Biology - Circulatory System & Blood Flashcards
Arteries & Veins
Name two structural differences between arteries and veins
- Veins have valves so blood doesn’t flow backwards.
- Arteries have thicker walls because the blood is at higher pressure
What is the function of red blood cells?
Red blood cells carry oxygen
Describe two changes in the composition of blood after it has passes through the capillaries of the lungs
- Oxygen added
- Carbon Dioxide removed
- Water removed (that’s three changes :))
Why can this happen ?
Because the walls of the capillaries are very thin, they’re only one cell thick
What to white blood cells do?
- They ingest pathogens (bacteria & viruses) and destroy them
- The make antibodies to destroy pathogens (bacteria & viruses)
- They make antitoxins to neutralise toxins (poisons) made by the pathogens
Name the blood vessels labelled A and B
What is the function of plasma in the blood?
Plasma carries: blood cells, minerals, nutrients, hormones, enzymes, antibodies, carbon dioxide
- it carries heat - regulates body temperature
- maintains blood pressure
Arteries & Veins
Why do arteries have much thicker walls than veins?
Because blood is pumped through the arteries and is at higher pressure
What causes a person’s pulse?
It’s the heart pumping blood out to every part of the body.
Every heart beat creates a pulse
Why is blood considered to be a tissue?
It’s made of cells with similar functions
What do you remember about gaseous exchange in the lungs?
Gas exchange between alveoli and capillaries
An athlete’s resting pulse rate is 70
After 10 minutes of strenuous exercise it’s 130
After 5 minutes rest it reduces to 74
Account for the rise and fall in heart rate?
More energy requires more oxygen (higher heart rate)
Less energy requires less oxygen (lower heart rate)
