The Human Digestive System
Function : to break down _food__ into a __usable__ form; large organic molecules into small
organic molecules
Corresponding Life Process/Function : ____nutrition________
Corresponding Cell Organelle : _vacuole and lysosome____
Picture/Diagram of :
1. mechanical digestion :
chewing/churning food
into smaller pieces =
increase surface area for
faster enzyme action
gall
bladder
pancreas
2. chemical digestion :
hydrolysis of carbohydrates,
proteins and lipids using
digestive enzymes; nutrients
end in a form that can be
absorbed into the blood and
used by the cells
3. absorption : nutrients
absorbed into the blood
through the villi by the
process of diffusion
They travel to the cells
where they can be used
to carry out metabolic
activities.
Important Organs :
In the digestive tube :
mouth  _esophagus__  __stomach__  _small intestine__  _large intestine___  _rectum__  anus
Accessory organs (important, but not part of the tube): salivary glands, _liver___, _gall bladder_,
pancreas
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A Closer Look : Small Intestine
 Completes _chemical digestion_
 Absorbs _nutrients__ into _blood___
Villi - _finger_-like projections where _absorption__ occurs
Following the completion of _chemical_digestion, there is a high
Figure 1. A Villus
concentration of _nutrients__(amino acids, sugars, fatty acids, etc…) in the small intestine. These nutrients
are _absorbed_ into the blood/lymph by _diffusion_, moving from high concentration to low
concentration. The blood then transports these building blocks to our cell’s, where they are used to build
(_synthesize_) new organic compounds or to make _energy (ATP)_ during cell respiration.
The digestive system works with the : _circulatory system__
Describe relationship :
The _nutrients_ in the _small intestine_ are absorbed into the _blood_, which _transports__ them to
the body cells
The digestive system works with the: _respiratory system__
Describe relationship :
_Respiratory_ system provides _oxygen__ and the _digestive__ system supplies _glucose_. These
are the _reactants__ needed for _respiration_ to occur (_ATP__ production)
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The Human Respiratory System
Function : __Trading oxygen and carbon dioxide between the external
environment and the lungs
Corresponding Life Process/Function : _gas exchange_
The process of gas exchange should not be confused with _cell respiration_, the energy-releasing reactions that occur within
the mitochondria of the cell.
Corresponding Cell Organelle : _cell membrane_
The Respiratory Surface
The respiratory surface is the place in the organism where gas exchange occurs. A respiratory surface must have the
following characteristics :

_thin, one-cell_____

_moist_____

_large surface area____

_contact with oxygen___
Gas exchange takes place by _diffusion__ - the movement of molecules from areas of high concentration to areas of
low concentration. An _increase_ in the surface area of the respiratory surface will increase_ the rate of gas
exchange.
Picture/Diagram of :
Nasal cavity
pharynx
larynx
trachea
bronchi
lung
bronchioles
alveoli
diaphragm
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The diagram to the right is a single
alveolus (air sac) in the lung. There are
millions of these alveoli in the lung.
Why is this important?
_Increase the surface area
_for diffusion_____
What structures surround each alveolus?
_capillaries___
To what body system do these structures belong?
_circulatory system___
There is a high concentration of _oxygen___ in the alveoli and a _low____ concentration of oxygen in the blood.
Therefore, oxygen will _leave__ the alveoli by the process of _diffusion___. At the same time, there is a _high_
concentration of _carbon dioxide_ in the blood and a low concentration of CO2 in the alveoli. As a result, CO2 will
_enter__ the alveoli by diffusion.
The respiratory system works with the _circulatory system___
Description: transports the O2 from the lungs to body cells and CO2 from cells to lungs.
The respiratory system works with the excretory system_____
Description: lungs act as an excretory organ and remove CO2.
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The Excretory System
Function : _Removal of cell (metabolic wastes) from the body
Life Process : excretion___
Cell Organelle(s) : vacuole, cell membrane
Types of Metabolic Wastes
METABOLIC WASTES
HOW PRODUCED
Water
Respiration, dehydration synthesis
Carbon dioxide
respiration
Salts
metabolism
Urea
Protein metabolism
Describe the role of blood in excretion.
Transports wastes from body cells to kidneys
I. Diagram of the Excretory System
Renal vein
Renal artery
urethra
ureters
renal artery
renal vein
kidney
urinary bladder
Kidney
ureter
Urinary bladder
urethra
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II. Organs of Excretion
1) Skin
_water__,_salts__ and _urea___
exit the body when you SWEAT.
2) Lungs
The lungs excrete _carbon dioxide__ and _water__,
which are both waste products of aerobic _respiration__.
3) Liver - Functions of the Liver :
1) Production of Urea
What is urea? What end products of digestion are broken down to make urea?
Urea is the waste product formed by the breakdown of excess amino acids in the liver.
4) The Urinary (excretory) System
Organ
renal arteries
Function(s)
Blood carrying wastes enters the kidneys
kidneys
filter wastes out of blood to make urine; maintain water balance & blood
pH
ureters
tubes that carry urine to the bladder
urinary bladder Stores urine
urethra
renal veins
tube where urine exits the body
“clean” blood (no wastes) leaves the kidneys to re-circulate around the body
The functional units of the kidneys are called NEPHRONS. There are millions of these
microscopic structures in each kidney. The nephrons filter the blood, return useful
substances to the blood and collect urine.
The excretory system works with the : __circulatory system_____
Describe relationship :
___the blood carries wastes to the kidneys to be removed;
__it returns the cleaned blood back to the body
The excretory system works with the: __respiratory system_
Describe relationship :
___the lungs excrete CO2 - one of the waste products of cell respiration
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The Human Circulatory System
Function : ___transports nutrients, gases, and wastes to all cells of the body__
Corresponding Life Process/Function : _transport___
Why do most animals require a circulatory system ?
Large organisms whose cells are not in contact with the external environment need a system to move
materials.
Corresponding Cell Organelle(s) : __Endoplasmic Reticulum (ER)____
Humans have a CLOSED circulatory system consisting of three parts:

