B5 Flashcards
(77 cards)
1
Q
State 3 functions of skeletons
A
- Support
- Protection
- Provides framework for muscle attachment to allow movement
2
Q
State a disadvantage of an external skeleton
A
Can restrict growth so has to be shed so animal can grow
3
Q
State the name of the process in which bone hardens and explain it
A
Ossification:
- Calcium phosphate deposited in cartilage
- This causes cartilage to harden
4
Q
Explain why moving someone with a broken backbone can be dangerous
A
Their spinal cord may be damaged
5
Q
Describe the structure of a long bone
A
Structure:
- Hollow - makes it light
- Hard bone outer coating - makes it strong
- Smooth cartilage on ends to reduce friction between bones
- Contains red bone marrow which produces red blood cells
- Contains yellow bone marrow which stores fat
6
Q
State and explain 3 types of fracture
A
- Simple - bone breaks cleanly
- Compound - bone breaks and sticks out through skin
- Green-stick - bone bends
7
Q
Why are old people more susceptible to fractures
A
They may have osteoporosis (soft bones)
8
Q
Explain how the arm bends and straightens
A
Bends:
- Biceps contracts and pulls radius upwards
- Triceps relaxes
- Tendon connecting biceps to radius does not bend
Straightens:
- Biceps relaxes
- Triceps contracts and pulls ulna downwards
9
Q
What is an antagonistic pair of muscles?
A
When one muscle contracts, the other relaxes (and vice versa)
10
Q
Explain how the arm acts as a lever
A
- Elbow is the pivot point (fulcrum)
- Hand moves greater distance than muscles
- Muscles exert greater force than the load carried by the hand
11
Q
State 3 types (not categories) of joints and explain their range of movement
A
- Fixed joints - no movement
- Ball and socket joints - can move in many different directions
- Can only move in one plane (direction)
12
Q
Describe the structure of a synovial joint
A
- Capsule of ligaments (bone to bone)
- Synovial membrane - secretes synovial fluid
- Synovial fluid - lubricates the joint
- Smooth cartilage (on bone ends) - reduces friction
13
Q
What is the difference between an open and closed circulatory system?
A
In closed, blood moves in blood vessels while blood moves freely through body cavities in an open one
14
Q
What is the difference between a single and a double circulatory system?
A
Single - blood competes one circuit from heart
Double - blood completes two circuits from heart
15
Q
State an advantage of a double circulatory system over a single one
A
Materials are transported more quickly around the body because the heart is a double pump which generates a higher pressure than a single pump heart
16
Q
Explain the contributions of Galen and Harvey towards our understanding of the circulatory system
A
Galen - noticed blood darker in veins than arteries, thought that liver made blood and pumped it in the veins to organs
Harvey - published a book showing how blood circulates in the body (heart to lungs to body to heart) and discovered that veins have valves
17
Q
Explain why the left ventricle produces a higher blood pressure than the right ventricle, in terms of the structure of the heart.
A
It has a thicker muscular wall
18
Q
Explain the cardiac cycle
A
- Sinoatrial node produces electrical impulses, which travel across the atria walls, causing them to contract. This forces the atrioventricular valves open and pushes blood into the ventricles.
- Atrioventricular node conducts the impulses across the Purkyne fibers (conducting muscle fibres) to the tips of the ventricles. The ventricle walls contracting, closing the AV valves and forcing blood through the open semilunar valves into the arteries.
- The atria relax to fill with blood.
19
Q
State 2 reasons why heart rate increases
A
- Brain detects extra carbon dioxide levels during exercises and sends impulses to the SAN to speed up heart rate
- Adrenaline is produced during exercise which travels in the blood to the SAN, speeding up heart rate
20
Q
State 2 heart defects which may need an artificial pacemaker
A
- Irregular heartbeat
- Damaged AVN - impulses do not travel to ventricles
21
Q
Explain how a baby can be born with a hole in the heart and the effects of this
A
- Embryo has a hole in the heart because it receives oxygen from the placenta, which travels from the right to the left side of the heart, then to the body.
