The circulatory and cardiovascular system:
The circulatory system includes:
- Heart
- Blood vessels
- Blood
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:
Liquid components:
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
Cellular / formed components:
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.
The coronary circulation:
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.
Portal circulation
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:
- Superior mesenteris vein - from the small intestine and beginning of the large intestine.
- Gastric vein from the stomach
- Splenic vein form the spleen and pancreas
- Inferior mesenteric vein from the large intestine
- Cystic vein from the gall bladder
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.
- Central areas of the body means the heart itself with the immediate vessels, and the vital organs
- Peripheral means the areas moving away from the heart to the limbs.
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.
The vessels are:
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
- exercise
- illness (rheumatic fever)
- obesity
- congenital abnormalities.
The symtoms include:
- Swelling in the legs
- Increased weight due to water retention
- Shortness of breath
- increase size around the abdomen
- Fatigue
- Palpitations / feels like skipped beats in the heart when lying flat)
Blood is divided into “formed”/cellular parts and plasma/liquid
55 % Liquid
Plasma:
Liquid transport medium for the cells and materials. Around 55% of the blood is made up of plasma
Plasma Proteins:
– 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
45 % Cellular/ formed parts
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.
Structure:
- Selectively permeable membrane
- Erythrocytes are biconcave discs
- no nucleus
- contain haemoglobin which combines with oxygen and carries it to the body
Interesting facts:
- RBC do not use any of the Oxygen that it transports because there is no metabolism inside the cell.
- RBC Cannot divide or metabolise
White blood cells:
Also known as Leukocytes. There are different types of leukocytes, whcih will be discussed in a later slide
