Cells & Systems Flashcards
Cells & Systems covers all the material which we have learned within the second unit of grade 8 science.
1
Q
What does biotic mean?
A
Living.
2
Q
What does abiotic mean?
A
Non-living.
3
Q
What are the characteristics of living things? (6)
A
- Made of cells.
- Need energy.
- Grow and develop.
- Respond to the environment.
- Reproduce.
- Adaptations.
4
Q
What do you have to keep in mind about the characteristics of living things when it comes to biotic and abiotic features?
A
All living things, or organisms, have all six characteristics. Non-living things may have some of these, but not all.
5
Q
What is the basic unit of life?
A
Cells. All living things are made up of them. They perform all the processes that life depends on.
6
Q
Are abiotic things made up of cells?
A
No, unless the material was alive at one time.
7
Q
Provide an example of a non-living feature in which cells can be found. Why is that the case?
A
A piece of wood; because the wood came from a tree that was once alive.
8
Q
Define energy.
A
The ability to make things move or change.
9
Q
How do plants and animals differ in how they get their energy?
A
Plants use the energy from the sun, whereas animals get their food from the environment around them.
10
Q
Define nutrient.
A
Nutrients are substances that provide the energy and materials that organisms need.
11
Q
What do plants and animals use nutrients for? (3)
A
- Grow.
- Develop.
- Reproduce.
12
Q
Where do plants and animals obtain nutrients from? (2)
A
- Food.
2. The environment.
13
Q
Define stimulus.
A
Anything that causes a response in an organism.
14
Q
What is an example of a stimulus?
A
If you are crossing the street, and a car is coming towards you, you will probably jump out of the way. In this situation, the car is the stimulus, and jumping out of the way is the response.
15
Q
Is growth getting taller? Provide an example.
A
Yes, but that’s not all. It’s also changing in structure.
For example, once you reach a certain height, you will not grow any taller. But your skin cells will continue to replace themselves.
16
Q
Define adaptation.
A
A characteristic that allows an organism to live in its environment.
17
Q
Provide an example of adaptation.
A
A cactus has spines to stop animals from eating it.
18
Q
What’s the difference between a structure and a function?
A
Structures are different body parts. Functions are what the structures are good for.
19
Q
What organs are part of your circulatory system? (5)
A
- Heart.
- Arteries.
- Veins.
- Capillaries.
- Blood.
20
Q
What are the functions of the circulatory system? (4)
A
- Transport oxygen, food, and other substances throughout the body.
- Transports some wastes to other organs for elimination.
- Defends the body against diseases.
- Connects all other organ systems.
21
Q
What organs are part of your respiratory system? (6)
A
- Nose.
- Mouth.
- Trachea.
- Diaphragm.
- Bronchi.
- Lungs.
22
Q
What are the functions of your respiratory system? (2)
A
- Transport oxygen from the outside air to the blood.
2. Transport carbon dioxide from the blood to the outside air.
23
Q
What organs are part of your digestive system? (9)
A
- Salivary glands.
- Mouth.
- Esophagus.
- Stomach.
- Liver.
- Pancreas.
- Gall bladder.
- Small intestine.
- Large intestine.
24
Q
What are the functions of your digestive system? (1)
A
- Breaks down food pieces into much smaller pieces (particles) so they can be absorbed and transported throughout the body.
25
What organs are part of your nervous system? (4)
1. Brain.
2. Spinal cord.
3. Nerves.
4. Eyes, ears, and other sensing organs (hands, nose, etc.)
26
What are the functions of your nervous system? (2)
1. Coordinate and control the actions of all organs and organ systems.
2. Detect, process, and respond to changes in external and internal environments.
27
What organs are part of your excretory system? (5)
1. Kidneys.
2. Bladder.
3. Lungs.
4. Skin.
5. Liver.
28
What are the functions of your excretory system? (1)
1. Removes chemical and gaseous wastes from the blood.
29
What organs are part of your skeletal system? (2)
1. Bones.
| 2. Cartilage.
