CARDIO VASCULAR SYSTEM

CARDIO VASCULAR SYSTEM


1) What are the two parts of the cardiovascular system?

Blood
Blood vessels and the heart
(2) What are the functions of the cardiovascular system?

The heart pumps blood all through the body.
The blood helps fight infections, regulates temperature, and regulated ph levels.
(3) What are the types of blood vessels?
Arteries, capillaries, and veins.
(4) What is the structure and function of these vessels?

Arteries: Consists of three levels. 1) Endothelium: thin cells that make up the inner level 2) Middle layer is smooth muscle 3) The outer layer is connective tissue. These walls allow the artery to be protect under pressure and allows them to expand. Arteries carry blood from the heart.
Capillaries: Arterioles branch out and become capillaries. Capillaries are made of endothelium.
Veins: Veins have the same layers as arteries but has less of the middle layer. Veins are thinner than arteries, because of this they can expand further. Veins carry blood to the heart.
(5) Why is the heart a double pump?

The heart is a double pump because it is pumping blood to the lungs and blood to the body at the same time but they never intersect.
(6) What causes the "lub" and the "dup" of the heart sounds?

Lub: "Cusps of Av valve" slam shut due to pressure
Dup: When the ventricles relax and the blood begins to glow again.
(7) What keeps the heart beat regular?

The SA node sends a signal ever .85 seconds which causes the atria to contract. The signal is then sent to the AV.
(8) What does the pulse rate of a person indicate?

The pulse rate tells how many beats the heart has beat in a minute.
(9) What accounts for blood flow in the arteries?

The blood flow in the arteries is called blood pressure .
(10) What accounts for blood flow in the veins?

Skeletal pump: caused by skeletal muscle contraction
Respiratory Pump: caused by breathing
valves in the veins

The human body consists of many organs that are useful to carry out the functions of the body properly. All organs in the body are very much essential for normal functioning of the human body. In the similar manner, cardiovascular system is the most essential part of the body. It comprises of three main parts: blood, the heart, and the blood vessels, arteries and capillary veins.

The main function of cardiovascular system is to transport oxygen to all other organs of the body. Thus, this process provides sufficient amount of nutrition to several parts of the body. It is the most interesting and essential component of the body. Many researchers and scientist have toiled their life to get all the detailed information about this system. Every part of the system has different facts and functions. Thus, we may discuss here some interesting facts about blood, heart and blood vessels.

Blood:

Blood is the nutrition of the body that provides us energy for survival. Blood is actually a carrier of nutrition and oxygen to all other organs and cells of the body. Some interesting facts will help you to understand the proper functioning of blood.

Blood is made up of blood cells which are in the form of liquid, known as blood plasma. Seven % of the blood comprises in the total weight of the body. An adult human body contains an average of five liters of blood. There are two types of blood in the body: Red blood cells (RBC) and white blood cells (WBC). Blood even comprises of leukocytes and platelets. Hemoglobin is the main component of RBC, which is protein with iron that is very much essential for body to transport oxygen. Blood is made up of connective tissues and is generated within bones.

Heart:

The heart is the most important component of the body. It supplies blood and oxygen to all other parts of the body. The heart of male weighs approximately 300-350 grams whereas, female heart weight almost 250-300 grams. Its size is equivalent to the size of your hand fist. The heart is wrapped by double layer sac- Pericardium. Our heart is made up of three main parts: Innermost layer (Endocardium), Middle layer (Myocardium) and the Uppermost layer( Visceral layer) Heart comprises of four chambers: two arteries and two ventricles.

Blood vessels:

Blood vessels transport blood to the heart and other organs of the body.

The blood vessels in divided into three types: veins, capillaries and arteries. Each blood vessel carries out an important function of the body. The veins transport blood cells to the heart while, arteries pull away the blood from the heart. The Capillaries exchange chemicals with water. Aorta is the largest artery in the blood vessels that transports the blood from the heart. It is divided into: carotid artery, celiac trunk, renal artery, iliac artery, subclavian artery, and mesenteric arteries.


The heart is the pump responsible for maintaining adequate circulation of oxygenated blood around the vascular network of the body. It is a four-chamber pump, with the right side receiving deoxygenated blood from the body at low presure and pumping it to the lungs (the pulmonary circulation) and the left side receiving oxygenated blood from the lungs and pumping it at high pressure around the body (the systemic circulation).

The myocardium (cardiac muscle) is a specialised form of muscle, consisting of individual cells joined by electrical connections. The contraction of each cell is produced by a rise in intracellular calcium concentration leading to spontaneous depolarisation, and as each cell is electrically connected to its neighbour, contraction of one cell leads to a wave of depolarisation and contraction across the myocardium.

This depolarisation and contraction of the heart is controlled by a specialised group of cells localised in the sino-atrial node in the right atrium- the pacemaker cells. These cells generate a rhythmical depolarisation, which then spreads out over the atria to the atrio-ventricular node.
The atria then contract, pushing blood into the ventricles.
The electrical conduction passes via the Atrio-ventricular node to the bundle of His, which divides into right and left branches and then spreads out from the base of the ventricles across the myocardium.
This leads to a 'bottom-up' contraction of the ventricles, forcing blood up and out into the pulmonary artery (right) and aorta (left).
The atria then re-fill as the myocardium relaxes.

The 'squeeze' is called systole and normally lasts for about 250ms. The relaxation period, when the atria and ventricles re-fill, is called diastole; the time given for diastole depends on the heart rate