- When baby is born, this hole normally closes and blood follows the normal circuit involving lungs.
- In some babies this hole remains open, so oxygenated blood may flow from the left to the right side of the heart.
- This results in breathlessness and fatigue, because body tissues do not receive enough oxygen.
22
Q
State a possible consequence of damaged heart valves and explain why this might happen
A
- Damaged heart valves may not close properly
- So blood will flow backwards
- This may result in heart failure
23
Q
Why is there no risk of rejection of heart valves?
A
Because heart valves have no capillaries supplying them
24
Q
Explain the possible consequences of having blocked coronary arteries
A
- Heart muscle cells will not receive enough oxygen to release energy (from respiration) to contract efficiently
- This can lead to a heart attack
25
What is the disease caused by blocked coronary arteries?
Coronary artery disease
26
What is the surgery used to 'treat' coronary artery disease?
Bypass surgery
27
State a pro and a con of an 'opt-out' donor card system rather than an 'opt-in' one
Pro - would end shortage of donors
| Con - some people may opt out for religious reasons e.g. Jehovah's witnesses regard blood as sacred
28
State 3 disadvantages of a heart transplant
- Traumatic operation
- Immunosuppressant drugs need to be taken which may lead to infection due to weak immune system
- Shortage of heart donors
29
State 2 advantages of artificial heart valve and pacemaker replacements over heart transplant surgery
- Less traumatic
| - No risk of rejection
30
State a disadvantage of artificial pacemakers and heart valves
Need to be replaced
31
State 3 types of people who need blood transfusions
- Haemophiliacs
- People who have lost lots of blood through injury or surgery
- Some cancer patients
32
State what may happen if blood types are not matched in a blood transfusion and explain why this may happen
Agglutination (clumping or clotting of the blood, preventing blood circulation and leading to death)
33
Why do frogs need to live in damp places?
Because their skin is permeable to gases so they are susceptible to water loss
34
Describe gas exchange in a fish
1. The fish gulps water into its mouth
2. The fish closes its mouth and raises the floor of its mouth, forcing water over the gills
3. Oxygen diffuses from the water, through the gills, into the blood
4. Carbon dioxide diffuses from the blood, through the gills, into the water
35
Describe the process of ventilation in the human body
Inspiration:
- Diaphragm flattens
- Intercostal muscles contract, causing ribcage to move up and out
- Volume inside lungs increases, pressure inside lungs falls, so air rushes into lungs from higher pressure outside
Expiration:
- Diaphragm domes up
- Intercostal muscles relax so ribcage moves down and in
- Volume inside lungs decreases and pressure increases, causing air to move out into area of low pressure
- Residual air left in the lungs to prevent the alveoli closing up
36
Define: 'residual air', 'tidal volume', 'vital capacity' and 'lung capacity'
- Residual air - air kept in lungs to prevent alveoli closing up
37
State 4 adaptations for efficient diffusion in organs
- Large surface area
- Permeable
- Thin walls
- Good blood supply
38
Explain how the respiratory system protects itself (3 steps)
1. Mucus traps small particles and pathogens
2. Cilia waft mucus to the back of the throat
3. Here it can be swallowed, so the stomach acid kills the pathogens, or it can be coughed out
39
Explain the purpose of pleural membranes
Pleural space between pleural membranes contains pleural fluid, which allows slippage of the lungs during breathing and prevents the lungs collapsing
40
State 3 respiratory diseases (not asthma), their causes and their symptoms
Cystic fibrosis - genetically inherited - causes build-up of mucus, causing chest infection and reducing gas exchange, leading to lung damage
Asbestosis - asbestos fibres trapped in alveoli, causes inflammation and scarring of the lungs, limiting gas exchange
Lung cancer - tar in tobacco smoke - cells rapidly divide, forming a tumour, which reduces the surface area of the lungs
41
Describe what happens during an asthma attack
Airway lining becomes inflamed, causing a build-up of mucus in the airways. Bronchi and bronchioles contract, constricting the airways
42
State 2 examples of physical digestion in the body
- Squeezing of food in the stomach
| - Chewing food in the mouth
43
State the enzymes that digest carbohydrates, fats and proteins, the part of the body where the enzyme works, and then products of the digestion
- Carbohydrates - carbohydrase - mouth and small intestine - starch converted to maltose and then broken down to form glucose (simple sugar)
- Fats - lipase - small intestine - broken down into fatty acids and glycerol
- Proteins - protease - small intestine and stomach - broken down into amino acids
44
Where is bile made? Where is it stored? How does it aid in digestion?
