Unit 2.2 The Circulatory System Flashcards
What is the circulatory system?
The circulatory system (also referred to as the cardiovascular system) is the transport system of the body by which food, oxygen, water and other essential nutrients are carried to the cells and waste products such as urea and carbon dioxide are carried away.
What are the 3 essential parts of the circulatory system?
1) The blood - a liquid containing suspended cells which carries substances around the body.
2) The heart - a muscular pump which provides the force needed to move the blood to the lungs and pick up oxygen and around the body.
3) The blood vessels - the tubes through which the blood travels to, through and from the tissues.
What is the blood?
Blood as both liquid and solid components and is actually a complex tissue in which living blood cells are suspended in non-living fluid matriculates called plasma.
How much blood does an average adult have in their body?
Between 3 - 5 litres.
What are the main constituents of blood?
The plasma which makes up about 55% of blood volume.
The RBCs which make up about 44% of the volume
The remaining 1% consists of WBCs inc leukocytes and lymphocytes and platelets.
Where does the red colour of blood come from?
The red colour comes from the pigment haemoglobin found in the red blood cells.
Why does circulating blood appear bright red in the arteries?
Circulating blood appears bright red in the arteries because in the arterial system the haemoglobin is fully oxygenated and oxyhemoglobin is bright red.
What happens to oxyhemoglobin during its passage through the body?
During its passage through the body, oxyhemoglobin gives up this oxygen to the tissues leaving more purplish red blood in the veins of the body.
What is plasma?
Plasma is the fluid portion of the blood and is a clear, straw coloured watery fluid similar to the liquid you see in a blister.
What components is the plasma made from?
- Water
- Proteins
- Salts
- Urea
- Glucose
Other substances inc. vitamins, enzymes, antibodies, and antitoxins are also carried around the body in the plasma.
What does the water component of the plasma do?
Many of the substances carried in plasma are dissolved in water. It replenishes the intercellular fluid which bathes all the body cells and renders the intracellular fluid (fluid within cells) Up to 90% of the plasma is water.
Where are many of the plasma proteins made?
In the liver.
What are the plasma proteins albumin and globulin responsible for?
For maintaining the osmotic press of blood, preventing excess fluid loss into the tissues
What is the plasma proteins responsible for blood clots called and what is the plasma called without this protein?
Figrinogen is essential for when the blood clots. Plasma with the fibrinogen removed is called serum - the is the clearest fluid that leads out when a clot is formed.
What are the salts found primarily in the plasma?
Chlorides, sulphates and phosphates of sodium, potassium and calcium.
What do the salts do?
They help to maintain the pH of the body, neutralising acids or alkalis taken into or formed within the body, thus keeping the blood and body tissues at a slightly alkaline pH of about 7.4
What is Urea?
Urea is a waste product of protein metabolism in the liver, where amino acid are broken down (metabolised). It is transported along with other waste products to be removed from the body (excreted) by the kidneys.
What is glucose?
Glucose is a simple sugar, a product of carbohydrate digestion and is used in cellular respiration in all cells. it is transported along with other digested food products such as amino acids from the gastro-intestinal tracts to all parts of the body.
How many types of blood cells are there?
There are essentially 3 types of blood cells.
What are Red Blood Cell also called?
Erythrocytes or red corpuscles
What are RBCs?
They are bi-concave discs which do not have a nucleus - packed full of haemoglobin
How many RBCs are there per mm cubed of blood?
5,000,000
How do RBCs develop?
The RBCs develop in the bone marrow, they are formed from stem cells and then under the influence of B12, vit C, cobalt, copper and folic acid they mature so they can be released into the bloodstream. During this process they build up haemoglobin and lose their nucleus and other organelles
What is haemoglobin? what does it do?
Haemoglobin is an iron-containing protein that transports most of the oxygen that is contained within the blood. Haemoglobin absorbs oxygen from the lungs and releases it to tissues.
What does losing the nucleus of RBCs means for the cells?
Losing the nucleus makes more space in the RBCs for oxygen carrying haemoglobin but it means the cells have a limited life span of up to about 120 days in the circulation and they cannot divide to make new cells.
What are White blood cells also known as?
Leukocytes or white corpuscles.
What makes them different to other cells in the blood?
They are the only complete cells in the blood containing nuclei and organelles.
How many WBCs per mm cubed of blood?
Between 6,000 - 10,000
Where are WBCs made and matured?
WBCs are made in the bone marrow but some of them mature in the lymphatic system
What are the 2 main types of leukocyte in the blood?
Granulocytes (also known as polymorphonuclear leukocytes) and agranulocytes.
What are the types of granulocytes?
Neutrophils, Eosinophils and basophils.
What percentage of WBCs do Neutrophils, eosinophils and basophils make up?
Neutrophils make up 40-70% of WBCs
Eosinophilss make up 1-4% of WBCs
Basophils make up 0-1% of WBCs, the rarest WBC.
What do neutrophils do?
Neutrophils are active phagocytes, they move about independently and engulf and digest other cells or cell fragments. They protect the body from bacterial invasion as well as removing cell debris.
What do eosinophils do?
They kill parasitic worms.
What do Basophils do?
They contain histamine and are involved in inflammation and allergic reactions.
What are the types of agranulocytes?
Lymphocytes, monocytes and macrophages.
What percentage of WBCs do lymphocytes make up?
25-30%
What do the lymphocytes do, where are they produced?
