Circulatory System Flashcards
What are three components of the Circulatory System?
- Blood
- Blood vessels
- Heart (pumps the blood)
What are the two main functions of the circulatory system?
Transport of substances eg. Hormones, urea, absorbed food molecules eg. glucose, amino acids
Protection against disease
Name two blood vessels that carry blood to the liver.
Hepatic Portal Vein
and
Hepatic Artery
Give two advantages of veins having a large lumen.
Reduces friction
and
Aids movement of blood
What is the function of platelets?
Small cell fragments that clot the blood and form scabs
What do phagocytes do?
Engulf and digest micro organisms through phagocytosis
What do lymphocytes do?
Produce antibodies
What do white blood cells do?
Protect the body against disease
What are the adaptations of a red blood cell?
- No nucleus- more room to pack in hemoglobin
- Contain hemoglobin- rich in iron to carry oxygen
- Biconcave disc shape- large surface area for diffusion of oxygen
What do red blood cells do?
Carry oxygen to all the cells of the body
How does the blood travel in the capillaries?
Slowly under low pressure
What is the width of the walls of the capillaries?
Thin- one cell thick
What is the function of the capillaries?
Connect the veins and the arteries
What size of lumen do veins have?
Large
- reduces friction
- aids movement of blood
What are the width of the walls in the veins?
Thin walls and elastic fibres
Why do veins have valves?
Prevent backflow of blood as it flows under low pressure
What type of blood do the veins carry?
Deoxygenated
What direction do the veins carry blood?
Towards the heart
What size lumen do the arteries have?
Small
What type of blood do the arteries carry?
Oxygenated
What width are the walls of the arteries? Explain why.
Thick
-withstand the high pressure
Do arteries have valves?
No
What prevents cell lysis from occuring?
Salt and other chemicals in the plasma keep the concentration of the plasma stable, and similar to the concentration of a red blood cell.
Why do red blood cells burst in water?
No cell wall to prevent them from swelling and bursting when placed in water or a more dilute solution
What happens when red blood cells are placed in water?
They take in water by osmosis and burst. This is called cell lysis.
What does plasma do?
Transport substances
eg. hormones, urea, carbon dioxide, absorbed food molecules (glucose and amino acids)
Describe how platelets work.
Convert the protein fibrinogen to fibrin which forms a mesh that traps other blood components to form a scab.
What does the vena cava do?
Returns deoxygenated blood to the heart
What does the right ventricle do?
Pumps blood to the lungs
What does the right atrium do?
Receives blood from the vena cava
What does the left ventricle do?
Pumps blood around the body
What does the left atrium do?
Receives blood from the lungs
What is the coronary artery?
Very narrow artery that supplies the heart muscle with oxygen and glucose
What does the aorta do?
Carries blood under high pressure away from the heart
What is the difference between the heart rate of a fit person who exercises regularly and someone who does not?
> Fit person has a lower resting heart
Fit person’s heart rate rises slower
Maximum heart rate lower than unfit person
Shorter recovery time than unfit person
What is recovery rate?
The time it takes for the heart rate/pulse rate to return to normal after exercise.
Why does the body need extra oxygen after exercise?
Get rid of lactic acid
Why does it take your body awhile to return to normal after exercise?
It has to clear waste products of exercise:
> carbon dioxide
> lactic acid
How does regular exercise benefit the circulatory system?
> strengthens heart muscle
> increases cardiac output even when not exercising
Why does the pulse rate increase during exercise?
The body needs more energy, so the heart pumps harder to get more blood to our muscles so that they get more oxygen for respiration
Why are heart rate and pulse rate the same?
Each beat causes a new pulse
What does pulse rate mean?
How often a pulse/surge of blood passes around the body
What does heart rate mean?
How often the heart beats
Which arteries supply the heart muscle with blood?
Coronary arteries
Explain why the wall of the left ventricle is thicker than the wall of the right ventricle.
Left is thicker as a greater force is required to pump blood around the whole body whereas the right ventricle only requires to pump blood to the lungs.
What is a double circulatory system?
Blood travels through the heart twice in one circulation of the body
Where does the right side of the heart pump blood to?
Lungs
Where does the left side of the heart pump blood to?
Body
What seperates the left side of the heart from the right side?
Septum
What are the bottom chambers of the heart called?
Left ventricle
and
Right ventricle
What are the top chambers of the heart called?
Left atrium
and
Right atrium
How many chambers is the heart divided into?
Four
What special type of muscle are the walls of the heart made up of?
Cardiac muscle
or
Myacardium
Where does oxygenated blood enter the lungs from?
Pulmonary vein
What does the aorta do?
Carries oxygenated blood from the heart to the body
Where does deoxygenated blood enter from the body?
Vena cava
What does the pulmonary artery do?
Carries deoxygenated blood to the lungs
