Flashcards in B5 Deck (94):
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 two components usually make up and internal skeleton?
HOWEVER some animals, such as sharks, have internal skeletons made solely from cartilage.
What are external skeletons (exoskeletons) made from?
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.
1. Simple fracture - where the bone is broken cleanly
2. Greenstick fracture - where the bone is not broken completely
3. 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.
A joint is where two or more bones meet.
What joins bone to bone?
What joins muscle to bone?
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.
1. Hinge joints - e.g. the elbow and knee bend in ONE direction only
2. 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.
1. Synovial membrane secretes synovial fluid
2. Synovial fluid lubricates bones during movement
3. Smooth cartilage prevents friction between bones
4. 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
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?
Describe the differences between an open and closed circulatory system.
1. An Open Circulatory System, such as used by insects, fills up the body cavity rather than being contained within blood vessels.
2. 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.
1. Blood flows around in a SINGLE circuit.
(E.g. Heart - Gills - Body - Heart)
2. The heart has two chambers:
- Deoxygenated blood is pumped to the gills
- Oxygenated blood is pumped to the body
3. 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)
1. Blood flows through the heart in two circuits
(E.g. Heart Lungs Heart Body )
2. Heart has four chambers
3. In one circuit, deoxygenated blood is pumped from the heart to the lungs and back to the heart
4. In the other circuit, oxygenated blood is pumped from the heart to the respiring body cells and back to the heart.
5. 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.
6. 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?
1. The heart relaxes and blood enters both atria from veins. The atrioventricular valves are open.
2. The atria contracts to push blood into the ventricles.
3. 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)
1. Greek doctor
2. Practising in 200AD on gladiators
3. Believed blood flowed like a tide between the liver and heart
In 1628, British doctor William Harvey found... (3 points)
1. The heart pumped through the body through blood vessels
2. Arteries carried blood under high pressure away from the heart
3. 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
Advantages of pacemakers and heart calves (4 points)
1. Less risk of rejection
2. They involve less traumatic operation
3. Can be mechanical - no human donor needed
4. Shorter waiting times than for a donor heart
Disadvantages of pacemakers and heart valves (2 points)
1. The patient must take anticoagulants for the rest of their life
2. They may need replacing
Advantages of heart transplantation (2 points)
1. The transplanted organ will last for a lifetime - no replacement needed
2. The patient will immediately feel better and lead a full life
Disadvantages of heart transplantation.
1. Major, expensive operation
2. The replacement must come from a dead donor
3. Long waiting times for suitable donors
4. The patient will need to take immunosuppressants for the rest of their life
Describe how blood clots and what medications/condition could impair clotting.
• Platelets gather at a cut in the skin and form a clot.
• This temporarily prevents further blood loss
• However fibrin is needed to build over the wound
• The combination of platelets, fibrin and plasma form a scab
- Anticoagulant drugs such as warfarin, heparin and aspirin reduce clotting
- Haemophilia is an inherited disease where blood fails to clot due to a faulty clotting protein, suffers can bleed to death.
Name the four blood groups & how they can be further divided.
• A, B, AB and O
• Rhesus - positive or negative
• Each group can be positive or negative e.g. A+ or A-
What happens as a result of an unsuccessful blood transfusion?
• Agglution - blood clumping which can cause serious problems which is why blood has to be checked thoroughly before being given in a transfusion.
What must all living organisms does to obtain oxygen?
• Gas exchange!
• So they can release energy from food by aerobic respiration
• Some small organisms like amoeba and earthworms are small enough to obtain this by diffusion
Fish use gills to exchange gases by...
1. Absorbing oxygen by the many fine filaments in the gills
2. Then transporting the oxygen away from the gill filaments by the blood supply
Why can't fish breathe air?
• Air isn't dense enough to push between the gill filaments
• Amphibians can easily lose water through their permeable skin
• Both organisms' method of gas exchange limits the to their own environment
What's the trachea?
• A flexible tube, surrounded by rings of cartilage to stop it collapsing
What's the bronchi?
• Branches of the trachea
What are the Bronchioles
• Branches of the bronchus
What do the lungs do?
• Inhale and exhale air for gas exchange
What is the alveoli?
• (air sacs) Site of gas exchange
What do the intercostal muscles do?
• Raise and lower the ribs
What do to pleural membranes do?
• Protect and lubricate the surface of the lung
What is the diaphragm?
• A muscular sheet between the thorax and the abdomen
What does oxygen do during gas exchange?
1. Enters blood in the lungs
3. Leaves the blood into body tissues via the lungs
What does carbon dioxide do during gas exchange?
1. Enter blood from body tissues
2. Leaves via the lungs
How does surface area affect the exchange of gases?
• It affect the gas exchange massively, the larger the surfCe area the more oxygen can be absorbed
• This is why lungs have such a large surface area
What two parts of the body change the volume and pressure of the chest cavity during ventilation (breathing)?
1. The intercostal muscles
2. The diaphragm
What happens during 'inspiration' (breathing in)?
- Ribcage is moved upwards & outwards
- Diaphragm flattens and contracts
- This increases the volume of the chest cavity
- As the the pressure drops in the lungs, the air rushes in
What happens during expiration (breathing out)?