__Arteries _______

__veins ____

__capillaries______
Like other relatively large, multicellular organisms, plants require a means of transporting materials. In plants,
__xylem_____ tissue carries water from the roots to the stems and _phloem___ tissue carries food (sucrose) from the
leaves to the stems and roots.
The Blood Vessels
1. Arteries
a. __transport oxygenated blood______
EXCEPTION : pulmonary arteries
b. _transport blood AWAY from heart_______
c. branch into smaller tubes called arterioles
d. A person’s heart rate can be measured by taking their _pulse__.
The pulse is created by the pressure of the blood against the artery walls as the
heart pumps. The blood in the arteries is under relatively HIGH pressure. It can be detected where
arteries lie close to the surface of the body  side of neck or wrist.
e. The largest artery is the __aorta__.
The picture to the left shows an artery and
the buildup of cholesterol in the artery. This
buildup leads to many types of
cardiovascular disease, including
arteriosclerosis, high blood pressure, heart
attack and stroke.
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2. Capillaries
a. ___one cell thick_______
b. ___exchange of nutrients, gases, and wastes_____
The capillaries are microscopic  therefore, they come into contact with EVERY CELL in the
body. The exchange of materials between the blood and the body cells is usually
accomplished using ___DIFFUSION_____.
Ex Examples :
 capillaries in the small intestine (villi)
to absorb nutrients

capillaries in the lungs (alveoli) to
absorb oxygen; release CO2

capillaries in the kidneys filter wastes
and reabsorb glucose, H2O
3. Veins
a. __carry deoxygenated blood______
EXCEPTION : pulmonary veins
b. ___carry blood to the heart____
c. branch into smaller tubes called venules
d. Blood in the veins is under relatively low pressure. Therefore, veins contain
__valves__ that prevent the blood from flowing backwards 
They keep the blood moving in one direction!
e. The largest veins are the __vena cava___.
The picture on the left shows a normal
vein – note the valves that are preventing
the blood from flowing backwards.
A varicose vein is pictured on the right.
Your veins may stretch if you repeatedly sit
or stand for a long time. This stretching can
sometimes weaken the walls of your veins
and damage your vein valves, especially in
people who are susceptible to this problem.
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The Heart
The heart is the _”pump”___ in the circulatory system. It contains a special kind of muscle
tissue called ___cardiac_ muscle, that has the ability to “beat” on its own.
The heart has four chambers:
(a) There are two _atria___ which are thin-walled receiving chambers at the top of the heart.
(b) There are two _venticles___ which are thick, muscular chambers that pump blood away from
the heart back to body cells.
(c) There are __valves__ between each atrium and ventricle, as well as between each ventricle
and corresponding blood vessel.
(d) The _septum__ is the wall that separates the two sides of the heart and prevents oxygenated
blood from mixing with deoxygenated blood.
(e) The heart is an __involuntary__ muscle  it is controlled by signals
from the brain (medulla) ,
as well as from the heart’s _pacemaker___, or S-A node.
Diagram of the Human Heart
Key
red = blood with oxygen
bue = blood without oxygen
arrows represent the direction of blood flow through the heart
Pulmonary arteries
Pulmonary veins
aorta
Left atrium
Superior vena
cava
Right atrium
Left ventricle
Inferior vena
cava
Right ventricle
J
septum
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