Brainscape's Knowledge GenomeTM

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


See full index

PHYL1007 > GIT > Flashcards

GIT Flashcards

1
Q

6 major functions of GIT

A
  • ingestion
  • digestion
  • motility
  • secretion
  • absorption
  • elimination
    Also…
  • immune defence
  • nutrition & metabolism
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Layers of the GIT

A

1) Mucosa
- epithelium
- lamina propria (loose CT, rich in blood)
2) Submucosa
- dense irregular CT, large vessels
- submucosal glands, secrete buffers and enzymes
- submucosal plexus
3) Muscularis externa
- smooth muscle
- myenteric plexus
4) Serosa
- serous membrane

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

lining of the small intestine is made up of…

A 
Plicae circularis
- folds supported by submucosa
Villi
- finger like projections of mucosa
Microvilli
- tiny structures on enterocytes (absorptive cells)
- increase surface area 600-fold
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is each villus lined by?

A

simple columnar epithelium

  • enterocytes
  • goblet cells
  • enteroendocrine cells
  • paneth cells
  • stem cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

regulation of motility and secretion of GIT through neural mechanisms

A 
Extrinsic (autonomic)
- parasympathetic (stimulate)
- sympathetic (inhibit)
Intrinsic (enteric nervous system)
- submucosal plexus (local effects)
- myenteric plexus (whole tract motor control)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

regulation of motility and secretion of GIT through hormonal mechanisms

A

enteroendocrine cells (EEC) are present (peptides)

1) gastrin - from stomach
2) cholecystonkinin (CKK) - from SI
3) secretin - from duodenum
4) GIP - from SI
5) motilin - throughout gut
6) somatostatin - stomach and duodenum

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

GIT smooth muscles

A
  • small spindle shaped cells form tube
  • in muscularis mucosa and externa
  • are syncytium-electrically coupled
  • joined by gap junctions
  • contractions are slow, waved
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

types of intestinal motility

A 
Peristalsis
- move intestinal content distally
- more longitudinal muscle cells
Segmentation
- mixing of chyme
- more circular muscle cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

3 paired salivary glands in oral cavity

A

Parotid - water and enzymes
Submandibular - mucous, enzymes and water
Sublingual - mucous

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

content and function of saliva

A
  • lubrication, coating and protection
  • 99% water
  • high K+ and HCO3-
  • IgA (immune defence)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

3 stages of swallowing

A

1) oral stage
- voluntary
- upper oesophageal sphincter (UES) closed
2) pharyngeal stage
- involuntary
- UES open
- epiglottus blocks larynx
2) oesophageal stage
- involuntary
- USE re-closed

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

dysphagia

A

difficulty in passage from mouth to stomach

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

layers of the stomach wall

A

Mucosa
- simple columnar epithelium and lamina propria
Gastric pits
- depression in mucosa
Gastric glands
- secrete mucous, gastric juice and gastrin

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

HCL secretion in the stomach

A

1) formation of carbonic acid (CO2 + H2O -> H2CO3)
2) dissociation of carbonic acid (H2CO3 -> H(+) + HCO3-)
3) H+ pumped from cell to lumen by proton pump (H-K-ATPase)
4) Cl- and HCO3- antiporter transports HCO3- into plasma and Cl- from plasma into cell
5) Cl- pumped into lumen through facilitated diffusion
6) Cl- and H+ join in lumen to form HCl

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

roles of HCL

A
  • chief cells secrete pepsinogen
  • HCL activates pepsinogen to pepsin
  • HCL converts ingested Fe3+ to Fe2+
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

stomach protective mechanisms

A

1) Mucosa coat
- highly alkaline mucous produced by neck cells
- resists action of acids and enzymes
- protects from auto-digestion by pepsin and HCl
2) Tight gap junctions between epithelial cells
3) Cell replacement

17
Q

Phases of digestion

A

1) cephalic phase
- prepare stomach for food
2) gastric phase
- stomach acts on food
3) intestinal stage
- maximise absorption

18
Q

segments of the SI

A 
duodenum
- like a mixing bowl
- mixing chyme with secretions for pancreas and liver
jujunum
- most chemical digestion and absorption
- increase in SA
ileum
- B12
19
Q

exocrine cells of the pancreas

A

Acinar cells
- contain zymogen granules with digestive enzymes
Ductal cells
- produce alkaline solution to help move enzymes
- neutralise acidic chyme

20
Q

endocrine cells of the pancreas

A
  • Insulin
  • Glucagon
  • released from beta-cells
21
Q

regulation of pancreatic exocrine secretion

A
  • primarily controlled by hormones from duodenum
  • also by the digestion and absorption of nutrients in the small intestine
  • sectretin - works on ductal cells (release buffers HCO3-)
  • CCK - works on acinar cells (releases digestive enzymes)
22
Q

functions of the liver

A

1) metabolic functions
- carb metabolism (maintain blood glucose)
- lipid metabolism
- synthesis proteins and hormones
- drug metabolism
- RBC recycling
- storage
2) Bile production
- bile salts break down fat particles into tiny particles so they can be attacked by lipase
- bile salts are reabsorbed in the SI
3) Blood circulation and filtration

23
Q

regulation of bile secretion

A

trigger for bile production is fatty acids and amino acids entering the duodenum and is stimulate by

  • PSNS
  • sectretin - works on ductal cells
  • CCK - works on acinar cells
24
Q

nutrient absorption

A

carbs - monosaccharides - blood
proteins - amino acids - blood
fats - glycerol, fatty acids - lymph/blood

25
Q

lipid digestion

A

1) fatty acids enter epithelial cell
2) bind together to form triglyceride
3) combine with protein to for chylomicron
4) exit cell into lymph
5) lymph takes it away

26
Q

carbohydrate digestion

A 
carbohydrate
- salivary a-amylase
polysaccharide
- pancreatic a-amylase
monosaccharide
- active transport
monosaccharide in blood
27
Q

protein digestion

A
  • pepsin breaks down amino acids in the stomach
  • enzymes begin acting in small intestine
  • absorption - Na co-transporter
28
Q

elimination of waste

A 
Defecation reflex
- started by distention (stretch receptors in sigmoid colon and rectum)
Internal sphincter
- smooth muscle
- PSNS - relax
- SNS - constrict
External sphincter
- skeletal muscle
- somatic spinal efferent
- voluntary control
29
Q

Vitamin A

A 
Biochemistry
- retinol - transport and storage of Vit A
- retinal - vision
- retinoic acid - cell differentiation and growth
Functions
- maintains epithelial cells
- night and peripheral vision
- bone growth
Sources
- liver
- yellow/orange veges
- fats of milk and eggs
30
Q

Vitamin D

A 
Occurs in 2 forms
- Vit D3 or cholecalciferol - from sunlight 
- Vit D2 or ergocalciferol - limited range of foods
Functions
- enhance dietary Ca absorption
- enhance dietary P absorption
- bone mineralisation
Calcitriol is active form
31
Q

Vitamin E

A
  • prevents oxidisation of polyunsaturated fats in the body (phospholipid cell membranes)
  • reduces risk of CVD
32
Q

Vitamin K

A
  • synthesised by bacteria in the gut
  • assists in blood clotting
  • found in green leafy veges, wheat bran and plant oils

PHYL1007 (7 decks)

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