The circulatory system includes:
The transport medium is blood which is a thick viscous fluid, heavier than water and it takes up 7 – 8%% of the body weight.
Functions of the blood constituents:
1. Plasma – straw coloured fluid in which the different cells are suspended.
Liquid transport medium for the cells and materials. Around 55% of the blood is made up of plasma
2. Plasma proteins - protein bodies that act as substrates for different nutrients (to help binding).
Plasma proteins are the bigger proteins, the albumin and globulins which are formed in the liver. Plasma proteins are very important in the immune response.
Globulins: They bind to, neutralise and destroy foreign materials
Help with transportation of some hormones eg thyroglobulin
Help to transport mineral salts eg transferrin carries mineral iron
Albumin: Maintain osmotic pressure
Act as carriers for lipids and steroid hormones
1. Red blood cells - called erythrocytes
Formation of Red blood cells: Called hemopoiesis. Before birth: this is done in the embryionic sac, liver, spleen, thymus gland, lymph nodes, and red bone marrow. After birth RBC are made in the red bone marrow of flat bones
Function: carry haemoglobin which attahces to oxygen and transports oxygen to the cells and carbon dioxide away from the cells.
2. White blood cells – or leukocytes which are responsible for the immune response of the body, and there are many different types of leukocytes
3. Inorganics salts - used in various processes in the body eg Calcium is essential for the heart to beat
4. Waste products - breakdown products after metabolism, unused products and by-products where only part of a substance was used.
5. Gases - carbon dioxide is carried to the lungs for excretion oxygen for uptake.
6. Hormones - carried to the various target organs from the endoa dn exocrine glands.
7. Nutrients - taken from the stomach and intestines and transported to the body
The circulatory system is a connective system which connects the parts of the body together, help with transports of blood and all its compounds. The heart and circulatory system is also known as the cardiovascular system as it is responsible for circulating the blood to the body. The circulatory system is divided into systemic circulation and pulmonary circulation.
Oxygenated blood from the left ventricle travels through the aorta, which branches off into the descending and ascending aorta, and also to itself via the coroanry circulation to replenish the oxygen in the organs.
Right and left coronary arteries branch off just above the semi lunar valve (which stop the blood flowing back).
Deoxygenated blood from the heart is transported through the coronary veins through the coronary sinus which empty into the left atrium.
The portal circulation is the system of veins and its tributaries which supply the intestines and the liver. It is also called the portal venous system.
The portal vein system is responsible for transporting hte blood from the intestines, to the liver with all the nutrients which can then be metabolised and processed before continuing to the heart. It also includes drainage from the spleen and pancreas. this metabolism before moving to the rest of the body is called the first pass effect.
The portal system has the following branches:
The heart is essential to survival, and thus called a vital organ. It is a unique muscular pump that forces the blood to the body parts.
The circulatory system is a transport system, taking oxygen and nutrients to cells in the body, while removing the toxins, byproducts out of the system and transporting deoxygenated blood back to the lungs.
The cardiovascular system includes the heart, veins, arteries, capillaries and is divided into central and peripheral areas.
Another name for the heart is cardiac muscle or myocardium and the system is known as the cardiac system. In summary, the hearts function is to feed the central organs, peripheral organs and itself with essential nutrients, gases and remove toxins from those areas so that the body can function optimally.
Cardiac veins : carrying deoxygenated blood to the heart muscle
Cardiac arteries: feeding oxygenated blood to the heart muscle
An enlarged heart means that the heart over works over a long period of time, due to over exercising, obesity, congenital problems.
When the heart is not able to pump enough oxygen to the body, it is known as cardiac INSUFFICIENCY.As the oxygen grows less, the area of the heart muscle dies and this is called infarction. A myocardial infarction is commonly known as a “heart attack”. Myocardial infarctions/ heart attacks can be caused by a clot of blood preventing the blood taking oxygen to the area, or a fat embolism () or an enlarged heart is too overworked to get the blood to the correct areas.
