The Circulatory System Flashcards
What is the purpose of the circulatory system?
Facilitates the transport of materials within the internal environment for exchange with cells through structure and function.
What is the purpose of the lymphatic system?
Functions to return tissue fluid to the circulatory system and to assist in protecting the body from disease.
What are the main components of the circulatory system?
The heart, blood vessels, blood, the chambers, the valves.
What is the function of the blood vessels?
Blood is pumped by the heart into the blood vessels, which carry the blood to the cells of the body/lungs and bring it back to the heart again.
What is the function of blood?
The transporting medium carries nutrients, wastes, hormones, and gases.
What is the function of the right side of the heart?
The right side of the heart makes up the pulmonary circuit. It collects deoxygenated from the heart and pumps it into the lungs
What is the function of the left side of the heart?
It makes up the systemic circuit. It receives oxygenated blood from the lungs and pumps it to the rest of the body.
What is the right atrium?
The receiving chamber for deoxygenated blood that has been through the capillaries of the body.
What is the function of the right ventricle?
Pumps blood to the lungs. Its wall is thinner that the left ventricle wall because not as much force is required to push blood to the lungs.
What is the left atrium?
The receiving chamber for blood from the lungs. Pushes blood into the left ventricle
What is the left ventricle?
Has a thick muscular wall for pumping blood into the aorta and out the body.
What is the pulmonary trunk?
Divides into two pulmonary arteries that carry deoxygenated blood to each lung.
What is the function of semilunar valves?
Prevent backflow of blood from arteries to ventricles.
What is the function of the pulmonary vein?
Brings oxygenated blood to the heart from the lungs
What are the atrioventricular valves?
- Between the atria and the ventricle.
- Flaps of thin tissue with the edges held by tendons called chordae tendinae.
- Prevents backflow of blood from the ventricles to the atria
How does blood become deoxygenated?
As oxygenated blood flows through the capillaries of the body, oxygen and nutrients diffuse from the blood into the body cells, and carbon dioxide and other wastes diffuse from the cells and into the blood, becoming deoxygenated.
How does blood become oxygenated?
As deoxygenated blood flows through the capillaries of the lungs, oxygen diffuses from the air into the blood and carbon dioxide diffuses from the blood into the air, becoming oxygenated.
What are the main components of blood?
- Plasma (55%)
- Erythrocytes (RBCs - 41%)
- Leucocytes (WBCs)
- Thrombocytes (Platelets)
What is plasma?
A mixture of water with dissolved substances such as sugar and salts.
What is the function of plasma?
Transports the components of blood throughout the body.
- Cells, nutrients, wastes, hormones, proteins, and antibodies.
What are the main functions of blood?
Transport - nutrients, O2, CO2, and hormones
Regulation - Regulates the body’s temp and pH
Protection - Prevents blood loss if blood vessels are damaged. Protects the body against pathogens and toxins.
What are erythrocytes?
A biconcave disc is round and flat without a nucleus, which helps increase its surface area so more oxygen can be carried.
- Can change shape without braking, as it squeezes single file through capillaries.
What do erythrocytes contain?
Haemoglobin is a protein molecule specifically designed to hold oxygen and carry it to cells that need it.
What are leucocytes?
- Protect the body from infection.
- They are larger than RBCs.
- Remove dead/injured cells and invade micro-organisms
What are the main types of white blood cells?
- Macrophages
- Lymphocytes.
What is the role of macrophages?
They engulf and digest micro-organism
What is the role of lymphocytes?
Some lymphocytes fight disease by making antibodies to destroy invades by dissolving them, others make antitoxins to break down poisons.
What are thrombocytes (platelets)?
Very small cell fragments with no nucleus
- 1/3 of a RBC and are formed in the bone marrow.
What is the role of thrombocytes?
They produce fibrinogen fibres to form a net. This net traps other blood cells to form a blood clot.
What are the main roles of blood vessels?
- Deliver oxygen and nutrients to cells
- Carry away waste products from cells
- Part of maintaining blood pressure
What are the main types of blood vessels?
- Arteries
- Capillaries
- Veins
What are arteries?
- Blood vessels that carry blood away from the heart
- Have a blood pressure that increases as the ventricles contract and decreases as the ventricles relax.