- Intercostal muscles relax
- The ribcage moves downwards and inwards
- Diaphragm relaxes and pushes upwards
- Decreases volume of the chest cavity
- Pressure in the lungs increases so air is pushes out
Define: Tidal Air
• Volume of air breathed in or out in a normal breath
Define: Vital capacity air
The maximum volume of air that can be used for gas exchange in the lungs - a maximum breath in followed by a maximum breath out
Define: Residual air
• The volume of air that stays in the lungs when we breathe out
Name the two stages of gas exchange.
1. Carbon dioxide diffuses from the blood into the alveoli.
2. Then oxygen diffuses from the alveoli into the blood .
Gas exchange surfaces are well adapted. How are the alveoli adapted for gas exchange? (3 points)
• A massive surface area
• A moist, thin, permeable surface
• An excellent blood supply
How does the respiratory system protect itself from disease? (2 points)
The trachea and bronchi:
• Produce mucus to trap dust and microorganisms
• Are lined with millions if cilia (like lots of tiny hairs) which move the mucus from the lungs into the throat where it's swallowed and broken down by stomach acid.
• Industrial disease
• Caused by inhaling asbestos fibres
• Fibres then get caught in air sacs, reducing gas exchange
• Resulting in: excessive coughing, breathlessness and death
• Causes coughing, wheezing, a feeling of tightness in the chest and difficulty breathing.
• Treated by using an inhaler containing medicine to relax bronchiole muscles
• The inflammation of the bronchi
Describe Cystic Fibrosis
• Genetically inherited
• Too much overly sticky mucus is produced in the lungs
• makes breathing become difficult
Describe Lung Cancer
• Often caused by lifestyle factors such as smoking
• Tar in cigarette smoke cause cells in the lung to mutate and grow uncontrollably
• This reduces surface area in lungs lowering gas exchange rate
• Caused by a virus or bacterial infection
• It causes inflammation in the lungs where fluid builds up
Name the three stages of an asthma attack. + Why are respiratory systems become prone to disease?
1. The lining of the bronchioles becomes inflamed
2. Fluid and mucus build up in the airways
3. Muscles around the bronchioles contract, constricting the airways
• The respiratory system is prone to disease because the lungs are a dead end
What does the mouth, oesophagus, stomach and small intestine do to aid digestion? Both physical & chemical.
• Mouth - has salivary glands which make saliva
• Oesophagus (gullet) - peristalsis occurs here, food squeezed down by wave-like muscles contractions
• Stomach - digestion do proteins
• Small intestine - digestion and absorption of food into blood
What does the liver and gall bladder, pancreas and large intestine do to aid digestion?
• Liver & Gall bladder - produces bile
• Pancreas - makes digestive enzymes and insulin
• Large intestine - absorption of water into blood
Give two examples of physical digestion.
1. Chewing your food in your mouth
2. Squeezing food in your stomach to break it down into smaller pieces so it can pass through your gut easily
What factor speeds up chemical digestion?
• Surface area
How does chemical digestion break down large insoluble molecules?
• Enzymes are used to break the large,insoluble molecules into smaller soluble molecules.
• These can then diffuse through the walls of the small intestines
• Ending up in blood plasma or lymph
Why is hydrochloric acid released by cells in the wall of the stomach?
• It creates the correct pH that helps the enzyme protease work effectively
Stomach acid provides optimum pH for which enzyme to work?
Protease which breaks down protein - other digestive enzymes in the mouth and small intestine have higher optimum pHs
Why does the body produce bile and what job does it do?
• The body uses bile to emulsify fat droplets which are hard to digest
• Bile breaks down large droplets to smaller droplets - increasing their surface area
• This enables lipase enzymes to work much faster
• Bile comes from the gall bladder to aid digestion
What is the word equation for the breakdown of starch?
Starch --> Maltose --> Glucose
(Large polymer) (Double sugar) (Single sugar)
How is the small intestine adapted for efficient absorption of food?
• It is long with a thin lining
• Large surface area - provided by the villi and microvilli
• It has a permeable surface
• Rich blood supply
Why do the small, soluble food molecules get absorbed in to the bloodstream through the small intestine?
• Diffusion - they travel from an area of high concentration (small intestine) to an area of lower concentration (the bloodstream)
What is egestion?
• Getting rid of waste through the anus -mainly undigested food
What is excretion?
Getting rid of waste products by body processes, for example:
• carbon dioxide
What two factors impact the volume of urine produced?
• How much you drink
• How much you sweat
Job do the brain respond to high levels of carbon dioxide in the blood?
• Breathing rate increases to remove excess carbon dioxide
Why is the amount of water in the blood important? What happens if there is too much/too little?
• If there is not enough water in the blood you become dehydrated and blood becomes thick and difficult to pump
• If there's too much water in the blood, blood pressure could be dangerously high
Which organ controls the amount of water in the blood?
• The kidneys
Describe what the kidney's function
• Clean the blood
• Excrete urea, water and salts
• They have millions of tubules very close to blood capillaries
Why do the kidneys filter blood at a high pressure?
• Filtering blood at high pressure separates small molecules from the blood
• Then they reabsorb useful substances - such as sugar and water