Transcript Cells and Systems Notes

UNIT 2
CELLS AND SYSTEMS
TOPIC 1 : LIVING ORGANISMS
Characteristics of Living Things
Scientists agree that living organisms have some of the following characteristics:
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They need energy.
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They respond and adapt to their environment.
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They reproduce.
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They grow.
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They produce wastes.
Functions and Structures
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In order to carry out the above functions, living things have different structures.
Basic Unit of all Living Things
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The basic unit of every system is a cell.
All living organisms are made of cells.
The cell is the most important characteristic that plants and animals share
Structures
On your own...think about and answer the following:
1. Name and explain 4 different structures for animals to
gather food.
2. Name and explain 4 different structures to help animals
respond to stimulus.
3. Name and explain 2 structures that animals have that
respond to physical activity.
4. Name and explain 4 structures that animals have to
communicate.
5. Name and explain 3 structures that animals have to
move.
TOPIC 2 : MICROSCOPES AND CELLS
Parts of the Microscope and function
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You need to label and describe what each part of a microscope does.
Early Microscopes
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Anton Van Leeuwenhoek created the first microscope.
Cell Theory
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All living things are composed of one or more cells
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Cells are the basic units of structure and function in all organisms
Microscopes Today
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Light Microscopes – The best can magnify up to 2000x
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Electron Microscopes – The best can magnify up to 2 000 000x. Beams of
electrons are used instead of light and displayed on a screen.
Take a break
TOPIC 3 : THE CELL AND ITS
STRUCTURES
Cells
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Living things are either:
a) Single cellular – Paramecium and viruses. These are smaller and less complex
organisms.
b) Multi cellular – Humans and plants. These are more complex organisms and
larger in size.
Cell parts
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Structures in a cell are called organelles.
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Each organelle has a role to play in the survival of the cell and organism.
Organization of multi cellular organisms (Organs, Systems, Tissue, Cells)
Cells
Tissue
Organs
Systems
Differences between Plant and Animal cells
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Plant cells have a cell wall and chloroplasts and animal cells don’t.
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Cell walls give the plant cell support (because they don’t have skeletons) and
chloroplasts are where photosynthesis occurs.
Why are cells so small?
Look on page 125 and try to answer in your own words, the reason that cells are
so small
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To carry out their work cells need oxygen, water and food. They must also
get rid of wastes.
These materials must enter the cell membrane, go to the middle and then
wastes must exit the membrane.
If a cell was very big, this process would take way too long and be difficult
to keep going. Large cells would also produce too much waste.
Growing bigger
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When organisms get bigger, they add more cells, the cells don’t actually get
bigger.
TOPIC 4 : FLUID MOVEMENT IN CELLS
Cell Membrane
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Materials move into the cell through the cell membrane by osmosis. Only
certain materials can move through the selectively permeable cell
membrane.
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In cells, nutrients move from an area of higher concentration outside the
cell to an area of lower concentration inside the cell. This is done by the
process of diffusion.
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Wastes then move from an area of higher concentration inside the cell to an
area of lower concentration outside the cell. This again is done by diffusion.
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Diffusion is when a substance moves from an area of higher concentration
to an area of low concentration.
TOPIC 5 : CELL SPECIALIZATION AND
ORGANIZATION
Specialized Cells
Multi celled organisms have many different cells that have different shapes
and perform different jobs.
Cell
Muscle Cell
Shape
Elongated
Function
Move body parts
Skin Cell
Flat and brick shaped
Form protective layer
Nerve Cell
Long and branch like
Deliver messages to body
Bone Cell
Thick walled
Provide support
Advantages of being Multi cellular
Multi celled organisms:
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Live in a wide variety of environments
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Can grow very large
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Obtain energy from many sources
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Have complex bodies
Organization of multi cellular organisms
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Cells with the same structure and function form tissue
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Tissue forms organs
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Organs work together and make systems
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Systems work together to form an organism
Take a break
TOPIC 6 : BODY SYSTEMS IN HUMANS
The Digestive System
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Food enters the body through the mouth
Food is broken down in the mouth, stomach and intestines
Unused food is expelled as waste
Digestive System Cartoon Assignment
Respiratory System
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We inhale and bring in oxygen
We exhale and get rid of waste carbon dioxide
The respiratory system is responsible for gas exchange
Respiratory System Drawing Assignment
Circulatory System
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The circulatory system transports food and oxygen through the body
Made of the heart, blood and blood vessels
Circulates blood around the body to deliver food particles, dissolved gas and other materials to
cells
Also takes away waste material from the cells
Circulatory System Drawing Assignment
Nervous System
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Coordinates and controls the actions of the organs and organ systems
Detects, processes and responds to stimuli in the environment
Excretory System
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Removes wastes from the system
Digestive System
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Mouth – Food broken down by chewing and chemical action of saliva.
