two blood vessels
- Blood from your upper body tissues enters from your superior vena cava
OR
- Blood from your lower body tissues enters from your inferior vena cava
Your right atrium then beats and blood enters the right ventricle through your atrioventricular valve (specifically, the tricuspid valve)
-This valve is supported by tough cords called chordae tendineae and prevents blood from flowing backwards
Blood then leaves your right ventricle through the semilunar valves (specifically, the pulmonary semilunar valve) to go towards your lungs via your left pulmonary arteries
Blood is then oxygenated in the lungs and returns to your heart via the right pulmonary veins
-It enters your left atrium, and then is pushed towards your left ventricle through the mitral valve (the other atrioventricular valve)
Blood then gets pushed through the semilunar valve (specifically, the aortic semilunar valve) and enters the aorta so it can be distributed through the body
Your heart is divided into two sides by the…
septum
The right side of your heart receives blood from your…
systemic (body) circuit and circulates blood to your pulmonary (lung) circuit
The left side of your heart receives blood from your…
pulmonary (lung) circuit and circulates blood to your systemic (body) circuit
TRUE OR FALSE: Your heart has a high demand for oxygen because it is constantly working
TRUE
What is the name of the hearts own supply of blood vessels?
coronary blood vessels which branch off the aorta
Your heart is protected by…
a double layer membrane called the pericardium
Like the pleural membrane around the lung, it is filled with fluid and prevents friction by providing lubrication
How is the circulatory system tied to the respiratory system?
- Circulatory system brings blood to and from lungs
- gas exhange occurs in lungs in order for oxygenated blood to be brought back to heart
- lungs expel CO2 and take in O2
pericardium
a two-layered fl uid-fi lled
membrane that surrounds the heart and
prevents friction between the heart and
other tissues and organs
coronary blood vessel
a blood vessel
that circulates blood to and from the
muscle cells of the heart
semilunar valve
the valve located
between the left ventricle and the aorta
and the right ventricle and the pulmonary
arteries to prevent the backfl ow of blood
when the ventricles relax
atrioventricular valve
the valve located
between each atrium and ventricle to
prevent the backfl ow of blood from the
ventricles to the atria
chordae tendineae
tendons that support
the atrioventricular valves
cardiac cycle
the contractions and
relaxations of the heart muscles during a
complete heartbeat
diastole
the period of the cardiac cycle
when the ventricles are relaxed; blood
fills the ventricles
systole
the period of the cardiac cycle
when the ventricles contract; blood is
ejected from the ventricles
