B5 Test

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Why is an internal skeleton better than an external skeleton?
It provides an internal framework for the body, it grows with the rest of the body, it is flexible due to the many joints, and it allows easy attachment of muscles
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What are both cartilage and bone?
They are both living tissues containing living cells
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What does a long bone consist of?
A long bone consists of a long shaft containing bone marrow with blood vessels. At each end there is a head covered with cartilage
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Why are long bones hollow?
Long bones are hollow, so they are stronger and lighter than solid bones
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Why can cartilage and bone be infected by bacteria and viruses?
Because cartilage and bone are living tissues, they can be infected by bacteria and viruses. However, they are able to grow and repair themselves
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What is ossification?
In the early stages, the human skeleton is made up of cartilage. By the process of ossification (the decomposition of calcium and phosphorus) the cartilage is slowly replaced by bone.
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How can you tell if a person is still growing?
If some cartilage remains between the head and shaft, the bone and the person is still growing
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What happens if you receive a sharp knock?
Even though bones are very strong they can easily be broken with a sharp knock
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What happens to elderly people's bones?
The bones of elderly people can lack calcium and phosphorus, which can result in osteoporosis, making them prone to fractures
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In an accident what can it be dangerous to do?
In an accident it can be dangerous to move a person with suspected bone fracture. Broken vertebrae in the backbone can damage the spinal chord, resulting in paralysis or death
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What does a synovial joint contain?
Synovial joints, such as ball and socket joints and hinge joints, contain synovial fluid, a synovial membrane, ligaments and cartilage.
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What does a ball and socket joint have that a hinge joint doesn't?
A ball and socket joint has a wider range of movement than a hinge joint, which is restricted to only an up and down movement
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What are the functions of each part of a synovial joint?
The synovial fluid acts as a cushion against shock and a lubricant for easy movement. And a synovial membrane holds in the synovial fluid. Cartilage protects the bone head. The ligaments hold the bone in place.
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What is raising and lowering the forearm an example of?
Raising and lowering the forearm is an example of a lever, with the elbow acting as a fulcrum (pivot). The effort is multiplied resulting in a greater force.
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Why do many animals need a blood circulatory system?
Many animals need a blood circulatory system toensure all their cells
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What happens as blood flows through arteries, veins and capillaries and why?
As blood flows through arteries, veins and capillaries, the blood pressure decreases. High blood pressure would damage the fragile walls of the capillaries
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Why do veins have valves?
Veins have valves to ensure there is no backward blood flow
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What is a single circulatory system?
A single circulatory system (such as in fish) has a single blood circuit of the heart, gills and body.
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What is a double circulatory system?
A double circulatory system (such as in mammals) has two circuits: the heart adn lungs form one (to obtain oxygen), the heart and rest of the body form teh other (to deliver oxygen to body cells)
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What does a double circulatory system require?
A double circulatory system requires a four-chambered heart: two atria to receive blood (from the lungs and body) and two ventricles to distribute blood (to lungs and body). It ensures high blood pressure for efficient and fast circulation of food a
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What does a single circulatory system need?
A single circulatory system needs only two chambers in the heart, one to receive and one to distribute blood
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What did Galen think?
In the second century, Galen knew that the heart acted as a pump and the importance of the pulse. However, he thought that the liver made blood that flowed backwards and forwards.
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What did William Harvey know?
In the seventeenth century, William Harvey knew that blood ciculated around the body, that the heart has four chambers and about tiny vessels that today we know as capillaries
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What is the cardiac cycle?
The cardiac cycle is the sequence of events as blood enters and leaves the heart
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How do the heart muscles stop backwards flow into the atria?
The muscles of two atria contract together as the two ventricles relax to receive blood through the atrio-ventricular valves, which prevent backwards flow into atria
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How do the heart muscles stop backwards flow into the ventricles?
