Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Kerri's Part 1 Biomed Slides > 7. Digestive System Part 1 - New > Flashcards

7. Digestive System Part 1 - New Flashcards

1
Q

Describe the THREE things which contribute to the following statement:

‘You are what you eat’

A

Digestion
Absorption
Excretion

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

Name THREE accessory organs of the digestive tract.

A

Salivary glands
Gallbladder
Pancreas
Liver

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

Describe the 6 ways that our food is taken in and digested as it goes through the body

A

Ingestion: Oral intake of substances

Secretion: Release of digestive juices - water, acid, enzymes and juices

Mixing and propulsion: Contraction / relaxation in walls to help mix and propel food

Digestion: Mechanical and chemical processes to break down ingested foods

Absorption: Substances passing through the walls of the GIT into the lymph and blood

Excretion: Excretion of waste and indigestible materials

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

Name FOUR layers of the gastrointestinal tract.

A

Mucosa
Submucosa
Muscularis Externa
Peritoneum

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

The mucosa layer of the GIT is made up of three layers. What are they

A

Epithelial:

Simple epithelium for protection in the mouth, pharynx, oesophagus an anus.

Columnar epithelium in the stomach and intestines for absorption with
- Microvilli in the small intestines
- Goblet cells
- Enteroendocrine cells

Lamima Propria:

Connective tissue and lots of blood and lymphatic vessels

Contains MALT

Muscularis Mucosa:

Very thin layer of smooth muscle

Creates the villi that increase surface area for absorption

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

Describe the role of Microvilli

A

Microvilli are folds in the small intestine that increase surface area and therefore assist with absorption

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

Describe the role of Goblet cells

A

Produced by the parietal cells in the peritoneum wall and they produce mucus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Explain what is meant by MALT.

A

Mucosa Associated Lymphoid Tissue.
It is a collection of immune cells such as lymphocytes and macrophages.

In the gut we call it GALT

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

Describe the role of GALT.

A

Gut Associated Lymphoid Tissue.

It is a collection of immune cells such as lymphocytes and macrophages in the GIT.
It is the first line of defence against ingested pathogens
GALT contains 70% of the bodies immune cells.

It is situated in the lamina propria

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

Name locations of MALT in the body.

A

It is especially prevalent in tonsils, oesophagus, small intestine, appendix and large intestine but in the GIT it is called GALT.

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

List TWO functions of involuntary smooth muscle contractions in the digestive tract.

A

Peristalsis for moving food down the digestive tract
Mixing of food - churning in the stomach with digestive juices

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

Describe the role of the peritoneum.

A

The peritoneum is a thin layer of tissue that coats the lining of the abdomen and pelvic cavity.

It is a serous membrane with a visceral layer covering the wall of the abdomen and pelvic cavity. In between the two layers is the peritoneal cavity which has a serous fluid

It has many blood and lymph vessels.

It provides a physical barrier to local spread of infection.

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

Outline the main difference between ‘ascites’ and ‘peritonitis’ and name ONE cause for each pathology.

A

Ascites is a build up of fluid (oedema) in the peritoneal cavity. A cause could be heart failure or liver disease leading to fluid backflow. Look pregnant!

Peritonitis is an acute inflammation of the peritoneum and a cause could be appendicitis or bacterial infection.

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

Name TWO functions of the ‘greater omentum’.

A

The greater omentum is the largest fold of the peritoneum and drapes like an apron over the transverse colon.
It stores fat. When it stores too much fat it looks like a beer belly and interferes with the endocrine system.
Functions:
1. **Fat storage **
2. Lymph nodes containing macrophages and pkasma cells (which produce antibodies) to combat infections of the GIT

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

Name ONE role of the ‘lesser omentum’.

A

A smaller fold in the peritoneum that suspends the stomach and duodenum from the liver.

Functions:
1. Pathway for the blood vessels entering the liver
2. Contains the** hepatic portal vein** which carries blood from the digestive system to the liver

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

What is the role of the of the PNS and the SNS in the behaviour of the myenteric and submucosal plexus?

A

PNS
Myenteric plexus: Increases muscle activity - peristalsis
Submucosal plexus: Increases release of digestive juices

SNS
Myenteric plexus: Decreases muscle activity
Submucosal plexus: Decreases release of digestive juices

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

What are the three types of neurons in the enteric nervous system?

A

Sensory neurons – incoming signal about the mucosal envirpnment from chemoreceptors and stretch receptors.
What you are sensing, whats coming in.