Bile is made in the liver and stored in the gall bladder. It adds in digestion by emulsifying fat molecules (breaking fats into smaller droplets) to give lipase enzymes a greater surface area to work on
45
Explain the purpose of: salivary glands, stomach, pancreas, liver and gall bladder, small intestine, large intestine
- Salivary glands - add enzymes to food
- Stomach - churns food (physical digestion) and begins chemical digestion
- Pancreas - produces enzymes
- Liver and gall bladder - produces and stores bile
- Small intestine - where digested food is absorbed into the blood
- Large intestine - where water and minerals are absorbed into the blood
46
How does digestion food move into the blood from the small intestine?
The products of digestion diffuse across the small intestine wall into the blood
47
State 3 adaptations of the small intestine to its function
- It is long - large surface area
- Covered in villi and microvilli which increase surface area
- Thin lining/wall
- Good blood supply
48
What is the difference between excretion and egestion?
Excretion is the removal of wasted produced in the body while egestion is the removal of waste not made in the body
49
Why is it important to control the level of water in the body?
If there is too much water, cells may swell and burst. If there is too little water, cells may shrivel up and not function
50
State the 4 main organs of excretion and the products they excrete
- Kidneys - urea, water, salts
- Skin - salts, water
- Lungs - carbon dioxide
- Liver - urea
51
What product do the lungs excrete? Why do they do this?
The lungs excrete carbon dioxide made in cells during respiration. They do this because high levels of carbon dioxide in the blood can lower the pH of the blood, causing enzymes to stop working, which can result in death.
52
Explain how your breathing rate is made to increase after exercise
The brain detects excess carbon dioxide levels. It increases breathing rate to remove more carbon dioxide per second
53
Describe how the liver makes ammonia into a safer product
It reacts ammonia with carbon dioxide to make urea
54
Describe the structure of a kidney
(refer to diagram in textbook)
55
State the 4 substances that are filtered out of the blood in the kidneys and the 3 substances that are reabsorbed
```
Filtered out:
- Water
- Salts
- Urea
- Glucose
Reabsorbed:
- Some water
- All glucose
- Some salts
```
56
Explain fully how the nephron works
1. Blood enters the kidney via the renal artery
2. The renal artery branches out into many arterioles, each arteriole carries blood to each glomerulus
3. Blood enters the glomerulus via the afferent arteriole and leaves via the efferent arteriole
4. The efferent arteriole has a smaller diameter than the afferent arteriole, which creates a bottleneck effect as blood cannot leave the glomerulus as quickly as it enters is
5. The capillaries of the glomerulus are leaky, and the bottleneck effect creates a high pressure, which results in high pressure filtration
6. Substances with small molecules such as glucose, salt, water and urea are squeezed out of the glomerulus in high pressure filtration
7. The filtered substances move along the tubules of the nephron, dissolved in the liquid that was squeezed out of the glomerulus
8. Some of the filtered substances are reabsorbed at the loop of Henle, where selective reabsorption happens
9. The loop of Henle also regulates water reabsorption with the use of ADH produced in the pituitary gland
57
What is the mechanism that controls the regulation of water levels in the body?
Negative feedback
59
Explain how ADH works, including where it is produced
ADH is a hormone which causes the kidney to reabsorb water:
1. The hypothalamus detects how watery the blood is
2. If the blood is dilute (watery), less ADH is produced by the pituitary gland, so less water is reabsorbed, making the urine more dilute and frequent
3. If the blood is not very water (concentrated), more ADH is produced, so more water is reabsorbed by the kidney, making the urine concentrated and less watery
60
What are the primary sexual characteristics?
