Bio 233 Ch. 18: The Heart Exam With Complete
Solutions
The heart - ANSWER Powers the entire circulatory system, transporting nutrients,
oxygen, waste, heat, hormones, and immune cells throughout the body, over and over.
Truth is, the heart is really just a pump- a big, wet, muscly brute of a pump. The heart has
only one concern: maintaining pressure - ANSWER The heart maintains pressure by
generating high hydrostatic pressure to pump blood out of the heart, while also creating
low pressure to bring it back in. This gradient of force is what we mean when we talk
about blood pressure.
Blood Pressure - ANSWER A measure of the amount of strain your arteries feel as your
heart moves your blood around.
The average human heart is about the size of 2 fists clasped together. - ANSWER The
heart is hollow, vaguely cone-shaped, and only weighs about 250 to 350 grams- a
The heart is located in the center of your chest contrary to popular belief that its located
more on the left side. It is snuggled in the mediastinum cavity between your lungs. It sits
at an angle, though, with one end pointing inferiorly toward the left hip, and the other
toward the right shoulder. So most of its mass rests just a little bit left of the midsternal
line. - ANSWER The heart is nestled in a double-walled sac called the pericardium. The
tough outer layer, of fibrous pericardium, is made of dense connective tissue and helps
protect the heart while anchoring it to some of the surrounding structures, so it doesn't
bounce all over the place while beating.
, Meanwhile, the inner serous pericardium consists of an inner visceral layer, or
epicardium- which is actually part of the heart wall- and an outer parietal layer. These
two layers are separated by a thick film of fluid that acts like a natural lubricant providing
a slippery environment for the heart to move around in so it doesn't create friction as it
beats. - ANSWER The wall of the heart itself is made of yet more layers, three of them:
that epicardium on the outside, the myocardium in the middle, which is mainly
composed of cardiac muscle tissue that does all the work of contracting, and the
innermost endocardium, a thin white layer of squamous epithelial tissue.
The general system of chambers, valves, veins, and arteries all work together to circulate
blood around your body. - ANSWER Of course, fluid likes to move from areas of high
pressure to areas of low pressure, and the heart creates those pressures, form once again
following function.
Your heart is divided laterally into two sides by a thin inner partition called the septum.
This division creates the four chambers- two superior atria, which are the low pressure
areas, and two inferior ventricles that produce the high pressures. Each chamber has a
corresponding valve, which acts like a bouncer at a club at closing time- he'll let you out
but not back in. - ANSWER When a valve opens, blood flows in one direction, into the
next chamber. And when it closes, that's it- no blood can just flow back into the chamber
it just left. When you heart your heart thumping, you're really hearing your heart valves
opening and closing.
Pulmonary semilunar valve - ANSWER Between the right ventricle and the pulmonary
artery, allows blood to flow from the heart to the lungs
Solutions
The heart - ANSWER Powers the entire circulatory system, transporting nutrients,
oxygen, waste, heat, hormones, and immune cells throughout the body, over and over.
Truth is, the heart is really just a pump- a big, wet, muscly brute of a pump. The heart has
only one concern: maintaining pressure - ANSWER The heart maintains pressure by
generating high hydrostatic pressure to pump blood out of the heart, while also creating
low pressure to bring it back in. This gradient of force is what we mean when we talk
about blood pressure.
Blood Pressure - ANSWER A measure of the amount of strain your arteries feel as your
heart moves your blood around.
The average human heart is about the size of 2 fists clasped together. - ANSWER The
heart is hollow, vaguely cone-shaped, and only weighs about 250 to 350 grams- a
The heart is located in the center of your chest contrary to popular belief that its located
more on the left side. It is snuggled in the mediastinum cavity between your lungs. It sits
at an angle, though, with one end pointing inferiorly toward the left hip, and the other
toward the right shoulder. So most of its mass rests just a little bit left of the midsternal
line. - ANSWER The heart is nestled in a double-walled sac called the pericardium. The
tough outer layer, of fibrous pericardium, is made of dense connective tissue and helps
protect the heart while anchoring it to some of the surrounding structures, so it doesn't
bounce all over the place while beating.
, Meanwhile, the inner serous pericardium consists of an inner visceral layer, or
epicardium- which is actually part of the heart wall- and an outer parietal layer. These
two layers are separated by a thick film of fluid that acts like a natural lubricant providing
a slippery environment for the heart to move around in so it doesn't create friction as it
beats. - ANSWER The wall of the heart itself is made of yet more layers, three of them:
that epicardium on the outside, the myocardium in the middle, which is mainly
composed of cardiac muscle tissue that does all the work of contracting, and the
innermost endocardium, a thin white layer of squamous epithelial tissue.
The general system of chambers, valves, veins, and arteries all work together to circulate
blood around your body. - ANSWER Of course, fluid likes to move from areas of high
pressure to areas of low pressure, and the heart creates those pressures, form once again
following function.
Your heart is divided laterally into two sides by a thin inner partition called the septum.
This division creates the four chambers- two superior atria, which are the low pressure
areas, and two inferior ventricles that produce the high pressures. Each chamber has a
corresponding valve, which acts like a bouncer at a club at closing time- he'll let you out
but not back in. - ANSWER When a valve opens, blood flows in one direction, into the
next chamber. And when it closes, that's it- no blood can just flow back into the chamber
it just left. When you heart your heart thumping, you're really hearing your heart valves
opening and closing.
Pulmonary semilunar valve - ANSWER Between the right ventricle and the pulmonary
artery, allows blood to flow from the heart to the lungs
