Biol121 Week 10 Lecture 2 Digestion: Organ Structure, Function & Histology

Front 1

What are the key functions of the oral cavity? (5)

Back 1

- ingestion

- sensory analysis

- lubrication

- mechanical processing

- initiates chemical digestion

Front 2

What enzymes are secreted in the oral cavity?

Back 2

Salivary amylase

Lingual lipase

Front 3

How does lubrication happen in the oral cavity?

Back 3

Saliva moistens and lubricates materials in the mouth

Front 4

How does sensory analysis happen?

Where?

Back 4

Saliva dissolves chemicals that stimulate taste buds and provide sensory info

Oral cavity

Front 5

What informs what we voluntarily ingest?

Back 5

Sensory analysis

Front 6

What is the secondary function of saliva, after lubrication?

Back 6

Provides a fluid that enzymes can travel through.

Chemical digestion.

Front 7

What parts of the oral cavity are involved in mechanical digestion? What is this also known as?

Back 7

- teeth

- tounge

- palatale surfaces

Mastication.

Front 8

What does the palate separate?

What is another helpful aspect of the palate?

Back 8

The oral cavity from the nasal cavity.

Helps in mechanical digestion/mastication by being a rough surface that the tongue can manipulate food against.

Front 9

What are the 2 parts of the pharynx that food moves through, and to what?

Back 9

The oropharynx

The laryngopharynx

to the oesophagus

Hint 9

Front 10

What is a fancy word for swallowing?

Back 10

Deglutition

Front 11

What are the 3 phases of deglutition?
Is it voluntary or involuntary?

Back 11

1. buccal phase

2. pharyngeal phase

3. oesophageal phase

Voluntary at first but once initiated can't be stopped!

Hint 11

Front 12

What is the oesophagus lined with and why?

Back 12

Stratified squamous epithelium

Because it is an area of high friction

Hint 12

Front 13

What glands exist within the oesophagus?

Back 13

Mucous glands to reduce friction along with the stratified squamous epithelium

Front 14

What are the 4 major roles of the stomach?

Back 14

1. Chemical digestion

2. Mechanical processing

3. Absorption

4. Storage of food

Front 15

What is chyme?

Back 15

The liquid gastric secretions + partially digested good that is ejected from the stomach into the small intestine

Front 16

What is the stomach lined with?

Back 16

Simple columnar epithelium.

Front 17

What is the pH in the stomach?

Back 17

Very acidic. 1.5-2.0.

Front 18

What does the epithelium in the stomach contain?

Back 18

Gastric glands that secrete:

Chief cells & parietal cells.

Front 19

What do parietal cells do?

Back 19

Secrete: intrinsic factor & hydrochloric acid (Hcl).

Front 20

What does hydrochloric acid do? (HCl) (4)

Back 20

- provides the perfect acidity for gastrin to work

- denatures proteins (and enzymes)

- breaks down cell walls + connective tissue

- provides a defence against infection

Front 21

What do chief cells do?

Back 21

Secrete pepsinogen (inactive pepsin), & pepsin aids in protein digestion. (pepsinogen is converted within the stomach)

Front 22

What do G cells do in the stomach?

Back 22

Secret Gastrin

Front 23

What do D cells do in the stomach?

Back 23

Hormone control

Secret somatostatin (which inhibits gastrin)

Front 24

What happens to amylase in the stomach?

Back 24

It is denatured by stomach acids, effectively turned "off" for now and can't do anything with any carbs

Front 25

What are the three regions of the small intestine?

Back 25

DUODENUM

JEJUNUM

ILEUM

Hint 25

DONT JUMP IN

Front 26

What is the main role of the small intestine, and what 4 things are involved here?

Back 26

Absorption

Monosaccharides (carbs at smallest form)

Amino acids (proteins)

Fatty acids + monoglycerides (lipids)

Alcochol

Front 27

What is the purpose of motility in the small intestine? (3)

Back 27

- Mixes chyme with intestine juice, bile + pancreatic juice

- Churns chime to increase contact with mucosa + aid absorption

- Moves residue towards intestine

Front 28

What is segmentation?

