Digestive Flashcards
(34 cards)
What is the biggest immune system?
The Gut. You are what you eat, needs probiotics and prebiotics
What factors can influence composition and function of human gut microbiota
- Birth mode
- Breast feeding
- Geography
- Diet
- Exercise
- Disease
- Ageing
- Drugs
Anabolism v.s. Catabolism
Anabolism = Building = using amino acids to build proteins
Catabolism = breaking down = proteins to amino acids.
Essential nutrients = cant make these, must get food.
Salivary Glands
3 pairs = exocrine
Carbohydrate digestion starts in mouth due to amylase
Parotid Salivary Glands
Produce serous secretion - Enzyme salivary amylase = breaks down starches into glucose, maltose
Sublingual Salivary Glands
Produce mucous secretion - acts as a buffer and lubricant
Submandibular Salivary Glands
Secrete buffers, glycoproteins (mucins) and salicary amalyse
Do alligators chew food?
NO!
Functions of the stomach
Store Foods
- Release gastric acids = HCl = strong acid; kills
bacteria, breaks down proteins & activates
pepsinogen - Releases pepsinogen = inactive -> pepsin is active
- Mucous is released = 2 types
- Release intrinsic factor = important for vitamin B12
absorption which is needed for RBC production - Release gastrin = a hormone that stimulates gastric
activity
What are the Types of Mucous?
- Protects stomach
- Keeps digesting food slimy
- Someone w/ gastric reflux can damage esophagus bc. no protection in esophagus
What are parietal, chief, and g-cells
Parietal: releases HCl & Intrinsic factor
Chief Cells: Pepsinogen
G-Cells: Gastrin = hormones
What does HCl do?
- Kills microorganisms
- Denatures proteins and inactivates enxymes in food
- Helps break down plant cell walls and connective tissue in meat
- Activates pepsin = digests proteins
Active process = Use ATP
Explain the process of HCl secretion from parietal cells
- CO2 + H2O -> H+ + HCO3- in presence of carbonic anhydrase
- H+ is actively pumped out via H+/K+ ATP-ase K+ will leak out
- HCO3- is exchanged for Cl- = antiporter
- CL- moves out through cell via channel = facilitated diffusion
- Alkaline tide = increases in HCO3- after feeding = metabolic alkalosis
Metabolic Alkalosis = fixed by hypoventilation
pH is very acidic = 1-2
How is acid and enzyme production by gastric mucosa regulated?
- Controlled by the CNS
- Regulated by short reflexes of ENS = Enteric Nervous System = brain of the gut
- Regulated by hormones of digestive tract
What are the 3 phases of gastric activity
- Cephalic phase
- Gastric phase
- Intestinal phase
What role does the small intestine do?
Roles in digestion and absorption of nutrients
What is the Duodenum?
- the segment of small intestine closest to stomach
- “mixing bowl” that receives chymes from stomach and digestive secretions from pancreas and liver
- modify it HCl & use HCo3 to neutralize acid
Function:
- Receives chyme from stomach
- Neutralize acids before they can damage
absorptive surfaces of the small intestine. Lost of
bicarbonate to neutralize H+ from HCl and lots
enzymes
HCO3- + H+ -> CO2 +H2O
What are the components of the Small Intestine?
The Jejunum and The Ileum
What is the Jejunum?
- Middle segment of small intestine
- Is the location of most
a. Chemical digestion = lots of enzymes =
lipases (Fats) ; amylases (carbs); proteases
(proteins)
b. Nutrient absorption
- Is the location of most
What is the Ileum?
- Final segment of small intestine
- End at the ileocecal valve, a sphincter that
controls flow of material from the ileum in to the
large intestine.
What does Absorption Cells do?
- Absorb nutrients
- Have microvilli
What does Goblet Cells do?
- Release mucous into Small Intestine
What does Enteroendocrine cells do?
- Secretes lots of hormones
What does Paneth Cells do?
- Release antimicrobial agents into Small Intestine such as lysosomes.
- Capable of phagocytosis