What is blood?
Blood is a liquid tissue consisting of:
- Plasma
- White blood cells
- Red blood cells
- Platelets
What are the functions of the blood?
- Plasma transports all your blood cells and dissolved substances (e.g. amino acids) around the body
- Red Blood Cells contain haemoglobin that binds (sticks) to oxygen to transport it from the lungs to the tissues
- White blood cells help to protect the body against infection
- Platelets are cell fragments that start the clotting process at the wound
What function do plasma help the blood with?
-Is a yellow liquid
-Plasma transports all your blood cells + dissolved substances around the body including:
Hormones
Nutrients, such as water, glucose, amino acids, minerals + vitamins
-Waste substances e.g. carbon dioxide + urea
What function do Red blood Cells help the blood with?
-Red Blood Cells contain haemoglobin that binds (sticks) to oxygen from the air in your lungs to transport it from the lungs to the tissues
What function do White blood cells help the blood with?
-White blood cells form part of the body’s defence system against harmful microorganisms
Some white blood cells form:
•Antibodies against microorganisms
•Antitoxins against poisons made by microorganisms
•Engulf and digest bacteria and viruses
What function do Platelets help the blood with?
- Platelets are cell fragments that start the clotting process at wound sites to form a scab
- This protects the new skin as it grows + stops bacteria entering through the wound
What makes blood red?
-The red blood cells
What makes up the human circulatory system and what does it do?
- The blood
- Blood vessels
- The heart
-It transports substances to and from the body cells
How does blood flow around the body?
- In the blood vessels
- Main types of blood vessels are arteries, veins and capillaries
What are the functions and features of arteries?
- They carry blood away from the heart (always oxygenated blood except from the pulmonary artery which goes to lungs)
- Have thick muscular walls
- Have small passageways for blood
- Contain blood under high pressure
- Small lumen
What are the functions and features of veins?
- Carries blood to the heart from the organs(always de-oxygenated blood except from the pulmonary vein which goes from lungs to heart)
- Have thin walls
- Contain blood under low pressure
- Have valves to prevent blood flowing backwards
- Large lumen
What are the functions and features of capillaries?
- Form a huge network of tiny vessels linking the arteries and the veins
- Found in the muscles and lungs
- Very thin walls
- Very low blood pressure
- Where gas exchange takes place. Oxygen passes through capillary wall and into tissues, Carbon dioxide passes from tissues into the blood
Do humans beings have a double circulatory system?
Yes
What are the four chambers of the heart?
- Right Atrium
- Left Atrium
- Right Ventricle
- Left Ventricle
What path does the blood follow as it enters and leaves the heart?
- Blood comes from the veins(pulmonary + vena cava) to the atriums
- It travels through the tricuspid and the bicuspid valve to the left and right ventricles
- Then the ventricles contract so the blood can exit through the arteries (pulmonary + aorta)
What is the heart?
An organ that pumps blood around the body
What is a stent and how can it solve the problem of coronary heart disease?
- A stent is a metal mesh that is placed in the artery
- It can be used to keep narrowed or blocked arteries open anywhere in the body
What do statins do?
-Reduced cholesterol levels in the blood, reducing the risk of coronary heart disease
How can damaged heart valves be replaced?
- Using biological valves taken from animals such as pigs or cattle or from human donors
- Using mechanical valves made of materials such as titanium and polymers
How is the resting heart rate controlled?
-By a group of cells in the right atrium that form a natural pacemaker
How do artificial pacemakers work?
- The electrical device sends strong, regular electrical signals to your heart that stimulate it to beat properly
- Used to correct any irregularities in the heart rhythm
What is a natural pacemaker?
A group of cells in the right atrium that control the heart rate
When are artifical hearts used?
- To keep patients alive while they wait for a transplant
- So their own diseased heart can rest and recover
What does the phloem transport?
Food (sugar)
