The Lungs And The Circulatory System Flashcards
Where are the lungs
- In the thorax
Where is the thorax
- the top part of your body
- it’s separated from the lower part of the body by the diaphragm
Describe the lungs
- They are like big pink sponges and are protected by the rib cage
- They’re surrounded by the pleural membranes
Where does the air you breathe go
- through the trachea
- This splits into 2 tubes called bronchi (each one is a bronchus), one going to each lung
- The bronchi split into progressively smaller tubes called bronchioles
- The bronchioles finally end at small bags called alveoli where the gas exchange takes place
What is the function of the alveoli
- carry out Gas exchange in the body
What is the alveloli
- little air sacs in the lungs, surrounded by a network of blood capillaries
- this is where gas exchange happens
How do the alveoli work
- blood passing next to alveoli (just returned to lungs from rest of body) contain lots of CO2 and very little oxygen
- Oxygen diffuses out of alveolus (high concentration) into the blood (low concentration)
- CO2 diffuses out of the blood (high concentration) into the alveolus (low concentration) to be breathed out
What happens when the blood reaches body cells
- Oxygen diffuses from red blood cells (high conc) and diffuses into body cells (low conc)
- At the same time, CO2 diffuses out of the body cells (where there’s a high concentration) into the blood (where there’s a low concentration).
- It’s then carried back to the lungs
How do you calculate the breathing rate
Breaths per minute
What type of circulatory system do humans have
Double circulatory system — two circuits joined together
What is the circulatory system made up of
- the heart
- blood vessels
- blood
What does the right ventricle do
- pumps deoxygenated blood to the lungs to take in oxygen
- The blood then returns to the heart
What does the left ventricle do
- pumps oxygenated blood around all the other organs of the body
- the blood gives up its oxygen at the body cells and the deoxygenated blood returns to the heart to be pumped out to the lungs again
How is blood pumped around the body
By the heart contracting
What are the walls of the heart made up of
Muscle tissue
What is the job of the heart valves
- make sure that blood flows in the right direction — they prevent it flowing backwards
How does the heart use its four chambers to pump blood around
1) Blood flows into the 2 atria from the vena cava and the pulmonary vein
2) The atria contract, pushing the blood into the ventricles
3) The ventricles contract, forcing the blood into the pulmonary artery and the aorta, and out of the heart
4) the blood then flows to the organs through the arteries, and returns through veins
5) The atria fill again and the whole cycle starts over
What are the hearts 4 chambers
- Right atrium
- Right ventricle
- Left atrium
- Left ventricle
What is the job of the coronary arteries
- they are arteries that branch off the aorta and surround the heart
- they make sure that the heart gets all the oxygenated blood it needs
- The heart needs it’s own supply of oxygenated blood
-what is your resting heart rate controlled by
- a group of cells in the right atrium wall that act as a pacemaker
- These cells produce a small electrical impulse which spreads to the surrounding muscle cells, causing them to contract
What happens if someone’s natural pacemaker cells don’t work properly (e.g. if a patient has an irregular heartbeat)
- An artificial pacemaker can be used
- It’s a little device that’s implanted under the skin and has a wire going to the heart
- It produces an electrical current to keep the heart beating regularly
What are the 3 different types of blood vessel
1) Arteries — carry blood away from the heart
2) Capillaries — involved in the exchange of materials at the tissues
3) Veins — carry the blood to the heart
Describe Arteries
- The heart pumps the blood out at high pressure so the artery walls are strong and elastic
- The walls are thick compared to the size of the hole down the middle (the “lumen”)
- They contain thick layers of muscle to make them strong and elastic fibres allow them to stretch and spring back
Describe the Capillaries
- they are really small
- the arteries branch into the capillaries
- They carry the blood really close to every cell in the body to exchange substances with them
- They have permeable walls, so substances can diffuse in and out
- They supply food and oxygen, and take away waste like CO2
- Their walls are usually only 1 cell thick — This increases the rate of diffusion by decreasing the distance over which it occurs
Describe the veins
- they take blood back to heart
- Capillaries join up to form veins
- The blood is at lower pressure in the veins so the walls don’t need to be as thick as artery walls
- They have a bigger lumen than arteries to help the blood flow despite the lower pressure
- They also have valves to help keep the blood flowing in the right direction
Calc rate of blood flow
Rate of blood flow = volume of blood / number of mins
What do red blood cells do
- carry oxygen from the lungs to all the cells in the body
- Their shape is a biconcave disc — this gives a larger SA for absorbing oxygen
- They don’t have a nucleus — this allows more room to carry oxygen
- They contain a red pigment called haemoglobin
- In the lungs, haemoglobin binds to oxygen to become oxyhemoglobin
- In body tissues, the reverse happens — oxyhemoglobin splits up into haemoglobin and oxygen, to release oxygen to the cells
What do white blood cells do
- Defend against infection
- some can change shape to engulf microorganisms in a process called phagocytosis
- Others produce anti bodies to fight microorganisms, as well as antitoxins to neutralise any toxins produced by the microorganisms
- unlike red blood cells, they do have a nucleus
What do platelets do
- help blood clot at a wound — to sop all your blood pouring out and to stop microorganisms getting in
- they are small fragments of cells — they have no nucleus
- lack of platelets can cause excessive bleeding and bruising
What does plasma do
- a pale straw-coloured liquid which carries everything in the blood
It carries: - red and white blood cels and platelets
- nutrients like glucose and amino acids
- CO2 from the organs to the lungs
- urea from the liver to the kidneys
- Hormones
- Proteins
- Antibodies and antitoxins (produced by white blood cells)
