Brainscape's Knowledge GenomeTM

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


See full index

psio 120 > digestive system > Flashcards

digestive system Flashcards

1
Q

structures of the digestive system

A
  • oral cavity, teeth and tongue
  • pharynx
  • esophagus
  • stomach
  • small intestine
  • large intestine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Accessory glands

A
  • salivary glands
  • liver
  • gall bladder
  • pancreas
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Role of the digestive system

A

breaks down ingested food for the use of the body

  • chemical breaking of bonds releases energy and helps maintain body temperature.
  • rebuilding of food molecules into those needed requires energy
  • excess = defacation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

6 essential activities

A
  1. ingestion
  2. mechanical digestion
  3. propulsion
  4. chemical digestion
  5. absorption
  6. defacation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

1st layer of GI tract

A

serosa layer (visceral peritoneum)

  • tough, dense
  • blood vessels that go into gut
  • to protect internal layer
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

2nd layer of GI tract

A

muscularis externa

  • muscular layer
  • circular and longitunal layers
  • when contrcats - anables nutrients to move through the gut
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

3rd layer of GI tract

A

submucosa

  • connective tissue and blood supply
  • anchoring for mucosa
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

4th layer of GI tract

A

the only layer that is specialised

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

mechanical digestion

A
  • through chewing and muscular action the food is broken down to smaller and smaller pieces.
  • food is now chyme
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

chemical digestion

A
  • the addition of enzymes to the food causes chemical bonds to be broken
  • proteins - amino acids
  • staches and large polysaccharide sugar - monosaccharides
  • large lipid molecules - smaller molecules
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How does food move through the GI tract ?

A
  1. swallowing in the oesophagus
  2. churning in the stomach
  3. expulsion to the small intestine
  4. mass movement in the large colon
  5. defecation from the anus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

the function of the GI tract?

A
  1. local factors - stimulus for digestive activities
    - coordinates responses to changes in the pH of the contents of the lumen, physical distortion in the tract or presence of chemicals.
  2. neural control mechanisms
    - short reflex = chemoreceptors or stretch receptors by myenteric plexus
    - long reflex - interneuron and motor neuron to CNS move materials from one area to another
  3. Hormonal control mechanisms
    - 18 different hormones
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Salivary glands

A
  • Salivary amylase
    commences breakdown of starches - small intestine
  • Salivary lipase
    activated in the stomach to assist in lipid breakdown - small intestine
  • Detention
    Proteolytic enzymes that kill bacteria in food
  • Mucous
    Moistens food
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Role of the hard palate

A

underlain with bone: hard surface to aid with mechanical digestion

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

Role of the soft palate

A
  • skeletal muscle

- rises to close off the nasopharynx when we swallow.

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

Role of the tongue

A
  • skeletal muscel and mucous membrane
  • helps from of oral cavity
  • extrinsic muscles - position of tongue
  • intrinsic muscles - shape of tongue
  • papillae - taste

Functions

  • grips + re-positions food
  • mix food with saliva and form bolus
  • form words
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How is food swallowed? (pharynx)

A
  1. Buccal phase
  2. pharyngeal phase
  3. esophageal phase
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Buccal phase

A

contraction of the tongue to push the bolus up against the soft palate and then posteriorly into the oropharynx by the tongue and palate

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

pharyngeal phase

A

bolus moves from the oropharynx to the esophagus (involuntary)

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

esophageal phase

A

moves through the esophagus to the stomach

21
Q

Function esophagus

A

Mucus is secreted and muscular contractions propel food into the stomach. No digestive enzymes are secreted and no absorption takes place.

22
Q

Function of the stomach

A
  • mixing chamber and storage for ingested food
  • rugae for allowed increased volume
  • ## pyloric sphincter regulates movement of chyme into small intestine
23
Q

mucous epithelial cells

A
  • protect lining from acid and pepsin

- to help the churning into chyme

24
Q

Histamine

A

stimulate pareital cells to produce acid

25
Q

Pareital cells

A
  • HCL
  • INtrinsic factor = binds to b12 for absorption
  • cheif cells = produces pepsinogen which becomes pepsin in the presence of HCL
  • G cells = release gastric hormones to blood in response to muscle strength receptors.
26
Q

