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Bio 133 > Chapter 23/24 Digestion > Flashcards

Chapter 23/24 Digestion Flashcards

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Biology 101 flashcards
1
Q

What makes up the digestive system

A

two main categories:

  1. alimentary canal/ gastrointestinal: mouth, pharynx, esophagus, and small/large intestine
  2. accessory organs: teeth, tongue, gallbladder, and intestinal glands
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2
Q

what are the six main activities of digestion

A

ingestion, propulsion (swallowing/ peristalsis), mechanical digestion, chemical digestion, absorption, and defecation

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3
Q

what is the difference between peristalsis and segmentation

A

peristalsis: waves of contraction that moves food down tract.
Segmentation: altering waves of contractions that move food up and down and mix it. increases absorption

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4
Q

what are the serous membranes in the digestive system

A

visceral peritoneum- lines the digestive tract
parietal peritoneum- covers the body wall
mesenteries- double layer, routes for vessels and nerves and is attachment for body wall

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5
Q

where are the greater and lesser omentum located

A

the great omentum stores fat and hangs over the intestines and the lesser omentum is between the stomach and the liver

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6
Q

histology of the gi tract:

there are four tunic layers. what are they?

A

mucosa- absorbs, secretes and protects
submucosa- services (blood vessles, lymphatic, lymphoid follicles, and nerve fibers)
muscularis externa- peristalsis and segmentation
serosa- visceral peritoneum

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7
Q

what are the two neural reflex pathways in the gi tact?

A

two ways: intrinsic or extrinsic.

short: mediated entirely by enteric or gut in response to stimuli in the gi track
long: controlled by stimulants inside or outside the gi track involving the CNS and extrinsic autosomal nerves

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8
Q

anatomy of the mouth: accessory organs

Lips, cheeks, palate, and tongue

A

labia (lips) and cheeks- oral vestibule (between cheeks and teeth) and the oral cavity (between teeth, roof of mouth) - palate is the roof of the mouth, hard plate is for chewing, it in on roof of mouth in root of teeth, soft plate is skeletal muscle covers nasopharynx when swallowing (behind the hard plate). the tongue has different taste buds on the papillae and the lingual frenulum which connects the tongue to floor mouth

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9
Q

what are the three salivary glands

A

parotid, submandibular, and sublingual

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10
Q

what are the components of saliva and what is the function

A

saliva is 97% water but also contains IgA antibodies, lysozyme, defensins, and friendly bacteria. the function of saliva is to dissolve food chemicals, moisten food and aid in compacting it, begin digesting starchy foods through the enzyme amylase

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11
Q

explain the Pharynx

Details about teeth (what is dentition)

A

shared tube for food and air, epiglottis blocks off trachea

dentition is development of teeth and arrangement in mouth. there are 20 baby teeth and 32 permanent teeth including the wisdom teeth. these teeth include canine, incisors, premolar, and molars

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12
Q

esophagus

what is mastication?

A

hiatus through diaphragm, muscular tube, contains a cardiac sphincter at stomach

process of chewing, food being crushed by teeth. form the bolus, begin digestion of starch, then deglutition (swallowing)

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13
Q

function: from mouth to esophagus- chewing and swallowing. Describe the 5 steps from mouth to stomach.

A
  1. upper esophagus sphincter contracts, tongue presses against hard plate and forces food bolus down oropharynx
  2. the uvula and the larynx rise preventing food from entering the respiratory passageway. tongue blocks off the mouth, the upper esophagus sphincter relaxes allowing food the enter the esophagus.
  3. constrictor muscles in pharynx contract forcing food into esophagus, upper esophagus sphincter contracts after food has entered.
  4. peristalsis moves food down esophagus to stomach
  5. the gastroesophageal sphincter opens to cardial orifice allowing food to move into the stomach.
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14
Q

what is the purpose of the stomach

what are the layers of the stomach

A

storage and mixing, mechanical and chemical digestion, generates acid chyme, and primarily protein digestion

Mucosa [surface epithelia, lamina propria, and muscularis mucosae], submucosa [sub mucosal plexus], muscularlis externa [oblique layer, circular layer, and longtitudinal layer], and serosa

