The Circulatory System Flashcards
The walls of the chambers are composed of
Cardiac muscle
What does a double circulation mean?
In a double circulation there are two circuits that the blood follows in which blood travels through the heart twice in order to complete one full lap of the circulatory system
Why the left ventricle is so much more muscular than the right ventricle
The left ventricle generates more pressure to pump blood around the rest of the body, whereas the right ventricle pumps blood to the lungs
Why mustn’t cardiac muscle tire?
To pump blood around the body at all times to deliver oxygen to the cells
Cardiac output equation
Volume of blood per beat X BPM
Name three substances found dissolved in the plasma
Hormones, glucose and carbon dioxide
Flatter top surface of the heart
Dorsal
Rounder lower surface of the heart
Ventral
List, in order, all the chambers and vessels that blood passes through on one complete passage through both sides of the heart
Blood passes through the vena cava and into the right atrium. Blood if pumped down into the right ventricle and them upwards in the pulmonary artery to the lungs. Oxygen enters the blood in the lungs and leaves via the pulmonary vein. Blood then enters the left atrium, pushed downwards into the left ventricle and then into the aorta
What is blood made up of?
Red blood cells, white blood cells, platelets and plasma
What are phagocytes?
They detect, engulf and digest invading microorganisms in a process called phagocytosis
What are lymphocytes?
Lymphocytes are responsible for the production of proteins called antibodies that can detect foreign or infected cells and either mark them for destruction or bind the target cells in a large clump
Adaptions of the red blood cells
- Biconcave discs that result in a greater surface area : volume ratio
- Contains haemoglobin that binds to oxygen to allow transport
- No nucleus which allows more space for haemoglobin
- Flexible membrane that allow red blood cells to squeeze through the narrow capillaries
What is the role of platelets?
They convert fibrinogen to fibrin which causes blood clotting and scab formation
Blood vessel coming out of the left ventricle
Aorta
Blood vessel going into the liver
Hepatic artery
Blood vessel coming out of the liver
Hepatic vein
Blood vessel going into the liver from the intestines
Hepatic Portal vein
Blood vessel going into the kidneys
Renal artery
Blood vessel coming out of the kidneys
Renal vein
Blood vessel going into the right atrium
Vena Cava
Blood vessel going into the lungs
Pulmonary artery
Artery: carotid
Part of body supplied?
Head and neck
Name of artery: hepatic
Part of body supplied?
Liver
Name of artery: renal
Part of body supplied?
Kidneys
Name of artery: Iliac
Part of body supplied ?
Legs
Name of artery : coronary
Part of body supplied :
Heart
Differences between veins and arteries (5)
Arteries carry blood away from the heart. Veins carry blood back to the heart. The blood in arteries is high pressure whereas the pressure in veins is much lower and therefore the walls do not contain as much elastic and muscle. Walls of arteries contain a thick layer of muscle and elastic fibres. Arteries have very narrow lumens which maintains the pressure but veins have much wider lumens. Veins have valves but arteries don’t.
What are red blood cells?
A specialised cell adapted to oxygen transport
What is the role of plasma?
To transport cells, food molecules, carbon dioxide, hormones and urea
Describe capillary vessels
- Single layer of cells
- Very small lumen
- Molecules move in or out of blood stream and they are the sites of gas exchange
- Low blood pressure
- No valves
- Have permeable walls
What do arteries do?
Carry blood under high pressure away from the heart (usually oxygenated blood)
What do veins do ?
Carry (usually deoxygenated) blood under low pressure towards the heart, with valves that maintain the direction of flow
What are the effects of exercise on the pulse rate and heart ? (5)
- Heart rate increases
- This is to ensure that the exercising muscles have enough glucose and oxygen in order to release more energy during respiration
- This also ensures that the extra carbon dioxide produced during respiration is taken away.
- Blood pressure also increases as a greater volume of blood is being forced through the vessels
- Exercise also strengthens the heart muscle, making it more efficient.
Equation for cardiac output -
Volume of blood per beat x BPM
What happens to the organ systems not directly involved in exercise during exercise?
The blood flow to them is reduced as the vessels leading to these organs are constructed. Additionally blood flow to the skin is increased as this helps the body release heat, a by-product of exercise
Why do veins have large lumens ? (2)
- Reduces friction
- Further aids the movement of blood
Suggest one reason why it is necessary that blood pressure is low in the capillaries
- the blood pressure needs to be low since the capillaries only have walls that are one cell thick to be permeable and allow diffusion to take place