Lymphocytes are active phagocytes. They are produced in the bone marrow then enter the circulation and lymph nodes, Primarily involved in defence against disease by producing antibodies and antitoxins.
Where are the monocytes made and what do they do?
Monocytes are made in the red bone marrow and lymphatic tissue. They are the largest of the blood cells, they remove foreign particles by phagocytosis.
What are the macrophages?
Macrophages are cells derived from a monocyte that acts as a phagocyte in the non-specific responses. They form an antigen-presenting cell in the specific immune response.
What are platelets? Where are platelet (also known as thrombocytes) made and what are they essential for?
Platelets are small cytoplasmic fragments of large cells in the bone marrow. They are made in the bone marrow and are essential for blood clotting (coagulation) approx a third of a RBC.
Do platelets have a nucleus?
In humans they do not have a nucleus.
How many platelets are there per mm cubed of blood?
250,000 per mm cubed.
When you cut yourself the blood needs to form a solid clot. What happens when the blood clots?
The clotting of your blood involved a series of enzyme controlled reactions which produce a net of fibres made of a protein called fibrin formed from the fibrinogen in blood plasma. the fibrin fibres then trap many red blood cells and more platelets and form a jelly lie clot that dried to form a scab, the skin heals under the scab
What are the 9 blood functions?
- To carry oxygen to the tissues using the haemoglobin in RBCs.
- to carry dissolved, digested food such as glucose of amino acids to the tissues.
- To remove waste product such as CO2 or urea from the tissues and transport them to the appropriate organ for excretion.
- To carry water to the tissues and cells. Excess water is removed mainly through the kidneys but water los can also occur through lungs, skin and bowels.
- To defend the body against the entry of pathogens and so protect against disease, using the WBCs to engulf pathogens and other foreign material and to produce antibodies and antitoxins.
- To provide the materials from which glands make their secretions.
- To carry hormones around the body.
- To distribute heat evenly around the body and help to regulate body temp.
- To stop bleeding and blood loss from cuts through clotting.
What are antigens?
Antigens are cell surface proteins. The combination of antigens on your cells is unique, they are different from others unless you are an identical twin. Therefore antigens on microorganisms that get into your body are also different from the ones on your own cells.
What recognises foreign antigens?
Your immune system (WBCs and lymphatic tissue) recognise different antigens. Lymphocytes make antibodies which attach to the antigens and either destroy the cell carrying the antigen or let neutrophils or monocytes engulf and digest them.
What results in different human blood groups?
The different antigens found on the surface of RBCs.
What is the best known blood grouping system? H ow many blood groups in this?
ABO system. with the 4 blood groups A, B, AB and O.
In this system what possible antigens and antibodies are there on the RBCs and in the plasma?
In this system there are 2 possible antigens on the RBCs, antigen A and B. There are 2 possible antibodies in the plasma, Antibody Anti-A or Anti-B. These antibodies are there all the time and not made in response to any particular antigen.
For each Blood group, A, B, AB and O what antigen is on the RBC and what antibody is in the plasma?
A = A antigen and Anti-B antibody. B = B antigen and Anti-A antibody. AB = A and B antigen and No antibody. O = No antigen and Anti-A and Anti-B antibody.
What happens if blood from different groups is mixed?
If blood from different groups is mixed there may be a reactions between the antigen and the complementary antibody which causes the blood to agglutinate for example antigen A and antibody A. This means they do not work properly and clog up capillaries or even larger vessels. This can be fatal if someone needs a blood transfusion.
Why is blood group O useful?
The cells have no antigens so it does not react to any blood antibodies. It is the universal donor and can be given to anyone.
What blood groups can be mixed safely?
A blood group can receive A or O
B blood group can receive B or O
AB blood group can receive A, B, AB or O
O blood group can receive O
What is the rhesus factor?
The rhesus factor is a protein which acts as an antigen found on the red cells of around 85% of the population. Those with are Rh+ and those without are Rh-. Rhesus compatibly also have to be taken into account in blood transfusions. Incompatibility can cause problem in pregnancy is baby and mom are different.
2.2.2 The Heart:
Where is the heart positioned? what is it?
The heart is a hallow muscular organ lying between the lungs and behind the sternum, it is positioned at an angle so the main pumping chambers lie mainly to the left of the sternum.
The heart is a double pump, what does this mean?
One half pumps deoxygenated blood to the lungs to pick up oxygen and the other side pumps oxygenated blood all around the body. It dives both the pulmonary and systemic circulations.
How many times does the heart beat per minute?
About 70 times per minute.
What is the heart made from?
The heart is made of specialised muscle tissue called cardiac muscle or myocardium which has its own intrinsic rhythm.
What does cardiac muscle not get, like striated muscle responsible or skeletal movement and maintaining posture?
Fatigued.
What does the external health muscle suppled with oxygen by and what does this mean for the heart?
The external heart muscle is supplied with oxygen by the coronary arteries so the heart muscle does not use oxygen from blood inside the heart?
How is the heart divided?
The heart is divided from base to apex by a muscular septum into two distinct halves, the left heart and the right heart.
In the normal heart there is no communication between the left side and the right side, when is there an exception?
Before a baby is born there is a hole in the septum which allows blood to pass between the two halves this normally closes after birth.
What is the heart contained in?
The heart is contained in a fibrous sac called the pericardium.
What is the smooth membrane lining of the chambers of the heart called?
Endocardium.