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15
Q

Gastric pits of the stomach

A

gastric pits have mucosa neck cells that secrete mucous that coats the stomach. there are parietal cells that produce H+ and Cl- to produce HCl in lumen. Chief cells secrete pepsinogen which is activated into pepsin by HCl. Pepsin is what digest proteins. Chief cells also produce lipase which digest fats. enteroendocrine cells (G cells) release chemical messages such as gastrin which regulate stomach secretions

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16
Q

parietal cells and chief cells

A

parietal cells: secretes H+ and Cl- producing HCl which kills bacteria, activates pepsinogen, and denatures proteins. also secretes intrinsic factor that binds to B12 to help absorb it. B12 is needed to mature erythrocytes
Chief cells: produce pepsinogen- active pepsin and lipase for fat breakdown

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17
Q

mucosal barrier: gastric juice is very acidic (pH 1.5-3.5). how does mucosa protect the stomach?

A

alkaline mucous, tight junctions between epithelial cells, and damaged epithelial mucosal cells are replaced quickly. 3-6 days

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18
Q

what are gastric ulcers and what causes them?

A

breakdown of stomach walls. 90% are caused by heliobactor pylori. most others caused by ibuprofen. treatment through antibiotics.

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19
Q

digestive processes in the stomach:

How is gastric secretions regulated?

A

two mechanisms:
Hormonal or neural
Hormonal: enteroendocrine cells produce gastrin.
Neural: vagus nerves and local extrinsic nerves

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20
Q

give an example how the gastrin phase helps with digestion

A

when you eat a steak, the rise in pH stimulates the release of gastrin which releases more HCl for breakdown the protein in steak.

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21
Q

3 main stages of digestion explain each phase:

A
  1. cephalic phase: prepares stomach for digestion through anticipation for food through though, smell, sight or taste. impulses are transmitted by the vagus nerve (this can be inhibited by loss of appetite or depression).
  2. Gastric phase: when food enters stomach, gastric juices are released. lasts about 3-4 hours. this happends two ways: a) distension (neuronal stimuli): stretch receptors b) chemical stimuli: eg peptides, caffeine, rise in pH. G cells release gastrin which triggers parietal cells to release HCl. this can inhibited by acidity or stress (sympathetic nervous system)
  3. Intestinal: a) stimulatory component- chyme enters duodenum which stimulates intestinal glands to release gastrin. this further stimulates the gastric glands. b) inhibitory component: when duodenum distends, enterogastric gland relaxes. this prevents more food from entering the small intestines and gastric secretions decline.
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22
Q

give an example how the gastrin phase helps with digestion

A

when you eat a steak, the rise in pH stimulates the release of gastrin which releases more HCl for breakdown the protein in steak.

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23
Q

how does mechanical digestion happen.

A
  1. stomach filling- rugae flatten
  2. mixing of stomach contents- peristalsis
  3. stomach emptying- takes 3-4 hours
24
Q

what are the 3 components of the small intestines and what happens here

A

for absorption and secretion

3 components are 1. duodenum 2. jejunum 3. ileum

25
Q

modifications for absorption - that help increase surface area

A
  1. length
  2. circular folds- mucosa and submucosa have fold to force chyme to spiral through lumen
  3. Villi- projections of mucosa that contain absorptive columnar cells
  4. microvilli- contain a brush boarder that contains enzymes to complete digestion of proteins and carbs
26
Q

modifications for absorption - that help increase surface area

A
  1. length
  2. circular folds- mucosa and submucosa have fold to force chyme to spiral through lumen
  3. Villi- projections of mucosa that contain absorptive columnar cells
  4. microvilli- contain a brush boarder that contains enzymes to complete digestion of proteins and carbs
27
Q

what are some specializations of the mucosa and the submucosa?

A

mucosa- A) villi have simple columnar absorptive cell with microvilli
B) intestinal crypes- between villi. pits lead into intestinal crype cells that secrete mucous and water for nutrient transport. enteroendocrine cells that secrete cholecystokinin and secretin that activate pancreas and bile. there are intraepithelia lymphocytes for immunity and paneth cells that produce lysazomes (anti-bacterial)

Submucosa-

28
Q

what are some specializations of the mucosa and the submucosa?

