Animal Tissues, Organs, and Organ Systems Flashcards
1
Q
What are cells?
A
- basic building blocks of all organisms
2
Q
What are tissues?
A
- group of cells with similar structure and function
3
Q
What are organs?
A
- aggregations of tisssues performing specific functions
4
Q
What are organ systems?
A
- work together to form organisms
5
Q
What are enzymes?
A
biological catalysts
6
Q
What is the lock and key theory?
A
- enzymes have active site that only binds to 1 substrate
- forms enzyme-substrate complex
7
Q
How do digestive enzymes work?
A
- break down substrate into smaller molecules
- food into smaller molecules = absorbed into bloodstream
8
Q
How do enzymes build new carbohydrates/ proteins/ lipids?
A
- catalyse reaction to join small molecules together
9
Q
What are enzymes?
A
- proteins folded into ball-like shape
- held together by chemical bonds
10
Q
What does it mean when an enzyme is denatured?
A
- extreme temperature/ pH changing shape of enzyme
- active site changes shape
- substrate no longer fits in active site
11
Q
What is the optimum temperature for human enzymes?
A
- 40C
12
Q
Why does increasing the temperature increase the rate of reaction? (until the optimal temp.)
A
- provides more kinetic energy to molecules
- collide and react more frequently
13
Q
What is the effect of pH on enzyme activity?
A
- optimum pH = highest activity
- extreme pH = denature
14
Q
What does amylase do?
A
- breaks starch down into glucose
15
Q
What does protease do?
A
- breaks protein down into amino acids
16
Q
What does lipase do?
A
- break lipids down into glycerol and fatty acids
17
Q
Where is amylase produced?
A
- salivary glands
- pancreas
- wall of small intestine
18
Q
Where is protease produced?
A
- wall of stomach
- pancreas
- wall of small intestine
19
Q
Where is lipase produced?
A
- pancreas
20
Q
What does bile do and where is it made?
A
- made in liver
- stored in gall bladder
- released through bile duct into small intestine
- neutralises hydrochloric acid in partially digested food
- emulsifies fats to from small droplets = increases SA
21
Q
How do you test for sugar?
A
- mix food with few cm^3 of Benedict’s solution
- heat it
22
Q
Describe the positive result for the Benedict’s solution for sugar
A
- blue -> orange-red precipitate
23
Q
Describe the positive test result for starch
A
- orange brown -> blue-black solution
24
Q
How do you test for starch?
A
- add few drops of iodine solution into food
25
How do you test for protein?
- mix food with few cm^3 of **Biuret reagent**
26
Describe the positive test result for protein
- blue to purple
27
How do you test for lipids?
- shake food with **ethanol**
- **pour into water**
28
Describe the positive test result for lipids
- clear solution -> **emulsion** forms as cloudy white layer
29
How do you reduce the risk of scalding from hot steam and spilling hot water while heating the Benedict's test?
- keeping water temp. **below 60C**
- **standing up** while heating
30
How is continuous sampling used to measure the time taken for amylase to digest a starch?
- **amylase, starch and buffer solution heated** in water bath
- every 30 secs **sample mixture** into spotting tile
- add drop of **iodine solution**
- observe **change of colour** (blue-black to orange-brown)
31
Describe what happens when the heart pumps
1) **deoxygenated blood** from body enters right atrium through **vena cava**
2) **right ventricle** pumps blood to the lungs via **pulmonary artery** (for gas exchange)
3) **oxygenated blood** from lungs enter left atrium through **pulmonary vein**
4) left atrium contracts and left ventricle contract, sends oxygenated blood to **rest of body via aorta**
| valves between atria and ventricles and veins to prevent backflow
32
What is a double circulatory system?
- blood flows through heart twice during one complete circulation
33
What do pacemaker cells do and what is used to correct irregularities in heart rate?
- sends electrical impulses to heart to contract
- artificial pacemakers = correct irregularities in heart rate
34
What do arteries do and how are they adapted?
- carry blood at **high pressure** **away from heart**
- **narrow lumen** - maintains pressure
- **elastic fibres** in walls to stretch and recoil to maintain pressure
- **thick walls** resist bursting
- no valves - high pressure keeps blood moving
35
What do capillaries do and how are they adapted to their function?
- **exchange of substances** in cells
- **very narrow lumen** - keeps RBC close to tissue cells
- **very thin walls** - minimises diffusion distance
- no valves
36
What do veins do and how are they adapted to their function?
- carry blood at a **low pressure to heart**
- **large lumen** - little resistance to blood flow
- **relatively thin walls** - low pressure
- **valves** - prevents backflow of low pressure blood
| doesn't always have to be deoxygenated - see pulmonary vein
37
Describe ventilation
- **trachea** leads to two **bronchi**
- divides into bronchioles, into air sacs - **alveoli**
- **intercoastal muscles** contract + relax to move air in and out of airways
38
How do alveoli work during gas exchange?
- surrounded by network of **capillaries** - steep concentration gradient
- high conc. of CO2 and low conc. of O2
- CO2 diffuses out of blood O2 diffuses into blood
39
How are the lungs adapted for gas exchange?
- **large SA** - alveoli has **folded** surfaces
- **short diffusion pathway** - alveoli wall + capillary wall = one cell thick
- **steep concentration gradient** maintained by good **blood supply** and **ventilation**
40
What is blood made of?
- plasma
- platelets
- RBC
- WBC
| blood is a tissue
41
What is the function of plasma?
- transporting substances around body
- **digested food**
- waste products = **urea, CO2 **
- transported to **kidneys for excretion**
42
What is the function of red blood cells and how are the adapted to it?
- carry oxygen
- **haemoglobin** binds to oxygen in lungs
- **biconcave disc = increases SA** for diffusion of oxygen
- **small and flexible** = squeeze through capillaries
- **no nucleus** = increases space for carrying oxygen
43
What is the function of white blood cells?
- **defence against infection**
- recognises non-self cells
- **phagocytes engulf** microorganisms
- **lymphocytes** produce **antibodies**
44
What are platelets and what is the function of platelets?
- **fragments** of cells
- aids blood **clotting**
- traps cells to plug holes in damaged blood vessels
45
What is coronary heart disease caused by?
- **fatty material** building up in coronary arteries
- **narrows arteries**, reducing blood flow
- **insufficient oxygen** reaches heart = heart attack/ damage to heart
46
How can coronary heart disease be treated?
- **statins** = drug reduces blood cholesterol levels (slows buildup in arteries)
- **stents** = wire-mesh tube supports artery
- **mechanical/ biological valves** (cow/ pig valves)
- **donor heart** transplant
- **artificial heart** used to keep patient alive while waiting for transplant/ allows heart to rest = recovery
47
What are the drawbacks of each type of treatment for coronary heart disease?
- transplants = **rejection** (drugs taken to suppress immune system)
- artificial valves = greater risk of **blood clots**, becomes **faulty**
- statins = digestion problems/ **liver damage**
48
What is health?
- the state of a person's **physical** and **mental** wellbeing
49
What are communicable diseases?
- diseases that can be transferred from one person to another
50
What are pathogens?
- disease causing microorganisms
51
How can diseases interact?
- **defects in immune system** = more likely to suffer from infectious diseases
- **viruses living in cells** = trigger for cancers
- **immune reactions** caused by pathogen = **trigger allergies** (skin rash, asthma)
- severe physical ill health - **lead to depression**/ mental illness
52
How do scientists study disease in populations?
- random sample in population
- avoid bias
- larger sample = more representative
- all other risk factors = controlled
53
What are lifestyle factors?
- the way people live their lives
- eg diet, exercise, smoking and alcohol intake
54
What is obesity a risk factor for and why?
- **type 2 diabetes**
- cells of overweight people = **less sensitive to insulin**
- blood sugar levels = not controlled
55
What is alcohol intake a risk factor for?
- poor liver + brain function
- **cirrhosis of liver**
- **memory loss**, pernament brain damage
56
What is smoking during pregnancy a risk factor for?
- **premature birth**
- **low birthweight**
- abnormal facial features + problems in brain + nervous system
57
What are the risk factors of cardiovascular disease?
- **diet** (high energy foods)
- **lack of exercise** (associated with obesity - buildup of fatty deposits)
- chemicals from **smoking** damage arteries + high blood pressure
58
What are the effects of smoking on the lungs?
- **lung cancer** = **carcinogen**s in cigarette smoke
- **lung disease** = **toxins** damage walls of airways and alveoli (reduced oxygen exchange = shortness of breath)
59
What are genetics a risk factor for?
- **inherited mutations** = higher risk of some **cancers**
60
What are carcinogens a risk factor for?
| what are they?
- **chemical or physical agent** that can cause the **development of cancer** in some cells
- eg asbestos, ionising radiation, UV light
61
What is cancer caused by?
- uncontrolled growth and division of cells
62
What are malignant tumours?
- can **detach** and **invade neighbouring tissues** (metastasis)
- squeeze through **capillary walls**
- move into **blood stream**, gets carried to different part of body
- **enter other tissues** -> divide form **secondary tumours**
63
What are begnign tumours?
- growths of abnormal cells that **do not invade** other parts of the body
- contained in 1 area, usually **surrounded by membrane**
- removed by **surgery**
| health risks = lower than malignant tumours