Motor neurons – outgoing action signal in the submucosal and myenteric plexus.
What action you take

Interneurons – connect the two plexuses.

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

List TWO ways in which sensory neurons (enteric nervous system) receive information about environmental changes.

A

Chemoreceptors – sense changes in arterial carbon dioxide, oxygen, and pH

Stretch receptors – sense distension in the stomach

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

Name TWO veins that drain the digestive system.

A

Portal Vein drains lower oesophagus, stomach, pancreas, both intestines, upper rectum, spleen

Iliac vein drains lower part of the rectum and anal canal

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

Name the main artery that supplies the digestive tract with oxygenated blood and nutrients.

A

Mesenteric Arteries

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

Name FOUR functions of the oral cavity.

A

Mastication
Speech
Taste
**Swallowing **- bolus pushed by the tongue into the pharynx closing the nasopharynx - **pharynx reflex action **

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

Name THREE glands that produce saliva.

A

Parotid
Sublingual
Submandibular

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

Describe how saliva production is affected by:

a. Parasympathetic nervous system

b. Sympathetic nervous system

A

a. Parasympathetic nervous system
Saliva release is stimulated

b. Sympathetic nervous system
Saliva release is inhibited leading to dry mouth

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

List TWO enzymes found in saliva.

A

Amylase
Lysozymes

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

Name ONE immunoglobulin found in saliva.

A

IgA

Low IgA when stressed which is why the mouth is often compromised when stressed.

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

Is saliva mildly acidic or mildly alkaline?
Mildy acidic

A

Mildy acidic

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

Name FOUR functions of saliva.

A

Secretion of enzymes
Lubrication
Immune function – defence
Cleansing or oral cavity
Releases bicarbonate as an acid buffer

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

In relation to the digestive system, what is the role of the ‘epiglottis’?

A

It is a flap of cartilage that stops food entering the trachea

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

Describe the function of the lower oesophageal sphincter.

A

Acts as a seal to prevent acid and the contents of the stomach from entering the oesophagus

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

Name TWO sphincters in the stomach.

A

Lower Oesophageal at the top – Entry sphincter
Pyloris at the bottom – Exit sphincter

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

What is the pH of the stomach?

A

2-3

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

Name TWO substances secreted by the parietal cells in the stomach.

A
  • ## Intrinsic Factor to allow B12 to connect and thus be absorbed by the small intestine
  • Hydrochloric Acid (HCL) – H and CL and secreted separately in the stomach and then join up. They are too acidic to join together earlier because only the stomach has the capacity to handle such high acid levels.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What role does hydrochloric acid (HCL) play in the following:

A

a. Protein digestion – activates an enzyme called pepsinogen which is only activated in the presence of HCL where it is converted to pepsin that helps to digest proteins

b. Ingested iron is converted into a soluble form

c. Bile and pancreatic juice flow - HCL is detected by the duodenum and this triggers release Choleycystokinin (CCK) which in turn tells the pancreas to release proteases for digestion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What are the three types of exocrine cells in the stomach and what do they secrete?

A

Parietal cells secrete Intrinsic Factor and HCL
Goblets cells secrete mucus
Chief cells secrete pepsinogen and Gastric Lipase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Name ONE vitamin and ONE mineral used to make HCL.

A

Vitamin B6 and Zinc. Therefore if you are deficient in these it could explain low stomach acid.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

List FOUR functions of the stomach.

A
  1. Chemical and mechanical digestion
  2. Mixing chamber for churning up food
  3. Holding reservoir – storage
  4. Defence due to high acidity – not much survives
  5. Makes iron and calcium into a form you can better absorb
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Name ONE function of the hormone ghrelin.

A

Stomach hormone that stimulates hunger

38
Q

List TWO functions of gastrin.

A

Stomach hormone

Responds to stomach distension leading to stimulationg gastric juice secretion and gastric motility.

39
Q

Name ONE pancreatic enzyme involved in:

a. Lipid / fat digestion

b. Carbohydrate digestion

c. Protein digestion

A

a. Lipid / fat digestion
Lipase

b. Carbohydrate digestion
Amylase

c. Protein digestion
Protease – Tripsin, Chymotripsin, ribonuclease, deoxyribonuclease

40
Q

Name the cell that produces bile.

A

Hepatocytes

41
Q

Name three components of bile.

A

Bilirubin, mineral salts and cholesterol

42
Q

Describe the role of emulsification.

