Exam 3 Flashcards
Name layers of GI tract - innermost to outermost
Mucosa
Submucosa
Muscularis Externa
Serosa
What is the function of the mucosa?
Secretes mucus, digestive enzymes, absorbs end products of digestion
What is the function of the submucosa?
nerve plexus surrounding GI tract
What is the function of the muscularis externa?
segmentation and peristalsis
What is the function of the serosa?
reduces friction
4 Types of Gastric Pit Cells
Mucous neck cells
parietal cells
chief cells
enteroendocrine cells
What do mucous neck cells produce?
mucous
What do parietal cells produce?
HCl Acid to denature proteins
Intrinsic Factor for vitamin b absorption
What do chief cells produce?
Pepsinogen to avtivate pepsin
Liapses
What do enteroendocrine cells produce?
Chemical messengers that act as paracrines - serotonin and histamine
Hormones - somatostatin and gastrin
What is pepsinogen? Who is it produced by? How is it activated?
Produced by chief cells, precursor to pepsin, activated by HCl
Bile - What is its purpose? Where is it produced?? Where is it stored ?? What nutrient class is it used to digest?
1) Bile is fat emulsifier and carry away waste,
2) produced in liver
3) stored in gallbladder
4) Fats
Phases of Swallowing
Buccal
Pharyngeal-esophogeal
What is the Buccal Phase of swallowing
Voluntary contraction of tongue
What is the 2. Pharyngeal-esophageal phase of swallowing?
involuntary
3 parts of the small intestine - top to bottom
Duodenum
Jejunum
Illeum
Where is the duodenum? What happens there?
1) retroperitoneal cavity;
2) complete first phase of digestion,
3) food mixed with enzymes and bile to break down food
Where is the jejunum? What happens there?
1) Intraperitoneal cavity
2) absorb nutrients (carbs, fats, minerals, proteins and vitamins) and water
Where is the illeum? What happens there?
1) intraperitoneal;
2) final digestive phase, absorbs bile acids, fluid and b-12;
3) contains villi
Where does the majority of absorption occur?
Small intestine
What are the small intestine modifications?
- Circular Folds
- Villi
- Microvilli
Parts of Large Intestine - in order
- Cecum
- Appendix
- Colon
- Rectum
- Anal Canal
Parts of Colon
Ascending, transverse, descending, sigmoid
What is unique about large intestine?
Not essential for life; No food breakdown happens here
Role of small intestine
4 nutrient classes
carbs
protein
lipids
nucleic acids
What enzyme breaks carbs? Into what? Where does it travel?
- Broken down by salivary amylase and pancreatic amylase
- Into monosaccharaide
- Enter bloodstream
What enzyme breaks proteins? Into what? Where does it travel?
- Pepsin and Pancreatic Enzymes
- Into amino acids
- Bloodstream
What enzyme breaks lipids? Into what? Where does it travel?
- Bile and Bile Salts, Pancreatic Lipases
- Triglycerides
- Lymph
How is water absorbed?
Osmosis
What is mechanical digestion? Where does each part occur?
Physical breakdown
Chewing (mouth)
Churning (stomach)
Segmentation (small intestine)
What is chemical digestion? Where does it occur?
Acids, Enzymes and Secretions break food into building blocks for nutrient absorption
Starts in mouth, then stomach and into small intestine
Where are microvilli found and what are they good for?
Found in small intestine
Good for final protein and carb digestion
What happens in glycolysis?
Breakdown of glucose into pyruvic acid then enters 1 of 2 pahways - no oxygen or oxygen
What do you start with in glycolysis? What is the end product?
- Start with glucose (6 carbon)
- Broke into 2 carbon pyruvate acid molecules each with 3 carbon
2 ATP
What is the molecule that enters the Krebs Cycle?
Coeyzyme A hooked onto acetic acid
How do you oxidize glucose?
Glycolysis
Krebs Cycle
Electron Transport Cycle
Where does glycolysis occur?
Cytoplasm/cytosol
In glycolysis, if no oxygen is available, what happens?
- mitochondria not invovled
2. lactic acid produced
In glycolysis, if oxygen is available, what happens?
