Digestive System
Also called the gastrointestinal
tract or GI tract
Main Function: to convert food into simpler molecules
that can be absorbed by the body.
Salivary Gland
Mouth
Esophagus
Stomach
Large Intestine
Anus
Small Intestine
Rectum
Digestive System Organs (in the order that food travels)
Part
Function & Enzymes / Secretions Involved
Mouth
Mechanical Digestion: teeth breaks down food into smaller
units to be swallowed
Chemical Digestion: saliva has enzymes to break down sugars
Esophagus
Flat muscular tube that connect the pharynx with the stomach.
Wave-like muscular contractions, called peristalsis, push the
food downward from the mouth to the stomach.
Stomach
Muscular sac that begins the chemical digestion of food by the
secretion of hydrochloric acid and other enzymes.
Small
Intestine
Most digestion and absorption of nutrients occurs here. It
absorbs the nutrients into the bloodstream. Have finger-like
projections, called villi, that line the walls to increase surface
area for absorption. (“Small” due to diameter/not length; it is longer
than the large intestine)
Large
Intestine
Rectum
Also called the colon. (“Large” due to diameter/not length)
Absorbs water into the bloodstream to form solid feces.
Last straight part of the intestine in which feces (undigested
waste material) passes out of the body through an opening called
the anus.
Other Organs Involved in
Digestion:
1. Pancreas – organ which makes
digestive fluids and the hormone
called insulin.
2. Liver – largest internal organ
that makes bile, which is a green
liquid that digests fats; stores
excess glucose
3. Gallbladder – small sac that
stores bile.
Liver
Gallbladder
Pancreas
Excretory System
Main Function: to remove metabolic
wastes from the bloodstream. Metabolic
wastes include excess salt, water, carbon
dioxide, and urea.
Excretory System Organs
Organ
Function
Kidneys
Filters the blood to remove metabolic wastes to
form urine.
The kidneys are two bean-shaped organs, one
located on either side of the spinal column near
the lower back. Each one is about the size of a
tightly clenched fist.
Ureters Two tubes that carry urine from the two kidneys
to the urinary bladder
Urinary
Stores urine until it exits the body.
Bladder
Urethra Tube in which urine exits the body from the
urinary bladder
Excretory System Organs
Adrenal Gland
Kidney
Ureters
Urinary Bladder
Urethra
Other Organs of Excretion
Lungs
Removes _CO2 and water
vapor___from the body
Skin
Removes excess water, and salt in
the form of ___sweat_______.
Control of Kidney Function
What is ADH? – Antidiuretic Hormone. It is secreted from the pituitary
gland.
Actions of ADH as a Feedback Mechanism.
Increases amount
of water in blood
and decreases
amount of urine
produced.
Tells pituitary
that amount
of water in
blood is low.
Tells pituitary
that amount
of water in
blood is high.
Releases ADH
into
bloodstream.
Stops
releasing ADH
into
bloodstream
Reabsorb
more water.
Reabsorbs
less water.
Decreases amount
of water in blood
and increases
amount of urine
produced.