A

Emulsify = to disperse

Breaks fats down into smaller particles to increase the surface area for lipase to work on and allow for further breakdown.

43
Q

Describe the connection between bile and the enterohepatic circulation.

A

90-95% of bile is absorbed in the GIT and then transported back to the liver from the ileum. This is known as enterohepatic (GIT + Liver) circulation

44
Q

Name THREE regions of the small intestine.

A

Dueodenum
Jejunum
Ileum

45
Q

Name THREE brush border enzymes.

A

Maltase, Sucrase, Lactase

46
Q

Describe the location of brush border enzymes.

A

Embedded in the microvilli (brush border cell membranes) of the small intestine.

They are attached to the intestinal lining as transmembrane proteins.

They are essential for aborption

47
Q

Describe FOUR functions of cholecystokinin (CCK).

A

Triggered when acidic chyme enters the duodenum.

Functions include:
1. Stimulates hepatic production of bile
2. Stimulate the contraction of the gallbladder to release bile
3. Stimulate the pancreas to release pancreatic enzymes.
4. Mediates satiety

48
Q

List TWO dietary factors that stimulates CCK production.

A

High fat and high protein in chyme

49
Q

Outline FOUR functions of the small intestine.

A

Absorption of nutrients and water mostly through the jejunum. 90% of absorption occurs in small intestine

Digestion mostly through the duodenum

Movement through the small intestine – through peristalsis

Hunger / satiety mediated through Coleycystokinin

**Immunity ** abundance of white blood cells. GALT, Peyers patches are a clusters of white cells

50
Q

Describe how the following are absorbed from the small intestine:

a. Amino acids

b. Monosaccharides

c. Fatty acids / cholesterol

A

a. Amino acids
Active and passive transport into capillaries into the blood straight into the cardiovascular system

b. Monosaccharides
Active transport into capillaries into the blood straight into the cardiovascular system

c. Fatty acids / cholesterol

Emulsified through bile&raquo_space;> enter intestinal cells through simple diffusion&raquo_space;> Packaged into cholymicrons&raquo_space;> absorbed into the lacteals – a lymphatic vessel of the small intestine&raquo_space;> travel through the lymphatic system and enter the blood in the subclavian vein.

51
Q

Describe specifically how vitamin B12 is absorbed in the body.

A

It is absorbed in the terminal ilium and it needs intrinsic factor which is released from parietal cells of the stomach for absorption to be possible

52
Q

Explain what could happen if the ileo caecal valve in the large intestine is faulty.

A

It is a valve so it allows one way movement of substances, in this case from the small to the large intestine.

If it is faulty, microbes which are abundant in the large intestine can move into the small intestine and overpopulate it., This can lead to an illness called SIBO – small intestine bacterial overgrowth

53
Q

Name the process that manages final nutrient extraction in the colon.

A

Microbial Fermentation - Bacteria ferment fibre to produce short chain fatty acids which feed intestinal epithelial cells which helps them to keep their integrity. Support GI tight junctions.

So, the presence of healthy bacteria helps to prevent leaky gut.

54
Q

Explain how short chain fatty acids (SCFAs) play a role in the digestive system.

A

Short chain fatty acids support GI tight junctions and prevent leaky gut.

55
Q

Name TWO vitamins produced in the large intestine.

A

B12 and K2

56
Q

Describe how the large intestine contributes to:

a. Faecal colour

b. Faecal odour

c. Flatulence

A

a. Faecal colour – Bilirubin is decomposed into simpler molecules and these pigments contribute to the colour of faeces

b. Faecal odour - Fermentation of residual amino acids to various compounds including hydrogen sulphide

c. Flatulence – Bacterial fermentation creates methane

57
Q

Describe specifically the stages involved in the ‘defaecation reflex’.

A

Mass peristaltic movement pushes faecal matter into the rectum where distension of the rectal wall stimulates stretch receptors and the DEFACATION REFLEX.

DEFACATION REFLEX involves
- sending sensory impulses to the sacral part of the spinal cord.
- Motor impulses travel down the PNS back to the rectum and anus

Rectal muscles contract, increasing abdominal pressure that opens the internal sphincter

The external anal sphincter is voluntarily relaxed.

58
Q

What are the four regions of the large intestine?