External genitals
61
State 2 secondary sexual characteristics that develop in males during puberty
- Voice breaks (deepens)
- Testes begin producing sperm
- Hair grows on face and body
- Body becomes more muscular
62
State 2 secondary characteristics that develop during puberty
- Hips widen
- Pubic hair and hair under the arms grows
- Periods begin (menstruation)
- Breasts develop
63
Explain the menstrual cycle
1. Pituitary gland produces FSH, which causes an egg to mature in the ovaries and stimulates the ovaries to produce oestrogen
2. Oestrogen stimulates the pituitary gland to produce LH
3. LH causes an egg to be released from the ovaries (ovulation)
4. Oestrogen repairs the uterus lining and inhibits FSH
5. Progesterone maintains the uterus lining and inhibits LH
64
What is conception?
When a sperm meets an egg and fertilises it
65
What is contraception?
Preventing pregnancy
66
State 3 possible causes of infertility
- Low sperm production
- Blocked fallopian tubes or sperm ducts
- Egg doesn't develop or is not released from the ovaries
67
State what 'in vitro' means and describe the process of IVF
- 'in vitro' means 'in glass'
1. Woman is injected with FSH, stimulating her ovaries to produce eggs
2. The eggs are collected and mixed with the man's sperm in a glass dish - one sperm is injected into each egg
3. The fertilised eggs begin to grow into embryos
4. When the eggs have become small balls of cells, two of them are inserted into the woman's uterus
68
State and explain the 4 types of fertility treatment other than IVF
- Artificial insemination - if the male has a low sperm count his sperm cells can be inserted straight into the woman's vagina
- Surrogacy - if a woman has had her uterus removed, she can have her embryo implanted in another woman's (surrogate mother) uterus. When the baby is born, it is given back to the biological mother
- Ovary transplant - if a woman has had her ovaries removed or is infertile, she can have another ovary transplanted into her
- Egg donation - a woman can donate her eggs to another woman who cannot produce her own eggs
69
State 2 ethical issues raised by amniocentesis (foetal screening)
- Some people believe screening out disabilities means disabled people are undervalued in society
- There is a small chance that amniocentesis could cause a miscarriage and therefore abort a healthy foetus
70
Why are a baby's body length and mass measured at birth
So they can be compared with the average to alert the midwife of any growth problems
71
What is the hormone that stimulates the growth of long bones in the body?
Human growth hormone
72
Which part of the brain detects how watery the blood is?
The hypothalamus
73
State and briefly describe the 5 stages of human growth
- Infancy - (up to 2 years of age) - highest growth rate
- Childhood - (2-11 years - up to puberty) - lower growth rate than infancy
- Adolescence (11-15 years) - puberty begins, growth spurt, increased growth rate
- Maturity - longest life stage
- Old age - (60-65 years) - physical abilities begin to deteriorate
74
State 5 factors that determine final height
- Genes
- Hormones
- Health and disease
- Exercise
- Diet
75
State 3 reasons life expectancy has increased
- Better housing
- Vaccinations to prevent infectious diseases
- Healthier diets - so fewer cases of deficiency diseases
- Improved lifestyle
- Less industrial disease
- Better treatments for cancer and heart disease
76
Explain the implications of an increased life expectancy
- There are more people over 60-65 than under 16
- Many old people will need medical care or treatment, increasing demand for resources for health services
- Old people may compete with younger people for jobs as they have to/want to work
- The country cannot afford to pay pensions for so many people so the pension system will be redesigned
77
State the 4 factors that medical engineers have to take into account for transplants
- Size - must fit in the body
- Battery life - must last a long time to prevent having to frequently replace it
- Body reactions - must be made of inert materials so it doesn't react with bodily fluids
- Strength - must be strong enough to remain intact in the body
78
Explain the 2 problems associated with transplants
- Risk of organ rejection
| - Immunosuppressant drugs used to prevent rejection may weaken the immune system, increasing risk of infection
