Human Physiology Digestion (All) Flashcards

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1
Q

Digestion Parts

A

Ingestion, Digestion, Absorption, Assimilation, elimination

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2
Q

What is DNA and RNA broken into

A

Nucleotides

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3
Q

Why is temperature of body 37 degrees

A

Optimum enzyme controlled temperature.

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4
Q

What process controls the way food moves through the Alimentary Canal

A

Automatic Nervous System keeps food moving, as it controls the contraction of the fibers of the inner circular muscles in a process knows as peristalsis

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5
Q

Automatic Nervous System

A

regulates involuntary physiologic processes including heart rate, blood pressure, respiration, digestion, and sexual arousal.

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6
Q

Where is peristalsis occurring the most and the least

A

Highest at the esophagus
Lowest at the Intestines

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7
Q

Digestive Process that occurs in the mouth

A

Mechanic Breakdown, done through chewing
Enzymatic Breakdown, Salivary Amylase - pH 7

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8
Q

Digestive Process that occurs in the Esophagus

A

None, just persistalsis

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9
Q

Digestive Process that occurs in the Stomach

A

Mechanic Breakdown, Churning of food
Enzymatic Breakdown, Lined by Gastric Pits that release digestive juices creating an acidic environment for pepsin to function

Stomach has gastric glands, that release digestive acids, that create a low pH. environment of 2 ph. This acidic environment denatures proteins, and other macro molecules. The stomach consists of an epithelium that contains a mucus membrane that prevents acid from damaging the gastric lining.

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10
Q

ph of stomach

A

Around 2 (1.5 to 3)

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11
Q

Digestive Process that occurs in the liver

A

Breakdown of toxic products, storage of glucagon, production of bile

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12
Q

Digestive process that occurs in the pancreas

A

Produce bicarbonate ions that neutralize the stomach acid. Produces enzyme = trypsin, pancreatic amylase, lipase, nuclease, endopeptidase, Insulin production from B cells of islets of Langerhans

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13
Q

Function of Gall bladder

A

Storage of bile

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14
Q

Small intestine parts

A

Duodenum, jejunum, ileum

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15
Q

pH of small intestine

A

7

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16
Q

Function of Large intestine

A

Absorption of h20 and dissolved minerals to form indigestible food residue.
Many bacteria’s are found here that is useful for immune system

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17
Q

Mechanical Digestion parts

A

Chewing, Segmentation, Churning

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18
Q

Function of uvula

A

Prevents bolus from entering nasal cavity

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19
Q

Chyme

A

Semi digested pasta found in the stomach that consists of partially digested food and gastric Juices

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20
Q

Persistalsis

A

Longitudinal smooth muscles contract and relax

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21
Q

Segmentation

A

Non adjacent circular muscles contract and relax

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22
Q

Why is segmentation bidirectional

A

Slows down chyme movement, so there is better absorption of nutrients through the small intestine

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23
Q

Chemical digestion

A

Enzymes, acid, bile

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24
Q

What does bile consist of

A

Bile salts

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25
Q

Definition of enzymes

A

Catalysts that speed up chemical reaction rate by lowering activation energy

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26
Q

Why are enzymes for digestion of disaccharides often immobilized on the epithelial lining of the small intestine, near the channel proteins

A

The membrane will be embedded with immobilized digestive enzymes and channel proteins to assist in material uptake allowing for more absorption to occur

27
Q

HCl activates which enzyme

A

Pepsinogen into pepsin

28
Q

Parts of a small intestine

A

Serosa,
Muscle layer
Submucosa
Mucosa

29
Q

Parts of a villi

A

Microvilli
Rich blood supply
Single layer epithelium
Lacteals
intestinal glands
Membrane proteins

30
Q

Parts of a villus epithelium

A

Tight junctions
microvilli
mitochondria
pinocytotic vesicles

31
Q

Serosa Definition

A

Protective Outer Covering composed of a layer of cells reinforced by fibrous connective tissues

32
Q

Muscle Layer Definition

A

Outer Layer of longitudinal muscles and inner layer of circular muscle

33
Q

Submucosa Definition

A

Connective Tissue separating muscle layer from innermost mucosa

34
Q

Mucosa Definition

A

Highly folded inner layer (villi) that absorbs material through surface epithelium from intestinal lumen

35
Q

Microvilli definition

A

Ruffling of epithelium membrane through finger like projections, to increase surface area to volume ratio

Membrane is embedded with immobilized digestive enzymes and channel proteins to assist in material intake.

