Добавил:
Sekretar
kiopkiopkiop18@yandex.ru
t.me/Prokururor I Вовсе не секретарь, но почту проверяю
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз:
Предмет:
Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3777_Библиотеки_им_академика_М_И_Перельмана
.pdf
CHAPTER 3 The Circulatory System
Arteries
1. Carry blood from the
heart, carry oxygenated
blood (except
pulmonary artery)
2. Normally bright red
in color
3. Elastic walls that expand
with surge of blood
4. No valves
5. Can feel a pulse
Vei ns
1. Carry blood to the heart,
carry deoxygenated
blood (except
pulmonary vein)
2. Normally dark red
in color
3. Thin walls/less elastic
4. Valves
5. No pulse
ARTERIES VERSUS VEINS
Artery Arteriole Capillaries Venule Vein
From
Heart
To
Heart
https://t.me/med1917
63
Arteries
Arteries are blood vessels that carry blood away from the heart (see
Figure 3-3). Blood is pumped from the ventricles into large, elastic arteries.
The largest artery is the aorta, about 2.5 centimeters in diameter. It has
thick walls because it receives blood under the highest pressure, directly
from the left ventricle. The large, elastic arteries branch into smaller
arteries. As the arteries grow smaller, they become less elastic and begin
to have more smooth (involuntary) muscle tissue. The smallest arteries
are called
brane, called the tunica intima, is a layer of endothelium that forms a
smooth surface. This smooth surface enables blood to ow easily through
arterioles.
Arteries are composed of three layers, or tunics. The innermost mem-
Delmar/Cengage Learning
Figure 3-3 Blood ow from artery to capillary to vein. See color insert.
Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).
Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.
Elastic
fibers
Tunica interna, or intima
endothelium, areolar,
and elastic tissue
Internal
elastic
membrane
Tunica
media
(muscle
tissue)
Tunica adventitia or
externa (connective tissue)
Endothelium
External
elastic
membrane
Tunica media
smooth muscle
Endothelium
Capillary
Tunica externa,
or adventitia
connective tissue
Lumen
VeinArtery
Artery Vein Capillary
Lumen
(B)
Val ve
(A)
https://t.me/med1917
64
PART 2 Blood and Urine Collection
the vessel. The middle layer, or tunica media, is the thickest layer and
is made of smooth muscle combined with elastic connective tissue. The
tunica adventitia is the outermost layer, and it is composed of support-
ing connective tissue. See Figure 3-4.
Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).
Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.
Figure 3-4 (A) The three layers of the walls of an artery and a
vein. (B) Cross section of blood vessels. See color insert.
Delmar/Cengage Learning
CHAPTER 3 The Circulatory System
https://t.me/med1917
65
Capillaries
Arterioles transport blood from the small arteries to capillaries. There are
about 10 billion capillaries in the body. Capillaries are microscopic in size.
They are 0.5 to 1 millimeter long, and they branch without a change in their
diameter. They have the thinnest walls of all the vessels: a one-cell layer
(refer to Figure 3-4). Capillary walls are transparent and consist of endothelium surrounded by a layer of loose connective tissue. Because of the thinness of the walls, direct exchanges between the blood and body cells are
made. Red blood cells ow in single le through the capillaries. As the blood
ows through the capillaries, it gives up oxygen and nutrients to the tissues.
In exchange, it picks up carbon dioxide and other by-products. Blood pressure forces uid out of the capillaries, and osmosis moves uid into the capillaries. Blood ow through the capillaries is cyclic, due to the contraction and
relaxation of the precapillary sphincters. Precapillary sphincters are smooth
muscle cells located at the points where capillaries branch. The contraction
and relaxation of the sphincters is regulated by the metabolic needs of the
tissues. Blood ow is increased when oxygen levels decrease. Blood ow is
also increased when levels of glucose, amino acids, and fatty acids decrease.
An increase in carbon dioxide or a decrease in pH (increase in acid level of
blood) causes the precapillary sphincters to relax. Please refer to Figure 3-3.
Veins
Blood ows from capillaries into venules (see Figure 3-3). Venules are
the smallest veins, and their walls are only slightly thicker than those of
capillaries. Their diameter is also slightly larger. Venules are composed
of endothelium surrounded by a connective-tissue membrane. As the
venules connect with small veins, the vessel walls become thicker. Even
small veins are larger in diameter than venules. Medium-size veins
collect blood from small veins and transport it to large veins. Although
their walls become thicker as veins increase in size, veins have much thinner walls than arteries. In addition, the blood they carry is under much
lower pressure. Like arteries, veins are composed of three layers, but the
veins’ middle tunic is thinner.
