The Heart And Blood Vessels Flashcards
What is an open circulatory system?
Where the heart pumps blood into vessels that are open-ended. E.g spiders
What is an open circulatory system?
Where the heart pumps blood into vessels that are open-ended. E.g spiders
What is an open circulatory system?
Where the heart pumps blood into vessels that are open-ended. E.g spiders
Is a closed system or an open system more efficient?
A closed system is more efficient
Why is a closed circulatory system better than an open one?
- Blood can be pumped around the body faster, allowing the animal to be more active
- It allows the flow of blood to different organs to be increased or decreased
What is the composition of a closed circulatory system in humans?
- Blood
- Blood vessels
- The heart
What are arteries?
Arteries carry blood away from the heart. Arteries divide into smaller vessels called arterioles
What are veins?
Veins carry blood to the heart. Small veins are called venules
What are capillaries?
Capillaries are tiny vessels that link arteries and veins
What is the outer layer of veins and arteries?
Inelastic protein (collagen) which prevents the walls from over expansion
What is the outer layer of veins and arteries?
Inelastic protein (collagen) which prevents the walls from over expansion
What is the middle layer of veins and arteries?
Muscle and elastic fibres. The muscle is involuntary and can alter the size of the vessel. The elastic fibres bring the vessel back to shape when the muscle relaxes. The recoil of the artery also helps to pump blood.
What is blood pressure?
The force the blood exerts against the wall of a blood vessel
When is blood pressure the highest?
When the heart contracts
How can a pulse be detected?
By the expansion of the artery
What is the purpose of valves?
Valves help control the direction of blood flow
What adaptation do capillaries have?
Capillary walls are permeable so they allow exchange of materials between the blood and body tissues (diffusion)
What is the heart made of?
Cardiac muscle
What is the pericardium?
A double membrane surrounding the heart
What does pericardial fluid do?
Helps to reduce friction when the heart beats
How is cardiac muscle suitable for its role?
Cardiac muscle is slow to fatigue
What is the septum?
A wall that divides the heart in two sides
What do the atria do?
Pump blood to the lower chambers or ventricles.
Do atria have thick or thin walls?
Thin walls
What do the ventricles do?
Pump blood out of the heart
Which ventricle pumps blood to the lungs?
The right ventricle
Which ventricle pumps blood to the head and body?
The left ventricle.
Which ventricle is thicker?
The left ventricle
What hold valves in place
Tough cords called Tendons
How are tendons attached to the walls of the heart?
By projections called papillary muscles
What do the valves ensure happens?
That blood can only flow from the atria to the ventricles
What name of the valve on the right hand side?
The tricuspid valve
What is the name of the valve on the left hand side?
The bicuspid valve
What is the purpose of the semilunar valves?
They allow blood to flow out of the heart into the 2 main arteries
What is the LORD acronym?
LO= Left Oxygenated
RD= Right Deoxygenated
What word is used to refer to the front of the heart?
Ventral
What word is used to refer to the back of the heart?
Dorsal
What is the pulmonary circuit?
Where blood is pumper to the lungs, here gas exchange can take place
What is the systemic circuit?
Pumps blood to everyone in the body but the lungs, it has a much longer route hence the thicker left ventricle wall
What is a benefit of a double-circulation system?
It ensure that blood pressure is high enough to reach all parts of the body
What is a portal system?
A blood pathway that begins and ends in capillaries
What is a portal system?
A blood pathwa6 that begins and ends in capillaries
What is the hepatic portal vein?
It connects the stomach and intestines to the liver
What supplies the heart muscles with blood?
The coronary (cardiac) arteries
Where do coronary arteries come from
The aorta
What does a blockage of the coronary artery cause?
Heart attack
What is a pulse?
The alternate expansion and contraction of the arteries
What is the average adult pulse rate?
72 beats per minute
What is blood pressure?
The force exerted by the blood against the walls of the blood vessels (mainly the arteries)
What is systolic pressure?
The pressure of blood as a pulse passes through the artery (when the ventricles contract)
What is diastolic pressure?
The pressure when there is no pulse (when ventricles are relaxed)
What is an average blood pressure reading of a young adult?
120/80 mm of mercury
What controls the heartbeat?
The SA Node (pacemaker)
Where is the SA Node located?
In the wall at the top of the right atrium
What are factors that increase the rate of heartbeat?
Exercise, temperature, emotions
Factors that decrease rate of heartbeat
Sleep, alcohol, relaxation
Diastole
When the heart chambers relax
Systole
When the heart chambers contract
What sound does the heart make?
‘Lub-dub’
What makes the sound of the heartbeat?
The sound is caused by valves being forced shut