What does it allow?

Back 28

- cycles of contraction without a set pattern like peristalsis but without movement forward

- enhances digestion and absorption (mixing & rotating what is touching the wall)

Hint 28

Front 29

What is received by the duodenum?

Back 29

Chyme from the stomach

Digestive secretions from pancreas and liver

Front 30

What takes place in the jejunum? (2)

Back 30

– Chemical digestion

– Nutrient absorption

Front 31

When does the ileum end?

Back 31

At the illeocal valve, which controls the flow of chyme into the large intestine

Front 32

What is the lining of the small intestine? (2)

What is secreted here?

Back 32

- simple columnar epithelium

- microvilli

mucous, brush boarder enzymes (enteropeptidase = switches on all enzymes)

Front 33

What glands are found in the small intestine?

Back 33

Intestinal glands that produce hormones. Duh.

Front 34

What do the lymphatic capillaries of the small intestine do?

Back 34

Absorb fatty acids

Front 35

What are the main roles of the large intestine? (3)

Back 35

1. Reabsorption (water, bile salts)

2. Absorption (10% nutrients)

3. Compaction (& storage of fecal matter)

Front 36

What is the order of anatomy in the large intestine?

Back 36

Large bowel

Cecum

Colon

Rectum

Front 37

What are the pouches called along the large intestine?

Back 37

Haustra

Hint 37

Poo houses!

Front 38

What is the role of the rectum?

Anal canal next.

Back 38

To be an expandable organ for the temporary housing of feces

&

the movement of feces into the rectum stimulates the urge to defecate

Front 39

What are the two sphincters within the anal canal?

Give the muscle type.

Back 39

Internal anal sphincter - smooth muscles.

External anal sphincter - skeletal muscles

Front 40

How does the large intestine differ from the small intestine? (3)

Back 40

1. Much smoother - lacks villi

2. Many mucous cells to lubricate feces

3. Doesn't produce enzymes

Front 41

What are the accessory organs of the digestive tract? (5)

Back 41

1. Liver

2. pancreas

3. tongue

4. salivary glands

5. gall bladder

Front 42

What are the three important vessels of the liver?

Back 42

1. Hepatic artery. Brings O2 blood to the liver.

2. Hepatic vein. Takes lowO2 blood away from liver.

3. Hepatic portal. Brings lowO2 nutrient-laden blood from digestive organs direct to liver.

Front 43

Describe the hepatic portal system.

Back 43

Blood from the stomach, small intestine & large intestine goes directly to the liver & not the heart.

Front 44

What are the functions of the liver? (5)

Back 44

1. Detoxification of toxins + drugs

2. Removes damaged/old RBC

3. Carbohydrate, amino acid + lipid metabolism

4. Storage of glycogel, vitamins + minerals

5. Synthesis of bile, lipoproteins + plasma proteins

Front 45

Where is the pancreas in the body?

Back 45

Lies posterior to the stomach, bound to the posterior wall of the abdominal cavity

Hint 45

Front 46

What is the endocrine function of the pancreas? (2)

Back 46

Release:

insulin & glucagon

Front 47

What is the exocrine role of the pancreas? (1 role, 4 parts)

Back 47

to secrete pancreatic juices, which contain:

– Alpha-amylase

– Lipase

– Nucleases

– Proteases, Peptidases

& neutralise stomach acids

Front 48

What duct does the gall bladder and liver share?

Back 48

The cystic duct.

Gall bladder concentrates the bile salts that the liver producers

Front 49

What is the role of the gall bladder?

Back 49

1. stores + concentrates bile

2. releases bile into the duodenum

Front 50

What control mechanisms exist in saliva?

Back 50

- lysosomes & antibodies for bacterial control

Front 51

What are the issues with the digestive system as we age? (5)

Back 51

1. Division of epithelium slows, abraision more likley

2. Smooth muscle tone + motility decreases (peristalsis weaker)

3. Cummulative damage from toxins (alcohol)

4. Colon cancer + stomach increase

5. Decline in olfactory + gustatory sensitivity (diet changes then lead to digestive issues)