An enlarged heart occurs when the heart has been overworked over a long period of time due to
The symtoms include:
Blood is divided into “formed”/cellular parts and plasma/liquid
Liquid transport medium for the cells and materials. Around 55% of the blood is made up of plasma
– these are the bigger proteins, the albumin and globulins which are formed in the liver.
Plasma proteins are very important in the immune response. Globulins and Albumin are 2 examples.
Globulins: They bind to, neutralise and destroy foreign materials. Functions of globulins: 1) they help with transportation of some hormones eg thyroglobulin. 2) Help to transport mineral salts eg transferrin carries mineral iron
Albumin: Functions of albumin 1)Maintain osmotic pressure 2) Act as carriers for lipids and steroid hormones
Red blood cells:
Red blood cells are called Erythrocytes.
Formation of RBC is called hemopoiesis. Before and after birth hemopoeisis works differently.Before birth formation of RBC is done in the embryionic sac, liver, spleen, thymus gland, lymph nodes, and red bone marrow. After birth RBC are made in the red bone marrow of flat bones
Function: carries oxygen to the cells and carbon dioxide away from the cells.
White blood cells:
Also known as Leukocytes. There are different types of leukocytes, whcih will be discussed in a later slide
The heart is a muscular pump situated in the centre of the thorax, between the lungs, behind the sternum. The apex (tip of the heart) points slightly to the left. A normal heart size is about the size of the persons fist.
The heart is made up of 4 compartments, the right and left sides are divided by a septum (wall of muscle), while the top and bottom compartments on the left and right side are dividies by valves , allowing the blood to pass through. it serves to pump blood to the lungs to be oxygenated, then to pump the blood to the rest of the body with teh oxydenated blood.
The heart receives the blood from the body through the superior (body above the level of the heart) and inferior (below the level of the heart) vena cava (big veins transporting deoxygenated blood). THe blood comes into the first compartment canlled the right atrium.
From the right atrium is goes down through the tricsupid valve to the right ventricle. From here the blood follows the Pulmonary artery to the lungs to fetch the oxygen from the alveoli.
Once the blood is oxygenated, the capillaries form veins and these all come together to form teh pulmonary vein which goes back to the heart. the oxygenated blood returns to the heart through the left arium, passes though the mitral valve into the largest and strongest part of the heart, the left ventricle.
The left ventricle pumps the blood throught the aorta to the body.
The heart has 4 chambers, 2 atria (one top, one bottom) and 2 ventricles (one top one bottom).
The main artery leaving the heart is the aorta
The main veins are the inferior vena cava and the superior vena cava
The top atrium have thinner muscular walls as the blood does not get pumped very far.
The bottom ventricles have much thicker walls because there is more pressure needed and the thickest/strongest muscular wall is the left verntricle.
The aorta is the biggest artery in the body, almost as wide as 2 fingers together. While the vena cavas are the biggest of the veins.
The heart wall is made up of 3 layers:
Epicardium: thin outermost layer which protects the heart and helps to lubricate
Myocardium: the thick middle layer responsible for pumping the blood.
Endocardium: inner lining of the heart, made up of simple squamous epithelium. The endothelium 's main function is to prevent the blood sticking to the wall of the heart.
the tricuspid vavle is found between teh right atrium and the right ventricle.
The mitral valve (also know as biscuspid valve)is found between the left atrium and left ventricle.
The semilunar valves are at the base of the pulmonary areter and arota, and prevent blood from slipping back into the heart
There is a group of specialised cells in the wall of the heart which send electrical impulses to the heart muscle to allow it to contract. The contraction causes a pumping motion which pumps the blood to the next phase.
The 5 important parts of the elctrical conduction system are:
The SA node is located in the right atrium, starts with an electrical impulse.
the atria contract pushing blood through the valves to the ventricles.
The impulse travels to the AV node which is located in the atria.
The impulse follows to the bindle of His and then divides left and right to the Purkinje fibres causing the ventricles to contract.
The left ventricle contracts slightly before the right.
The heart now relaxes.
Electrical activity is mesured using an ECG - electrocaridogram. This is one of the best ways to view the function of the heart.
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