Enters Krebs cycle and Electron transport chain
Enters mitochondria
Where does the krebs cycle occur?
mitochondria
What is the end product of the krebs cycle?
6 CO2
8 NADH + H
2 FADH2
2 ATP
What happens in the electron transport chain?
Uses energy from krebs cycle to pump H across membrane into proton gradient, some H combined with O to produce water
What happens when you’re abundant in ATP?
Absorpative/Fed State
Anabolsim > Catabolism
Dominated by insulin
Excess nutrients stored as fat if not used
What happens when you don’t have any ATP?
Fasting State/Post Absorpative
Dominated by glucagon
Catabolism of fat, glycogen and proteins
What are the macronutrients?
Carbs, Lipids, Proteins
How much ATP is produced from carbs/proteins vs lipids?
carbs/proteins - 4
lipids - 9
What are essential nutrients?
Nutrients that must be eaten because the body cannot synthesize them from other nutrients
What is anabolism?
synthesis of large molecules from small ones (amino acids to proteins)
What is catabolism?
hydrolysis of complex structures to simpler ones (proteins to amino acids)
Glycogenesis
making glycogen with excess glucose, occurs in liver and skeletal muscle
Glycolysis
breakdown of glucose to pyruvic acid
Glycogenolysis
breaking down glycogen in response to low blood glucose
Gluconeogenesis
new glucose from non-carbs, occurs in liver
Lipolysis
breakdown of stored fats into glycerol and fatty acids
Lipogenesis
synthesis of fat
What are the fat soluble vitamins? Where are they Stored?
A - converted from beta carotene
D - skin
E - stored in liver and fat tissue
K - colon
What molecules make up triglycerides?
Glycerol + 3 fatty acids
Where is urea produced?
The Liver
Where is Angiotensin II produced?
The Kidneys during the renin-angiotensin complex
Where is renin produced?
Produced by kidneys in granular cells to raise blood pressure to initiate angiotensin-alderstone mechanism
What are corticol nephrons? How are they different from juxtamedullary nephrons? Where are they found?
1) 85% of all nephrons,
2) short nephron loop, glomerulus further from the cortex-medulla junction; efferent arteriole supplies pertibular capillaries
3) found in cortex;
What are juxtamedullary nephrons? How are they different from corticol nephrons? Where are they found?
1) long nephron loop, glomerulus closer to cortex-medulla junction,
2) efferent arteriole supplies vasa recta
3) Found in renal medulla
What substances SHOULD be found in initial glomerular filtrate
Blood plasma minus blood cells and protein
What is filtration? Where does it occur?
movement of water and solutes from plasma to renal tubule; occurs in rental corpuscle in glomerulus
What is Reabsorption?
movement of water and solutes from tubule back into plasma; occurs in proximal convoluted tubule in cortex
Where does secretion occur?
Distal convoluted tubule
Hormone Controlled Reabsorption
Distal Convoluted Tubule - Sodium/Aldosterone, Calcium (PTH), Chrloride follows sodium
Collecting Ducts - H20/Water
Granular Cell - What do they do? Where are they
Sense blood pressure and secrete renin
Enlarged smooth muscle of arteriole
Macular Densa - Where are they? What do they do?
Ascending limb
Chemoreceptor for NaCl content of filtrate
Extraglomelular - What is it?
Gap junction, pass signals between macula densa and granular cells
Which layer of the alimentary canal is responsible for the movements of segmentation and peristalsis?
Muscularis externa
The pancreas secretes a number of products into the duodenum in the pancreatic juice. What are the functions of pancreatic juice?
1) Acidifying the contents of the duodenum
2) Neutralizing the chyme entering the duodenum from the stomach
In which segment of the alimentary canal does the majority of nutrient absorption occur?
Jejunum and ileum
What is the primary function of the large intestine?
Water absorption and feces formation
Weakening of the ________________ sphincter can lead to heartburn and GERD.
Gastro-esophageal
The segment of the small intestine that is first in line after the stomach is the
Duodenum
What is true about the liver?
