Digestive System Flashcards

1
Q

6 Functions of Digestive System

A

Ingestion
Mechanical Processing
Digestion
Secretion
Absoprtion
Excretion

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2
Q

6 Subdivisions of Digestion Tract

A

Oral Cavity (+Teeth/Tongue)
Pharynx
Oesophagus
Stomach
Small Intestine
Large Intestine

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3
Q

Oral Cavity Digestive Function

A

Mechanical Processing
Moistening
Salivary Secretions

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4
Q

Pharynx Digestive Function

A

Propulsion

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5
Q

Oesophagus Digestive Function

A

Transport of materials to Stomach

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6
Q

Stomach Digestive Function

A

Chemical Breakdown
Mechanical Processing

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7
Q

Small/Large Intestine Digestive Function

A

Enzymatic Digestion
Absorption

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8
Q

4 Accessory Organs of Digestive System

A

Salivary Glands
Liver
Gallbladder
Pancreas

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9
Q

Salivary Gland Digestive Function

A

Secretion of Saliva

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10
Q

Liver Digestive Function

A

Secretion of Bile

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11
Q

Gallbladder Digestive Function

A

Storage of Bile

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12
Q

Pancreas Digestive Function

A

Secretion of Buffers and Enzymes

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13
Q

Peritoneum Definition

A

Cavity holding DIgestive Organs
Lined by Serous Parietal Membrane

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14
Q

Function of Peritoneal Fluid

A

Found in Peritoneum
Lubrication of organs during contraction/expansion
Allows organs to slide over each other

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15
Q

Mesentery Definition/Function

A

Attaches portions of digestive tract to peritoneum.
Allows for passage of blood vessels, nerves and lymphatic vessels

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16
Q

Function of Digestive Tract

A

Protection against Digestive Acids/Enzymes, Mechanical Stress and Bacteria

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17
Q

4 Major Layers of Digestive Tract

A

Mucosa
Submucosa
Muscularis Externa
Serosa

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18
Q

Plica Circulares Definition/Function

A

Microvilli lining the Digestive Tract
Increases SA on digestive tract

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19
Q

3 Structures of Mucosa

A

Mucosal Epithelium - Simple Columnar for faster absoprtion
Lamina Propria - Areolar Tissue with blood/lymphatic vessels
Muscularis Muscosae - Smooth muscle changing shape of Plica

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20
Q

Contraction of Muscularis Muscosae/Externa

A

Inner Circular Layer contraction decreases diameter of Plica
Outer Longitudinal Layer contraction decreases length of Plica

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21
Q

Submucosa Definition/Function

A

Layer of dense irregular connective tissue
Contains large blood vessels and lymphatic vessels
Acts as service corridor

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22
Q

Muscularis Externa Definition/Function

A

Smooth Muscle controlling shape of GI tract
2 Layers, similar to Muscularis Mucosa

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23
Q

Structure similar to Serous Membrane

A

Adventitia
Dense sheath of collagen fibres
In Oral Cavity, Pharynx, Oesophagus, Rectum

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24
Q

Cells controlling smooth muscle activity

A

Pacesetter Cells - Similar to Pacemaker Cells in Heart
Cells undergo spontaneous depolarization in waves

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25
Q

Peristalsis Definition

A

Involuntary Contraction/Relaxation of Smooth Muscle in Digestive Tract to move food

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26
Q

3 Steps of Peristalsis

A

Circular Muscle Contracts behind bolus
Longitudinal Muscle Contracts ahead of bolus
Circular Muscle Contracts to force bolus forward

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27
Q

Functions of Oral Cavity

A

Sensory Analysis
Mechanical Processing
Lubrication
Limited Digestion (carbs+lipids)
Passageway for air,food and liquids

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28
Q

Functions of Saliva

A

Lubricates mouth and contents
Dissolves chemicals
Initiating digestion of complex carbs via salivary amylase

