Lesson 2: transport Flashcards
structure and adaptations of capillaries
- very narrow lumen: red blood cells travel in a sing filed line
- very thing walls: short diffusion distance
- highly branched: large surface area
structure and adaptations of arteries
- thick walls: prevent bursting
- elastic fibres: recoil + stretch to minimise pressure changes in blood
- narrow lumen: maintain high blood pressure
structure and adaptations of veins
- thin walls: low blood pressure
- wide lumen: maximise volume of blood flow
- valves: prevent backflow
Methods of measuring pulse rate
- radial artery (neck or wrist)
- stethescope and counting the number of beats per minute
Consequences of occlusions of coronary arteries/coronary heart disease
Heart attacks
Causes of occlusions of coronary arteries/coronary heart disease
- build up of plaque in the coronary artery leading to reduced blood flow
- plaque can rupture causing blood clots which further reduces blood flow.
Function of tissue fluid
transports substances from capillaries to cells
composition of tissue fluid
oxygen, water and nutrients
difference in composition of tissue fluid and plasma
tissue fluid does not have plasma proteins, platelets and red blood cells
Explain how tissue fluid is formed
- Tissue fluid is forced out of capillary at arteriole end due to high pressure called hydrostatic pressure
- the loss of water and the concentration of plasma proteins in the capillary lowers its water potential called onotic pressure.
- some of the water diffuses back into the capillary at the venule end via osmosis
What happens to excess tissue fluid?
flows into the lymphatic system where it becomes lymph
advantages of single circulatory system
Less complex
does not require complex organs
advantages of double circulatory system
The heart can pump blood further around the body
High pressure
Fast flow of blood
What are the steps of blood flow in the heart?
Vena cava
Right atrium
AV valve (tricuspid valve)
Right Ventricle
SL Valve
Pulmonary artery
Lungs
Pulmonary vein
Left Atrium
AV valve (bicuspid valve=
Left ventricle
SL valve
Aorta
Body
disadvantages of single circulatory system
Low blood pressure
Slow movement of blood
Activity level of the animal tends to be low