Plays role in detoxifying blood
Target organ for diseases such as Hep A and Hep C
Produces Bile
What is the site of “intrinsic factor” production?
The parietal cells of the gastric pits
What is the site of hydrochloric acid production?
The parietal cells of the gastric pits
hich of the following is the breakdown product of carbohydrates?
Monosaccharides
True or False: B vitamins and Vitamin K are produced by bacteria in the large intestine
True
A scarring of the liver tissue as a result on long term chronic inflammation such as alcoholism is
Cirrhosis
The vermiform appendix is a worm-like structure that is attached to the
Cecum
Which type of nutrient does not enter the bloodstream directly, but enters the lymphatics as chylomicrons and is then dumped into the blood by the lymph vessels?
Fats
Glycolysis is the breaking of the 6-carbon glucose molecule into
Two 3-carbon Pyruvic acid molecules
Which of the statements about Glycolysis only is FALSE?
It occurs in the mitochondria
It does not consume or need oxygen to take place
It occurs in the cytoplasm
It can produce lactic acid
It occurs in the mitochondria
How many ATP are produced from glycolysis of a single glucose molecule?
2
When there is abundant
ATP available in the cell, what occurs?
Lipgenesis
Glyocgen is produced
Glucose catabolism is inhibited
Which of the three nutrient classes below yields the highest amount of energy per gram?
Lipids
What is special about essential amino acids?
They must be provided in the diet; the body cannot synthesize them
The breakdown of organic macromolecules into their smaller units is called
catabolism
Which of the following statements are TRUE about the Absorptive (fed) state?
A. Glucagon secretion is stimulated
B. Occurs during periods of fasting, not right after a meal
C. Catabolism exceeds anabolism
D. Insulin secretion is stimulated
D. Insulin secretion is stimulated
Which of the following terms means the formation of glucose from non-carbohydrate molecules
Gluconeogenesis
Which term below refers to the breaking apart of glycogen to yield glucose?
Glycogenolysis
Which of the following is TRUE about the Post-Absorptive (fasting) state?
Anabolism exceeds catabolism
Glucagon secretion is inhibited
Insulin secretion is stimulated
Energy is provided by catabolism of stored nutrients such as lipids and glycogen
Energy is provided by catabolism of stored nutrients such as lipids and glycogen
The electron transport chain and oxidative phosphorylation produces large amounts of energy for the cell to use in the form of ATP. What is the part of the electron transport chain and oxidative phosphorylation that yields this ATP in the actual ETC?
The movement of hydrogen ions back into the cell at the site of ATP synthase
Aerobic breakdown of pyruvate occurs in which organelle of the cell?
mitochondria
Oxygen is necessary for the life of cells. What exactly is oxygen used for?
Oxygen is the Hydrogen ion acceptor in the electron transport chain
Where is glycogen stored in the body?
liver and muscle
What does GFR stand for?
Glomerular filtration rate
Which of the following processes are functions of the kidney?
Activation of Vitamin D
Gluconeogenesis
Release of Renin
Release of erythropoietin
Which of the following structures may be found in the medulla of the kidney?
Glomerulus
Proximal convoluted tubule
Loop of Henle
Afferent arteriole
Loop of Henle
What is the role of the the juxtamedullary nephrons?
Forming concentrated urine
Which of the following substances WOULD be found in the initial
glomerular filtrate?
Glucose
Red blood cells
White blood cells
Proteins
Glucose
Which part of the nephron is the primary site of REABSORPTION?
roximal convoluted tubule
What is meant by the “co-transport” or “secondary active transport” by the PCT?
When Na+ is actively transported, glucose and amino acid come along too
What part of the tubule is the primary site of hormone controlled reabsorption?
Distal convoluted tubule
How does ADH work?
Triggers reabsorption of water in the collecting ducts
Which of the following is the standard substance used to measure GFR?
Inulin
A patient had a disease that damaged his kidney, and now has kidney damage. The GFR is calculated as 50 ml/minute. How would you describe this damage?
Chronic damage. This is in the range for chronic renal disease.
A significant consequence of renal disease and reduced GFR is
High levels of nitrogen waste in blood