- Thick, muscular, elastic walls
- No valves
Provide 2 examples of an artery
- Aorta (largest)
- Pulmonary artery
What are veins?
Carry blood towards the heart. The capillaries join into small veins, venules, which join up to make larger veins
What are the characteristics of veins?
- Constant, relatively low blood pressure
- Thin, relatively inelastic walls with little muscle
- Often have valves
Provide two examples of a vein
- Inferior vena cava
- Superior vena cava
What are capillaries?
- The link between arteries and veins.
- Microscopic blood vessels form a network to carry blood close to almost every cell.
- Enables cells to get their requirements.
What are capillary properties?
- Smallest blood cell
- Deliver oxygen/nutrients to cells
- Remove CO2/H2O from cells
- Thin selectively permeable walls
What is the heart?
A hollow muscular pump that moves blood throughout the body. It lies in the chest cavity behind the breastbone and slightly to the left
What are the two loops?
Blood flows along two pathways in the body with both pathways converging at the heart.
- Pulmonary Circuit
- Systemic Circuit
What happens in the pulmonary circuit?
- Right side of the heart
- Deoxygenated blood is carried from the heart to the lungs
- Blood picks up O2 from the air
- Blood releases CO2 in the air
- Oxygenated blood returns to the heart to be pumped around the body.
What happens in the systemic circuit?
- Left side of the heart
- Oxygenated blood is carried from the heart to the body.
- Blood releases O2 to the body cells
- Blood picks up CO2 from the cells
- Deoxygenated blood returns to the lungs to be pumped to the lungs.
What are the semilunar valves?
Valves between the:
- Right ventricle and pulmonary artery
- Left ventricle and aorta
What are the atrioventricular valves?
Separates the atria from the ventricles
What is blood pressure?
The resulting force that the blood exerts on the artery walls. When ventricles contract, they create pressure
What is blood pressure used for?
To drive blood through the body via arteries and capillaries
How is blood pressure measured?
- mm of mercury (mmHg)
- represented by 2 numbers separated by a slash
What are the two types of blood pressure?
- Systolic
- Diastolic
What is systolic pressure?
- The highest pressure in an artery
- Produced when the ventricles contract
What is diastolic pressure?
- The lowest pressure in artery
- Produced when the ventricles relax
What does haemoglobin do in the blood?
Increases oxygen carrying capacity by 60-70 times.
When does oxygen combine with HB?
When the oxygen concentration is high
- lung capillaries
When does the HBO2 break down?
When the oxygen concentration is low
- tissue fluid around cells
What colour is HBO2?
Bright red, so arterial blood is also bright red.
What colour is HB?
Bright blue/purple so venous blood is also darker
How is carbon dioxide carried?
- 8% dissolved in plasma
- 22% attached to globin of HB - carbaminoglobin
- 70% as bicarbonate ions - HCO3
What are two ways blood clotting helps small injuries to blood vessels?
- Muscles in the walls of the damaged arteries constrict.
- The internal wall of the damaged vessel is rough, causing thrombocytes to stick to it and form.
How does blood clotting happen?
Threads of insoluble proteins called fibrin trap blood cells, thrombocytes and plasma.
What are clot retractions?
Contractions of the fibrous threads of a blood clot which pulls the damaged blood vessels together.
What are blood groups?
The differences in human blood due to the presence/absence of antigens/antibodies
Where are antigens and antibodies located?
- Antigens = surface of red blood cells
- Antibodies = plasma
What are antigens and antibodies?
A substance that can stimulate the production of antibodies.
Antibodies combine with the antigen to destroy it
What is blood group A?
- A antigens
- B antibodies
What is blood group B?
- B antigens
- A antibodies
What is blood group AB?
- A/B antigens
- Neither antibodies
What is blood group O?
- Neither antigens
- A/B antibodies
Blood group O is known as?
Universal donors
Blood group AB is known as?
Universal receivers
How are transfusions successful?
If the recipient doesn’t have antiobdies against the donor’s antigens. If so, the RBCs in the donated blood with clump (agglutination).
What is agglutination?
When blood reacts with the antibodies. No agglutination means the blood doesn’t have any antigens binding to the antibodies.