A

Caecum with appendix attached – part of the immune system and contains macrophages, lymphocytes and bacteria

Colon – ascending, transverse, descending

Rectum

Anal Canal containing internal and external sphincter

59
Q

Name ONE phagocytic cell found in the liver

A

Kupffer cells are phagocytic cells that remove foreign bodies in the blood by engulfing microbes in the blood to remove them

60
Q

Explain what is meant by ‘hepatic first pass’.

A

Blood that has gone through the digestive tract is carried to the liver through the portal vein to be filtered before entering systemic circulation.

61
Q

List FOUR functions of the liver (not storage).

A
  • Production of bile
  • Metabolism of carbs, fat and protein
  • Filtering/cleansing blood of microbes
  • Detoxification - drugs, toxins, alcohol
  • Storage – Vitamins (A, D, E, K, B12), iron, copper, glycogen
  • Production – Vitamin A, CoQ10, activation of Vit D
  • Production of plasma proteins for blood clotting
  • Haemolysis – supporting the spleen in the break down of red blood cells.
62
Q

Name TWO vitamins or minerals stored in the liver.

A

Vitamins A, D, E, K, B12
Minerals – Iron, copper

63
Q

Describe the two phases of liver detoxification in detail

A

A healthy liver deals with thousands of toxins a day – airborne, ingested. It is highly energy dependant and uses enzymes made on the spot.

There are two major classifications of chemical compounds.
- Hydrophilic which are excreted in urine and bial
- Lipophilic which must be chemically altered into hydrophilic compounds in order to facilitate elimination.

The two phases of liver detoxification are for transforming lipophilic compounds into hydrophilic compounds.

Imagine you have a shed in the garden…

a. Phase I liver detoxification

BIOACTIVATION - makes the toxin more reactive

Take the shed apart and make a mess. Deactivates it.

The CYP450 family (there are more than 50 in the class) convert water-insoluble toxins into water soluble substances. They are converted to more reactive substances which can be metabolised in Phase 11

b. Phase II liver detoxification

CONJUGATION reactions helps to get it excreted.

Take the bits of deactivated shed and stacks them up neatly in the back of the van.

Molecules are attached to the toxins to neutralise them making them stable (non-reactive) and water soluble to be excreted. Various enzymes are also involved in inducing chemical reaction.

64
Q

Name ONE key antioxidant which supports Phase II detoxification.

A

Glutathione is a key antioxidant in the liver important in phase II detoxification.

65
Q

Name THREE monosaccharides

A

A single sugar unit

Glucose
Fructose
Galactose (which breaks down to lactose)

66
Q

Complete the following:

These are all disaccharides

a. Maltose = ——- + ——–

b. Sucrose = ——- + ——–

c. Lactose = ——- + ——–

A

These are all disaccharides

a. Maltose = glucose + glucose

b. Sucrose = glucose + fructose

c. Lactose = glucose + Galactose

67
Q

Explain the main role of cellulose

A

Cellulose is a polysaccharide.

It is indigestible in the human body but bacteria can digest it. It also drags everything out of our bowels.

68
Q

Name the organ where glycogen is stored.

Explain the main role of glycogen.

A

Glycogen is a polysaccharide. It is stored in the liver

It is the body’s way of storing lots of sugars together. We absorb glucose molecules and stick them into a big polysaccharide in the liver and in the muscles

69
Q

Name TWO functions of lipids.

A
  1. Energy
  2. Insulation
  3. Integrity of cell membrane - The fatty acids (lipids) we ingest ultimately are incorporated into cell membrane of all cells
  4. Hormone production
  5. Protection of organs
70
Q

Name THREE dietary lipids

A

Triglycerides
Phospholipids
Cholesterol

71
Q

Describe the key difference between ‘saturated’ and ‘unsaturated fats’.

A

A saturated fat is a molecule containing the greatest number of hydrogen atoms without any double bonds

Unsaturated fatty acids have one or more double bonds between carbon atoms

Where C=C

72
Q

Describe the key difference between ‘cis’ and ‘trans’ fats

A

The location of the Hydrogen around the double bond is very important to note.

Trans is a configuration when the H atoms are on the opposite sides of the double bond.
H
I
C = C
I
H

Sis is a configuration when the H atoms are on the same side of the double bond
H H
I I
C = C

In nature nearly all fats have a cis structure.

When we try to create fats in laboratories they position the H atoms on the opposite sides where they have more space

73
Q

Name the building blocks of proteins.

A

Amino Acids

74
Q

What must happen to ingested proteins before protease enzymes can act?

A

They must be denatured where the properties of the protein molecule is destroyed.

