CH 5 The Circulatory System transports materials throughout the body Flashcards
What is the circulatory system?
The body’s transport system consisting of the heart, blood, blood vessels and lymph vessels
What are the 8 functions of blood?
- Transporting oxygen and nutrients to all cells to the body
- Transporting carbon dioxide and other waste products away from the cells
- Transporting chemical messengers, called hormones to the cells
- Maintaining the pH of body fluids
- Distributing heat and maintaining body temperature
- Maintaining water content and ion concentration of the body fluids
- Protecting against disease causing mirco-organisms
- Clotting when vessels are damaged, preventing blood loss
What are formed elements?
Any cell of cell like structure in blood
What is plasma?
- 55%
- The fluid part of the blood in which cells are suspended
- Function: transport the components of blood, including cells, nutrients, wastes, hormones, proteins and antibodies throughout the body
What are red blood cells? (erythrocytes)
- 45%
- One of the formed elements of the blood that contains haemoglobin
- Function: transport oxygen from the lungs to cells through the body
What is a haematocrit?
The ratio of red blood cels to the total volume of blood
What does biconcave mean?
Shaped concave on both sides dipping inwards in the centre
What are white blood cells? (leucocytes)
- less than 1%
- One of the blood cells containing a nucleus
- Function: protecting the body from infection
What are monocytes?
Form other cells including macrophages that engulf pathogens and ages or damaged cells by phagocytosis
What are lymphocytes?
Involved in the immune response; cell mediated immunity uses T-lymphocytes and antibody- mediated immunity uses B- lymphocytes
What are basophils?
Responsible for allergic reactions producing heparin and histamine to defend the body against parasites and bacteria
What are eosinophils?
Lead to inflammatory responses; they respond to larger parasites such as worms
What are platelets? (thrombocytes)
- very small %
- A fragment of cytoplasm enclosed in a membrane but lacking a nucleus
- Function: adhere to the lining and form a scaffold for the coagulation of the blood to form a clot
What is haemoglobin?
- The pigment in red blood cells
- it is involved in the transport of oxygen and carbon dioxide through the body
What is oxyhaemoglobin?
Oxygen combined with haemoglobin
What is oxygenated blood?
Blood containing a lot of oxygen
What is deoxygenated blood?
Blood that contains little oxygen
What is carbaminohaemoglobin?
A molecule resulting from a combination of carbon dioxide and haemoglobin
What is alveoli?
Air sacs in the lungs
What is metabolic waste?
Substances produced by cells that cannot be used and that would be harmful if allowed to accumulate
Explain the process of blood clotting?
- Vasoconstriction: the muscles in the walls of the small arteries that have been injured constrict immediately to reduce blood flow and blood loss
- Platelet plug: The internal walls of blood vessels are normally very smooth but any damage creates a rough surface to which the platelets stick. Sticking platelets attract others and so a plug is built at the site of the injury. The platelets release substances that act as vasoconstrictors which enhance the constriction of damaged vessels. For many of the small tears that occur in capillaries the plugging action and constriction is sufficient to stop any bleeding.
- Coagulation: The formation of a blood clot is a complex process involving a number of chemical substances or clotting factors that are present in the blood plasma. The series of reactions results in the formation of threads of a protein called fibrin. The fibrin threads form a mesh that traps blood cells, platelets and plasma. This mesh is the clot. the threads stick to the damaged blood vessels and hold the clot in position.
What is blood clotting/coagulation?
Formation of a blood clot and the blood becoming gel-like
What are clotting factors?
Chemical substances in blood plasma that allow blood to clot
What is fibrin?
An insoluble protein that forms blood clots by holding blood cells, platelets, plasma together in a mesh
What is a clot/thrombus?
Blood cells, platelets and plasma trapped in a mesh of fibrin
What is clot retraction?
Contraction of the fibrous threads of a blood clot
What is a serum?
The protein rich fluid that separates out when blood coagulates
What is the heart?
A hollow muscular organ that pumps blood
What is the sternum?
The breast bone
How does blood move through the body?
- the right atrium receives blood from the body and passes it to the right ventricle
- the right ventricle pumps blood to the lungs
- the left atrium receives blood from the lungs and passes it to the left ventricle
- the left ventricle pumps blood to the body
What is the pericardium?
Membrane enclosing the heart
What is the cardiac muscle?
The muscle that forms the wall of the heart
What is the septum?
The partition between the left and right sides of the heart
What is the atria?
The top chambers of the heart
What are ventricles?
The bottom chambers of the heart
Why is the left ventricle thicker than the wall of the right ventricle?
This is because it needs to be much stronger to pump blood through the blood vessels to the whole body
Explain the valves in the heart?
Valves ensure that blood can only go in one direction and that there is no backflow
What are atrioventricular valves?
Valves within the heart that ensure the blood flows through it in one direction
What is the chordae tendineae?
Tendon-like structures that connect papillary muscle to valves
What are papillary muscles?
Muscles in the ventricles of the heart that anchor the valves
What are semilunar valves?
Valve preventing blood from flowing back into the ventricles, located at the start of the aorta and pulmonary artery