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29
Q

4 Steps of Swallowing

A

Buccal Phase - Bolus is pushed to back of mouth by tongue
Pharyngeal Phase - Food pushes back epiglottos cartilage, closing the trachea
Oesophageal Phase - Food travels down oesophagus
Food enters stomach

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30
Q

4 Features of Oesophagus

A

Contains Stratified Squamous Epithelium
Resting muscle tone prevents air from entering
Conveys food and liquid to stomach
Contains Adventitia

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31
Q

Functions of Stomach

A

Storage of Ingested Food
Mechanical/Chemical Breakdown
Production of Intrinsic Factor

32
Q

2 Modes of Chemical Breakdown

A

Enzymes - e.g. Pepsin, amylase, lipase
Acid (HCl) - for pathogens and plant cell walls

33
Q

Function of Intrinsic Factor

A

Needed for B12 Absorption

34
Q

Function of Rugae

A

Folds in Stomach Lining that allow for Mechanical expansion of Stomach

35
Q

Epithelium in stomach

A

Simple Columnar Epithelium
Produces mucus using gastric pits/glands

36
Q

3 Layers of Muscle in Stomach

A

Oblique
Circular
Longitudinal

37
Q

3 Cell Types in Gastric Glands + Functions

A

Parietal Cells - Secrete Intrinsic Factor and HCl
Chief Cells - Secrete Pepsinogen
G Cells - Secrete Gastrin

38
Q

Pepsinogen Definition

A

Proenzyme of Pepsin
Converted to Pepsin via HCl

39
Q

4 Steps of HCl Secretion in Parietal Cells

A

Carbonic Acid converted to H2O + CO2 via Carbonic Anhydrase, dissociates to H+ ions
Countertransport mechanism ejects bicarbonate ions and imports Cl- ions
Cl- ions diffuse across cell and exit through open Cl- channels into gastric gland lumen
H+ ions transported into gastric gland lumen via active transport

40
Q

3 Regions of Small Intestine

A

Duodenum
Jejunum
Ileum

41
Q

4 Duodenum Features

A

25 cm Long
Neutralises Chyme
Receives secretions from pancreas/liver
Few Plica/villi

42
Q

3 Jejunum Features

A

2.5m long
Location of most chemical digestion/absorption
Prominent Plica/Villi

43
Q

2 Ileum Features

A

3.5m long
Contains Lymphoid nodules

44
Q

Lacteal Defintion

A

Central Lymphatic Vessel in Intestinal Wall

45
Q

Chyme Definition

A

Acidic fluid in stomach containing gastric juices/food from stomach to small intestine

46
Q

Features of Villi

A

Large SA and many blood vessels for high rate of transport
Contains Lacteal

47
Q

Secretion at Intestinal Glands

A

Rapidly dividing epithelium cells disintegrate at tips of villi to secrete enzymes to lumen
= Holocrine Secretion

48
Q

Brush Border Enzymes Definition/Function

A

Integral membrane proteins on intestinal microvilli
Breaks down materials in contact with brush border
e.g. Enteropeptidase - activates proenzyme tryspinogen

49
Q

Function of Enteroendocrine Cells

A

Produces Hormones in respone to pH changes in GI Tract
e.g. CCK and secretin - increases enzyme/bile secretion

50
Q

Duodenal Gland Function

A

Produces mucus to raise pH

51
Q

4 Secreted Enzymes in Pancreas

A

Pancreatic Alpha-Amylase
Pancreatic lipase
Nucleases
(Inactive) Proteases/Peptidases

52
Q

Endocrine/Exocrine Function in Pancreas

A

Endocrine Cells in Pancreatic islets secrete insulin and glucagon into bloodstream
Exocrine Cells in Pancreatic acini secrete pancreatic juice

