Transcript The Cardiovascular System

PPT showed by Clinical medicine Dept ,class 6 group 3
Group leader of medical English subject: 郭涵
Group members :陶训勋 李丝丝 陈银妹 任芹 刘璐 戴晓峰 马强 龚宇
蒋凯南 沈海林 刘成
Section B
Readings
Passage One
The Cardiovascular System
Main contents:
Structure of the cardiovascular
Primary functions of its organs
Associated medical terms
system
myocardium
n. 心肌
subdivision n.细分；分支
endocardium
n.心内膜
arteriole n. 小动脉
epicardium n.心外膜
pericardium
n.心包
atrium 【复】atria n.心房
ventricle n. 心室
aorta n. 主动脉
platelike adj. 盘状的
carbon dioxide n. 二氧化碳
bloodstream n. 血流
lining n. 内层
interventricular adj.（心）室间的
venule n. 小静脉
septum n. 隔
valve n. 瓣膜
interatrial adj. （心）房间的
tunic n. 层
innermost adj. 最里层的
endothelium n. 内皮
The cardiovascular system is made up of the heart and blood
vessels. The heart is situated between the lungs with its apex
directed toward the left. The thick muscle layer of the heart wall is
the myocardium ,which is lined on the inside with a thin
endocarium and is covered on the outside with a thin epicardium.
The heart is contained with a fibrous sac, the pericardium.
the upper receiving chambers of the heart are the atria. The
lower pumping chambers are the ventricles. The interventricular
septum separates the two ventricles; the interatrial septum divides
the two atria.
There are three major types of blood vessels,
i.e. ,arteries, veins ,and capillaries. Arteries lead
blood from the heart. These blood vessels have the
thickest walls because they receive the pumping drive
from the ventricles of the heart. These are three coat
(tunics) which resemble the three tissue layers of the
heart. These are :1)the innermost membrane of
endothelium ,which forms a smooth surface over
which the blood may easily move;2)the second, more
bulky layer, which is made of involuntary muscle
combined with elastic connective tissue; and 3)an
outer tunic ,which is made of a supporting connective
tissue. The largest artery ,the aorta, is about 1 inch in
diameter and has the thickest wall.
The smallest subdivisions of arterioles ,have
thinner walls in which there is very little
connective tissue but relatively more muscle.
These smaller branches of the arteries carry blood to
the tiniest of blood vessels, the capillaries.
Capillaries have walls that are only one epithelial cell
thick. The capillary walls are transparent and are made
of smooth platelike cells that continue from the lining of
the arteries. The walls are so thin that they can allow
passage of oxygen and nutrients out of the bloodstream
and into the tissue fluid surrounding the cells. At the
same time, waste products such as carbon dioxide and
water pass out of the cells and into the thin-walled
capillaries. The capillary boundaries are the most
important center of activity of the entire circulatory
system.
Veins are thinner-walled than arteries. They conduct
waste-filled blood toward the heart from the tissues.
Veins have little elastic tissue and less connective
tissue than arteries. The smallest vein ,called venule,
are formed by the union of capillaries. Their walls are
only slightly thicker than those of the capillaries. As the
veins become larger ,the walls become thicker.
However, veins have much thinner walls than those of
comparable arteries. Although there are three layers of
material in the walls of the larger veins, as in the artery
walls ,the middle tunic is relatively thin in vein walls .
Therefore, veins are easily collapsed, and slight
pressure by a tumor or some other mass may interfere
with the return blood flow. Most veins are equipped with
one-way valves that permit the blood to flow in only one
direction. They are most numerous in the veins of the
extremities.
The heart pumps blood through two
circuits . The right side of the heart pumps
blood to the lungs to be oxygenated through
pulmonary circuit. Pulmonary vessels
include the pulmonary artery and its branches ,
and the veins that drain the lung capillaries.
The pulmonary arteries carry blood low in
oxygen from the right ventricle, while the
pulmonary veins carry blood high in oxygen
from the lungs into the left atrium. This circuit
concerns itself with eliminating carbon dioxide
from the blood and replenishing its supply of
oxygen. The left side of the heart pumps blood
to the remainder of the body through the
systemic circuit. This circuit is concerned with
supplying food and oxygen to all the tissues of
the body and carrying away waste materials
from the tissues for disposal.
Blood returning from tissues other than the lungs enters
the heart by way of the venae cavae : the superior vena cava
and the inferior vena cava. The venae cavae empty into the right
atrium. When the atria contract, blood in the right atrium is forced
through the tricuspid valve(三尖瓣） into the right ventricle. When
the ventricle contracts, blood in the right ventricle is forced through
the pulmonary semilunar valve（肺动脉瓣） into the pulmonary
artery; at the same time ,the tricuspid valve close to prevent the
backward flow of blood into the atrium. Blood that enters the
pulmonary artery is carried to the lungs. There it undergoes
oxygenation, a process in which carbon dioxide (a waste product of
cellular metabolism) is exchanged for oxygen from the environment.
Two circuit :
Pulmonary circuit
Systemic circuit
Oxygenated blood returns to the heart by way of pulmonary veins,
which empty into the left atrium. Atrium contraction force blood from the
left atrium through the mitral valve, also called bicuspid valve(二尖
瓣）, into the left ventricles. When the ventricles contract ,blood in the
left ventricle is forced through the aortic semilunar valve（主动脉瓣）
into the aortic, the body’s largest artery, for distribution to the tissues.
The aortic is one continuous tube divided into the following regions :1）
the ascending aorta（升主动脉） ,which is near the heart and inside the
pericardial sac; 2) the aortic arch（主动脉弓）, which curves from the
right to the left, and also extends backward; 3) the thoracic aorta（胸主
动脉） ,which lies just in front of the vertebral column behind the heart
and in the space behind the pleura; and 4) the abdominal aorta（腹主动
脉 ） , which is the longest section of the aorta, spanning the
abdominal cavity.
翻译：腹主动脉——主动脉的最长部分，横跨腹腔。
正常心脏
血管解剖：
心瓣膜与
血流方向:
WISE拍摄星云图酷似心
脏 仿佛还有血液流动
据美国《连线》杂志报道，近期美国宇
航局“广域红外探测器”(Wide-Field
Infrared Survey Explorer，简称WISE)
拍摄到一张神奇星云图片，两个相邻的
星云外形都酷似心脏，星云内部仿佛还
有红色的血液在流动。
5月24日，加州大学洛杉矶分校的
天文学家奈德·赖特(Ned Wright)在参加
美国天文学会(American Astronomical
Society)的一次会议时向外公布了这张
照片。赖特表示：“这两个星云，其中
一个酷似情人节心形心脏，而另一个则
类似于人体心脏，十分神奇。”据悉，
这两个星云位于仙后座星系，距离地球
约有6000光年的距离。
There are two phases of the heartbeat: diastole (relaxation)
and systole (contraction). This diastole-systole cardiac cycle
(relaxation-filling, then contraction-pumping) lasts about 0.9 second
and occurs between 70 and 80 times per minute. That is to say ,the
ventricles pump blood into the arteries regularly about 70 to 80
times a minute. The force of ventricular contraction starts a wave of
increased pressure which begins at the heart and travels along the
arteries. This wave is called the pulse. It can be felt in the arteries
that are relatively close to the surface, particularly if the vessel can
be pressed down against a bone. At the wrist the radial artery
passes over the bone on the thumb side of the forearm, and the
pulse is most commonly obtained here. Other vessels sometimes
used of obtaining the pulse include the carotid artery in the neck
and the dorsalis of the top of the foot.
That’s all for our presentation.
Thanks for listening !