1. The Digestive System
The Digestive System
Prepares food for use by all
Prepares food for use by all
body cells.
body cells.
2. Digestion
Digestion
The chemical breakdown of complex
The chemical breakdown of complex
biological molecules into their component
biological molecules into their component
parts.
parts.
– Lipids to fatty acids
Lipids to fatty acids
– Proteins to individual amino acids
Proteins to individual amino acids
– Carbohydrates into simple sugars
Carbohydrates into simple sugars
3. Function
Function
Produces various chemicals to
Produces various chemicals to
break down the food.
break down the food.
Filters out harmful substances.
Filters out harmful substances.
Gets rid of solid wastes.
Gets rid of solid wastes.
5. Digestion
Digestion
Chemical
Chemical
– Changes the chemical composition of food
Changes the chemical composition of food
with the aid of digestive enzymes
with the aid of digestive enzymes
Carbohydrate
Carbohydrate
Protein
Protein
Lipid
Lipid
– Digestive enzymes are special proteins that
Digestive enzymes are special proteins that
help break up large molecules of food into
help break up large molecules of food into
very tiny molecules that can be absorbed and
very tiny molecules that can be absorbed and
used by the cells in the form of nutrition.
used by the cells in the form of nutrition.
6. Phases of Digestion
Phases of Digestion
Ingestion
Ingestion
Movement
Movement
Digestion
Digestion
Absorption
Absorption
Further digestion
Further digestion
7. The Digestive Tract
The Digestive Tract
A long muscular
A long muscular
tube with many
tube with many
sections and
sections and
areas.
areas.
Begins with the
Begins with the
mouth and ends
mouth and ends
with the anus.
with the anus.
8. The Digestive Tract
The Digestive Tract
Parts of the Digestive
Parts of the Digestive
Tract
Tract
– Mouth
Mouth
– Pharynx
Pharynx
– Esophagus
Esophagus
– Stomach
Stomach
– Small Intestine
Small Intestine
– Large Intestine
Large Intestine
9. Accessory Parts
Accessory Parts
Organs that are not in the digestive tract
Organs that are not in the digestive tract
but helps in the digestion
but helps in the digestion
– Teeth
Teeth
– Tongue
Tongue
– Salivary glands
Salivary glands
– Liver
Liver
– Gall bladder
Gall bladder
– Pancreas
Pancreas
10. Mouth
Mouth
Functions:
Functions:
– Food enters in the mouth or oral
Food enters in the mouth or oral
cavity
cavity
– Tasting
Tasting
– Mechanical breakdown of food
Mechanical breakdown of food
– Secretion of salivary glands
Secretion of salivary glands
(salivary amylase)
(salivary amylase)
11. Mouth
Mouth
Structures in the mouth that aids digestion:
Structures in the mouth that aids digestion:
Teeth – cut, tear, crush and grind food.
Teeth – cut, tear, crush and grind food.
Salivary glands – produce and secrete
Salivary glands – produce and secrete
saliva into the oral cavity.
saliva into the oral cavity.
– Parotid (beneath the cheeks)
Parotid (beneath the cheeks)
– Submaxillary (below the jaw bone)
Submaxillary (below the jaw bone)
– Sublingual (below the tongue)
Sublingual (below the tongue)
–
– saliva moistens the
saliva moistens the
food and contains enzymes (
food and contains enzymes (ptyalin
ptyalin or
or
salivary
salivary amylase
amylase) that begins digestion
) that begins digestion
of starch into smaller polysaccharides.
of starch into smaller polysaccharides.
12. Mouth
Mouth
Tongue
Tongue
– Mixes and rolls food into tiny
Mixes and rolls food into tiny
mashed up bits
mashed up bits (
(Bolus
Bolus)
)
– Pushes the bolus toward the
Pushes the bolus toward the
pharynx and into the esophagus
pharynx and into the esophagus
when swallowing.
when swallowing.
13. Anatomy of the Mouth and
Anatomy of the Mouth and
Throat
Throat
15. Mechanism of Swallowing
Mechanism of Swallowing
Swallowing is a coordinated activity of the
Swallowing is a coordinated activity of the
tongue, soft palate, pharynx and esophagus.
tongue, soft palate, pharynx and esophagus.
Phases
Phases
– Food is pushed into the
Food is pushed into the pharynx
pharynx by the
by the
tongue. (voluntary)
tongue. (voluntary)
– Tongue blocks the mouth
Tongue blocks the mouth
– Soft palate closes off the nose
Soft palate closes off the nose
– Larynx (Adam’s Apple) rises so the
Larynx (Adam’s Apple) rises so the
Epiglottis
Epiglottis (a flap of tissue) can close the
(a flap of tissue) can close the
opening of the trachea.
opening of the trachea.
16.
17. Esophagus
Esophagus
A straight muscular tube that is about 10 inches
A straight muscular tube that is about 10 inches
(25 cm) long which connects the mouth with the
(25 cm) long which connects the mouth with the
stomach
stomach
Food takes about 4 to 8 seconds as it passes
Food takes about 4 to 8 seconds as it passes
through to the stomach.
through to the stomach.
