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1. Terdapat tiga sistem peredaran yang bergabung menjadi sistem peredaran darah badan.Nyatakan sistem-sistem ini dan terangkan bagaimana ketiga-tiga sistem ini berfungsi untuk

menyempurnakan sistem peredaran darah badan.

There are three circulatory processes occurring simultaneously within the body. Firstlysystemic circulation carries blood around the body, pulmonary circulation carries blood

to the lungs and coronary circulation provides the heart with its own supply of blood. Systemic Circulation

At the start of the blood circulatory cycle the heart pumps oxygenated blood out of the

left ventricle, through the Aorta (the largest artery in the body). The aorta divides into

smaller arteries, then arterioles and finally into microscopic capillaries, found deep

within muscles and organs. Here the Oxygen (and other nutrients) passes through the

thin capillary walls, into the tissues where it can be used to produce the energy muscles

require to contract. (See the diagram below)

A waste product of energy production (metabolism) is Carbon dioxide and in order to be

removed, it too passes across the walls of the capillaries, into the blood stream. The

blood continues back towards the heart, through venules and then veins, into the right

atrium.

Systemic circulation is the circulation of the blood to all parts of the body except the

lungs. Systemic circulation is the portion of the cardiovascular system which transports

oxygenated blood away from the heart through the Aorta from the left ventricle where

the blood has been previously deposited from pulmonary circulation, to the rest of the

body, and returns oxygen-depleted blood back to the heart. Systemic circulation is,

distance-wise, much longer than pulmonary circulation, transporting blood to every part

of the body

Pulmonary CirculationOnce blood returns to the heart it is then pumped from the right ventricle through the

Pulmonary arteries to the lungs, where the waste carbon dioxide can be expelled andmore Oxygen collected. The Pulmonary vein carries oxygenated blood back to the left

atrium of the heart, where the cycle starts again.

The pulmonary circulatory system is the portion of the cardiovascular system in which

oxygen-depleted blood is pumped away from the heart, via the pulmonary artery, to the

lungs and returned, oxygenated, to the heart via the pulmonary vein.

Oxygen deprived blood from the vena cava, enters the right atrium of the heart and

flows through the tricuspid valve (right atrioventricular valve) into the right ventricle,

from which it is then pumped through the pulmonary semilunar valve into the

pulmonary artery to the lungs. Gas exchange occurs in the lungs, whereby CO2 is

released from the blood, and oxygen is absorbed. The pulmonary vein returns the now

oxygen-rich blood to the heart.

Coronary circulationThe coronary circulatory system provides a blood supply to the muscles of the heart. As

it carries oxygenated blood to muscles, it is by definition a part of the systemic

circulatory system. It arises from the aorta and drains through the coronary sinus into

the right atrium. Back flow of blood through its opening during atrial systole is

prevented by the Thebesian valve. The smallest cardiac veins drain directly into

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chambers of the heart. This is the circulation in the arteries near in the heart like aorta,

superior and inferior vena cava.

2. Gambar di atas menunjukkan pembekuan darah berlaku. Jelaskan mekanisme pembekuan darahberlaku dan menyatakan sel-sel atau bahan-bahan plasma yang terlibat.

3. Jelaskan fungsi utama sistem peredaran darah serta lukiskan sistem peredaran darah danlabelkan.

Fungsi asas peredaran darah ialah menyampaikan zat-za makanan dan oksigen kepada sel-sel di

dalam badan dan mengeluarkan karbon dioksida dan bahan yang tidak dikehendaki dari sel

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4. Saluran darah mempunyai tiga jenis saluran yang mempunyai fungsinya sendiri. Namakan danterangkan perbezaan berdasarkan fungsinya. Lukiskan tiga saluran ini

Functions of capillaries

Capillaries have no smooth muscle surrounding them and have a diameter less than that of red

blood cells; a red blood cell is typically 7 micrometers outside diameter, capillaries typically 5

micrometers inside diameter. The red blood cells must distort in order to pass through thecapillaries.

These small diameters of the capillaries provide a relatively large surface area for the exchange

of gases and nutrients.

What capillaries do

In the lungs, carbon dioxide is exchanged for oxygen

In the tissues, oxygen and carbon dioxide and nutrients and wastes are exchanged

In the kidneys, wastes are released to be eliminated from the body

In the intestine, nutrients are picked up, and wastes released

Arteries

(from the Greek - artria, "windpipe, artery")[1] are blood vessels that carry blood away

from the heart. This blood is normally oxygenated, exceptions made for the pulmonary and

umbilical arteries.

The circulatory system is extremely important for sustaining life. Its proper functioning is

responsible for the delivery of oxygen and nutrients to all cells, as well as the removal of carbon

dioxide and waste products, maintenance of optimum pH, and the mobility of the elements,

proteins and cells of the immune system.

Veins

In the circulatory system, veins (from the Latin vena) are blood vessels that carry blood towards

the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptionsare the pulmonary and umbilical veins, both of which carry oxygenated blood to the heart. Veins

differ from arteries in structure and function; for example, arteries are more muscular than

veins, veins are often closer to the skin and contain valves to help keep blood flowing toward

the heart, while arteries carry blood away from the heart.

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5. Semasa memotong sayur, Ali telah melukakan tangannya dengan tidak sengaja. Darah telah

mengalir keluar dan selepas beberapa minit, darahnya masih lagi mengalir dan tiada simptom-

simptom yang menunjukkan darahnya akan berhenti mengalir keluar. Jelaskan kenapa keadaan

ini berlaku. Terangkan apa tindakan yang perlu diambil oleh dia untuk menghentikan

pengeluaran darahnya.