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Exam 2 questions 1-10
Terms in this set (10)
Intestinal Nutrient Absorption
takes place in the small intestine except the absorption of biotin, vitamin K, and some water. The large intestine absorbs biotin, vitamin K, and creates B12.
Transcellular transport vs paracellular transport and specific nutrients and formed substances.
1. Paracellular (passive diffusion) refers to the transfer of substances across the epithelium by passing through the intercellular space between adjacent cells
Tight junction is the prime determinant of paracellular permeability
2. Transcellular (lipophilic) travel through the cell membrane - positively charged particles
Oral and pancreatic digestive enzymes
Oral: Salivary amylase, lingual lipase
Pancreatic: amylase, lipase, proteases
SNS vs PSNS effects on GI function
1. PSNS is responsible for SLUDD
Salivation, lacrimation, urination, digestion and defecation
2. PSNS will be impacted or slowed by SNS
Mechanism of berries and pre-cancerous oral-esophageal lesions
Polyphenols, a component in berries and cherries, convert precancerous oral-esophageal lesions into remission w/ 60% effectiveness
Stress on immune function
1. Stress increases visceral perception (the feeling of butterflies in your stomach), this leads to the gastro colic reflex which can contract your colon and result in defacation. Also stress causes vasoconstriction in the blood vessels of the gut which leads to less mucus production and reduces the health of the intestinal flora. Chronic stress shifts our inflammatory profile so we can't respond to acute stressors as well. This means that inflammation in the gut will be longer lasting and disruption of the intestinal barrier will be triggered.
The MALT and leak vs the claudin pathway
- MALT - mucosa-associated lymphoid tissue - collections of B cells, t cells, plasma cells, macrophages and APCs in mucosal lining; serves GI tract as an important site of innate and adaptive immune regulation
Claudin (pore pathway) - characterized by small pores created by tight junctions claudin proteins with charge selectivity and can be modified by external stimuli such as cytokines
Leak pathway - flux increased by TNF-alpha and interferon gamma. Does not show charge selectivity and allows for large solutes to cross
Cytokines TNF-alpha and IFN-gamma are pro-inflammatory and lead to increased permeability (leak pathway)
Cytokine IL-10 is anti-inflammatory, MLCK (myosin light-chain kinase) is inhibited and tightens barrier
GI absorption of iron. Roles of intrinsic factor, vitamin C, and associated deficiencies.
- Iron: transported by mucosal transferrin and is stored in ferritin delivered to the body as needed. Vitamin C increases non heme iron absorption by 300% (non heme iron is harder to absorb)
- Intrinsic factor is a glycoprotein secreted by the stomach and enables the body to absorb vit. B12
Conversion of ALA to EPA and DHA via nutrient synergy.
- anthocyanins found in berries are able to help increase ALA's conversion to EPA and DHA, which are usable Omega 3's in the body
Reasons the stomach doesn't "digest itself."
- bicarbonate in the unstirred layer , alkaline
- Stress can slow production of unstirred layer and make the stomach vulnerable to ulceration. - ulceration occurs when stomach does begin to digest itself
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