30
What are the functions of your skeletal system? (2)
1. Provide a moveable support frame for the body.
| 2. Protect soft-tissue organs such as the heart and lungs.
31
What organs are part of your muscular system? (2)
1. Muscles.
| 2. Tendons.
32
What are the functions of your muscular system? (2)
1. Move bones.
| 2. Move organs that contain muscle tissue (such as the heart and stomach).
33
What organs are part of your integumentary system? (1)
1. Skin.
34
What are the functions of your integumentary system? (2)
1. Protects the body's internal environment from the external environment.
2. Senses pain, pressure, and temperature.
35
What are your organ systems called? (8)
1. Circulatory system.
2. Respiratory system.
3. Digestive system.
4. Nervous system.
5. Excretory system.
6. Skeletal system.
7. Muscular system.
8. Integumentary system.
36
What is the smallest known functioning unit of life?
A cell.
37
What do cells make up?
cells --> tissues
tissues --> organs
organs --> organ systems
38
Define organelle.
A specialized structure that carries out specific functions found within a cell.
39
What are the parts of a cell? (7)
1. Nucleus.
2. Mitochondria.
3. Cell membrane.
4. Vacuoles.
5. Cytoplasm.
6. Cell wall.
7. Chloroplasts.
40
Which organelles are found in a plant cell but not in an animal cell?
Which organelle does an animal have several of, but a plant only has one of?
A cell wall and chloroplasts are only found within plant cells.
Animal cells have several small vacuoles, while a plant cell has one large one.
41
What is the function of the nucleus?
Directs all cellular activities such as movement, growth, and other life functions.
42
What is the nucleus also known as?
A "command centre".
43
What is the function of the mitochondria?
Chemical reactions occur here. They convert the energy the cell receives into a form it can use.
44
What are the mitochondria also known as?
The "powerhouses" of the cell.
45
What is the function of the cell membrane?
Lets needed materials in and waste materials out.
46
What is the cell membrane also known as?
A "controllable gateway".
47
What is the function of the vacuole(s)?
Nutrients, water, or other substances can be stored here by the cell.
48
What is the vacuole also known as?
The "storage room".
49
What is the function of the cytoplasm?
Contains the nutrients required by the cell to maintain its life processes.
50
What is the cytoplasm also known as?
The "kitchen" of the cell.
51
What is the function of the cell wall?
It provides strength and support.
52
What is the cell wall also known as?
The "frame" of the cell.
53
What is the function of chloroplasts?
Carry out photosynthesis, converting the sun's energy into food for the cell.
54
What are chloroplasts also known as?
The "solar panels" of the cell.
55
Define multicellular.
An organism that is made up of two or more cells.
56
What are examples of multicellular organisms?
Plants and animals.
57
Define unicellular.
An organism that is made up of one cell.
58
What are two examples of unicellular organisms?
Most micro-organisms, such as mycoplasma, amoeba, and paramecium. Diatoms are single-celled plants.
59
What is an organism called that is made up of two or more cells?
Multicellular.
60
What is an organism called that is made up of one cell?
Unicellular.
61
There is a tendency to consider unicellular organisms as ___.
Simple.
62
Why is there a tendency to consider unicellular organisms as simple?
Because they lack the tissues and organs of more advanced creatures.
63
Is the idea that unicellular organisms are simple right? Why or why not? (5)
No. A single-celled organism can do most things that we need trillions of cells to do:
1. Eat.
2. Move.
3. React to stimuli.
4. Get rid of waste products.
5. Reproduce.
64
What is an amoeba?
Amoebas are common unicellular organisms that live in water.
65
How does an amoeba survive?
They move around using foot-like projections called pseudopods. They extend a pseudopod and the cytoplasm streams into it. Amoebas also use these pseudopods to capture food. The ends of the pseudopods fuse together and create a vacuole around the food particle. The food in the vacuole is digested and absorbed into the cytoplasm.
66
Define pseudopod.