53
Q

Liver Blood Supply

A

2/3 from Hepatic Portal Vein
1/3 from Hepatic Artery

54
Q

Function of Hepatic Portal Vein

A

Carries toxins/nutrients extracted from digestive contents in stomach/intestine

55
Q

Function of Hepatic Artery

A

Suppies Liver with O2

56
Q

Blood Flow in Liver

A

Blood flows past hepatocytes to absorb solutes and secrete proteins

57
Q

3 Portal Areas in Liver

A

Hepatic Portal Vein
Hepatic Artery
Bile Duct

58
Q

Branches in Liver

A

Sinusoids drain into central Vein
Bile ductules drain into bile ducts

59
Q

3 Functions of Liver

A

Metabolic Regulation
Haematological Regulation
Bile Production

60
Q

Metabolic Regulation in Liver

A

Metabolism of carbs, lipids, amino acids
Waste Product Removal
Vitamin Storage
Mineral Storage
Drug Inactivation

61
Q

4 Steps of Bile Transport and Storage

A

Liver Secretes Bile
Bile is stored and concentrated in Gallbladder
Duodenal CCK triggers contraction of gallbladder for Bile to be ejected into duodenum
Bile salts breakdown lipid droplets via emulsification

62
Q

4 Large Intestine Functions

A

Absorption
Site of Bacterial vitamin production
Compations of faeces
Storage of faeces until defaecation

63
Q

Cecum Definition

A

Reservoir at the start of large intestine for anaerobic bacteria

64
Q

Appendix Definition

A

Structure that repopulates gut with bacteria and fights pathogens in the gut

65
Q

3 Features of Large Intestine

A

Lacks Villi
Abundant mucous cells for pathogen protection
Easier absorption

66
Q

Central Neural Control of Intestinal Movements

A

Parasympathetic ANS increases motility and secretion
Sympathetic ANS inhibits motility and secretion

67
Q

2 Central Gastric Reflexes

A

Gastroenteric Reflex - Stimulates motility and secretion along entire small intestine
Gastroileal Reflex - triggers opening of ileocaecal valve

68
Q

Ileocaecal Valve Function

A

Valve that allows for materials to pass from small intestine to large intestine

69
Q

4 Hormonal Pathways of Digestive System

A

Gastrin
GIP
Secretin/CCK
VIP

70
Q

Gastrin Hormonal Pathway

A

Food in Stomach stimulates Gastrin
Gastrin stimulates acid production in parietal cells and gastric motility

71
Q

GIP Hormonal Pathway

A

Chyme in Duodenum stimulates GIP
GIP Inhibits Gastrin Pathway
GIP stimulates release of insulin from pancreas
This facilitates nutrient utilization

72
Q

Secretin/CCK Hormonal Pathway

A

Chyme in Duodenum stimulates Secretin and CCK
Stimulates release of pancreatic enzymes and buffers/bile secretion

73
Q

VIP Hormonal Pathway

A

Chyme in Duodenum stimulates VIP
VIP stimulates dilation of intestinal capillaries
This facilitates nutrient absorption

74
Q

Digestive Breakdown of Carbohydrates
(Enzymes, locations, products, transport mechanisms)

A

Salivary Amylase in Oral Cavity to Di/Trisaccharides
Pancreatic Alpha-amylase in Small Intestine to Di/Trisaccharides
Lactase/Maltase/Sucrase in Brush Border to Monosaccharides
Facilitated diffusion and cotransport into Intestinal Mucosa
Facilitated diffusion into capillary

75
Q

Breakdown of Lipids
(Enzymes, locations, products, transport mechanisms)

A

Lingual Lipase in Oral Cavity to Monoglycerides/Fatty Acids
Bile and Pancreatic Lipase in Small Intestine to Monoglycerides/Fatty Acids
Diffusion into Intestinal Mucosa
Converted into Chylomicrons in Intestinal Mucosa
Exocytosis into Lacteal

76
Q

Breakdown of Proteins
(Enzymes, locations, products, transport mechanisms)

A

Pepsin in Stomach to Polypeptides
Trypsin, Chymotrypsin, Elastase, Carboxypeptidase in Small Intestine to Short Peptides/Amino Acids
Dipeptidases in Brush Border to Amino Acides
Facilitated DIffusion and Cotransport to Intestinal Mucosa
Facilitated Diffusion and Cotransport to Capillary