Transcript The Digestive and Excretory Systems

The Digestive and Excretory Systems
Objectives
• To list the organs of the digestive and excretory systems
• To describe the function of the organs of the digestive
and excretory system
• To compare and contrast the digestive and excretory
systems
• To explain how the digestive and excretory systems relate
to each other as well as in relation to other body systms
Components
•
•
•
•
•
•
•
Esophagus
Stomach
Small Intestine
Large Intestine
Gall bladder
Liver
Pancreas
Digestive System
• This system is responsible for breaking down
food into a useable form of energy for the
body
Alimentary Canal
• Path food travels through the body (your
digestive tract)
– From mouth to the anus
Organs of the Digestive system
• Mouth
– Digestion starts here
– Mechanically breaks down food by the chewing
mechanism
• Chewing is called mastication
– Here there are enzymes (present in saliva) that
also aid in the break down of food
• Enzymes are chemicals that simply break up
particles/bacteria/viruses… etc
– Words ending in –ase are usually enzymes
Esophagus
Stomach
Esophagus
• the tube that connects your
mouth and your stomach
• You have a trap door called the
epiglottis to cover your windpipe
when you swallow.
Organs of the Digestive System
• Esophagus- muscular tube through which
food travels to the stomach
– Food moves along the digestive system by means
of a muscular movement called peristalsis
• Peristalsis is an involuntary contraction (and relaxation)
of muscles in the digestive system that moves food
along the alimentary canal
– At the beginning of the esophagus is a small flap
(or gate-like structure) called the epiglottis that
closes off the entrance to the trachea when you
swallow
Peristalsis
11
Stomach
• A stretchy bag that
holds your food
after you eat
• Helps to break food
into smaller pieces
so your body can
use it for energy and
nutrition
Organs
• Stomach- muscular organ responsible for the
further breakdown of nutrients
– Mixing chamber and storage chamber
• Chemical break down through stomach acid
• Mechanical break down through churning/mixing
– No food is absorbed through the stomach wall
(which is coated with mucus to prevent the
stomach acid from “eating through” itself)
Small
Intestine
Small Intestine
• Tube that is 20 feet long.
• Continues to digest food
• Food stays in your small intestine for 4 to
8 hours
Organs
• Small intestine- chemical digestion continues
here; in fact, most of the chemical digestion
occurs here along with NUTRIENT
ABSORPTION!
– From ~15 to 32 feet
• Average 17 feet
– Has 3 sections
• Duodenum– ~10 inches
– digestive juice are secreted from intestine, pancreas and liver
are mixed with the food to further break it down
Small intestine cont
• Pt 2
– Jejunum- ~4 to 7 ft long
• Food nutrients are absorbed here
• Pt 3
– Ileum- ~5 to 7 feet long
• More food absorption occurs here
Small intestine
• Food absorption
– Villi- small tube structures that cover the wall of
the small intestine
• Used for food/nutrient absorption
– Food absorbed in the small intestine enters the
blood stream in the capillaries and is transported
throughout the body (to where needed)
Liver
Liver
• Factory for antibodies and bile
• Stores vitamins and sugars until your body
needs them
Food Processors
• Liver- the largest internal organ
– Functions as an aid to the digestive system in 2
ways
• 1 through production of bile- yellowish-greenish fluid
used for digestion of fats in the small intestine
• 2 to filter toxic substances from the body and it stores
excess glucose
Gall
Bladder
Gall Bladder
• Storage tank for bile (a greenish-yellow liquid)
that helps your body break down and use fats
• Located under your liver
• Shaped like a pear
Pancreas
• Helps you digest
food by breaking
down sugars
Large Intestine
Large Intestine
• Tube that is 5 feet long
• Gets waste from small intestine
• Waste stays for 10 to 12 hours
Garbage Disposal
• Large Intestine/Colon
– Measures about 5 feet long
– This organ absorbs most of the water and some of
the remaining nutrients left from the food you ate
– After food has finished its trip through the colon it
moves to the rectum and then anus to be excreted
as fecal matter
Large Intestine/Colon
• Also aids the immune system in that it
contains healthy bacteria to fight off harmful
bacteria (or microorganisms)
– These bacteria also provide vitamins for the body
Functions of the Digestive System
• Digest the food we eat
• Take the nutrients out of your food so
your body can use it
Human Excretory System
Excretory System
• The kidneys regulate the amount of water, salts and
other substances in the blood.
• The kidneys are fist-sized, bean shaped structures
that remove nitrogenous wastes (urine) and excess
salts from the blood.
• The ureters are tubes that carry urine from the pelvis
of the kidneys to the urinary bladder.
• The urinary bladder temporarily stores urine until it
is released from the body.