They are foot-like projections that amoebas use to move and capture food.
67
How does a paramecium survive?
Paramecium move swiftly through the freshwater where they live. They are covered in hair-like structures called cilia, which move back and forth like oars to move them through the water. Cilia also help them gather food. On one side of the cell is a channel called an oral groove. It is lined with cilia, which sweep food to the bottom of the groove. There, the food enters a food vacuole, which moves into the cytoplasm, and the food inside is digested.
68
Define cilia.
They are hair-like structures that move back and forth like oars to move paramecium through the water and help them gather food.
69
Define oral groove.
A channel that is found on one side of the cell of a paramecium. It's lined with cilia, which sweep food to the bottom of the groove.
70
Define diffusion.
Moves particles from an area of high concentration to an area of low concentration. It's a "balancing out" or "evening out" process that continues until the concentration of particles is the same everywhere.
71
When it comes to diffusion, how does the cell membrane act? What is this called?
Like a filter with extremely tiny openings that allow some particles to pass through. This is called selectively permeable.
72
Define selectively permeable.
The cell membrane allows the particles of some substances to pass through it, but not others. Therefore, we say that the cell membrane is selectively permeable.
73
Why are the openings in the cell membrane so small? (2)
1. To keep the cell's cytoplasm and organelles inside.
| 2. To keep particles of most substances in the cell's external environment out.
74
Define osmosis.
The diffusion of water through a selectively permeable membrane.
75
What is the difference between diffusion and osmosis?
Osmosis is specifically the diffusion of water.
76
What does the survival of a cell depend on?
Its ability to balance water uptake and loss.
77
What happens if a cell does not have enough water?
It will shrink.
78
What happens if a cell has too much water?
It will swell.
79
What happens if a PLANT cell does not have enough water?
The cell shrinks inside the cell wall, causing the cell to lose its stiffness.
80
Who are the three people who are famous for developing microscopes? Where are they from? When?
1. Hans Lippershey (Germany, late 1500s)
2. Zacharas Janssen (Netherlands, late 1500s)
3. Galileo Galilei (Greek, early 1600s)
81
What identifies a compound light microscope? (2)
1. Multiple lenses.
| 2. A light.
82
What kind of microscope has multiple lenses and a light?
A compound light microscope.
83
What are the parts of a compound light microscope? (11)
1. Eyepiece.
2. Coarse adjustment knob.
3. Fine adjustment knob.
4. Revolving nosepiece.
5. Objective lenses.
6. Stage.
7. Stage clips.
8. Diaphragm.
9. Lamp.
10. Arm.
11. Base.
84
What does the eyepiece do?
Contains the lens that magnifies.
85
Which part of the microscope contains the lens that magnifies?
The eyepiece.
86
What does the coarse adjustment knob do?
Moves the stage up/down to focus on the object to produce a clear, sharp image.
87
Which part of the microscope moves the stage up/down to focus on the object to produce a clear, sharp image?
The coarse adjustment knob.
88
What does the fine adjustment knob do?
Brings the object into sharper focus.
89
Which part of the microscope brings the object into sharper focus?
The fine adjustment knob.
90
What does the revolving nosepiece do?
Holds the three objective lenses.
91
Which part of the microscope holds the three objective lenses?
The revolving nosepiece.
92
What do the objective lenses do?
Provide different strengths of magnification.
93
Which part of the microscope provides different strengths of magnification?
The objective lenses.
94
What does the stage do?
Supports the slide that holds the object you want to view.
95
Which part of the microscope supports the slide that holds the object you want to view?
The stage.
96
What do the stage clips do?
Hold the slide firmly on the stage.
97
Which part of the microscope holds the slide firmly on the stage?
The stage clips.
98
What does the diaphragm (of a microscope) do?
Has different-sized holes that let different amounts of light pass through the object.
99
Which part of the microscope has different-sized holes that let different amounts of light pass through the object?
The diaphragm.
100
What does the lamp do?
Supplies the light that passes through the object.
