Lecture 3 - Digestion, Absorption and Transport Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

What are the 3 processes that food undergo when we eat it?

A

Digestion
Absorption
Elimination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the GI tract?

A

Series of organs arranged as a long tube

-from the mouth to the anus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the 2 components that make up the GI tract?

A

Organs (stomach, intestines)

Sphincters (muscles that control the passage if material from one organ to the next)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are challenges of the digestion process?

A
Multi-taskis of the mouth
Diaphragm
Steady movement
Lubrication of food
Digestive Enzyme functions
Management of waste
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is digestion?

A

The process of breaking large food molecules down to smaller molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the 2 ways in which we can digest food?

A

Mechanical via chewing and peristalsis

Chemical via enzymes and acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What re the 3 phases of digestion?

A
  1. Cephalic Phase- mouth (the thought of food, smell taste, chewing and swallowing)
  2. Gastric - Stomach
  3. Intestinal - Intestines
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How does digestion start in the mouth?

A

Chewing and grinding of food.
Saliva moistens food
Salivary amylase starts comical digestion of carbs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the 2 phases of swallowing you do voluntarily?

A

Oral preparatory phase ( formation of the bolus)

Oral transit phase ( bolus moves from the front to the back of your mouth for passage to the pharynx)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the Pharyngeal Phase?

A

Involuntary process that closes the nasal passage, tongue base to posterior pharyngeal wall contact, contraction of muscles, closure of epiglottis and opening of upper esophageal sphincter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How does the bolus move to the esophagus?

A

Through the upper esophageal sphincter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How does the bolus move down the esophagus?

A

Peristalsis moves the bolus down the esophagus to the stomach
-movement is also aided by gravity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is peristalsis?

A

Waves of squeezing and pushing contractions by muscles that move food through the GI tract

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What separates the stomach from the esophagus?

A

The lower esophageal sphincter

cardiac sphincter, where people feel heartburn

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Why do people get heartburn?

A

When stomach juices get past the lower esophageal sphincter. The pH is so low i hurts and can cause damage to the tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Does chemical or mechanical digestion occur in the stomach?

A

Both
Chemical digestion of proteins and fats

Mechanical digestion to mix food with gastric juices

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Where does gastric juices come from?

A

Secreted by the gastric glands

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is gastric juice composed of?

A

HCl- denature proteins and activate pepsin
Pepsin- digest protein
Gastric lipase- digest fat
Mucus-protect stomach lining

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is Chyme?

A

Semi-solid product of mechanical and chemical digestion in the stomach

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How does food from the top of the stomach get to the small intestine?

A

Peristalsis breaks down the food, mixing it with the gastric juices. When it breaks down it starts to drop to the bottom.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Why doesn’t chyme burn the small intestine?

A

When chyme enters the small intestines, the pancreas releases bicarbonate to neutralize the acidic chyme

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How does food get out of the stomach?

A

Slowly through the pyloric sphincter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are the 2 different movements of peristalsis?

A

P: continuous steady movement 9sneak eating food)

S: starting of the mechanical squeezing of the food products to become available for digestion

-combination of the 2 breaks down the chyme into small pieces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are the 3 accessory organs to digestion?

A

Liver - makes bile
Gall bladder - stores bile
Pancreas - makes digestive enzymes and bicarbonate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Why is liver bile important for digestion?

A

Bile acts as an emulsifier which helps digest fat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What happens when people don’t have a gall bladder?

A

You are unable to digest higher quantities of fat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is to note about the enzymes in the pancreas?

A

Pacrease produces enzymes but in the inactive form, they are only the precursors. When the enzymes hit the right pH in the intestine they are released

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What are the 4 sphincters, where are they and what are they meant to do?

A

Upper esophageal: opens in response to swallowing

Lower esophageal: prevents reflux of stomach contents

Pyloric Sphincter: holds chyme in stomach to be mixed and prevents intestinal contents from coming back up

Ileocecal Sphincter: Allows emptying of small intestine contents into large intestine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is absorption?

A

The process of taking molecules across a cell membrane and into cells of the body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Where does most absorption take place in the body?

A

Small intestines

-a little in the stomach (water, alcohol)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

How long does it take the body to absorb nutrients after you have eaten?

A

3-4 hours

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Why does absorption require a constant supply of blood?

A

To transport all the nutrients out of the small intestine and into the blood for it to be taken to all parts of the body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What are villi?

A

Folds in the lining that are in close contact with nutrient molecules

34
Q

What is the brush border?

A

Composed of microvilli which greatly increase the surface area

35
Q

Where does the absorption of iron and folate take place?

A

Duodenum

36
Q

Where does the absorption of B12 and bile salts tale place?

A

ileum

37
Q

Where does the absorption of carbs, fats, proteins, Ca, Mg, Vitamins and trace elements take place?

A

Small intestine as a whole

38
Q

Where does the absorption of short chain fatty acids take place?

A

Large intestines

39
Q

Where does water and electrolyte absorption take place?

A

All throughout the small and large intestines

40
Q

What produces the short chain fatty acids in the large intestines?

A

Bacteria in the colon

41
Q

After nutrient absorption into the blood, where does it go?

A

Liver which detoxifies the blood, then moves through to the heart, blood stream, tissue than organ

42
Q

What is different about fatty acid absorption?

A

Large fatty acids bypass the liver via the lymphatic system and first goes to the heart

43
Q

What is the vascular system?

