The Heart and Blood vessels Flashcards
What is the circulatory system?
It carries oxygen and nutrients to every cell in the body and removes waste products
Double circulatory system =
1) deoxgygenated blood flows into the right atrium and then into the right ventricle, which pumps it into the lungs to undergo gaeous exchange.
2) Oxygenated blood flows into the left atrium and then into the left ventricle, which pumps oxygenated blood around the body
Structure of the Heart:
- muscular walls to provide a strong heartbeat (thicker in the left ventricle because blood needs to be pumped around body)
- 4 chambers that separate the oxygenated blood from the deoxygenated blood
- Valves to make sure the blood does not flow backwards
- Coronary arteries cover the heart to provide its own oxygenated blood supply
The process of the heart:
1) Blood flows into the right atrium through the vena cava, and left atrium through the pulmonary vein
2) The atria contract forcing the blood into the ventricles
3) Ventricles contract, pushing blood from right ventricle into the pulmonary artery to be taken to the lungs, and blood from left ventricle to the aorta to be taken around the body
4) Valves close to make sure the blood does not flow backwards
What does a pacemaker and artificial pacemaker do?
Regulate the heart’s rhythm and rate by sending electric impulses.
An artificial pacemaker can be used if someone has an irregular heartbeat. It is an electrical device that produces a signal causing the heart to beat at a normal pace.
Equation for rate of blood flow =
volume of blood/minutes
What is the gas exchange system made up of?
trachea - the windpipe, air moves through
intercostal muscles - which contract and relax to ventilate lungs
bronchi - air from trachea moves into bronchi, leads to each lung
bronchioles - bronchi split into these, air moves in
alveoli - brionchioles lead here, air sacs where gaseous exchange occurs
diaphragm - separates lungs from digestive organs, moves down causing inhalation
How does ventilation work?
1) The ribcage moves up and out and the diaphragm moves down causing the volume of the chest to increase
2) Increased volume results in lower pressure
3) Air is drawn into the chest as air moves from areas of high pressure (the environment) to low pressure (lungs)
< The opposite happens when exhaling
How does gas exchange work?
1) Upon inhalation, the alveoli fill with oxygen
2) The blood in the capillaries surrounding the alveoli is deoxygenated. It has lots of carbon dioxide as this is a product of respiration
3) Oxygen diffuses down the concentration gradient into the capillary bloodstream, which has a low concentration of oxygen
4) Carbon dioxide diffuses down its concentration gradient from the blood to the alveoli
How are alveoli adapted for gas exchange?
- small and arranged in clusters, creating a large surface area for diffusion
- capillaries provide large blood supply, maintaining the concentration gradient
- The walls are very thin, meaning there is a short diffusion pathway (which allows quick transportation)
Equation for breathing rate =
number of breaths/minutes
Capillaries:
- Carry blood through body tissues, exchanging oxygen, nutrients + waste products between tissues and blood
- Smallest blood vessel - short distance of diffusion
- They are permeable, so substances can pass through
- Carry blood at low pressure
Arteries:
- Carry blood away from the heart
- Large and carry blood at a high pressure
- Thick walls and narrow lumen, which keeps the blood pressure high
- Muscle tissue provides strength and means direct blood flow
- Elastic tissue allow arteries to stretch
Veins:
- Carry blood towards the heart
- Large with thin walls and wide lumen because they carry blood at a low pressure
- Contain valves to prevent blood from flowing backwards