101
Which part of the microscope supplies the light that passes through the object?
The lamp.
102
What does the arm (of a microscope) do?
Allows you to carry the microscope securely.
103
Which part of the microscope allows you to carry the microscope securely?
The arm.
104
What does the base do?
Serves as a foundation for the rest of the microscope.
105
Which part of the microscope serves as a foundation for the rest of the microscope?
The base.
106
Why are unicellular organisms tiny?
There are limits to how large they can grow. One of the reasons involves diffusion and osmosis. These vital processes work well only over very short distances. Your body cells also reproduce to repair tissues that get damaged.
107
Why do unicellular organisms reproduce?
When unicellular organisms reach the limits of their size they reproduce. Amoeba do this by dividing into two, which results in smaller, identical copies of each organism.
108
Define specialized cells.
This means that there are various kinds of cells, and each kind carries out a specific function or functions needed to support life.
109
What kind of cells are multicellular organisms made up of?
Specialized cells.
110
What do red blood cells do?
Carry oxygen to all cells of your body. The red blood cells often must travel through extremely small blood vessels. Their thin, pliable disc shape enables them to do this.
111
What does marrow do?
The only way your body can make more red blood cells is by relying on specialized tissues in another body system. Most bones of the skeletal system contain a type of connective tissue called marrow, with specialized cells that make red blood ceels.
112
Define specialization.
The cells of a multicellular organism work together to support their own lives, as well as the life of the whole individual.
113
What are the types of animal tissues? (4)
1. Connective tissue.
2. Epithelial tissue.
3. Muscle tissue.
4. Nervous tissue.
114
What does the connective tissue do? (1)
1. Supports and connects different parts of the body.
115
What does the epithelial tissue do? (2)
1. Covers the surface of your body and the outside of your organs.
2. Lines the inside of some of your organs such as the intestine.
116
What does the muscle tissue do? (3)
Allow you to move.
1. One type of muscle allows you to move your body.
2. Cardiac muscle tissue pumps blood through your heart.
3. Smooth muscle moves food along your intestine.
117
What does the nervous tissue do? (1)
Makes up the brain, spinal cord, and nerves.
118
What does the connective tissue include? (5)
1. Blood.
2. Fat.
3. Cartilage.
4. Bones.
5. Tendons.
119
What are the types of plant tissues? (3)
1. Photosynthetic/storage.
2. Protective.
3. Transport.
120
How are tissues organized in plants?
Organized into the three organs that make up plants.
121
What are the three organs that make up plants?
1. Leaves.
2. Roots.
3. Stems.
122
What ability must organ systems have?
To react to changes both within and outside your body to maintain life.
123
How do your body's organ systems work together?
They depend strongly on one on another and interact as a single unit to carry out all the functions that are vital to your survival.
124
Explain what organs the heart works with and how. (5)
1. Lungs: heart pumps carbon dioxide to the lungs and lungs pump oxygen to the heart.
2. Muscles: muscles pump the heart.
3. Brain: brain controls the heartbeat.
4. Stomach: heart sends body nutrients to the stomach.
5. Kidneys: kidneys remove wastes from blood.
125
What does the digestive system do to aid your survival? (2)
1. Living organisms require energy to survive. They obtain energy from different sources such as carbohydrates (sugars and starches), lipids (fats and oils), and proteins -> they must be processed by your digestive system.
2. Your digestive system is in charge of breaking down the food you eat into parts small enough to be used by your cells.
126
What are the types of digestion? (2)
1. Mechanical digestion.
| 2. Chemical digestion.
127
What is mechanical digestion?
Involves the physical breakdown of food into very small pieces.
128
What is chemical digestion?
Involves the breakdown of large particles into smaller particles by substances called enzymes.
129
Where are the salivary glands?
1. In your mouth below your bottom row of teeth.
| 2. In the back roof of the mouth.
130
Where is the epiglottis?
On the windpipe.
131
Where does digestion begin?
In the mouth.
132
What happens in the mouth during digestion?
