Circulation Flashcards
What is the function of red blood cells?
Transports oxygen around the body
What are the adaptations of the red blood cells?
Have a biconcave disc shape → this provides a large surface area for diffusion of oxygen
Contain haemoglobin → that oxygen binds to
No nucleus → therefore there is more space to carry haemoglobin
What is the function of white blood cells?
protects the body against diseases
What are the adaptations of the white blood cells?
There are 2 types of white blood cells:
Lymphocytes → produce antibodies
Phagocytes → engulf and digest microorganisms by phagocytosis
What is the function of a platelet?
Help clot the blood
Explain how platelets help reduce blood loss
They convert Fibrinogen (soluble) into Fibrin (insoluble)
Fibrin forms a mesh to trap the blood and helps to form scabs
This reduces blood loss (after injury)
What is the function of plasma?
Yellow liquid part of the blood that helps to transport:
Blood cells / Food molecules / Carbon dioxide / Hormones (e.g. insulin) & Urea (waste)
What is the blood made up of?
Red blood cells, White blood cells, Platelets and Plasma
Explain why arteries have thicker muscular walls and more elastic fibres than veins
Thicker muscle → as the arteries are under high pressure (as they are close to the heart)
Elastic fibres → allows the artery to expand and recoil as blood pushes through
Explain why the vein has a large lumen and contains valves
Large Lumen → prevents friction and helps move the blood along
Valves → prevents the backflow of blood as the veins are under low pressure (ensure the blood moves in one direction)
Explain why a capillary is one cell thick and permeable
One cell thick → creates a short diffusion distance for molecules to be transported e.g. oxygen
Permeable → allows exchange between blood and body cells (e.g. diffusion of oxygen from red blood
Why is it a benefit for capillaries to be under lower pressure than the arteries?
To allow time for the molecules (e.g. glucose and oxygen) to diffuse out into the surrounding cells
What does the Hepatic vein contain?
Hepatic vein → carries glucose and amino acids from the liver to the body and carbon dioxide back to the lungs
What blood vessel bring blood to the kidney?
Renal artery
What blood vessel bring blood to the Liver?
Hepatic artery
What blood vessel takes blood away from the kidney and back to the heart?
Renal vein
What blood vessel takes blood from the small intestine to the Liver?
Hepatic portal vein
What is cardiac output?
CARDIAC OUTPUT = volume of blood pumped by the heart per minute
What is recovery rate?
RECOVERY RATE = the time it takes for the pulse or heart rate to return to normal
What are the effects of exercise on the heart?
-Exercise strengthens the heart (as it would any muscle) and increases cardiac output
-During exercise our muscles need more energy as they are contracting more often
-The heart has to pump more blood to our muscles so that they get more oxygen and glucose for respiration
-Increased cardiac output during exercise increases blood pressure and therefore increases blood flow to the muscles
What is double circulation?
the blood travels through the heart twice for each complete circuit of the body
What is a unidirectional pump?
The heart ensures that the blood is pumped in one direction
Why are the ventricles thicker than the atria?
The ventricles are thicker than the atria → as they require more pressure to pump the blood to either the lungs or the rest of the body
Why is the left ventricle thicker than the right?
As it requires more pressure to pump the blood to the whole body and not just to the lungs like the right
Which arteries supply the heart muscle with blood (containing oxygen and glucose)
Coronary arteries
What lifestyle factors can cause Coronary Heart Disease (CHD)?
Diet high in fat
Smoking
Lack of exercise or obesity
Stress
High blood pressure
Drinking too much alcohol
How does a heart attack occur? [6 marks]
-Buildup of cholesterol or fat in the coronary arteries (which forms a plaque)
-This causes the coronary arteries to narrow and makes it more difficult for blood to flow through them
-It may become so narrow that a blockage forms a clot
-Blood carrying oxygen and glucose cannot get through to muscle tissue in the heart
-The heart cannot respire or produced energy
-The heart cells die and cannot contract (i.e. the heart stops beating) causing a heart attack