Its walls contain smooth muscles that contracts
Its walls contain smooth muscles that contracts
in wavy motion (
in wavy motion (Peristalsis
Peristalsis).
).
Peristalsis propels food and liquid slowly
Peristalsis propels food and liquid slowly
down the esophagus into the stomach.
down the esophagus into the stomach.
Cardiac Sphincter (ring-like valve) relaxes to
Cardiac Sphincter (ring-like valve) relaxes to
allow food into the stomach.
allow food into the stomach.
19. Stomach
Stomach
J-shaped muscular sac
J-shaped muscular sac
Has inner folds (
Has inner folds (rugae
rugae) that increases the
) that increases the
surface area of the stomach.
surface area of the stomach.
Churns and grinds together the bolus into
Churns and grinds together the bolus into
smaller pieces.
smaller pieces.
Food is mixed with gastric juices
Food is mixed with gastric juices
(hydrochloric acid and enzymes) secreted
(hydrochloric acid and enzymes) secreted
by the stomach walls.
by the stomach walls.
HCL helps break down food and kills
HCL helps break down food and kills
bacteria that came along with the food.
bacteria that came along with the food.
21. Stomach
Stomach
Pepsin
Pepsin – major enzyme; converts
– major enzyme; converts
proteins into peptides in the presence of
proteins into peptides in the presence of
HCL.
HCL.
Mucus
Mucus – lubricates food and protects the
– lubricates food and protects the
gastric lining from strong digestive juices.
gastric lining from strong digestive juices.
Converts the bolus into a liquid
Converts the bolus into a liquid
(
(chyme
chyme)
) after 4 hrs of mechanical and
after 4 hrs of mechanical and
chemical digestion
chemical digestion
Chyme passes through the
Chyme passes through the pyloric
pyloric
sphincter
sphincter into the small intestine.
into the small intestine.
23. Small Intestine
Small Intestine
Long (20 ft), coiled tube beneath the
Long (20 ft), coiled tube beneath the
stomach.
stomach.
Has three parts:
Has three parts:
Duodenum – upper part; about 10 in; connected to
Duodenum – upper part; about 10 in; connected to
the stomach.
the stomach.
–
– where the digestive juices from the
where the digestive juices from the
pancreas and the liver combine with chyme
pancreas and the liver combine with chyme
making it thin and watery.
making it thin and watery.
Jejunum – about 8 ft
Jejunum – about 8 ft
Ileum – about 12 ft
Ileum – about 12 ft
25. Small Intestine
Small Intestine
Takes about 4 – 8 hrs to complete its journey.
Takes about 4 – 8 hrs to complete its journey.
Mucosa (inner wall) – secretes several enzymes
Mucosa (inner wall) – secretes several enzymes
that acts on the food.
that acts on the food.
Where the pancreatic enzymes are emptied into.
Where the pancreatic enzymes are emptied into.
Digested nutrients are absorbed through
Digested nutrients are absorbed through
intestinal walls.
intestinal walls.
Absorbed materials cross the mucosa into the
Absorbed materials cross the mucosa into the
blood then other parts of the body for storage or
blood then other parts of the body for storage or
further chemical change.
further chemical change.
26. Small Intestine
Small Intestine
Has folded inner walls covered with
Has folded inner walls covered with
fingerlike projections (
fingerlike projections (villi
villi; sing. – villus)
; sing. – villus)
Each villus has tinier projections called
Each villus has tinier projections called
microvilli
microvilli that absorbs digested food.
that absorbs digested food.
Villi and microvilli increases the surface
Villi and microvilli increases the surface
area of the small intestine for greater
area of the small intestine for greater
absorption.
absorption.
Peristalsis moves the undigested food to
Peristalsis moves the undigested food to
the large intestine.
the large intestine.
27. Movement in small intestine:
Movement in small intestine:
Mixing: Segmental contraction that occurs in small intestine
Mixing: Segmental contraction that occurs in small intestine
Secretion: Lubricate, liquefy, digest
Secretion: Lubricate, liquefy, digest
Digestion: Mechanical and chemical
Digestion: Mechanical and chemical
Absorption: Movement from tract into circulation or lymph
Absorption: Movement from tract into circulation or lymph
Elimination: Waste products removed from body
Elimination: Waste products removed from body
28. Large Intestine
Large Intestine
a.k.a. Colon
a.k.a. Colon
larger diameter, but shorter (5 ft)
larger diameter, but shorter (5 ft)
Water is absorbed from the
Water is absorbed from the
undigested food making the waste
undigested food making the waste
harder until it becomes solid.
harder until it becomes solid.
Waste stays for 10 – 12 hours.
Waste stays for 10 – 12 hours.
30. Large Intestine
Large Intestine
Waste is pushed into the expanded
Waste is pushed into the expanded
portion (rectum) of the large intestine.
portion (rectum) of the large intestine.
Solid waste stays in the rectum until it
Solid waste stays in the rectum until it
is excreted through the anus as
is excreted through the anus as
feces.
feces.
Appendix hangs on the right side of
Appendix hangs on the right side of
the large intestine.
the large intestine.
31. Accessory Organs
Accessory Organs
Produce or store enzymes that helps in
Produce or store enzymes that helps in
digestion.
digestion.