75
Q

ame TWO functions of proteins.
They have multiple functions.

A
  • Immunity (immunoglobulins, antibodies)
  • Structures – muscle, collagen
  • Enzymes
  • Hormones
  • Neurotransmitters
  • Energy
76
Q

Describe the unique structure of proteins.

A

Each protein structure has a unique 3D shape

77
Q

Explain the function of enzymes.

A

Biological catalysts which speed up chemical reactions. They are not changed or consumed in the process so they can perform the same function again and again.

78
Q

Name TWO factors that denature proteins.

A

PH and temperature changes

79
Q

What do you know about the Submucosa Layer

A

Connects Mucosa to the Muscularis Externa.

Contains blood and lymph vesels

Contains the submucosal plexis (the brain fo the gut)

80
Q

What do ypu know about the Muscularis Propria

A
81
Q

Where do we find the Submucosa Layer and what does it contain?

A

Connects Mucosa to the Muscularis Externa.

Contains blood and lymph vesels

Contains the submucosal plexis (the brain fo the gut)

82
Q

What type of muscle do we find in the Muscularis Propria and what is it for?

A

In the mouth, pharynx, upper oesophagus and anal spincter it is made of skeletal muscle to allow voluntary swallowing and defacating.

In the rest of the GIT it is mostly smooth muscle for the mixing of food wih digestive juoces and the propelling of food along the digestive tract.

It is made of two muscle layers
- inner circular muscle
- outer longitudinal

In between them we find the myenteric plexus

83
Q

What is the enteric nervous system

A

The brain of the gut.

We are now starting to realise that this system plays a bog role in mental health conditions.

84
Q

What type of muscle do we find in the Muscularis Propria and what is it for?

A

In the mouth, pharynx, upper oesophagus and anal spincter it is made of skeletal muscle to allow voluntary swallowing and defacating.

In the rest of the GIT it is mostly smooth muscle for the mixing of food wih digestive juoces and the propelling of food along the digestive tract.

It is made of two muscle layers
- inner circular muscle
- outer longitudinal

In between them we find the myenteric plexus

84
Q

Where do we find the Submucosa Layer and what does it contain?

A

Connects Mucosa to the Muscularis Externa.

Contains blood and lymph vesels

Contains the submucosal plexis (the brain fo the gut)

84
Q

What is the enteric nervous system

A

The brain of the gut.

We are now starting to realise that this system plays a big role in mental health conditions.

Arranged in two plexus (networks) and both contain a network of sympathetic and parasympathetic nerve fibres.

Myenteric plexus controls strength and frequency of muscle contraction.

Submucosal plexus controls digestive secretions and detests sensorty information

85
Q

GIT Blood Supply

A

Nutrient rich blood in the intestines is returned by portal vein and Iliac vein to the liver.

This blood also has toxins.

86
Q

What is the enteric nervous system

A

The brain of the gut. Regulated by the aurtonomic nervous system.

We are now starting to realise that this system plays a big role in mental health conditions.

Arranged in two plexus (networks) and both contain a network of sympathetic and parasympathetic nerve fibres.

Myenteric plexus located in the muscularis externa controls strength and frequency of muscle contraction.

Submucosal plexus located in the submucosal layer controls digestive secretions and detests sensorty information

86
Q

Where do we find the Submucosa Layer and what does it contain?

A

Connects Mucosa to the Muscularis Externa.

Contains blood and lymph vesels

Contains the submucosal plexis (the brain fo the gut)

86
Q

What is the oral cavity made up of

A

Hard palate
Soft palate
Uvula which swings up and vlocks the nasopharynx from food
Tongue - skeletal muscle. Covered in papillae which contain taste buds

86
Q

GIT Blood Supply

A

The GIT is suppplied with arterial blood from branches ofthe abdominal aorta including the mesenteric arteries.

Nutrient rich blood in the intestines is returned by portal vein and Iliac vein to the liver.

This blood also has toxins.

86
Q

What type of muscle do we find in the Muscularis Propria and what is it for?

A

In the mouth, pharynx, upper oesophagus and anal spincter it is made of skeletal muscle to allow voluntary swallowing and defacating.

In the rest of the GIT it is mostly smooth muscle for the mixing of food wih digestive juoces and the propelling of food along the digestive tract.

It is made of two muscle layers
- inner circular muscle
- outer longitudinal

In between them we find the myenteric plexus

Kerri's Part 1 Biomed Slides (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions