Chpt 26 The Heart And Blood Vessels Flashcards
We need a circulatory system because..
Diffusion is slow in large organisms
Open circulatory system
Blood pumped from heart to blood vessels, then leaves vessels and passes through different parts of the body the back to heart
Animals with open circulatory systems include
Insects, crabs
Closed circulatory system
In humans. Blood is enclosed in blood vessels. Faster circulation of blood. Easier regulation of blood such as when we are active needing direct movement to muscles
Arteries
Carry blood away from the heart
Blood in arteries
Is under high pressure
The walls of arteries are
Thick and strong
What type of lumen do arteries have
Small lumen
O arteries have valves
No
Veins carry blood
To the heart
Blood in the veins is under
Low pressure
The wall of veins are
Thin and weak
The lumen of vein is
Large
Do veins have valves
Yes
What is the name of the outer layer of protein
Collagen
Collagen function
Tough layer that prevents vessel from expanding too much
Function of muscle and elastic fibres
Alter size of vessel
What is the endothelium
A thin layer of living cells
Function of valves
Prevent backflow
Structure of capillaries?
Tiny branched vessels
Thin walls
What is porous?
In the walls of capillaries
So materials can easily pass in and out of capillaries
Deoxygenated blood enters the…
Through vena cava into right atrium
Function of right atrium
Pumps blood through tricuspid valve ,into right ventricle
The right ventricle pumps blood…
Through pulmonary artery to lungs
Oxygenated blood comes from the
Lungs
Blood from the lungs enters
The though pulmonary veins into left atrium
The left atrium pumps blood….
Through bicuspid valve to the left ventricle
Where does the left atrium pump blood?
Out the aorta to the rest of the whole body
Function of tricuspid and bicuspid valves?
Ensures blood does not pass from ventricles back to atria
Unction of semilunar valves
Ensure that blood can’t be sucked back into heart
Why are the walls of ventricles thick?
Because they pump blood a long distance (all around the body)
Thick wall on left ventricle because?
It has to exert a strong pressure to pump blood all the way around the body
Left had side of heart pumps blood to
The lung
Right hand side of heart pumps blood
Around the rest of the body
Advantages of double circulation ?
1 Oxygen Rich and oxygen poor are separated
2 blood pressure is high so can reach all body parts
Diastole
When the heart muscle is relaxed
Systole
When the heart is contracted
What is the pace maker?
Also called SA node
Located in the right atrium
It controls the rate of heartbeat
How does the pacemaker control heartbeat ?
Sends out electrical pulses
Causing aria to contract
When reacher a trio ventricular is the pulse is strengthened and send to septum
How is the rate of heart beat increased
Increased by exercise/drugs/excitement
How is heart rate decreased
Rest/sleep/drugs such as alcohol
Portal system
Is one in which the blood starts and ends in capillaries
Pulse is caused by
A surge of blood in arteries triggered by ventricular systole
The pulse indicates
The rate of heartbeat
How is blood pressure recorded?
By measuring the pressure needed to stop the flow of blood in the arteries of the upper arm
Why is smoking bad for the heart
Nicotine increases heart rate
Carbon monoxide reduces the ability oof blood to carry oxygen
Chemicals increase risk of blood clots
Diet affects the heart as
Rat rich diets increase blockage in arteries
Too much salt and overweight raises blood pressure /heart attacks
Does exercise help the heart
Yes is strengthens the heart