Salivary Glands - Saliva contains enzymes that break down carbohydrates
into smaller molecules.
Esophagus - The esophagus is a long tube that uses rhythmic, wave-like
muscle movements (called peristalsis) to force food from the throat into
the stomach.
Stomach - Food in the stomach is partly digested and mixed with stomach
acids
Liver - Makes bile which breaks down fats and some blood proteins. Helps
the small intestine in digestion.
Gall Bladder - It stores and releases bile into the small intestine.
Pancreas - Enzymes from the pancreas help in the digestion of
carbohydrates, fats and proteins in the small intestine.
Small Intestine – bile, pancreatic enzymes, and other digestive enzymes
produced by the inner wall of the small intestine help in the breakdown of
food. Most food is absorbed here.
Large Intestine - The large intestine is responsible for absorption of water
and excretion of solid waste material.
Rectum – Feces are stored here.
Anus – Where feces exits the body.
Nervous System
1. Brain - It helps to control all of the body systems and organs, keeping them
working like they should. The brain also allows us to think, feel, remember
and imagine.
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Spinal Cord - The brain communicates with the rest of the body through the
spinal cord and the nerves. Information passed through the spine tells the
body what to do and when to do it.
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Nerve Cells - Neurons carry messages in the form of a electrical impulses.
The messages move from one neuron to another to keep the body
functioning.
Take a break
Excretory System
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Kidney – Cleans the blood of waste products. Waste is passed out your body
in urine.
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Ureter – Takes urine from the kidney to the bladder.
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Bladder – Stores urine until it is passed out the body in urine.
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Urethra – Urine passes from the bladder to the urethra on the way out of
the body.
Respiratory System
Larynx – Place where moving air being breathed in and out creates sounds
Trachea – This is the windpipe, or the passage leading from the mouth and
throat to the lungs
Lungs – The lungs perform respiration or gas exchange
Bronchi or Bronchus – The two main tubes of the lungs
Bronchioles – The smaller divisions of the bronchi
Alveolus – The very small air sacs where breathed in air goes
Diaphragm – Strong wall of muscle that separates the chest cavity from the
abdominal cavity
Circulatory System
Heart – The body’s blood is circulated throughout the body by the heart
Veins – Veins carry blood to the heart. Veins carry dark red blood that doesn’t
have much oxygen
Arteries – Arteries carry blood away from the heart. Arteries carry bright red
blood that is high in oxygen
Blood – Carries food and oxygen to cells as well as carrying wastes away from
cells. Blood also carries disease fighting white blood cells through the body.
It also helps maintain constant body temperature.
Take a break
TOPIC 7 : BODY SYSTEMS AND YOUR
HEALTH
Blood – Body’s Transportation System
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In multi-cellular organisms, substances must be brought to the cells and
this is done by the blood.
Blood also takes wastes away from the body’s cells.
Blood is made of:
Plasma - Liquid portion of blood that carry nutrients, waste products and
blood cells
Red Blood Cells – carry oxygen
White Blood Cells – defend body against infections and cause clotting to
stop bleeding
Platelets – Help stop bleeding by forming clots
A Healthy Circulatory System
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Living a health lifestyle keeps your circulatory system healthy
Disorders of the Circulatory System
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Disorders of this system are the leading cause of death in North America
High blood pressure and heart attacks are common disorders
Smoking, lack of exercise, poor diet and high cholesterol can lead to
circulatory disorders
A Healthy Digestive System
Important Nutrients in food that lead to a healthy digestive system:
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Carbohydrates provide the body with main source of energy
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Fats are essential as they provide us with energy and cushion our organs
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Proteins are essential for muscle growth and repair of tissues
Disorders of the Digestive System
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Cancers and ulcers are common disorders
A Healthy Respiratory System
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Surrounding yourself with healthy air inside and outside the house keeps
your respiratory system healthy
Disorders of the Respiratory System
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Bronchitis, emphysema, lung cancer and asthma are common disorders of
the respiratory system
Smoking and other air pollutants are the major causes of respiratory
disorders.