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Chapter 9 Notes: Life Functions Common to Living Things
9.1 Life Functions Common All Living Things
-life functions (aka life processes) – seven activities carried out by cells and organ systems
1. transportation
2. nutrition
3. growth and repair
4. reproduction
5. regulation
6. metabolism
7. synthesis
-Cells and Tissues are Specialized
-recall: cells, tissues, organs and systems work together to keep an organism alive
-each is built in a specific way to help perform its function (i.e. they are specialized)
-Example
-digestive system contains all of the organs necessary to take food and change it
into a form that can be used
-plant’s root system includes a primary root, secondary roots, and root hairs –
brings in water and nutrients into the plant from its environment
**BLM 9-1, 9-2
9.2 Photosynthesis and Cellular Respiration
-all plants and animals need a continual supply of energy to grow and function
-animals obtain energy from food, plants make their own food in photosynthesis
-cellular respiration – food produced in photosynthesis goes through a chemical change and
releases energy – used both by plants and animals
-Storing Plant Food
-plants use light energy (from the Sun), along with CO2 and H2O to make glucose
-a by-product is oxygen which is released from leaves into the air
-any food not used immediately by the plant is stored and used later
-extra food is stored in a number of parts of a plant (see p. 184 table 9.1)
-Cellular Respiration
-potential energy stores in food are converted to other forms of energy (takes place in
the cells’ mitochondria)
-mitochondria – “powerplant” – convert energy from food into forms of energy
that can be used for growth and to perform functions
-about half of energy from glucose is released into the body as thermal/heat
energy – other half is used to carry out life functions
-food (glucose) is broken down to produce energy that cells can use
-cell resp needs oxygen – as glucose is used, it gradually breaks down to
produce CO2 and H2O which can be released into the air
-recall: photosynthesis stores energy
-cellular respiration releases energy
http://www.teachertube.com/viewVideo.php?video_id=159339
**BLM 9-7
9.3 Human Organ Systems
-the human body is like a machine
-it can perform the following functions:
-pump fluids for years and years without stopping
-release energy from food
-eliminate wastes
-send messages
-reproduce itself or parts of itself
-the body has many different systems to help perform these functions
Digestive System
-breaks down and digests food (change the food you eat into simple chemical
compounds (nutrients) that can enter the cells – uses the nutrients for energy, growth,
and repair (main nutrients are carbohydrates, proteins, fats, vitamins, minerals and
water)
-rids the body of solid waste
mouth — where food enters body; contains teeth and salivary glands
teeth — chew food into smaller pieces for swallowing
salivary glands — moisten food with enzymes that begin chemical breakdown
esophagus — pushes food to stomach through wave-like muscle spasms
stomach — muscles contract to mix food; releases acids that activate chemicals to
digest food; dissolves food into liquid form
small intestine — has chemicals to digest food; neutralizes stomach acid; absorbs 80
to 90 percent of nutrients
large intestine — absorbs vitamins, minerals, and water
gall bladder — stores bile
pancreas — provides most digestive enzymes; produces insulin to extract nutrients
from food
rectum — stores solid waste (undigested food)
anus — discharges solid mass of undigested food called feces
Nervous System
-provides a communication network
-regulates life functions
Circulatory System – moves blood throughout the body
-heart – pumps blood
-blood is pumped from the heart and eventually comes
back to the heart
-arteries/veins – blood vessels that transport blood
-lungs -> heart -> arteries -> body tissues -> veins -> heart -> lungs -> heart
-blood transports the following substances
-food molecules
-oxygen
-carbon dioxide
-wastes
*BLM 9-12
Urinary System
-kidney filters blood that has collected wastes from cells and then transports these
wastes to the urinary bladder
-urinary bladder holds wastes until they are excreted through the urethra
Working together – Digestive and Circulatory Systems
1.
2.
3.
4.
5.
Nutrients enter bloodstream from digestive system through thin capillary walls
Circulatory system carries digested food substances to cells of the body
Nutrients travel around (over and through each cell)
Waste molecules pass from cells back into the bloodstream (through capillary walls)
Circulatory system helps dispose of waste products and toxic materials (such as salts)
*BLM 9-13
9.4 Keeping an Eye on Life Functions
-To make sure the body is working properly, doctors start by asking how we feel
-they also have special equipment to help them make observations
-blood pressure cuff – used to check blood pressure
-stethoscope – checks heart rate
-EKG – provides printed record of rate and pattern of heartbeat
-EEG – study of brain activity – records changes in brain activity
-CT scans – X-ray of the brain
-X-rays
-endoscope – allows doctors to see inside of hollow organs such as the stomach
Blood Pressure
-because the heart is a pump it contracts and pushes blood through the arteries
-blood is forced out under pressure (we can feel this wave of blood when we check our
pulse)
-pulse tells us how fast the heart is beating – it is an indication of how hard the heart is
working
-in order for blood to reach our hands and feet, it must be pumped out of the heart
under great pressure – this pressure can be measured using a blood pressure cuff
(sphygmomanometer)
-blood pressure reading comes as two numbers (i.e. 120 over 80) - the two numbers
show blood pressure at two different stages of your heart’s pumping cycle
-blood pressure rises and falls as the heart contracts to pump blood – when the heart
pumps, blood pressure rises sharply – provides a high blood pressure reading known as
systolic pressure
-when the heart relaxes (just before it contracts to pump again), blood pressure is at its
lowest – diastolic pressure