• The urethra is the tube that carries urine from the
urinary bladder to the outside of the body.
• The outer end of the urethra is controlled by a
circular muscle called a sphincter.
Kidneys
• Two reddish organs just above the waist
behind the stomach
• Filter the blood and removes waste
Food Processors
• Gallbladder- located beneath the liver and
stores the bile produced in the liver
• Pancreas- located behind the stomach and
produces pancreatic juices
– Pancreatic juices are sent to the small intestine to
aid in digestion of carbohydrates, proteins and fats
The Job of the Kidneys
• They are responsible for cleaning the blood by
removing metabolic wastes, excess solutes,
and excess water and excreting them as urine
• Besides removing urea, it also removes excess
salts or glucose, the remnants of drugs
(reason for urine tests), and excess water.
Function of the Kidney
• The principal function of the kidney is to
filter blood in order to remove cellular
waste products from the body.
• At any given time, 20 % of blood is in the
kidneys. Humans can function with one
kidney.
• If one ceases to work, the other
increases in size to handle the workload.
NOTE
• Since the kidneys control what leaves and
what remains in the nephrons, they maintain
the levels of water, ions and other materials
nearly constant and within the limits to
maintain homeostasis.
Urinary Bladder
• Smooth muscle bag
• Stores waste solution - urine
Urethra
• Connects bladder to outside of the body
• Allows urine to pass out of the body
Ureter
• Connects the kidneys to the urinary bladder
Nephron
• Filtering unit of the
kidney
• Blood enters full of
waste and leaves
filtered
• Blood enters under high
pressure and flows into
the capillary beds
Regulation of Water Levels
• If the blood becomes too dilute or too
concentrated with solutes, then it can
interfere with normal cellular activity.
• The kidneys are able to regulate water
concentration in the blood by removing excess
water if the blood is too dilute or conserving
water in the blood if it is not dilute enough
Waste Products
• Carbon dioxide – a waste product of
cellular respiration is dumped into the
blood stream and eventually removed by
the lungs
• Ammonia (NH3) is removed through water
– This waste comes from the cells breakdown of
old proteins
– It is also what makes bleach smell so in high
concentrations it is poisonous to the cells and
must be removed
Formation of Urine
• If there is too much water in the blood, then it is
removed and put in urine.
• If there is not enough water in the blood, the kidneys
will not remove it.
• If there is too much urea or other solutes in the
blood, the kidneys will remove these excess solutes.
• By regulating solute numbers and water volume, the
kidneys normally maintain homeostasis in blood
solute concentration.
Why is excretion necessary?
• In order for cells to stay alive, they must
continually intake water and other molecules.
• The cells would continue to get bigger and bigger
if they only took in molecules
• They must also export molecules
– These molecules may be important signaling
molecules such as hormones, or they may be
molecules of glucose on their way to other cells, or
they may be waste products of cellular metabolism
that cells need to dispose.
Removal of Ammonia
• Once excreted into the blood stream by cells,
it is carried to the liver where it is converted
from ammonia into urea which is much less
toxic
• It is then carried from the liver to the kidneys
where it is removed
Excretory System Problems
• Kidney stones – crystalized mineral salts and uric
acid salts in the urine. Stones block flow of urine and
cause excrutiating pain.
• Kidney failure - can be caused by long-term diabetes,
infections, physical injuries, chemical poisoning.
Causes toxic materials to build up to lethal levels.
Dialysis or kidney transplant is the treatment.
Describe the functions of a
person's urinary system
Rids the body of wastes, control
blood volume, balances salts & water
Explain how the kidneys remove wastes
and keep fluids and salts in balance
Kidneys filter the blood to remove extra
wastes, sugar, water, and salt. Sugar,
water, and salt still needed by the body
is returned to the blood.
Describe what happens when the
urinary system does not function
properly.
Wastes are not removed. This causes the
destruction of cells. Water not removed
causes swellings and too much water around
the heart. Slats that are not taken away can
cause organ damage.
Compare the excretory system
and urinary system
The excretory system is made of all body
organs that get rid of wastes. The urinary
system is made of organs that produce
urine as a waste.
How is your urinary system similar
to a water-purification system?
It serves as a filter to screen out
harmful materials and helps get rid of
wastes in the blood
When you drink a lot of water, you
also need to urinate often. Why?
The job of the kidneys is to eliminate
excess water and wastes. If you drink
more than your body needs, it is
eliminated by the urinary system.
Healthy Habits
• Eat foods that
are high in
fiber like fruits
and vegetables
• Drink plenty of water
• Chew your food completely before
you swallow
Interesting Facts
• Food is in your digestive system
for about 24 hours
• Your stomach stretches when you
eat like a balloon being filled with
air