Liver
Liver
– Largest gland of the body
Largest gland of the body
– Stores vitamins A,D,E,K
Stores vitamins A,D,E,K
– Stores sugar and glycogen
Stores sugar and glycogen
– Produces
Produces bile
bile (watery, greenish
(watery, greenish
substance)
substance)
– Secretes bile to the gall bladder via the
Secretes bile to the gall bladder via the
hepatic duct and cystic duct.
hepatic duct and cystic duct.
32. Accessory Organs
Accessory Organs
Gall bladder
Gall bladder
– Stores bile in between meals
Stores bile in between meals
– Secretes bile to the duodenum through
Secretes bile to the duodenum through
the bile duct during mealtime.
the bile duct during mealtime.
Bile contains bile salts, pigments,
Bile contains bile salts, pigments,
cholesterol and phospholipids.
cholesterol and phospholipids.
Bile is an emulsifier NOT an enzyme.
Bile is an emulsifier NOT an enzyme.
Emulsifier – dissolves fat into the
Emulsifier – dissolves fat into the
watery contents of the intestine.
watery contents of the intestine.
33. Accessory Organs
Accessory Organs
Pancreas
Pancreas
– Produces a juice that contains
Produces a juice that contains
enzymes (
enzymes (amylase and insulin
amylase and insulin) to
) to
break down carbohydrates, fats
break down carbohydrates, fats
and protein.
and protein.
– Secretes the juice into the
Secretes the juice into the
duodenum through the pancreatic
duodenum through the pancreatic
duct.
duct.
34. Path of Digestion
Path of Digestion
Mouth
Mouth
Pharynx
Pharynx
Esophagus
Esophagus
Stomach
Stomach
Small Intestine
Small Intestine
Large Intestine
Large Intestine
Anus
Anus
35. The Excretory System
The Excretory System
Gets rid of wastes and other
Gets rid of wastes and other
substances that the body doesn’t
substances that the body doesn’t
need.
need.
36. Two Types of Wastes
Two Types of Wastes
Solid Waste – from the Digestive System
Solid Waste – from the Digestive System
in the form of feces.
in the form of feces.
Metabolic Wastes – produced by chemical
Metabolic Wastes – produced by chemical
reactions like respiration, hydrolysis,
reactions like respiration, hydrolysis,
synthesis and neutralization.
synthesis and neutralization.
– Water
Water
– Carbon Dioxide
Carbon Dioxide
– Salts
Salts
– Urea
Urea
37. Removal of Wastes
Removal of Wastes
Egestion
Egestion
– removal of digestive waste.
removal of digestive waste.
Excretion
Excretion
– removal of metabolic waste.
removal of metabolic waste.
38. Organs of Excretion
Organs of Excretion
Skin
Skin
–Allows water, salt and urea to
Allows water, salt and urea to
diffuse from the blood (capillaries)
diffuse from the blood (capillaries)
into the sweat glands.
into the sweat glands.
–Releases sweat from the sweat
Releases sweat from the sweat
glands through the sweat ducts out
glands through the sweat ducts out
to the skin pores.
to the skin pores.
39. Organs of Excretion
Organs of Excretion
Lungs
Lungs
– Excretes the waste product of
Excretes the waste product of
respiration during exhalation.
respiration during exhalation.
– Carbon Dioxide and Water
Carbon Dioxide and Water
Vapor.
Vapor.
40. Organs of Excretion
Organs of Excretion
Liver
Liver
–Part of the digestive, circulatory and
Part of the digestive, circulatory and
excretory systems.
excretory systems.
–Removes excess amino acids from
Removes excess amino acids from
the body.
the body.
–Breaks down the amino acids
Breaks down the amino acids
through
through deamination
deamination to form the
to form the
urea which is excreted in the urine.
urea which is excreted in the urine.
41. Organs of Excretion
Organs of Excretion
Kidneys
Kidneys
– Major excretory organs of the body
Major excretory organs of the body
which removes most of the body
which removes most of the body
wastes.
wastes.
– Purify blood by filtering out water, salts,
Purify blood by filtering out water, salts,
digested food particles and urea in the
digested food particles and urea in the
form of urine.
form of urine.
– Urine passes out through the urinary
Urine passes out through the urinary
tract.
tract.
43. Excretion of Urine
Excretion of Urine
Kidney
Kidney
Ureter – a tube that transports urine to the
Ureter – a tube that transports urine to the
urinary bladder.
urinary bladder.
Urinary Bladder – a sac of tissue that has
Urinary Bladder – a sac of tissue that has
the ability to expand as it fills with urine.
the ability to expand as it fills with urine.
Urethra – a tube at the bottom of the
Urethra – a tube at the bottom of the
bladder where urine passes out of the
bladder where urine passes out of the
body.
body.
44. Assignment
Assignment
Research and make a table about the different
Research and make a table about the different
Digestive Enzymes.
Digestive Enzymes.
Follow the following format:
Follow the following format:
Intestinal
Glands
Pancreas
Gastric Glands
Salivary Glands
Products
Substrates
Enzymes
Digestive
Gland
