Systems: digestive system process + organs

SBI3U (Secours) - rest of digestive system hyperdoc

Label the digestive system

A. Tongue

B. Salivary Glands (3)

C. Pharynx

D. Esophagus

E. Liver

F. Gallbladder

G. Stomach

H. Pancreas

I. Small Intestine

J. Colon/Large Intestine

K. Rectum

L. Anus

Accessory organs

organs that are used in digestion but through which food does NOT pass

5 Accessory Organs

1. Tongue

2. Salivary Glands

3. Liver

4. Gallbladder

5. Pancreas

4 Stages of food digestion

1. Ingestion: introduction of food into body

2. Digestion: mechanical and chemical breakdown of food into molecules that are small enough to pass through the cell membrane

3. Absorption: transport of digestion products from the digestive → circulatory system (which distributes to body)

4. Elimination: excretion of undigested solids

Digestion begins in the ______

mouth

Role of the teeth (and tongue)

help with mechanical digestion; break the food down into smaller pieces = greater surface area for chemical digestion

Enzyme (+ its role)

a protein that acts as a catalyst; it speeds up the chemical reaction

✄ acts like metabolic scissors to break bonds

3 roles of saliva

1. Lubricates food

2. Salivary amylase helps digest starches

3. Dissolves water-soluble food particles

Salivary amylase

an enzyme in the saliva, produced by salivary glands; it breaks down starches only

The esophagus moves food along through wave-like ________ called _________

contractions, peristalsis

The _________ sphincter separates the esophagus and the stomach, while the ________ sphincter separates the stomach and the _________.

gastroesophageal, pyloric, duodenum

When the gastroesophageal sphincter relaxes at the wrong time, this causes ____ _____

Acid Reflux (heart burn)

4 Layers of the Stomach

1. Mucosa

2. Submucosa

3. Muscular (composed of 3 layers)

4. Serosa (outermost layer)

the 3 muscular layers of the stomach are unique because?

they go in different directions - allows for better movement

Types of digestion that occur in the stomach

Both mechanical digestion(contraction of muscles - churning) and the chemical digestion of proteins (pepsin)

Pepsin

An enzyme present in gastric juices that digests proteins

The mucus of the stomach (mucosa layer) _______ the walls of the stomach from its ______ environment

protects, acidic

Hydrochloric Acid

the acid that breaks food into smaller pieces in the stomach

⇨ HCl only breaks down protein

HCl acid is regulated by the ___________ ________

Gastrin Hormone

Nothing is absorbed by the stomach EXCEPT _________

alcohol

The small intestine digests ____ and ________, along with any remaining undigested ______

lipids, carbohydrates, proteins

In addition to digestion, the small intestine must _______ these subunits so that they enter the __________.

ABSORB, bloodstream

Structural features of the small intestine (4)

1. Length (longest part of the digestive system!)

2. Interior is folded

3. Folds are covered in villi

4. Villi are covered in microvilli

The structure of the small intestine is linked to its function in that it ________ _________ _____

increases surface area

3 parts of the small intestine

1. Duodenum

2. Jejunum

3. Ileum

The ________ is connected to the pancreas and liver (ie. they empty out into it)

Duodenum

label this villus

1. Endothelial Cell

2. Capillary

3. Lacteal Vessel

4. Lymphatic Vessels

5. Blood Vessels

The lacteal vessels, which are connected to the _______ system, absorb primarily the subunits ________+____ _____

lymphatic, glycerol, fatty acids

The capillaries, which are connected to the __________ system, absorb primarily the subunits ________, ______ ______.

circulatory, monosaccharides (glucose), amino acids

Bolus vs Chyme

Bolus: food + saliva

Chyme: food + stomach juice

The pancreas produces _________ _____, which contains _________ and ____________.

pancreatic juice, enzymes, bicarbonate

3 enzymes produced by the pancreas + what they break down

1. Pancreatic Amylase: starch

2. Trypsin: undigested proteins

3. Lipase: lipids

☆ these enzymes are used by the small intestine

Bicarbonate function

neutralizes acid from the chyme

Function of the Liver

Produces bile, which emulsifies large fat globules into small fat droplets that can be chemically digested by the enzymes produced by the pancreas

⇨ also filters blood

Gallbladder function

attached to the liver, it stores bile and releases it when fatty food enters the duodenum

The small intestine’s 3 main absorption methods

1. Diffusion

2. Facilitated Diffusion

3. Active Transport

Diffusion in the small intestine

movement of particles from high concentration (inside) → lower concentration (the villi)

Facilitated Diffusion in the small intestine

type of diffusion that requires specialized membrane-embedded proteins to bind to and transport molecules across the membrane

Active Diffusion in the small intestine

type of diffusion that requires energy to transport the material across the membrane

The colon/large intestine are part of the ___________ and ___________ stages of food digestion

absorption, elimination

The large intestine ______ digest food. However, it can continue to absorb _______.

CANNOT, water

The remaining undigested material (feces) is made up of:

• water (75%)

• bacterial biomass

• proteins

• carbohydrates or undigested plant matter (fiber)

• fats (2-15%)

Bacteria in the colon produces _________ ___ and __, but can also cause flatulence by __________ ___.

vitamins, A, K, releasing gas

Rectum

fecal matter storage

Anus

eliminates waste by excreting it through the internal (involuntary) and external (voluntary) anal sphincters