Muscles of the two ventricles then contract togther to force blood to the lungs or around the body. Semi-lunar valves prevent backward flow into the ventricles
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What does more muscular activity cause?
More muscular activity causes a greater demand for oxygen and food. Heart rate therefore increases with increasing muscular activity
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What is heart rate increased by?
Heart rate is increased by the presenceof the hormone adrenaline
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What is a pacemaker?
Groups of cells in the heart form pacemakers, which control the rate of heart beat by producing a small electric current to stimulate muscle contraction.
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What is an artificial pacemaker?
An artificial pacemaker can be placed near the heart to send an electrical signal to the heart muscle
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What can be used to investigate irregular heart actions?
An electrocardiogram (ECG) (which shows changes in electrical impulses in heart muscle) and an echocardiogram (which displays a video of the heart in action) can be used to investigate irregular heart actions
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What are the two types of pacemakers?
Two pacemakers, the sino-atrial node (SAN) and the atrio-ventricular node (AVN) generate electrical impulses to coordinate heart muscle contraction.
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What do impulses from the SAN and AVN do?
Impulses from the SAN cause the atria to contract and stimulate the AVN. Impulses from the AVN cause the ventricles to contract
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What happens to excess and unwanted amino acids?
Excess and unwanted amino acids are broken down in the liver, forming urea, which is taken in the blood to the kidneys
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What happens to blood containing waste?
Blood containing waste such as urea enter each kidney by the renal artery. Blood without waste leaves by the renal vein. Each kidney has an outer cortex and an inner medulla. Waste removed from the kidney leaves through the ureters as urine
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Why does blood flow through the kidney under high pressure?
The blood flows through the kidney under high pressure so filtration to remove wastes also takes place under high pressure. Useful materials such as water, glucose and salt are reabsorbed back into the blood
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Where does filtration take place?
Each kidney has millions of microscopic kidney tubules (nephrons) where filtration takes place to form urine
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What does each nephron have?
A network of capillaries (the glomerulus) surrounded by a capsule: this forms a filtration unit. A region where some materials such as glucose are selectively reabsorbed. A region where reabsorption of some salt and water takes place
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When is a dialysis machine used and what do the tubes contain?
A dialysis mahcine is used when someone has a kidney failure. The machine has many tubes containing blood, surrounded by a liquid.
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What does a dialysis machine do?
The machine acts as an artificial kidney and removes urea from the blood. As urea molecules are small, they diffuse through the membrane. A dialysis machine also uses different sizes of tubes, so it slightly increases pressure during diffusion
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What does dialysis fluid contain?
The dialysis fluid contains sodium salts, so it is the same or slightly lower than the desired blood concentration. This maintains the sodium levels in the blood
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What happens after drinking a large quantity of water?
After drinking a large quantity of water, the quantity of urine produced increases and the urine concentration decreases
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What happens during strenuous exercise or in hot conditions?
During strenuous exercise or in hot conditions the body produces more sweat to cool down, so the quantity of urine produced decreases and the urine concentration increases
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What does the pituitary gland produce?
The pituitary gland produces the anti-diuretic hormone which controls the concentration of the urea by: Increasing the permeability of kidney tubules so that more water is reabsorbed. Using a negative feedback mechanism to control ADH production
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What is toxic at high concentration?
Carbon dioxide at high concentration is toxic and must be removed from the body
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What is the body more sensitive to?
The body is more sensitive to the level of carbon dioxide than to that of oxygen. An increase in carbondioxide in the blood is detected by receptors in the carotid artery.
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What does the nerve impulses do?
Nerve impulses inform the brain, which causes the rate of breathing to increase to remove more carbon dioxide via the lungs.
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Other cards in this set

Card 2


What are both cartilage and bone?


They are both living tissues containing living cells

Card 3


What does a long bone consist of?


Preview of the front of card 3

Card 4


Why are long bones hollow?


Preview of the front of card 4

Card 5


Why can cartilage and bone be infected by bacteria and viruses?


Preview of the front of card 5
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