Lecture 48- Digestive System Part 3 Flashcards
What is the function of the duodenum?
Releases secretions and hormones to aid in further digestion of chyme
Shortest
What is the function of the jejunum?
Major site of chemical digestion and nutrient absorption
Longest
What is the function of the ileum?
Absorbs bile acids, fluid, and vitamin B12
Immune function with Peyer’s patches when bacteria enters into ileum
What are the three parts of the small intestine?
- Duodenum
- Jejunum
- Ileum
Don’t Jump In
What do villi and microvilli do?
Increase surface area
What are epithelial cells in the small intestine like?
Very sensitive with high turnover rate and contains digestive enzymes
What is celiac disease?
An immune reaction to eating gluten which creates inflammation that damages small intestine lining
Gluten free diet
What are 5 symptoms of celiac disease?
- Diarrhea
- Constipation
- Bloating and floating stool
- Lactose intolerance
- Fatigue
What is non-celiac gluten sensitivity?
Test negative for celiac disease but experience similar symptoms to those who have it
What are the 2 potential culprits of non-celiac disease?
- Fructans
- Amylase-trypsin inhibitors
What is lactose intolerance?
Body’s inability to fully digest lactose, This occurs due to a deficiency of lactase, the enzyme responsible for breaking down lactose into simpler sugars that can be absorbed by the body
What is the mesentery and what is its role?
A fold of membrane that attaches the intestine to the abdominal wall and holds it in place/makes sure small intestine does not tie up
Highly vascularized/RBCs
Depot for fat
What is the major function of the large intestine (colon)?
Absorption: water, vitamins, electrolytes from chyme
What is the role of colonic bacteria?
-Produces vitamins
-Aids in digesting breast milk, fiber, the immune system, and brain health
What happens in constipation? What causes it?
Having fewer than three bowel movements a week
Lack of fiber, exercise, meds, IBS
True or false:
Drinking lots of water can treat constipation
FALSE
Excreted as urine, doesn’t keep water in system- that is what fiber does
What happens in diarrhea? What causes it?
Loose and watery stools
Bacterial infections, loss of water
What happens in diverticulosis? What causes it?
Pockets develop in the colon due to the weakness of muscle layers in the colon wall
Aging, low fiber diet, obesity, physical inactivity
What happens in hemorrhoids? What causes it?
Piles-swollen veins in the anus and lower rectum
Pressure on the veins from colon, lack of dietary fiber, sitting too long, obesity, pregnancy
What are the amylase enzymes for salivary, gastric, and pancreatic?
Sucrase
Maltase
Lactase
What are the three disaccharides that amylases convert starch into?
Sucrose
Maltose
Lactose
What type of vein does glucose enter the liver from?
Portal vein
What are the three main things the liver can do with glucose?
- Store it
- Use it
- Send it
What three areas can the pancreas secrete insulin on?
- Liver
- Muscle
- Adipose
What does the sensitivity and number of muscle insulin receptors depend on?
Movement
What does the sensitivity of insulin and sympathetic receptors depend on in adipose?
Adipose tissue
What type of synthesis is stimulated in muscle from insulin compared to adipose?
Muscle- glycogen and fat from glucose/proteins from amino acids
Adipose- ONLY fat from glucose
True or false:
Transport of glucose into the liver requires insluin
FALSE
Utilizes a concentration gradient/it not insulin-dependent
What two things does insulin stimulate the synthesis of in the liver?
What does it inhibit?
Stimulate glycogen and fat
Inhibits synthesis of glucose
Explain how glucagon raises blood sugar levels in response to low blood glucose
- Alpha cells
- Glucagon
- Break down to glycogen
- Glucose released to blood stream
Explain how the pituitary gland/medulla raises blood sugar levels in response to low blood glucose
- Pituitary gland
- Medulla
- Release epinephrine
- Gluconeogenesis from amino acids
- Glucose released to blood stream
Explain how the pituitary gland/cortex raises blood sugar levels in response to low blood glucose
- Pituitary gland
- Cortex
- Adrenal cortical tropic hormone
- Glucocorticoids
- Breakdown of muscle into amino acids
- Gluconeogenesis from amino acids
- Glucose released to blood stream
Explain how the hypothalamus raises blood sugar levels in response to low blood glucose
- Hypothalamus
- Activates hormone-sensitive lipase
- Fatty acids sent to muscles to make ATP
- Breakdown of muscle into amino acids
- Gluconeogenesis from amino acids
- Glucose released to blood stream
What are the two types of hypoglycemia?
- Fasting
- Reactive
What happens in fasting hypoglycemia?
This happens because the cells are…
When you stop eating and glycogen is not broken down into glucose
Hypoactive alpha cells
What happens in reactive hypoglycemia?
This happens because the cells are…
After a meal, insulin levels peak
Hypersensitive beta cells
What is the issue with Type 1 diabetes?
Not enough insulin production
What is the issue with Type 2 diabetes?
Insulin unable to bind to insulin receptors
What is gestational diabetes?
Occurs in late diabetes
Caused by placental hormones that block insulin receptors
Increases baby’s risk for diabetes
What is glycation?
Reaction of sugar and proteins
An accumulation of what product accelerates plaque build up in arteries?
What response occurs?
Advanced Glycation End Product
AGE products bind to collagen in muscles, CT, and arteries which stimulates an inflammatory response
How does diabetes and the accumulation of AGE affect the eye?
Causes cataracts
Glaucoma- glucose is converted to sorbitol and fructose which can’t leave the eye=pressure build up
How does diabetes affect the peripheral nerves?
Fructose and sorbitol accumulate in the nerves which produces osmotic pressure on the cell and draws water in which alters membrane potential
How does diabetes affect impaired immunity?
High glucose levels limit and deregulate neutrophil synthesis (type of WBC essential in immune system)
High blood sugar levels allow bacteria to grow/help infections develop quicker
How does diabetes affect the kidneys?
-Damages vasculature in kidneys
-Interferes with re-absorption processes/kidneys can’t clean blood properly–>proteins lost in urine
When the kidney is unable to absorb glucose, what chain of events happen?
- Glucose in the urine increases
- Osmotic pressure (water entering) increases
- Increased thirst
- Increased urination
- Dehydration
What happens with sorbitol+fructose production in the eye?
- Increased pressure on retina
- Blurred vision
What 2 things happen when there is poor glucose uptake in cells?
- Acidosis–>coma–>death
- Weight loss (Type 1)–>weakness
What are three ways to minimize a spike in blood sugar?
- Small/frequent meals
- Low glycemic index foods
- High soluble fiber
What is an important lifestyle modification to treat Type 2 diabetes?
Weight loss/physical activity
What is the role of exogenous insulin in Type 1 diabetes?
Insuline pumps/injections
What is the role of metformin in Type 2 diabetes?
Reduce glucose production in the liver
What is the role of sulfonylurea in Type 2 diabetes?
Sensitizes beta cells so that they produce more insulin
