Organ System Flashcards
Inhaling
Diaphragm - Contracts and moves downwards
Intercostal muscles - Contract, moving the ribs upwards and outwards
Lungs - expand
Pressure inside the chest - Decreases
Movement of air - Moves into the lungs
Exhaling
Diaphragm - Relaxes and moves up Intercostal muscles - Relax, letting the ribs move downwards and inwards Lungs - deflate Pressure inside the chest - Increases Movement of air - Moves out of the lungs
Where are the lungs?
In the thorax (top part of the body)
What is the journey that inhaled air goes on?
The air goes down the trachea, and then down the bronchi (trachea splits into 2 bronchus), then the air goes into smaller tubes called bronchioles and finally into small bags called alveoli which are the site of gas exchange
Gas exchange in the alveoli
The blood passing next to the alveoli has just returned from the rest of the body, so it contains lot’s of CO2 and very little O2. Therefore oxygen diffuses out of the alveolus (high conc) into the blood (low conc) and CO2 diffuses out of the blood (high conc) into the alveoli (low conc)
Gas exchange at body cells
When blood reaches the body cells, oxygen is diffused from the red blood cells (high conc) into the body cells (low conc), and CO2 diffuses out of the body cells (high conc) into the red blood cells (low conc)
Adaptations of alveoli
- Lungs contain millions of tiny air sacs called alveoli, meaning a high SA:V - which means quick diffusion rates
- Alveoli have walls that are 1 cell thick = a short diffusion path therefore easy diffusion
- Alveoli have a constant supply of blood, meaning the concentration gradient is maintained and oxygen is always moving into the blood, or carbon dioxide out.
Function of the circulatory system
The circulatory system transports oxygen and nutrients to every cell in the body, and removes waste like CO2
The circulatory system is a ______ ___________ system
double circulatory
What does it mean to be a double circulatory system?
In the first system: the right ventricle pumps deoxygenated blood to the lungs to take in oxygen and get rid of carbon dioxide, the blood then returns to the heart through the left atrium
In the second system: the left ventricle pumps oxygenated blood around all the other organs of the body, it gives up oxygen and collects carbon dioxide, returning to the heart through the right atrium
Why does the heart have valves
To make sure blood flows in the right direction - they prevent it flowing backwards, they can open and shut
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What happens to blood returning to the heart?
Blood flows into the 2 atria from the vena cava and pulmonary vein. The atria contract, pushing blood into the ventricles, the ventricles contract (the valves shut) and blood is pumped to the lungs and body out of the aorta and pulmonary artery
What are the coronary arteries?
The heart needs energy so that it can pump blood around the body, this means it needs its own oxygenated blood to do aerobic respiration. Arteries called the coronary arteries branch of the aorta and surround the heart, making sure the heart has it’s supply of oxygenated blood.
What are the 3 types of blood vessels and their functions
- Arteries - these carry blood away from the heart
- Capillaries - Involved with the exchange of material at tissues
- Veins - These carry blood to the heart
Specialities of arteries (3)
Arteries carry blood under high pressure,
- artery walls are strong and elastic
- They have thick walls and a small lumen
- They contain thick layers of muscle to make them strong
Arteries branch into…
capillaries
Specialities of capillaries (4)
- Capillaries are tiny
- They carry blood really close to every cell in the body for substance exchange
- They have permeable walls so substances can diffuse in and out
- Their walls are very thin (about 1 cell) = short diffusion path way and an increased rate of diffusion
Capillaries eventually join up to from…
veins
Specialities of veins (2)
- They have a bigger lumen than arteries to help blood flow despite lower pressure
- They have valves to help blood in the right direction, if they travel uphill
What is the resting rate of the heart controlled by?
A group of cells in the right atrium wall act as a pacemaker. They produce small electric impulses which spread to the surrounding muscle tissue causing them to contract
Why is the left side of the heart thicker than the right?
The left ventricle of your heart is larger and thicker than the right ventricle. This is because it has to pump the blood further around the body, and against higher pressure, compared with the right ventricle. Therefore, the left ventricle has more muscle tissue and is stronger