Veins having diameters greater than 2 millimeters have valves. Valves
allow blood to ow toward the heart but not in the opposite direction, and
they become more numerous with the increase in the size of the vein.
There are more valves in veins of the legs than in veins of the arms. These
valves prevent the pull of gravity from drawing the ow of blood down
toward the feet.
Phlebotomists come in contact most frequently with the arteries and
veins in the upper limbs. Therefore, this discussion of systemic circulation
Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).
Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.
66
https://t.me/med1917
PART 2 Blood and Urine Collection
will focus on the upper limbs. The arteries of the upper limbs consist of
the following:
• located just below the clavicle.
Subclavian artery,
Brachial artery,
• located in the arm; a continuation of the axillary
artery.
• located in the arm; it branches from the brachial to
Ulnar artery,
the medial, or little nger, side.
Radial artery
• located in the arm; it also branches from the bra-
,
chial artery, but on the thumb side.
See Figure 3-5 for an overview of the major arteries of the systemic
circulation.
The radial artery is the artery used most often in obtaining an arterial
blood sample for blood gases (a test ordered to assess lung function by
measuring oxygen and other gases of respiration).
The veins of the upper limbs can be divided into two groups:
• brachial veins
The deep veins that run parallel to the arteries. The
are the most noteworthy for our purposes. They accompany the
brachial artery and empty into the axillary vein.
The super cial veins that drain the blood in the arm into the deep
•
veins, including the cephalic vein, which empties into the subclavian vein, and the basilic vein, which empties into the axillary vein.
See Figure 3-6 for an overview of the major veins of the body.
The phlebotomist will be able to see many of the tributaries of the two
major super cial veins through the skin on the patient’s forearm and hand.
The median cubital usually connects the cephalic vein with the basilic vein.
The median cubital is usually quite prominent in the cubital fossa, the
anterior surface of the upper arm at the elbow, and is an ideal site for
performing a venipuncture. Please refer to gure 3-7.
Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).
Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.
BLOOD
Blood is classi ed as a connective tissue. It is made up of cells and cell
fragments moving freely in a liquid substance called plasma. Normally
the total circulating blood volume is about 8 percent of body weight.
About 55 percent of this volume is plasma.
Plasma is a pale yellow
cent dissolved substances such as proteins, ions, nutrients, gases, waste
products, and regulatory substances. Of the cells and cell fragments, or
formed elements, in the blood, about 95 percent are red blood cells, or
uid consisting of 92 percent water and 8 per-
Right external carotid artery
Right internal carotid artery
Right vertebral artery
Right subclavian artery
Brachiocephalic artery
Right axillary artery
Ascending aorta
Right brachial artery
Common hepatic artery
Descending (abdominal) aorta
Right common iliac artery
Right external iliac artery
Right femoral artery
Right popliteal artery
Right posterior tibial artery
Right anterior tibial artery
Right peroneal artery
Right dorsalis pedis artery
Right and left common
carotid arteries
Left subclavian artery
Aortic arch
Descending (thoracic)
aorta
Left gastric artery
Splenic artery
Left renal artery
Left radial artery
Left ulnar artery
Left internal iliac artery
https://t.me/med1917
CHAPTER 3 The Circulatory System
67
Figure 3-5 The major arteries of the systemic circulation. See color insert.
Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).
Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.
Delmar/Cengage Learning
68
Right external jugular vein
Right internal jugular vein
Superior vena cava
Right subclavian vein
Right axillary vein
Right hepatic vein
Inferior vena cava
Right common iliac vein
Right external iliac vein
Right internal iliac vein
Right femoral vein
Right popliteal vein
Right great saphenous vein
Right posterior tibial vein
Right anterior tibial vein
Right peroneal vein
Right dorsalis venous arch
Right and left
brachiocephalic veins
Left cephalic vein
Left brachial vein
Splenic vein
Left renal vein
Left radial vein
Left ulnar vein
https://t.me/med1917
PART 2 Blood and Urine Collection
Figure 3-6 The major veins of the body. See color insert.
Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).
Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.
Delmar/Cengage Learning
Median
Median Cubital
Cephalic
Basilic
https://t.me/med1917
CHAPTER 3 The Circulatory System
69
Delmar/Cengage Learning
Figure 3-7 The super cial veins of the arm. Refer to Figure 5-1 in color insert.
erythrocytes. Plasma also produces a buffy coat that consists of a layer
of yellowish plasma from which the red cells have settled out in coagulated blood. The remaining 5 percent consist of white blood cells, or
leukocytes, and cell fragments called platelets, or thrombocytes. Please
refer to Figure 3-8.
