Circulatory System Flashcards
The blood is made of 4 components…
red blood cells
white blood cells
plasma
platelets
Summary of red blood cells role
- made in bone marrow
- Oxygen moves by diffusion
into red blood cells in the lungs. They have a chemical inside them called haemoglobin, a red pigment which binds with the oxygen to carry oxygen to where it is needed for respiration - This reaction is reversed near the cells.
involved in carrying oxygen -> combined with haemoglobin to create oxyhaemoglobin
What is the function of the oxyhaemoglobin?
Oxyhemoglobin is defined as the form of hemoglobin that carries oxygen from the lungs to the tissues.
Adaptations of red blood cells?
Red blood cells do not have a
nucleus to maximise the oxygen they can carry.
They have dips on both sides to maximise their surface area to absorb oxygen as quickly as possible. This shape is called biconcave.
Thin so that they can move through the small capillaries.
Summary of function of white blood cells:
- part of the immune system
- made in the bone marrow
There are two types of white blood cell:
Phagocytes which surround, engulf and destroy pathogens
Lymphocytes which produce antibodies that stick pathogens together. This makes it easier for phagocytes to destroy the pathogens.
What are the two types of white blood cells?
Lymphocytes and Phagocytes
Plasma:
- liquid that makes up half of the blood -> it contains the other components listed above.
It carries all the platelets and red and white blood cells around the human body. It also carries
hormones, dissolved glucose for respiration, dissolved salts and
enzymes around the body.
Waste products like carbon dioxide are also transported in the plasma.
Platelets:
Like white and red blood cells platelets are made in the bone marrow and they are responsible for making the blood clot when there is an open wound in order to help heal the wound quickly preventing bacteria from entering the blood and causing an infection.
small, colourless fragments of cells that form scabs
The heart is a muscular organ
that contracts to pump blood around the body.
Order of how blood enters and exits the heart.
Deoxygenated blood (blood low in oxygen) enters the heart through the vena cava (the large vein).
This blood then flows into the right atrium of the heart.
When the right atrium contracts, blood moves through the valve into the right ventricle.
The right ventricle then contracts, forcing the blood through the pulmonary valve into the pulmonary artery.
The pulmonary artery carries the deoxygenated blood to the lungs, where it becomes oxygenated (blood picks up oxygen and releases carbon dioxide).
Oxygenated blood returns from the lungs via the pulmonary veins into the left atrium.
The left atrium contracts, pushing the blood through the valve into the left ventricle.
The left ventricle then contracts powerfully, sending the oxygenated blood through the aortic valve into the aorta.
The aorta delivers the oxygenated blood to the rest of the body.
In short:
Vena cava → Right atrium → Right ventricle → Pulmonary artery → Lungs (gas exchange) → Pulmonary veins → Left atrium → Left ventricle → Aorta → Body.
What do the heart valves do?
Blood is prevented from flowing back
Humans have a double circulatory system. What are the two parts? 1. pulmonary circulation
deoxygenated blood to the lungs:
oxygen diffuses into the blood via. the alveoli
carbon dioxide diffuses from the blood into the lungs
Humans have a double circulatory system. What are the two parts? 2. systemic circulation
oxygen and nutrients to the body
carbon dioxide and other wastes away from cells
Pacemakers:
- artificial pacemakers: a small, battery charged electronic device implanted in a person’s chest that sends out regular, adjustable electrical impulses to produce normal contractions of the heart.
- Digitalis - drug
The blood vessels:
- veins
- arteries
- capillaries
Veins:
always carry deoxygenated blood to the heart EXCEPT the pulmonary vein
Carry blood under low or negative pressure therefore thinner than arteries.
Wide lumen
Arteries:
Thick and muscular and elastic tissue to withstand high blood pressure
Carries oxygenated blood away from heart
Narrow lumen
Capillaries:
The walls of capillaries are just one cell thick. Capillaries therefore allow the exchange of molecules between the blood and the body’s cells - molecules can diffuse across their walls. This exchange of molecules is not possible across the walls of other types of blood vessel.