A

mucosa- A) villi have simple columnar absorptive cell with microvilli
B) intestinal crypes- between villi. pits lead into intestinal crype cells that secrete mucous and water for nutrient transport. enteroendocrine cells that secrete cholecystokinin and secretin that activate pancreas and bile. there are intraepithelia lymphocytes for immunity and paneth cells that produce lysazomes (anti-bacterial)

Submucosa- A) Peyers patch- aggregated lymphoid nodes, fight bacteria, concentrated in distal end.
B) Brunners gland- alkaline mucus for neutralization

29
Q

what are some specializations of the mucosa and the submucosa?

A

mucosa- A) villi have simple columnar absorptive cell with microvilli
B) intestinal crypes- between villi. pits lead into intestinal crype cells that secrete mucous and water for nutrient transport. enteroendocrine cells that secrete cholecystokinin and secretin that activate pancreas and bile. there are intraepithelia lymphocytes for immunity and paneth cells that produce lysozyme’s (anti-bacterial)

Submucosa- A) Peyers patch- aggregated lymphoid nodes, fight bacteria, concentrated in distal end.
B) Brunners gland- alkaline mucus for neutralization

30
Q

what are some specializations of the mucosa and the submucosa?

A

mucosa- A) villi have simple columnar absorptive cell with microvilli
B) intestinal crypts- between villi. pits lead into intestinal crypt cells that secrete mucous and water for nutrient transport. enteroendocrine cells that secrete cholecystokinin and secretin that activate pancreas and bile. there are intraepithelia lymphocytes for immunity and paneth cells that produce lysozyme’s (anti-bacterial)

Submucosa- A) Peyers patch- aggregated lymphoid nodes, fight bacteria, concentrated in distal end.
B) Brunners gland- alkaline mucus for neutralization

31
Q

what are some specializations of the mucosa and the submucosa?

A

mucosa- A) villi have simple columnar absorptive cell with microvilli
B) intestinal crypts- between villi. pits lead into intestinal crypt cells that secrete mucous and water for nutrient transport. enteroendocrine cells that secrete cholecystokinin and secretin that activate pancreas and bile. there are intraepithelia lymphocytes for immunity and paneth cells that produce lysozyme’s (anti-bacterial)

Submucosa- A) Peyers patch- aggregated lymphoid nodes, fight bacteria, concentrated in distal end.
B) Brunners gland- alkaline mucus for neutralization

32
Q

what is the main function of the liver? what does it produce and where is this stored? what are the four primary nodes?

A

main function of the liver is to filter and process blood. It produces bile that emulsifies fat and is temporarily stored in the gall bladder. the four primary nodes are left/ right caudate and quadrate

33
Q

what is the main function of the liver? what does it produce and where is this stored? what are the four primary nodes?

A

main function of the liver is to filter and process blood. It produces bile that emulsifies fat and is temporarily stored in the gall bladder. the four primary nodes are left/ right caudate and quadrate

34
Q

what is the functional unit of the liver? shape? type of cell? and where do they arise from?

A

function unit is liver lobule and it is hexagonal. it has plates of hepatocyte cells which radiate out of central veins

35
Q

what is the functional unit of the liver? shape? type of cell? and where do they arise from?

A

function unit is liver lobule and it is hexagonal. it has plates of hepatocyte cells which radiate out of central veins

36
Q

what are hepatocytes? what do they consist of and what is their function?

A

liver cells made up of RER SER golgi, mitochondria and peroxisomal (contains detoxifying enzymes)
function: produce bile, process nutrients, store fat-soluble vitamins, and detoxify

37
Q

what are hepatocytes? what do they consist of and what is their function?

A

liver cells made up of RER SER golgi, mitochondria and peroxisomal (contains detoxifying enzymes)
function: produce bile, process nutrients, store fat-soluble vitamins, and detoxify

38
Q

what is found at each corner of the hexagon in the liver cells and what do they consist of?

A

portal triads- consist of hepatic arteriole- oxygenated blood, hepatic portal venule- blood from digestive tract, and bile ducts.

39
Q

what is found at each corner of the hexagon in the liver cells and what do they consist of?

A

portal triads- consist of hepatic arteriole- oxygenated blood, hepatic portal venule- blood from digestive tract, and bile ducts.

