B5 Flashcards
What two components usually make up and internal skeleton?
- Bone
- Cartilage
HOWEVER some animals, such as sharks, have internal skeletons made solely from cartilage.
State four properties of an internal skeleton.
- Provides framework + shape of the the body
- Able to grow with the body
- Muscles are easily attached to them
- Joints provide greater flexibility
What are external skeletons (exoskeletons) made from?
Chitin
Summarise the properties of long bones. (4 points)
- Hollow shaft - contains bones marrow & blood vessels
- Weigh less than ordinary bones
- Stronger than ordinary bones
- Head of the bone coated in hard, slippery cartilage to lubricate movement against other bones
Explain what happens to the soft, flexible cartilage in an embryo when ossification occurs during growth in childhood.
• Soft cartilage is replaced by calcium and phosphorous salts during growth which makes the bones hard.
How can it be determined whether or not children are still growing?
- Adults only have cartilage at the ends of their bones.
- Therefore if scans show more than normal amounts of cartilage presents in the bone then it shows that the child is most likely still growing.
Identify and describe the three main types of break/fracture.
- Simple fracture - where the bone is broken cleanly
- Greenstick fracture - where the bone is not broken completely
- Compound fracture - is where the broken bone breaks through muscle and skin (visible from outside of the body)
What condition, in which bones are weakened, are older people likely to suffer from?
Osteoporosis leading to an increase in the likelihood of broken bones as they become more brittle.
Why is it dangerous to move someone with a suspected fracture?
- Moving them could cause further damage - especially if there is a risk of spinal injury
- Also, cartilage and bone can get infected if they are damaged.
Define: Joint.
A joint is where two or more bones meet.
What joins bone to bone?
Ligaments
What joins muscle to bone?
Tendons.
Give an example of a fixed joint.
• The skull is a fixed joint as it is bony plates fused together with zero movement.
Identify and describe the two different types of synovial (moving) joints.
- Hinge joints - e.g. the elbow and knee bend in ONE direction only
- Ball and socket - e.g. the shoulder and hip allow rotation, abduction, adduction, flexion & extension
Describe four adaptation of a synovial joint that make it fit for purpose.
- Synovial membrane secretes synovial fluid
- Synovial fluid lubricates bones during movement
- Smooth cartilage prevents friction between bones
- Ligaments joint bones to other bones
Describe the relationship between a pair of antagonistic muscles and give an example.
• The bicep and tricep are an example of a pair of antagonistic muscles
• As one relaxes the other contracts
–For Example–
1. To bend the arm, the bicep contracts, pulling the radius bone. The tricep relaxes.
2. To straighten the arm, the tricep contracts, pulling the ulna bone. The bicep relaxes.
Example how the elbow joint acts as a pivot. (4 points)
- The bicep muscle is attached close to the elbow so it only contracts a short distance.
- The radius bone acts as a lever so the hand moves much further
- A larger distance is moved by the hand than the muscles
- A larger force is exerted by the muscles than is exerted by the hand
If an animal doesn’t have a blood circulatory system how do they supply oxygen and nutrients to all parts of their body?
Diffusion
Describe the differences between an open and closed circulatory system.
- An Open Circulatory System, such as used by insects, fills up the body cavity rather than being contained within blood vessels.
- Closed Circulatory Systems, for example those used by humans, the blood is pumped through arteries, veins and capillaries.
Name the properties of a Single Circulatory System.
- Blood flows around in a SINGLE circuit.
(E.g. Heart - Gills - Body - Heart) - The heart has two chambers:
- Deoxygenated blood is pumped to the gills
- Oxygenated blood is pumped to the body - This is able to happen because there is enough pressure to get the blood around the body. Although the pressure is lower so materials are transported more slowly.
Name the properties of a Double Circulatory System. (6 points)
- Blood flows through the heart in two circuits
(E.g. Heart Lungs Heart Body ) - Heart has four chambers
- In one circuit, deoxygenated blood is pumped from the heart to the lungs and back to the heart
- In the other circuit, oxygenated blood is pumped from the heart to the respiring body cells and back to the heart.
- The blood returns back to the heart for another pump otherwise there wouldn’t be enough pressure to get it to the lungs to be oxygenated.
- Blood is under higher pressure in a double circulatory system so materials are transported quicker.
What does the heart do? What does it need to do this? (3 points)
- The heart is made up of powerful muscles to pump blood and nutrients to all parts of the body.
- To do this it needs a constant supply of glucose and oxygen to release energy through respiration.
- The heart never gets tired or needs rest which is why the energy requirements are so high
What is the job of the coronary artery?
• Supplies the heart itself with glucose and oxygen
What is the job of the pulmonary vein?
• It carries oxygenated blood from the lungs to the heart.
What is the job of the aorta?
• Carries oxygenated blood from the heart to the rest of the body.
What is the job of the vena cava?
• It carries deoxygenated blood from the parts of the body back to the heart
What is the job of the pulmonary artery?
• It carries deoxygenated blood from the heart to the lungs.
What are the three stages when the heart contracts?
- The heart relaxes and blood enters both atria from veins. The atrioventricular valves are open.
- The atria contracts to push blood into the ventricles.
- The ventricles contract (bottom chambers) contract to push the blood into the arteries and out if the heart. At this point the semilunar valves open to allow this whilst the atrioventricular valves close to prevent more blood coming in.
Who was Galen and what were his beliefs on circulation? (3 points)
- Greek doctor
- Practising in 200AD on gladiators
- Believed blood flowed like a tide between the liver and heart
In 1628, British doctor William Harvey found… (3 points)
- The heart pumped through the body through blood vessels
- Arteries carried blood under high pressure away from the heart
- Veins had valves to prevent backflow
Highlight the difference between arteries and veins.
- Arteries have thick, elastic, muscular walls to cope with high pressure within them
- However, Veins have thinner walls and less muscular fibre therefore result in lower pressure.
How do the pacemaker cells control the heart beat? Also what happens to these cells during exercise?
- They produce small electrical impulses which spread across the heart muscle stimulating it to contract.
- During exercise, muscles demand more energy so the heart rate speeds up to supply the oxygen and glucose to respiring muscles more efficiently.
What happens if the pacemaker fails? What else can affect heart rate?
- If the pacemaker cells fail, then it’s common to have an artificial pacemaker transplanted into the chest and wired up to the heart to keep the heart beat regular.
- Hormones, such as adrenaline, can alter heart rate.
What does the sinoartrial node (SAN) do?
- It produces impulses that spread across the atria to make them contract.
- Nerves connecting the heart to the brain can increase or decrease the pace of SAN to regulate the heart beat
What does the atrioventricular node (AVN) do?
• It relays impulses that spread over the ventricles to make them contract.
What does an electrocardiogram (ECG) monitor?
• It monitors the electrical impulses from the heart.
What does an echocardiogram do?
• It uses ultrasound to produces an image of the beating heart