The process of blood cell production is called hematopoiesis. In
the fetus, hematopoiesis occurs in the liver, thymus gland, spleen, lymph
Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).
Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.
70
Plasma
(55% of
total
volume)
Formed
elements
(45% of
total
volume)
Test tube
containing
whole blood
Erythrocytes
Thrombocytes
(platelets)
Neutrophil
Monocyte
Eosinophil
Lymphocyte
Basophil
Leukocytes
https://t.me/med1917
PART 2 Blood and Urine Collection
Figure 3-8 The major components of blood. See color insert.
Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).
Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.
nodes, and red bone marrow. In children, red blood cells are produced in
the marrow cavities of all the bones, and some white cells are produced
in lymphatic tissue. In adults, red blood cells, many white blood cells,
and platelets are formed in the bone marrow. By the time an individual
reaches age 20, the marrow in the cavities of the long bones, except for
the upper humerus and femur, has become inactive. Active marrow is
called red marrow, and inactive marrow is called yellow marrow. Yellow
marrow is mixed with fat. Bone marrow is one of the largest organs in the
body, and is comparable in weight and size to the liver.
Delmar/Cengage Learning
CHAPTER 3 The Circulatory System
https://t.me/med1917
71
Erythrocytes
Erythrocytes, or red blood cells, are manufactured in the bone marrow.
They are shaped like concave disks, thinner at the center than at the edges.
Erythrocytes live in circulation for about 120 days in men and 110 days in
women. The average normal red blood cell count is 5.4 million per cubic
microliter of blood in men and 4.8 million per cubic microliter in women.
There are approximately 25 trillion red blood cells in a 135-pound man.
Approximately 2.5 million red blood cells are produced every second, or
200 million every day. The primary functions of erythrocytes are to carry oxygen from the lungs to various tissues of the body and to assist in the transport
of carbon dioxide from the tissues to the lungs. Please refer to Figure 3-9.
Oxygen is transported by
hemoglobin. Hemoglobin is a pigmented
protein that gives blood its red color, and it is responsible for 97 percent
of the oxygen transported in blood. Each red blood cell contains approximately 270 million hemoglobin molecules. Iron is necessary for oxygen
transport, and approximately two-thirds of the body’s iron is found in
hemoglobin. About one-third of a red blood cell’s volume is hemoglobin.
Leukocytes
Leukocytes, or white blood cells, are another formed element in blood.
They are called white blood cells because they are white in color, as they
lack hemoglobin. Leukocytes are spherical in shape and are larger than
erythrocytes. They have nuclei of varying shapes and sizes. White blood
cells normally number 4,000 to 11,000 per microliter of blood. Leukocytes can leave the blood and travel in an amoeba-like fashion through the
tissues. They function to protect the body against invading microorganisms, and they remove dead cells and debris from the tissues. Whenever
pathogens (disease-producing agents) enter the tissues, white blood cells
called neutrophils and monocytes proceed by amoeboid movement to the
area of infection. Once there, they engulf the pathogens by phagocytosis. Phagocytosis is a process of ingestion and digestion by cells of substances such as bacteria, foreign particles, other cells, and cell debris. If
the pathogens are very strong, however, they may destroy the leukocytes.
A collection of leukocytes and bacteria forms pus.
There are different types of leukocytes. They are de
ned by their size,
the shape of their nucleus, and the appearance of granules in the cytoplasm.
Granulocytes are the most numerous of the white blood cells,
and they have a horseshoe-shaped nucleus. Granulocytes are divided into
neutrophils, eosinophils, and basophils. The granulocytes have granules
Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).
Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.
72
Neutrophil
Erythrocyte
Eosinophil
Basophil
Monocyte
Platelets
B Lymphocyte
T Lymphocyte
Blood cell Function
Life span
in blood
120 days O
2
and CO2 transport
Immune defenses
Defense against parasites
Inflammatory response
Cellular immune response
Blood clotting
Immune surveillance
(precursor of
tissue macrophage)
Antibody production
(precursor of
plasma cells)
7–12 hours
Unknown
Unknown
Unknown
Unknown
3 days–years
7–8 days
https://t.me/med1917
PART 2 Blood and Urine Collection
Figure 3-9 The function and life span of blood cells. See color insert.
Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).
Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.
Delmar/Cengage Learning
Соседние файлы в папке Библиотека им академика М.И. Перельмана