40
Q

list how blood flows through liver

A

hepatic portal vein and hepatic artery–> sinusoids–> central vein–> hepatic vein–> exit liver

41
Q

list how blood flows through liver

A

hepatic portal vein and hepatic artery–> sinusoids–> central vein–> hepatic vein–> exit liver

42
Q

What colour is bile? what does it consist of? what is the function of bile salts and where does it flow?

A

yellow-green colour. contains bile salts, phospholipids, bile pigment, cholesterol, and electrolytes. bile salts emulsify fat. helps digest cholesterol and fat and makes cholesterol soluble. bile salts flow through bile canaliculi and are recyclable

43
Q

why do enzymes produce in inactive form

A

so they do not start working in the pancrease

44
Q

what are the main functions of the large intestine?

A
  1. absorb water 2. produce vitamins 3. removes wastes
45
Q

what are the unique features of the large intestine?

A
  1. Haustrum- sacs caused by tenia coli
  2. epiploic appendages- fat filled sacs
  3. Tenia Coli- longitudinal muscle layer reduced to 3 bands
46
Q

what are the unique features of the large intestine?

A
  1. Haustrum- sacs caused by tenia coli
  2. epiploic appendages- fat filled sacs
  3. Tenia Coli- longitudinal muscle layer reduced to 3 bands
47
Q

how are the large intestine different from the small?

A

no folds, no digestive enzymes, no villi, lots of goblet cells, thicker mucosa, and deeper crypts

48
Q

how are the large intestine different from the small?

A

no folds, no digestive enzymes, no villi, lots of goblet cells, thicker mucosa, and deeper crypts

49
Q

how does defecation take place?

A
  1. stretching of the rectal walls sends impulse to the spinal cord.
  2. parasympathetic nerve fibres stimulates rectal walls to contract and relaxation of the internal anal sphincter
  3. voluntary signals ‘tell’ external sphincter to relax.
50
Q

how does defecation take place?

A
  1. stretching of the rectal walls sends impulse to the spinal cord.
  2. parasympathetic nerve fibres stimulates rectal walls to contract and relaxation of the internal anal sphincter
  3. voluntary signals ‘tell’ external sphincter to relax.
51
Q

how does chemical digestion occur

A

through hydrolysis- breakdown of molecules by adding water to break bonds.
molecules are broken down so they can be absorbed
catalyzed by enzymes

52
Q

how does chemical digestion break down carbohydrates, proteins, and fats?

A

carbohydrates= di- polysaccharides —> monosaccharides. starts in the mouth with the enzyme amylase
protiens–> amino acids. mostly broken down in the stomach from pepsin
Fats–> glycerol and free fatty acids. occurs first in the duodenum from bile salts and lipase

53
Q

how does chemical digestion break down carbohydrates, proteins, fats, and nucleic acid?

A

carbohydrates= di- polysaccharides —> monosaccharides. starts in the mouth with the enzyme amylase
protiens–> amino acids. mostly broken down in the stomach from pepsin
Fats–> glycerol and free fatty acids. occurs first in the duodenum from bile salts and lipase
Nucleic acid- DNA/ RNA–> bases, sugars, and phosphate ions, they are absorbed into the blood via the pancreas

54
Q

absorption of molecules: mostly by active transport

A

everything must go epithelial cells.
Carbohydrates: glucose is co-transported with Na+ then absorbed into the blood through facilitated diffusion.
Protein is digested into amino acids by the pancreas and by brush boarder enzymes. amino acids are absorbed by active transport into absorptive cells and leave by facilitated diffusion.
Lipids: micelle’s carry fatty acids and glycerol to mucosa where they enter the cell via diffusion and form chylomicrons. they are extruded by epithelial cells by exocytosis and enter lacteal and travel to the lympth.

55
Q

absorption of molecules: mostly by active transport

A

everything must go epithelial cells.
Carbohydrates: glucose is co-transported with Na+ then absorbed into the blood through facilitated diffusion.
Protein is digested into amino acids by the pancreas and by brush boarder enzymes. amino acids are absorbed by active transport into absorptive cells and leave by facilitated diffusion.
Lipids: micelle’s carry fatty acids and glycerol to mucosa where they enter the cell via diffusion and form chylomicrons. they are extruded by epithelial cells by exocytosis and enter lacteal and travel to in lympth.

Bio 133 (6 decks)

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