Transcript Accessory Structures

Accessory Structures
• Important additional structures of digestive
system.
• Although food
pass through them
they play a vital role in proper digestion and
absorption
SALIVARY GLANDS
• Produce a
softens and binds food into a
• Enzyme salivary
carbohydrates (hydrolysis)
fluid called saliva which
begins chemical digestion of
[carnivores which gulp their food lack enzymes in saliva ]
SALIVARY GLANDS
• 3 pair of exocrine glands located around the oral cavity
[
,
& submaxillary]
Accessory Organs- Pancreas
• Produces pancreatic fluid which is
sent to the
• Includes many enzymes: trypsin
and chymotrypsin (proteins),
pancreatic amylase (starch) and
lipase (fats).
• Also contains a bicarbonate which
Pancreas
• Functions as both an
gland
and an
- Endocrine since it
into the blood steam which moves sugar in blood into
the cells of the body
- Exocrine since it
which contain about 28 known digestive enzymes
PANCREATIC JUICES
• This fluid is
thus
the strong acid mixture (chyme) which arrives in the
duodenum from the stomach
• Flows through a short tube [pancreatic duct] into the
duodenum
Accessory Organs- Liver
• Largest internal organ of humans
• Secretes
stored in the
which is
• Bile salts are crucial in the
digestion of fats
Liver
• One of the most vital organs to the body because of its
many functions
• Stores and releases carbohydrates, packages fats,
synthesizes enzymes and clotting factors, regulates blood
cholesterol, stores fat soluble vitamins (A,D,E,B12),
breaks down a variety of foreign substances
Accessory Organs-Gall Bladder
• Stores extra bile between meals
• When food enters the small intestine the gall bladder sends bile into the
duodenum
Gall Bladder
• After meals in response to food in the
and duodenum, gall bladder contracts
through common bile duct into duodenum
Digestive Tract
Secretion
Site of production
Function
saliva
mouth
contributes to starch digestion via salivary amylase; lubricates
the inside of the mouth to assist in swallowing
mucus
mouth, stomach, small intestine,
and large intestine
protects the cells lining the innermost portion of the digestive
tract; lubricates food as it travels through the digestive tract
enzymes
mouth, stomach, small intestine,
and pancreas
promote digestion of food masses into particles small enough
for absorption into the bloodstream
acid
stomach
promotes digestion of protein
bile
liver (stored in gall bladder)
suspends fat in water, using bile salts, cholesterol, and lecithin
to aid digestion of fats in small intestine
bicarbonate
pancreas and small intestine
neutralizes stomach acid when it reaches the small intestine
hormones
stomach, small intestine, and
pancreas
stimulate production and/or release of acid, enzymes, bile,
and bicarbonate; help to regulate peristalsis
Ulcers
• Can occur in the
(gastric) or the
beginning of the small intestine (
).
It was thought that they may be caused by
and HCl or more recently by bacterial infection.
Inflammatory Bowel Diseases
• Crohn’s Disease inflammation of the
intestinal tract (Burril Crohn) resulting in abdominal
cramping, and fever.
• Ileitis/colitis - may require surgery and drug therapy
• IBDs(
)
may be caused by virus or
which can
be treated surgically and/or treated with antiinflammatory drugs.
Hepatitis
a. Hepatitis A (
)
• caused by
spread through

water and food
b. Hepatitis B (serum hepatitis)
• acquired from transfusions or exchange of body fluids
(tears, saliva, blood, semen) [vaccine available]
c. Hepatitis C
• Infected blood –
Cirrhosis
• Chronic disease of the
degeneration of liver cells
with
• Caused by
, hepatitis C
and nutritional deficiencies as well as poisons
and infections
Gallstones
• Cholesterol in the
,
blocking the bile duct and preventing the flow of
bile to the small intestine
Anorexia Nervosa & Bulimia
• Eating disorders caused by an inaccurate body
image
Obesity: Hormonal,
factors
and lifestyle
Chapter 6 Review
• Why are some amino acids classified as essential?
• Describe the relationship between the organs in the digestive tract.
• What are the benefits of having stomach stapling? What are the risks?
• Summarize chemical digestion of macromolecules.
• Explain how glucose levels are affected after meals. Include the effects of
different foods.
• The human body takes in matter from the environment in the form of food
and water. The human digestive system processes the food and water in
order to obtain the macromolecules it needs for survival.
Chapter 6 Summary
• Food passes through the digestive tract—the mouth, pharynx, esophagus, stomach,
small intestine, and large intestine—during physical digestion.
• The accessory organs—the salivary glands, liver, gall bladder, and pancreas—supply
chemicals that also contribute to the digestion of food as it passes through the digestive
tract.
• The stomach supplies chemicals to aid digestion as well as generating physical
contractions to physically break down food.
• The food is eventually liquefied into soluble units that can pass through cell membranes
for transport via the circulatory system to all the cells in the body.
• The waste materials from the digestive process leave the body via the large intestine.
Chapter 6 Summary
• The nutrients that food supplies include carbohydrates, lipids (fats), protein, and nucleic
acids.
• Carbohydrates and lipids are broken down to supply energy; lipids also supply material for
the cell membranes.
• Proteins are more structurally and functionally diverse than carbohydrates and lipids. They
assist in transport, immunity, and muscle action and are used to make up most cellular
structures.
• Nucleic acids direct growth and development. Enzymes speed up chemical reactions,
particularly for the production of energy.
• Vitamins and minerals are organic and inorganic substances that enable chemical reactions
to occur and aid in tissue development and growth and immunity. These substances are
needed for a healthy, functional human body.
Chapter 6 Summary
• Disorders of the digestive system and its accessory organs include ulcers,
inflammatory bowel disease, hepatitis, cirrhosis, and gallstones.
• All disorders that affect digestion, including eating disorders, can seriously
damage overall health by depriving the body cells of the nutrients they
need to survive.