Teeth mechanically digest the food by grinding it and mixing it with saliva. Three pairs of salivary glands located in the tissues surrounding your mouth produce saliva -> water is used to moisten food, making the food easier to swallow. It also contains an enzyme that chemically digests large starch molecules into smaller sugar molecules.
133
What are the enzymes found in the saliva called?
Amylase.
134
What is amylase?
The type of enzyme found in saliva.
135
Define peristalsis.
Caused by contractions of muscle tissue that lines the esophagus. This is what moves the food down the esophagus.
136
Explain where the food goes after the mouth.
When you are ready to swallow, your tongue pushes food to the back of your throat. As you swallow, a flap of skin called the epiglottis moves across your windpipe, and food is funneled into the ESOPHAGUS. The food moves down by a wave-like movement called peristalsis.
137
Where does the food go after the esophagus?
The stomach.
138
How does the stomach respond to the stimulus of the arrival of food? (2)
1. Muscular wall churns the food back and forth, mixing it with gastric juices.
2. The gastric juices chemically break down food.
139
How does the chemical digestion in the stomach continue? (2)
1. Digestive enzymes from the pancreas and the small intestine complete the breakdown of starch and proteins into very small particles.
2. The liver produces bile (stored in the gall bladder, and, thus, released by the gall bladder).
140
Where does food go after the stomach?
The small intestine.
141
What happens in the small intestine during digestion? (3)
1. Sends it to the small intestine where it breaks up large globules of lipids (fat) into much smaller droplets.
2. The small intestine absorbs these particles using villi. The nutrients are then transferred to the bloodstream.
3. The cells of the epithelial tissue have modified cell membranes that form more finger-like projections called microvilli. Microvilli further increase the surface area of the small intestine to help absorb nutrients.
142
Define villi.
Small finger-like projections which line the inside of the small intestine.
143
Define microvilli.
Smaller finger-like projections.
144
Where does food go after the small intestine?
The large intestine?
145
What happens in the large intestine during digestion? (3)
1. When the food arrives, mechanical and chemical digestion is complete.
2. The large intestine absorbs water, along with some vitamins and minerals.
3. Any food that has not been digested is formed into feces, which is collected into the rectum.
146
Where does food go after the large intestine?
The rectum.
147
What do your rib and diaphragm muscles do during breathing?
INHALE: these muscles contract, pulling your ribs up, and your diaphragm down; pulling air into your lungs, and making room for them to expand.
EXHALE: these muscles relax; your ribs go down and your diaphragm goes up. This decreases the size of your chest and lungs, forcing air out.
148
What is the first step in the gas exchange process?
The respiratory system draws oxygen-rich air into the lungs through bronchi.
149
Define bronchi.
Tube-like passageways through which oxygen-rich air is drawn into the lungs.
150
What is the second step in the gas exchange process?
Bronchi are lined with tough connective tissue to keep the walls from collapsing. These bronchi narrow to bronchioles that end in about 600 000 000 alveoli. The alveoli are made of specialized epithelial tissue, only one cell layer thick.
151
Define alveoli.
Tiny, air-filled sacs in which bronchioles end.
152
What is the third step of the gas exchange process?
The air in the alveoli has a high concentration of oxygen and a low concentration of carbon dioxide. The blood in the capillaries surrounding the alveoli has a low concentration of oxygen and a high concentration of carbon dioxide. So oxygen naturally diffuses from the alveoli into the capillaries, and carbon dioxide naturally diffuses in the other direction.
153
What is another name for the windpipe?
Trachea.
154
What is O2?
Oxygen.
155
What is CO2?
Carbon dioxide.
156
Which two organ systems have most to do with one another?
The circulatory system and respiratory system.
157
What are the main jobs of the circulatory system? (2)
1. Deliver nutrients absorbed by your digestive system to each cell in your body.
2. Transport oxygen to your cells and remove waste products.
158
What does the heart consist of?
Two pumps.
159
What is the job of the right side of your heart?
