What molecule does our body break down for energy? Where do we get this molecule? Recall from...
32
• What molecule does our body break down for energy? • Where do we get this molecule? • Recall from Biology Lab, what do Iodine and Benedict’s solution test for? • Explain the reactions of these two indicators. DO NOW:Digestive Enzymes Pre-Lab
What molecule does our body break down for energy? Where do we get this molecule? Recall from Biology Lab, what do Iodine and Benedict’s solution test
What molecule does our body break down for energy? Where do we
get this molecule? Recall from Biology Lab, what do Iodine and
Benedicts solution test for? Explain the reactions of these two
indicators. DO NOW:Digestive Enzymes Pre-Lab
Slide 2
Objectives To use your knowledge of indicators and
macromolecules to determine the effects of digestive enzymes. To
explain how digestion begins in the mouth.
Slide 3
Do Now What do we already know about the digestive system? List
3 things! What would happen if you were tied upside down, would you
still be able to eat? Explain.
Slide 4
The Digestive System! Chapter 15
Slide 5
Objectives To compare and contrast chemical vs. mechanical
digestion. To explain the general characteristics of the alimentary
canal. To explain the process of swallowing and peristalsis. To
identify the structures of the mouth and explain their function. To
understand the necessity of salivary glands and name each
type.
Slide 6
Digestion Chemical digestion- complex molecules are broken down
into smaller molecules Mechanical digestion- physical movement of
food that breaks it down into smaller pieces Ex. Chewing, grinding,
mashing Chewing is called mastication
Slide 7
Components of Digestive System Alimentary Canal digestive tract
Mouth, pharynx, esophagus, stomach, small intestine, large
intestine, and anal canal Accessory Structures: Salivary glands,
liver, gallbladder, & pancreas
Slide 8
Alimentary Canal Muscular tube that passes through the bodys
ventral cavity 9 meters long Contains 4 layers
Slide 9
Alimentary Canal 1)Mucosa: Protects the tissues beneath it
& carries out secretion and absorption Consists of epithelium,
underlying CT, and a little bit of muscle. 2) Submucosa: Nourishes
surrounding tissue and carries away absorbed materials Consists of
loose connective tissue, blood vessels, glands.
Slide 10
Alimentary Canal 3) Muscular Layer: Layer which moves the tube
Contains: Two coats of smooth muscle tissue & nerves (plexus)
Fibers of the inner coat surround the tube When they contract the
tubes diameter decreases Fibers on the outer muscular coat run
lengthwise When they contract the tube shortens 4) Serosa: Protects
underlying tissues and secrete serous fluid
Slide 11
Alimentary Canal
Slide 12
Movements of theAlimentary Canal Mixing Movement Occurs when
smooth muscle in small units of the tube contract rhythmically
Mixes food with digestive juices secreted by the mucosa Propelling
Movement Known as peristalsis
Slide 13
Organs of the Digestive System The Mouth Receives food and
begins digestion mechanically Reduces the size of solid particles
and mixes them with saliva Oral cavity - Lips, cheeks, tongue &
palate Vestibule - Narrow space between teeth, cheeks, &
lips
Slide 14
Salivary Glands Secrete saliva Contain 2 cells Serous cells:
produce amylase (breaks down carbs) Mucus cells: produce mucus to
bind to food and lubricate during swallowing.
Slide 15
Pharynx Connects nasal and oral cavities Contains 3 parts
Nasopharynx Oropharynx Laryngopharynx (passageway to the
esophagus)
Slide 16
Swallowing Mechanism 1.Food is chewed and mixed with
saliva,tongue rolls this into a mass or bolus and forces it into
the pharynx 2.Food stimulates sensory receptors around the
pharyngeal opening triggering the swallowing reflex. 3.Momentarily
inhibits breathing, peristalsis transports food into the esophagus
and to the stomach.
Slide 17
Do Now 1) Read the story about William Beaumont and his work
with St. Martin in the early 1800s. 3) Write a short summary of
what you read.
Slide 18
Objectives Explain the functions of the esophagus, stomach,
small intestines, and large intestines in digestion. Identify
different enzymes located in the digestive system and explain their
function. Understand different conditions caused by improper
functioning of the digestive system.
Slide 19
Swallowing Mechanism
Slide 20
Esophagus About 25 cm long Connects pharynx to the stomach
Separated from the stomach by the cardiac sphincter. Contracts and
closes the sphincter to prevent regurgitation.
Slide 21
Heartburn! Regurgitation of stomach acid into the
esophagus.
Slide 22
Stomach J shaped with about a 1 liter capacity. Contains rugae
which allow it to expand Divided into 4 regions Cardiac Fundic Body
Pyloric
Slide 23
Slide 24
Stomach
Slide 25
Stomach Ulcers Breaking down of the mucosal lining.
Slide 26
Stomach Juices Gastric Juice consists of HCl Mucus Viscous
alkaline secretion that coats the stomach Enzymes Proteases such as
Pepsin- digests protein (starts as pepsinogen and when mixed with
HCl makes pepsin) Intrinsic factor which helps the small intestine
absorb B12
Slide 27
Stomach Juices The mixture of gastric juice and the bolus gives
us chyme. Stomach contractions push chyme a little at a time into
the sm. Intestine. Type of food can effect rate of emptying Fatty
food = 3-6 hrs. in stomach Proteins move more quickly Carbs go
through the fastest!
Slide 28
Gastric Absorbtion The stomach mostly breaks things down Can
absorb only small amounts of water, certain salts, alcohol, and
some lipid-soluble drugs. EX: Aspirin
Slide 29
Pancreas Secretes pancreatic juice into the duodenum (1 st part
of sm. Intestine) Pancreatic enzymes: Pancreatic amylase Digests
carbs Pancreatic lipase Digests fats Nucleases Digests nucleic
acids Proteases: trypsin, chymotrypsin & carboxypeptidase
Digest protein
Slide 30
Liver Effects carbohydrate, lipid, and protein metabolism.
Produces bile Contains bile salts, bile pigments (bilirubin and
biliverdin) **bile salts emulsify fats (turn them into little globs
instead of big globs!) and also increase absorption of fat-soluble
vitamins (A,D,E, & K)
Slide 31
Review What is the process that occurs after swallowing? What
is the scientific name for the digestive tract? How many layers is
this tract? What are the 3 parts of the pharynx? What is absorbed
in the stomach? What does the pancreas do? Why are bile salts
important?