A

Closed system of vessels filled with blood

  • heart is the pump for continuous flow
  • delivers O2 and nutrients
  • removes CO2 and waste from tissues
44
Q

What is the order of blood circulation via the vascular system?

A

Heart –> Arteries –> Capillaries intestines –> Helatic portal vein –> capillaries in liver –> hepatic vein –> heart

45
Q

What is the body most metabolically active organ?

A

Liver

46
Q

How are nutrients delivered to the liver?

A
  1. Water soluble nutrients are absorbed through the vessels
  2. Vessels merge into the hepatic portal vein. brings all absorbed material to liver
  3. Hepatic artery bring oxygenated blood for liver cells
  4. Capillaries within the entire liver brand out to deliver O2 and nutrients to cells
  5. Hepatic vein gathers blood from liver and returns it to the heart
47
Q

What is the lymphatic system?

A

A one way rout that circulates between cells and collects into tiny vessels

48
Q

Where do lymphs collect?

A

In the thoracic duct

49
Q

How do lymph contents enter the bloodstream?

A

Via the left subclavian vein

50
Q

In the final stages, what happens to the undigested residues?

A

Continue through the GI tract, help exercise the GI muscles and are able to retain water

51
Q

What is normally found within the large intestine?

A
Bacteria (ferments fibre)
Recyclable materials (water, salts)
52
Q

What is the difference between pre and probiotic

A

Prebiotic is the bacteria food

Probiotic is the actual strain of the bacteria

53
Q

How does undigested food move from the SI to the LI?

A

via the ileocecal valve (another sphincter)

54
Q

How long it material stored in the large intestine before it is eliminated?

A

Material is stored 12-24 hours prior to elimination

-water and some nutrients are absorbed (short chain fatty acids, Na, K)

55
Q

What are the 4 sections of the large intestine?

A

Ascending colon
Transverse colon
Descending colon
Sigmoid colon

56
Q

What is the other excretion organ?

A

Kidney, filters passing blood, waste materials are concentrated and exerted as urine
-Na and K reabsorbed to help control blood pressure

57
Q

How is the GI tract kept healthy and regulated?

A

Gastrointestinal bacteria (flora) - # depends on diet, pH, peristalsis and other microorganisms

Probiotics

Ferment fibre and complex proteins

58
Q

What are the 2 GI hormone pathways?

A

Endocrine - releases hormones to make you feel satisfied

Nervous - sphincter opening and closing

59
Q

What is gastrin and how does it work?

A

Is a GI hormone that is secreted from stomach wall cells which responds to food in the stomach, which stimulates stomach glands to secrete HCl into the stomach

60
Q

What is secretin and how does it work?

A

Is a GI hormones that is secreted from the duodenal wall which responds acidic chyme in the SI which stimulates the pancreas to release bicarbonate juices into the SI

61
Q

What is Cholecystokinin and how does it work?

A

GI hormone that is secreted from the intestinal wall which responds to fat or protein in the SI, which stimulates the gall bladder to release bile into the duodenum and the pancreas to release bicarbonate and enzyme rich juices into the SI

62
Q

What does CCK do on the length of absorption?

A

Slows down the transit time int eh SI so we have more time to absorb nutrients and allow for the reactions to be completed

63
Q

At its best, what can the digestive system do?

A

Sensitive and responsive to environmental conditions

  • provides immunity
  • protection against invaders
64
Q

in order for the digestive system to be at its best, what does this depend on?

A

Healthy Blood supply

Lifestyle factors

Diet

65
Q

How does choking occur?

A

Food is stuck in the trachea and is blocking air.

-Epiglottis is open allowing the larynx to be open

66
Q

What is vomiting

A

Mechanism to get rid of unwanted things/ make you feel better

67
Q

What is diarrhea

A

Mechanism to rid the body of something that is upsetting it

-Frequent loose and watery stools

68
Q

What do vomiting and diarrhea have in common?

A

Both result in dehydration and elimination of foreign substance

69
Q

What is constipation?

A

Hard infrequent bowl movements

70
Q

Which foods produce gas?

A

Most common are foods rich in carbs (sugar, starches and fibre)
-foods must be determined individually to see if they actually cause gas

Partially digested carbs reach the LI then bacteria ferment them, producing gas as a byproduct

71
Q

What is heartburn?

A

Gastroesophageal refulx

-stomach acid into the esophagus

72
Q

What are ulcers?

A

Lesions or sores that lead to compromised cells

73
Q

What are the causes of ulcers?

A

Bacterial infections
NSAIDs: Non Steroidal Anti-Inflammatory Drugs
Excess acid production

74
Q

How to prevent choking?

A

Small bites

Chew thoroughly

75
Q

How to prevent belching?

A

Eat slowly
Relax
Chew thoroughly

76
Q

How to prevent intestinal gas?

A

Eat bothersome foods in moderation

77
Q

How to prevent Heartburn?

A
Eat small meals
Drink liquids between meals
Sit up while eating
Wait 3 hours before lying down
Don't wear tight clothes
Lose weight
78
Q

How to prevent ulcers?

A

Medicine
Avoid coffee and alcohol containing beverages
Minimize aspirin, ibuprofen and naproxen intake

79
Q

How to prevent diarrhea?

A

Rest

replace lost fluids

80
Q

How to prevent constipation

A

Fibre
Hydration
Exercise
Poop regularly