B9.3 & B9.4 - Blood Vessels & Blood Flashcards
What is the muscular wall like for arteries? [1]
thick
What is the muscular wall like for veins? [1]
thin
What is the muscular wall like for capillaries? [1]
no muscular wall
What is the lumen like in arteries? [1]
small
What is the lumen like in veins? [1]
large
What is the lumen like in capillaries? [1]
very small
Does an artery contain valves, why or why not? [2]
- no
- blood is travelling so fast so it won’t go back down
Does a vein contain valves? [1]
yes
Does a capillary contain valves? [1]
no
What is the function of a capillary? [2]
- connect arteries and veins
- allows for exchange of substances between the blood and the cells
How is the structure of an artery fit for its function? [4] (2 things with explanation)
- contains thick walls: withstands the high pressure of blood
- has thick layers of elastic tissues: it can stretch and recoil with each surge of blood
How is the structure of a vein fit for its function? [6] (3 things with explanation)
- thin walls: blood is at a low pressure
- large lumen: help the blood flow despite the low pressure
- has valves: helps blood flowing in right direction
How is the structure of a capillary fit for its function? [2] (1 thing with explanation)
- thin wall made of one cell: diffusion distance is shorter so diffusion rate increases
How are capillaries adapted for exchange of substances? [3]
- capillary walls = thin = short diffusion distance
- capillaries are highly branched = large surface area
- capillary beds are supplied with fresh blood = concentration gradient maintained
What are the components of blood? [4]
- plasma
- white blood cells
- platelets
- red blood cells
What is the function of a red blood cell? [4]
- transport oxygen around the body
- contains haemoglobin
- no nucleus = more space for haemoglobin
- bi concave shape
What is the function of white blood cells? [2]
- fights disease by making antibodies
- fights disease by changing shape to engulf microorganisms
What are the two types of white blood cells and what does each one do? [4]
- lymphocytes: makes antibodies
- phagocytes: engulf and digests pathogens
What is the function of platelets? [2]
- tiny structures
- help the blood clot
What is the function of plasma? [4]
- transports dissolved substances
- straw - coloured liquid
- 90%+ of plasma = water
- excess water from large intestines goes to kidneys to be removed
What things are dissolved in plasma? [5]
- hormones
- urea
- blood cells
- nutrients
- carbon dioxide
What is the role of blood clotting? [2]
- preventing blood loss
- preventing entry of pathogens
What happens to the speed of blood as if flows through capillaries and why? [2]
- it gets slower
- because there’s a larger surface area so more friction