36
Q

Rich Blood Supply definition

A

Dense capillary network rapidly transports absorbed products

37
Q

Single layer epithelium defintion

A

Minimizes diffusion distance between lumen and blood

38
Q

Lacteals Definition

A

Absorbs Lipids from the intestine into the lymphatic system

39
Q

Intestinal Glands Definition

A

Exocrine pits release digestive juices

40
Q

Membrane Proteins Definition

A

Facilitates transports of digested materials into epithelial cell

41
Q

Tight Junctions Definition

A

Occluding associations between the plasma membrane of 2 adjacent cells, creating an impermeable membrane

Ensures that digestive fluids are separated from tissues and maintains a concentration gradient to ensure one way movement.

42
Q

Mitochondria cells in the epithelial cells

A

large number as it needs large number of atp for active transport and pinocytosis.

43
Q

Exocrine Gland definition

A

Gland that secrete to a specific area through a duct

44
Q

Exocrine Glands secrete what in digestion

A

Saliva, Bile, Gastric Juice, Pancreatic Juice

45
Q

Exocrine Glands secrete what in digestion

A

Saliva, Bile, Gastric Juice, Pancreatic Juice

46
Q

Catabolism Definition

A

the breakdown of complex molecules in living organisms to form simpler ones, together with the release of energy

47
Q

Endocrine Gland in the Pancreas

A

Small group of cells that secrete the hormones insulin and glucagon into the bloodstream.

48
Q

Exocrine Gland in the pancreas

A

Secrete enzymes into the gut in response to eating a meal

49
Q

Adaptations in small intestine

A

7m in length
Folding of the inner surface
Villi - small finger like projections to increase the surface area
Micro Villi - extensions of the cytoplasm on the epithelial cells facing the lumen

50
Q

Amylose bonds

A

1-4 alpha glucose

51
Q

Amylopectin Bonds

A

1-4 alpha glucose and 1-6 glucose
Branched

52
Q

Properties of a dialysis tubing

A

Size specific permeability

53
Q

Why are digestive juices secreted when needed

A
  • Saves resources (Most digestive juices are enzymes which are synthesised from amino acids)
  • Saves energy (Protein is synthesis requires ATP)
54
Q

How is digestive juices secretion controlled

A

Hormonal and nervous mechanisms
- Secreted into the lumen of the gut by exocrine glands

55
Q

Secretory Cells acini cells features

A
  • many mitochondria to provide energy for protein synthesis
  • Large number of RER for synthesis of digestive enzymes
  • Nucleoli in the nucleus for synthesis of ribosomes for the RER
  • Several Golgi Apparatuses for processing the protein coming from the RER
  • Large number of secretory vesicles for storing the enzyme prior to secretion
56
Q

Control of release of gastric juice

A

Secretions involves both hormonal and nervous control
- Sight and smell of food trigger a nerve impulse. These nerve impulses are sent via the vagus nerve and reach the wall of the stomach.
- Nerve impulses stimulate the release of gastric juice when the food enters the stomach
- In the wall of the stomach, stretch receptions (mechanoreceptors) send nerve impulses to the brain
- Impulses from the brain stimulate the release of the hormone Gastrin from the stomach wall
- Digestion of protein specific amino acids which stimulate chemoreceptors in the wall of the stomach
- These send nerve impulses via a local nerve net to the Gastrin secreting glands. This maintains the flow of Gastrin
- Gastrin maintains the flow of gastric juice over a longer time period

57
Q

What does gastric juice contain

A

Pepsin, rennin and hydrochloric acid, mucus and water

58
Q

How is the stomach of the pH controlled

A

Via negative feedback, when it falls too low the release of Gastrin in inhibited by the hormones secretin and somatostatin

59
Q

Proton Pump Inhibitors

A

Proton pump inhibitors are drugs that block the activity of ATPase
The reduces proton secretion and the pH of the stomach becomes less acidic
This gives relief from heartburn
It allows the ulcerated part of the stomach wall to heal

60
Q

Helicobacteria Pylori and stomach cancer

A

The shape and the movement of the bacteria allow them to penetrate the protective mucus layer, they secrete substances that reduce the effectiveness of the mucus later and this allows gastric acid to reach the stomach wall and causes ulcers.

61
Q

Villi adaptations

A
  • Finger like shape
  • Microvilli
  • Enzymes
  • Many mitochondria
  • Dense capillary Networks
  • Lacteal
  • Tight junctions
  • Pinocytotic Vesicles
  • Different types of proteins on the apical surface
62
Q

What does faeces contain

A

Fibre, biliburin (from bile that comes from the breakdown of RBC in liver), undirected materials

63
Q

Explain Cholera and its effects

A

Caused by vibrio cholera
Bacteria spreads in water and food

When it reaches the intestine it releases a toxin that is taken up by the Villi through Endocytosis. The toxin causes a response in the cell to secrete chrolide and hydrogen Carbondale ions.

water leaves the cells through osmosis, that causes diarrhoea and dehydration that could lead to death.

Patients treated with rehydration salts.