Circulation Flashcards
What is blood made up of?
Plasma – 55%
Red blood cells (RBC) – 45%
White blood cells (WBC) – 0.1%
Platelets – 0.01%
What is the role of blood?
- Transports nutrients and gases from the external environment and transports wastes away from the cells to specific areas for disposal.
- The average healthy adult female has between 4 and 5 litres of blood.
- The average healthy adult male has between 5 and 6 litres of blood.
Red Blood Cells
Very Small
- Contains Haemoglobin
- Protein molecule which incorporates iron (haeme)
- Carries oxygen
- Oxy-haemoglobin – Haemoglobin when oxygen has bonded to it. Responsible for the bright red colour of oxygenated blood.
- Manufactured in bone marrow
White Blood Cells
- Nessecary to fight infection
- 5 different types of WBC and all have different roles
- Are able to move out of the bloodstream – will move and crawl through connective and epithelial tissue.
Platelets
- Fragments of cells
- Essential for blood clotting – prevents excess bleeding.
- Clump together at site of injury
- Works in conjunction with other factors, such as fibrin, to ‘plug up’ any holes that appear in blood vessels.
Plasma
- The fluid that the RBCs, WBCs and platelets travel in.
- Transports: CO2, Amino acids, Glucose, Proteins, Minerals, Vitamins, Waste material (urea, etc), Hormones
Heart
- blood around the body
- Made up of 4 chambers (2x Atria and 2x Ventricles)
- Left and right side of the heart seperated by the septum
Right Hand Pump of the Heart
Right atrium and right ventricle
- Deals with deoxygenated blood returning to the heart from different areas of the body.
- Blood enters the heart via the vena cava and is pumped to the lungs through the pulmonary artery.
Left Hand Pump
Left atrium and left ventricle
- Deals with oxygenated blood returning from the lungs.
- Blood enters the heart via the pulmonary vein and pumped out of the heart to the rest of the body via the aorta.
Left hand side valves (Keeps flow of blood in right direction)
Bicuspid valve – between left
atrium and left ventricle
Aortic valve – between the left
ventricle and the aorta
Right Hand Side Valeves (Keeps flow of blood in right direction)
Tricuspid valve – between right atrium and right ventricle
Semilunar valve – between right ventricle and pulmonary Artery
Blood Vessels
5 different types that blood moves through Arteries - Arterioles - Capillaries - Venules Veins
Ateries
- Carry oxygenated or deoxygenated blood away from the heart.
- Branch into smaller and smaller vessels (arterioles and capillaries)
- Blood is pumped through the arteries under high pressure
- High blood pressure means thick muscular walls
- Walls are quite elastic which enables them to expand
and contract to adjust to the amount of blood
traveling through them at any given time.
- Walls are quite elastic which enables them to expand
Arteries are composed of how many layers?
Three layers
Outer layer – connective tissue with elastic fibres, tough to protect artery. Connective tissue holds it in place and allows it to stretch
Middle layer – muscular tissue with elastic fibres, makes artery strong and flexible
Inner layer – epithelial cells, very smooth so blood can flow easily
Ateries during inspiration and expiration
Every time the heart beats, arteries expand and fill with blood.
When the heart relaxes, the artery contracts, exerting a force to help push the blood along.
Veins
- Return blood to heart
- Blood is generally deoxygenated (oxygen has been delivered to cells)
- Enters the heart via the vena cava.
- Returns under low pressure and is usually travelling against gravity.
Flow of blood in veins
Have thinner walls and are wider in diameter than arteries.
Have special valves to
prevent blood from flowing
backwards.
Movement of blood in veins also aided by contraction of muscles running alongside veins.
Capillaries
Smallest of the blood vessels
Weave their way through tissues of the body – accessible to every cell.
Made up of endothelium – a single layer of flat, overlapping cells.
Diamater of Capillaries
Diameter of capillaries just big enough to allow a slow, single file of red blood cells to pass through
- Maximises opportunity for the exchange of gases, nutrients and wastes between blood cells and tissue cells
Flow of blood in Capillaries
How much blood flows through capillaries controlled by arterioles
- Constrict to slow down flow
- Dilate to increase flow
Lymph originated from…. and does what?
Plasma and moves out of arterioles and flow to tissues
Lymph is known as extracellular fluid - found between cells. What does it do?
Delivers nutrients, oxygen and hormones to cells and picks up waste products from cells
- 90% will enter back into circulatory system via venules
- 10% will travel in the lymphatic system
Characteristics of the Lymphatic System
Does not have a pump
- Designed to allow lymph to only flow ‘up’. - Have valves to ensure lymph can not backflow.
Filtered by lymph glands (lymph nodes, lymph organs) as it travels.
Lymph re-enters the circulatory system via the subclavian veins at the base of the neck.
Part of the immune system.
Oedema is a disorder….
Where body fluid accumulates rather than returning to the blood.
e.g
Elephantiasis; Parasitic worms may block lymph vessels.
Protein deficiency; the blood consumes its own proteins, reducing blood pressure and the return of fluid from lymph. Elephantiasis; Parasitic worms may block lymph vessels. Malnutrition may thus result in swelling.
Lymph nodes contain…
Contain a honeycomb of connective tissue, filled with white blood cells.
e.g
When the body is fighting an infection, these cells rapidly multiply and the nodes swell.
Spleen
Inside the abdomen, just under the diaphragm.
- One of the filtering organs of the blood. As well as removing microbes, the spleen also destroys old or damaged red blood cells.
Thymus
Inside the ribcage, just behind the breastbone.
- Another filtering organ of the blood, that contains many white blood cells called lymphocytes.
Open Circulatory System
Common to invertebraes and arthropods. (Grasshoppers)
Open circulatory system pumps blood into a hemocoel with the blood diffusing back into the circulatory system between cells.
Free blood flow
No vessels to conduct the blood
Closed Circulatory System
Vertebraes (tigers, humans, etc.), and a few invertebraes (worms)
In closed circulatory system blood is pumped by a heart through vessels and does not normally fill body cavities.
Presence of blood vessels conducts blood throughout body.
Advantages of an open circulatory system
Dispels heat more efficiently
Creates loss of urgency
Disadvantages of an open circulatory system
Impossible to increase blood distribution
Requires a low metabolic rate
Only benefits small creatures because the size limits the distance the blood must travel to each body cavity.
Advantages of a closed circulatory system
Operates with higher blood pressure which is more effecient as it uses much less blood for even faster and higher levels of distrubution.
Lymphatic system that works seperately
Disadvantages of a closed circulatory system
More complex
Requires more energy for blood distribution