Brainscape's Knowledge GenomeTM

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


See full index

2TRN B12: Human Disease > 5: Digestive System > Flashcards

5: Digestive System Flashcards

1
Q

4 basic processes of DIGESTION

A
  1. motility
  2. secretion
  3. digestion
  4. absorption
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

motility

A

muscular contraction that MIX and MOVE FORWARD the contents of the tract

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

secretion

A

secretion of digestive juices by DIGESTIVE EXOCRINE GLAND CELLS

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

location of digestive endocrine gland cells

A

lining the digestive tract AND in acessory digestive organs

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

type of cell

A

specialised epithelial cells

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

mechanism of action

A

secrete also a range of signal proteins classified either as GI HORMONE or GI PEPTIDES –> enter blood –> carried to target organs, regulating digestive function

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

digestion

A

the breakdown of starch, glycogen and disaccharides into their constituent monosaccharides

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

absorption

A

transfer of vitamin, electrolytes, nutrients and some water from digestive tract lumen into the blood OR lymph

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

what makes up the digestive system

A
  1. digestive tract

2. accessory digestive organs

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

accessory digestive organs

A

1.the biliary system [liver and gallbladder]
2.exocrine pancreas
3.salivary glands
they lie outside the digestive tract but empty their contents into the digestive tract

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

length of digestive tract

A

4.5 m in its NORMAL CONTRACTILE STATE

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

organs comprising the digestive TRACT

A
  1. mouth
  2. pharynx (throat)
  3. oesophagus
  4. stomach
  5. small intestine (DJI - duodenum, jejunum, ileum)
  6. large intestine [CACR - cecum, appendix, colon, rectum]
  7. anus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

why these considered separate entities despite being continous w one another

A

because of their regional modifications allowing them to carry out their special function

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

when is a substance considered INSIDE the body

A

only after it moves from the lumen of digestive tract into absorptive epithelial cells (everything IN the DT is considered outside the body as the DT is continous w the external environment)

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

4 layers of digestive tract from innermost layer outward

A
  1. mucosa
  2. submucosa
  3. muscularis externa
  4. SEROSA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

1.mucosa’s innermost layer (1st)

A

mucous membrane

  • serves as protective surface
  • epithelial layer
  • modified in some areas for absorption/secretion
  • contains exocrine gland cells for secretion of DIGESTIVE JUICES
  • contains endocrine gland cells for secretion of blood-borne GI hormones
  • contains epithelial cells specialised in ABSORBING nutrients
17
Q

1.mucosa’s middle layer

A

lamina propria

  • thin middle layer of connective tissue
  • contains GALT which is important in defence against disease.
  • GALT = gut-associated lymphoid tissue
18
Q

1.mucosa’s 3rd layer

A

muscularis mucosa

  • outermost layer of smooth muscle
  • highly folded in some parts of the GIT (eg. small intestine) for greater surface area for absorption
  • pattern of surface folding can be modified by contraction
19
Q

2.Submucosa

A
  • thick layer
  • connective tissue
  • contains submucosal nerve plexus
  • contains large blood and lymph vessels
  • provides distensibility and elasticity
20
Q
  1. Muscularis Externa
A

MAJOR smooth muscle coat of the GIT
two layers
1.Inner Circular Layer
2.Outer Longitudinal Layer

21
Q

Inner circular layer

A

muscle fibres running circularly around the tube

contraction = decrease in diameter of tube at poin of constriction

22
Q

Outer longitudinal layer

A

muscle fibres running longitudinally along the length of the tube
contraction = shortening of GIT

23
Q

combined effects of contraction of these two

A

creates propulsive and mixing movements of GIT

24
Q

Myenteric Nerve Plexus

A

Between the inner circular & outer longitudinal layer.

-help regulate local gut activity

25
Q
  1. Serosa
A
  • outer connective tissue layer (covering)
  • secretes SEROUS fluid -lubricates &prevents friction of GIT w neighbouring organs
  • throughout much of the tract, SEROSA is continuous w Mesentry (suspends digestive organs from inner wall of abdominal cavity like a sling)
26
Q

4 factors involved in REGULATION of Digestive System Function

A
  1. Autonomous SMOOTH MUSCLE function
  2. intrinsic nerve plexuses
  3. extrinsic nerves
  4. GI hormones
27
Q

1.Autonomous Smooth Muscle Function

A
  • SLOW-WAVE POTENTIALS: self-induced electrical activity in digestive smooth muscle
  • by pacemaker cells “Interstitial Cells of Cajal”
  • located in the layers of MUSCULARIS EXTERNA
  • slow waves are NOT action potentials, only induce rhythmic cycles of depolarisation and repolarisation close to the threshold potential.
  • if waves REACH threshold potential at peak of depolarization–> rhythmic cycles of MUSCLE CONTRACTION
28
Q

another name for Slow-wave Potentials

A

BER (Basic Electrical Rhythm) of the digestive tract

29
Q

2.Intrinsic Nerve Plexuses

A

consists of:
1. The Submucosal Plexus
2. The Myenteric Plexus
collectively, referred to as ENTERIC NERVOUS SYSTEM. Has a considerable degree of self-regulation.
-the only body system to have its own INTRAMURAL NERVOUS SYSTEM

30
Q

Intrinsic Nerve Plexus subdivision

A

Intrinsic Afferent Neurons (respond to local stimuli in digestive tract)
Intrinsic Efferent Neurons: control smooth muscle.
-endocrine and exocrine cells of digestive tract

31
Q

Intrinsic EFFERENT Neurons affect…

A
  • digestive tract motility
  • secretion digestive juices
  • secretion GI hormones
  • LOCALLY
    eg. if large piece food stuck in oesophagus, local response to push the food forward
32
Q
  1. Extrinsic Nerves
A
  • formed from both branches of the autonomic NS (Sympathetic Division and Parasympathetic Division)
  • originate outside the digestive tract
33
Q

Extrinsic Nerves affect…

A
  • activity of intrinsic nerve plexuses
  • level of GI hormone secretion
  • act directly on Smooth Muscle AND glands
34
Q

Sympathetic division effect…

A
  • dominates in “fight or flight” situations-inhibit /slow down digestive tract CONTRACTION and SECRETION
  • digestive processes not of highest priority when faced w emergency situation
35
Q

Parasympathetic division effect…

A
  • dominates in quiet “rest and digest” situations
  • promotes smooth muscle motility
  • promotes secretion of digestive enzymes & hormones
36
Q

role of vagus nerve reflexes before food gets in the stomach (extrinsic nerve)

A

increases salivary secretion, stomach, pancreatic and liver secretion in anticipation of arrival of food

37
Q

4.GI Hormones

A

inhibitory or excitatory influences on digestive smooth muscle AND exocrine glands
-GI hormones produced by SPECIALISED ENDOCRINE cells in certain regions of the mucosa

38
Q

3 types of SENSORY RECEPTORS to LOCAL changes in GIT

A
  1. Chemoreceptors
    - sensitive to chemical components within the lumen
  2. Mechanoreceptors
    - stretch or tension within the wall
  3. Osmoreceptors
    - sensitive to osmolarity of luminal contents
39
Q

what does stimulation of either of these elicit

A

a. neural reflexes

b. secretion of hormones

2TRN B12: Human Disease (7 decks)

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