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
What are the three main stages of the cardiac cycle?
Atrial Systole
Ventricular Systole
Diastole
What does the diastole stage consist of?
The ventricles and atria relax.
The semi-lunar valves close.
Blood flows passively into the atria.
what is Systolic pressure?
pressure in the arteries during ventricular systole
What does the ventricular systole stage consist of?
- The ventricles contract, and the atria relax.
- The ventricular pressure increases.
- The semi-lunar valves open, and the atrioventricular valves close.
- Blood flows into the arteries.
What does the atrial systole stage consist of?
- The ventricles relax, and the atria contract.
- This increases the atrial pressure.
- The atrioventricular valves open.
- Blood flows into the ventricles.
What is Diastolic pressure?
pressure in the arteries during diastole
Which one is at the top of the fraction, diastolic or systolic pressure?
systolic pressure
What is the role of valves?
prevents backflow
what happens to valves when there is high pressure behind it?
opens
what happens to valves when there is high pressure in front of it?
closes
explain the steps of control of the cardiac cycle
SA node fires – Initiates impulse.
Atria contract – Pushes blood to ventricles.
AV node delays – Allows ventricular filling.
Impulse to ventricles – Via bundle of His and Purkinje fibers.
Ventricles contract – Blood ejected to lungs/body.
Ventricles relax – Refilling begins.
Explain the stages of an EGC showing the various stages of the cardiac cycle
refer to slide 64, lesson 2 of topic 5
P wave - Atrial systole
QRS - Ventricular systole
T wave - Diastole
Name all the heart problems and what happens
- Bradycardia – slow heart beat, less than 60 bpm
- Tachycardia – fast heart rate, more than 100 bpm
- Ectopic beat – extra beats follows by gaps
- Atrial fibrillation – irregular rhythm
What is the shape of arteries?
circular
What is the shape of veins?
flattened
………….(veins/arteries) have inner surface corrugation.
arteries
What is inner surface corrugation?
little folds on the inside of arteries
