Chapter 7: The Heart, Blood and Vessels Flashcards
Why do we need a circulatory system?
We have a small SA/V ratio, meaning that diffusion is inefficient. Therefore, we need a circulatory system to pump blood around the body, to carry O2, waste, nutrients and hormones, to fight infection and to maintain our body temperature.
What are the components of the circulatory system?
The heart, the blood vessels, and the blood
What are the two different circulations in the double circulatory system?
The pulmonary - blood to and from the lungs to exchange O2 and CO2 with airThe systemic - blood to and from the body to exchange O2 and CO2 with body cells.
What order does blood go through the heart?
Starting at the vena cava:Vena cava, right atrium, right ventricle, pulmonary artery, lungs, pulmonary vein, left atrium, left ventricle, aorta, rest of body
What is the cardiac cycle?
The heart is in diastole - blood flows into the atriaThe heart is in atrial systole - atria contract, AV valves open, blood flows into the ventriclesThe heart is in ventricular systole - ventricles contract, AV valves close, blood flows out of ventricles
What is meant by the term ‘heart rate’?
No. of beats your heart makes per minute
What is meant by the term ‘stroke volume’?
Volume of blood pumped per beat
What effect does exercise have on heart rate?
When you are exercising, your muscles need more energy, therefore the rate of respiration needs to increase. This means that more O2 and glucose is needed, which means that the heart rate and force of heart beat must increase.
What effect does stress have on the heart rate?
When you are overly stressed (anger, or fear), your body has the ‘fight or flight’ response. Adrenaline is released, which stimulates the pacemaker to increase your heart rate.
How does your body change your heart rate?
Osmoreceptors in the aorta sense the CO2 levels. This information is sent to the cardiac centre in the medulla via a sensory nerve. The cardiac centre then sends nerve impulses via an accelerator or deceleration nerve to the pacemaker. The pacemaker either increases or decreases the heart rate and blood pressure.
What effect does smoking have on the heart?
It can lead to heart attacks - clogging of arteries, and it puts a strain on your heart, making it work harder and faster.
What are the names of the arteries and veins that go to the liver?
Hepatic artery - from heartHepatic vein - to heart Hepatic portal vein - from stomach and digestive system
What are the names of the artery and vein that go to the kidneys?
Renal artery - from heartRenal vein - to heart
What is the function of an artery?
To take blood away from the heart and to the body
What is the function of the vein?
To bring blood to the heart from the body