How is digestion controlled in the stomach

A
  1. Cephalic phase
  2. gastric phase
  3. intestinal phase
27
Q

cephalic phase

A
  • initiated by the sight, smell, thought and taste of food
  • signals from the CNS
  • conditioned reflex
28
Q

gastric phase - chewing

A
  • 2/3 of gastric secretion
  • ingested food stimulates gastric activity by stretching the stomach and rating the pH of its contents; causes a cascade of events that leads to the release of hydrochloric acid = lowers the ph to break apart the food.
  • stimulated by each, histamine and gasterin
29
Q

Intestinal phase

A
  • stretching of teh duodenum enhances gastric function via the vagal nerve, as the chyme causes the secretion of gastrin
  • ## the acid and semi-digested fats in the duodenum trigger the enterogastric reflex
30
Q

Digestion

A

Mouth = amylase begins carbohydrate digestion
stomach = hydrochloric acid and pepsin breaks down large proteins
small intestine = pancreatic enzymes release to duodenum and small intestine breakdown of carbohydrates and proteins.

31
Q

roles of liver

A
  • metabolism of carbohydrates, lipids, proteins
  • process drugs and hormones
  • synthesize bile salts (to emulsify fats)
  • Storage (glycogen, vitamins, minerals)
32
Q

Liver structure

A
  • 4 lobes = right, left, quadrate and caudate

- each lobe forms many lobes (hepatocytes and sinusoids)

33
Q

reticuloendolethal cells

A

central cells

34
Q

gall bladder function

A
  1. liver secretes bile
  2. in the gallbladder bile becomes more concentrated
  3. CCK (hormone) triggers dilation + contraction of gall bladder + eject to the small intestine to break down lipid.
35
Q

Role of endocrine pancreatic secretions

A
  • Glandular epithelial cells = secret pancreatic juices (enzymes)
  • Pancreatic islets
    Hormones
    Glucagon - increase rate of glycogen to glucose conversion
    Insulin - glucose storage
    somatostatin (GHIH) slow digestion by inhibiting digestion and absorption
36
Q

Pancreatic juices

A
  • 1200-1500 ml
  • ph = 7.1-8.2
  • h20
    salt
    sodium bicarbonate
37
Q

Enzymes in the pancreas

A
  • amylase
  • ligase
  • trypsinogen - to form trypsin - former breaks down proteins to amino acids
  • nucleases - digest DNA in food
38
Q

structure of the small intestine

A

3 sections

  • duodenum
  • lejunem
  • lleum
39
Q

characteristics of structures

A
  • villi (contains blood vessels, nerves and lymphatic capillaries)
  • microvilli ( brush border enzymes - digestive enzymes - brush border of the villi)
    Intestinal juices (1-2 L per day).
  • Mucosa (Solitary lymphatic nodules)
  • Submucosa (duodenal - alkaline secretion to neutralise stomach acid
40
Q

What happens to food in the small intestine ?

A
  • Duodenal brush border enzymes ( for further breakdown of proteins)
  • Lipases
    Bile facilitates attachment of lipases to lipids
  • Pancreatic amylase (complexes starch digestion)
  • Enzymes (completion of the digestion of starches, protein + lipids.
  • Passage of digested nutrients from GI tract into blood or lymph.
41
Q

Where within the GI tract does most absorption of nutrients take place?

A

In small intestine

  • small molecules produced by digestion are absorbed
  • the villi create SA for absorption

LArge intestine

  • water, salts and vitamins
42
Q

structure of the large intestine

A 
- colon
Ascending 
Transverse 
Descending 
Sigmoid
  • Caecum
    attached appendix
  • Anal canal
43
Q

Histology of large intestine

A 
- Mucosa 
Absorphortive cells absorb mainly water 
Goblet cells secrete mucus 
- Muscularis 
contraction created by external smooth muscle + internal circular smooth muscle
44
Q

Movement of large intestines

A 
- gastroileal reflex 
intensifies after a meal 
occurs 3/4 days 
- Haustrak churning 
Distension and contraction of haustra 
Mass peristalsis (absorption along the large intestine)
45
Q

Role of the large intestine

A

production and storage of faeces

  • water absorption to produce semi-dried chyme
  • Absorption of the bacterially produced vitamins
46
Q

Role of bacteria in the large intestine?

A
  • ferment carbohydrates
  • break down proteins
  • produce some vitamins
47
Q

How is defaecation controlled?

A
  • empties the rectum
  • response to distension of rectal wall
  • external and sphincter voluntary relaxes
48
Q

short reflex in the anus

A

senses of peristaltic contractions that move faeces towards the anus

49
Q

long reflex in the anus

A

mass movements that push faeces towards the reaction from descending and sigmoid colon

psio 120 (9 decks)

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