The right side of the heart pumps blood to your lungs ( where it receives fresh oxygen and gives off carbon dioxide).
160
What is the job of the left side of your heart?
The left side of your heart receives this oxygen-rich blood from your lungs and pumps it to all the other parts of your body.
161
Which side of your heart pumps blood to the lungs?
Right side.
162
Which side of your heart pumps blood to the rest of the body?
Left side.
163
Define atria.
The top two chambers on each side of your heart.
164
Define ventricle.
The bottom two chambers in the heart.
165
What does the aorta do?
The aorta carries blood from the left ventricle to the body.
166
What does the right atrium do?
It receives blood low in oxygen from the body and pumps it into the right ventricle.
167
What does the right ventricle do?
When it contracts, it pumps blood to the lungs.
168
What does the left atrium do?
It receives oxygen-rich blood from the lungs and pumps it into the left ventricle.
169
What does the left ventricle do?
When it contracts, it pumps blood to the body.
170
How many chambers are there in the heart?
Four.
171
Define arteries.
The vessels that carry blood away from your heart to all the parts of your body.
172
Define veins.
The vessels through which blood is returned from your body to the heart.
173
What types of tissue are blood vessels made up of? Where are these tissues located? (3)
1. Connective - outside.
2. Muscle - middle.
3. Epithelial - inside.
174
What is a pulse?
Arteries have a thick muscular layer in the middle that expands and contracts to help push blood along - this expansion of your arteries is a pulse.
175
How are veins built differently and why?
Veins are thinner and have valves. The valves stop the blood from flowing backward.
176
What roles does diffusion play in the circulatory system? (2)
1. Diffusion is responsible for transporting oxygen from your air into your blood and carbon dioxide from your blood into your air.
2. Transports some nutrients from your small intestines to your blood.
177
Define capillaries.
Specialized blood vessels are located between arteries and veins, in which the diffusion of nutrients and gases occurs.
178
What are the adaptations of capillaries? (2)
1. They are made of specialized epithelial tissue that is only one cell layer thick.
2. They are very narrow so the blood cells must pass through in a single file.
179
What do the adaptations of the capillaries help them do?
Their adaptations help with exchanging gases and nutrients.
180
What is the second-largest example of connective tissue in your body?
Your blood.
181
What does blood consists of? (4)
1. Red blood cells.
2. White blood cells.
3. Platelets.
4. Plasma.
182
How much of your blood is plasma?
55%.
183
What is the liquid portion of blood?
Plasma.
184
What is the most major contributor to your blood?
The plasma.
185
How much of your blood is platelets/red blood cells/white blood cells?
45%.
186
What do red blood cells do?
They have the specialized function of carrying oxygen.
187
What are the adaptations of red blood cells and what do they let them do? (2)
1. To carry the most oxygen possible, mature red blood cells have no nuclei, which makes more room for oxygen.
2. Red blood cells are very flexible, allowing them to bend and twist through the tight spaces of your capillaries.
188
What do white blood cells do?
White blood cells are specialized to fight infection. Some of them are capable of eating bacteria at infection sites such as cuts.
189
What do platelets do?
Platelets are cells that help to stop the bleeding at cuts.
190
What does plasma do? (2)
1. Transports nutrients to your cells.
| 2. Carries wastes such as carbon dioxide.
191
Define excretion.
Waste removal; the body produces a number of different types of wastes that are poisonous, and, if not removed from the body, can cause serious harm.
192
Does the excretory system get rid of wastes?
The excretory system involves organs from other systems - different organ systems interact to get rid of wastes.
193
What happens when cells break down proteins?
They produce ammonia.
194
Define ammonia.
A very toxic compound.
195
What is one way the body produces ammonia?
When cells break down proteins.
196
What do chemical processes in the cells produce?
Water and salts as waste products.
197
What are three examples of waste products that the excretory system has to deal with?
1. Ammonia.
2. Salts.
3. Water.
198
What does the liver do with regard to excretion? (3 steps)
1. It takes the highly toxic ammonia produced by the body's cells out of the bloodstream.
2. Converts it into urea.
3. Since urea still has to be disposed of, the liver releases it into the bloodstream.
199
Define urea.
A less harmful substance (not harmless) that is formed when the liver converts ammonia.
200
What are the main organs of excretion?
The kidneys.
201
How do kidneys act?
As filters to the blood.
202
What do the kidneys do?
They strain out the unwanted urea, water, and other salts, and they produce urine.
203
How often is your blood filtered?
Every drop is filtered about 300 times a day by the kidneys.
204
How much urine do humans produce on average (daily)?
1.5L.
205
Explain how come the amount of urine you produce depends on how much water you drink.
The kidneys keep the proper amount of water in your blood. If there is too much water, they excrete lots of water and so produce a lot of urine.
206
What is the first step of the formation of urine?
First, blood enters the kidney by the renal artery. The artery branches into smaller and smaller vessels. These small capillaries enter filtering units called nephrons.
207
Define nephron.
They are filtering units within the kidney.
208
What is the second step of the formation of urine?
The nephrons remove wastes from the blood and produce urine.
209
What is the third step of the formation of urine?
The "clean" filtered blood return to the body through the renal vein, whereas the urine flows out a separate vessel and into the ureter.
210
Define ureter.
Long tubes that connect the kidneys to the bladder.
211
What is the bladder?
A sac covered in muscle tissue.
212
Where does urine go after the ureter? What happens?
As the urine enters the BLADDER, the bladder expands. When it is full, the bladder muscles contract and push the urine out through the urethra.
213
What does your skin do to contribute to excretion?
Your skin has thousands of sweat glands just below the surface. In addition to producing sweat to keep you cool, these glands remove excess salts from your body.
214
What can urine reveal?
Diseases; doctors can determine if you have certain diseases by testing your urine.
215
What are two examples of diseases urine can reveal?
1. Patients whose kidneys are failing often have protein in their urine because their kidneys have lost the ability to filter blood properly.
2. People who have diabetes will often have glucose in their urine. Their cells cannot absorb glucose, and glucose builds up in the bloodstream. Because the blood has so much glucose, the nephrons filter it out and add it to the urine.
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How can people whose kidneys don't function well still lead normal lives?
With a dialysis machine.
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What happens when a person undergoes dialysis?
The person's blood flows into special tubing inside the machine made of selectively permeable material. This allows only certain substances to diffuse through it. This tubing is surrounded by fluids. Wastes from the blood diffuse out of the blood into the fluid, and certain substances from the fluid diffuse into the blood. The blood then flows back into the person.
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How long does it take for a dialysis machine to fully clean the blood?
4-6 hours.
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Define stimulus.
A change in your environment.
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Stimuli can occur in many forms, such as... (6)
1. Pressure.
2. Heat.
3. Cold.
4. Light.
5. Sound.
6. Body chemistry.
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Stimuli can be what?
External or internal.
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What is the relationship between the nervous system and stimuli?
It is the job of the nervous system to monitor and respond to stimuli.
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What is the nervous system mostly made up of?
Nervous tissue.
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What is nervous tissue made up of?
Neurons.
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Define neurons.
Specialized cells that make up nervous tissue.
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What is a neuron's job?
To send and receive messages.
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How does a neuron receive messages?
A neuron receives messages from small branches of the cell called dendrites. The incoming messages are passed down from the dendrites through the cell body to the axon. The axon's branches transmit the message to the dendrites of neighbouring nerve cells.
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Define dendrites.
Small branches of neuron cells.
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Define axon.
A long extension of the neuron cell that ends in small branches.
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What are the most important parts of the nervous system? (2)
1. The central nervous system.
| 2. The peripheral nervous system.
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What does cranial mean?
Head.
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What does the central nervous system make up?
The central nervous system is composed of the brain and spinal cord.
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What does the peripheral nervous system make up?
The peripheral nervous system is made up of the cranial (head) and spinal nerves.
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What are the types of neurons that play a role in the peripheral nervous system? (2)
1. Sensory neurons.
| 2. Motor neurons.
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What do the sensory and motor neurons make up?
Each nerve of the peripheral nervous system.
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What do sensory neurons do?
Carry information from the body to the central nervous system.
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What do motor neurons do?
Carry information from the central nervous system to muscles or organs.
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What can the peripheral nervous system be divided between? (2)
1. Somatic nervous system.
| 2. Autonomic nervous system.
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STOP!
Take 15 seconds to breathe. You're amazing!
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STOP!
You got this. Make sure you go for a walk today.
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STOP!
Grab a drink and sit down for a few minutes. You need a break. You're doing great.
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STOP!
Turn off your device and listen to a few songs. Don't push yourself too hard. You'll rock this!
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What does the somatic nervous system do? Provide an example.
Conscious control over your responses to stimuli - these voluntary responses are controlled by the somatic nervous system.
For example: when you hear a noise, you can decide whether or not to turn your head to see what caused it.
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What does the autonomic nervous system do? Provide an example.
Unconscious control over your responses to stimuli - you don't have to think about it. These automatic responses are controlled by the autonomic nervous system.
For example: your body automatically adjusts the size of your pupils, your hert rate, blood pressure, breathing rate, and peristalsis in your digestive system.
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What is the role of the central nervous system?
The brain receives stimuli from the outside world as well as receives internal stimuli from the body itself and sends messages to the appropriate body parts.
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What are the main sections of the brain? (3)
1. The cerebrum.
2. The cerebellum.
3. The medulla.
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What connects the brain to the peripheral nervous system?
The spinal cord.
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Which section of the brain is the cerebrum?
The large upper part.
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Which part of the brain is the large upper part?
The cerebrum.
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Which part of the brain is the cerebellum?
The middle portion.
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Which part of the brain is the middle portion?
The cerebellum.
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Which part of the brain is the medulla?
The stem.
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Which part of the brain is the stem?
The medulla.
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What is the cerebrum responsible for processing? (8)
1. Hearing.
2. Smelling.
3. Tasting.
4. Talking.
5. Thinking.
6. Moving.
7. Touching.
8. Seeing.
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What is the cerebellum responsible for processing?
Balancing.
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What is the medulla responsible for processing? (2)
1. Breathing.
| 2. The beating of the heart.
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Define interneuron.
A type of neuron that connects one neuron to another.
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How does the spinal cord act? What does it contain?
The spinal cord connects the brain to the peripheral nervous system and it acts as a highway for messages between the brain and body. It contains interneurons.
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Define reflex.
An automatic response by the nervous system to an external stimulus. Sensory and motor neurons work together without involving the brain.
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Example: you accidentally touch a red-hot element on the stove. What is the stimulus?
The intense heat.
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Example: you accidentally touch a red-hot element on the stove. What is the first step of a reflex?
Sensory nerves in your hand react to the stimulus by sending nerve impulses to the spinal cord.
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Example: you accidentally touch a red-hot element on the stove. Sensory nerves have sent nerve impulses to the spinal cord. What now?
Interneurons relay the message to the motor neurons.
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Example: you accidentally touch a red-hot element on the stove. Motor neurons have been alerted. What now?
The impulse travels to the muscles of your arm, which quickly contract to remove your hand from the element.
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Example: you accidentally touch a red-hot element on the stove. Your hand has been removed from the stove. What now?
The sensory neurons also send a message to your brain. But, by the time the message gets there and your brain decides to react, your hand is already off the element. Reflexes protect you from injury by reducing the time it takes to react to harmful stimuli.
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What is special about touch from vision, hearing, smell, and taste?
It is not found in one specific place. The sense of touch is found in all areas of your skin, making it the largest sense organ.
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What parts of your body have the most amount of touch receptors?
Mouth, hands, and feet.
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What is special about the mouth, hands, and feet?
They have the most amount of touch receptors.
