Bio ch 9 digestion and excretory system

Question 1

what is the path of food in the GI tract starting from the mouth

Answer 1

Mouth—-> esophagus—> stomach —-> small intestine —> large intestine—> Rectum—-> anal sphincters

Question 2

mastication

Answer 2

Chewing

Question 3

What enzymes begin chemical digestion in the mouth and what glands are they secreted by

Answer 3

Salivary amylase - begins carb breakdown and is released by salivary glands

Lingual lipase - begins breakdowns of fats and is released by lingual glands

Question 4

what is a bolus

Answer 4

a ball-shaped mass which the tongue rolls food into in preparation for it to be swallowed.

Question 5

What is the pharynx

Answer 5

a tube which is shared by the digestive and respiratory systems which food passes thru .

Question 6

What is the esophagus and what does it do

Answer 6

a muscular tube which connects the mouth to the stomach and moves food down via peristalsis. Has two sphincters as well, the Upper and Lower Esophageal Sphincters. UES and LES

Question 7

What is peristalsis

Answer 7

the wavelike movement from smooth muscle contractions in the digestive system which helps to push food through.

Question 8

What occurs in the stomach during digestion

Answer 8

most of the chemical digestion of food occurs in the stomach

Question 9

What are the main glands involved in digestion within the stomach and what do they secrete ?

Answer 9

Gastric glands contains chief cells, parietal cells and Mucous cells

 - chief cells - release pepsinogen 
-Parietal cells - release HCL and intrinsic factor (for B12 absorption) 
 -mucous cells - release mucous 

Pyloric gland contains G cells
- G cells - releases Gastrin (stimulates parietal cells to release HCL in response to food in the stomach)

Question 10

What do chief cells secrete

Answer 10

pepsinogen and gastric lipase

Question 11

What is the function of pepsinogen

Answer 11

pepsinogen is the zymogen of pepsin and gets turned into pepsin upon contact with HCL in the stomach

Question 12

What is the function of pepsin ?

Answer 12

responsible for the breakdown of proteins into amino acids

Question 13

What is the difference between Peptidases, Pepsin, dipeptidases, and aminopeptidase

Answer 13

Peptidase - is a general term for any enzyme which breaks down proteins into peptides or individual amino acids

Pepsin- a type of peptidase located in the stomach and is the active form of pepsinogen, begins breakdown of proteins into smaller peptides in the stomach.

Dipeptidase- an enzyme which breaks down dipeptides (2 amino acids) into 2 separate amino acid monomers

Aminopeptidase - an enzyme which breaks off the amino (N) terminal of a peptide chain

Dipeptidase and aminopeptidase are both located in the small intestine

Question 14

What is trypsin and where is it located

Answer 14

Trypsin is a peptidase enzyme meaning it breaks down proteins. It is the active form of the zymogen trypsinogen and is secreted into the duodenum of the small intestine by the pancreas.

Question 15

What are brush-border enzymes?

Answer 15

Enzymes located on the microvilli of the intestinal epithelial cells lining the small intestine. Located here so that the nutrients they break down can be directly absorbed into the bloodstream. BBE breaks down nutrients into their simplest forms.

Brush border enzymes include carbohydrate-digesting enzymes, protein breakdown enzymes (peptidases), and nucleotide-digesting enzymes.

Question 16

What is the function of secretin hormone

Answer 16

Secretin is released when the acidic chyme enters the small intestine. Secretin signals the pancreas to release alkaline bicarbonate fluid into the duodenum to neutralize the acidity.

Question 17

What is the function of Cholecystokinin (CCK)

Answer 17

CCK is released upon the presence of fats in the duodenum. CCK signals the gallbladder to contract and release bile into the small intestine to begin fat emulsion.

Question 18

What is Carboxypeptiddase ?

Answer 18

Like aminopeptidase but it cleaved off the amino acid at the Carboxy (C) Terminal of the peptide chain

Question 19

Whats the difference between the transcellular and paracellular pathways of nutrient absorption

Answer 19

transcellular - mlcls go through the cells and the process is specific and regulated

paracellular- mlcls go between cells through the tight junctions and allow passive transport of water and ions

Question 20

what do salivary and pancreatic amylase enzymes do ?

Answer 20

salivary and pancreatic enzymes both digest carbohydrates. They break down polysaccharides into disaccharides. salivary amylase starts this process in the mouth and pancreatic amylase continues this in the small intestine.

Question 21

What does Disaccharidase enzyme do

Answer 21

breaks down disaccharides into monosaccharides (carbohydrate monomers)

Question 22

What is Bile and where is it produced?

Answer 22

Bile is a mixture of salts, cholesterol, and bilirubin and functions to emulsify ( not directly digest) fats in the small intestine. Bile is produce by the liver but not stored there.

Question 23

What is the gallbladder and its function?

Answer 23

The gallbladder is a pear-shaped organ beneath the liver which stores Bile and releases it into the small intestine in response to Choecystokinin signaling. CCK is released by the presence of fats in the duodenum.

Question 24

What does the pancreas do as it relates to digestion?

Answer 24

The pancreas secretes enzymes that digest carbs, proteins, and fats. Specifically, Pancreatic amylase, pancreatic peptidase, and pancreatic lipases which enter the duodenum via a duct.

Question 25

What are acinar cells?

Answer 25

They are a specialized group of cells in the pancreas responsible for producing pancreatic digestive enzymes.

Question 26

what does the enteropeptidase enzyme do?

Answer 26

It cleaves the inactive zymogen trypsinogen into its active form trypsin.

Question 27

What does the term osmolarity mean and what is the osmolarity of blood?

Answer 27

Osmolarity is the concentration of solute particles in a solution

Blood has approximately 300 mOsm (milliosmoles)

Question 28

What is the path of blood as it gets filtered out of the glomerulus and into the nephron for filtration to become urine ?

Answer 28

Blood —> Bowman’s capsule —> Proximal convoluted tubule —> Loop of Henle —> Distal Convoluted Tubule —> Collecting Duct

Question 29

What is the glomerulus ?

Answer 29

the collection of blood capillaries located inside the bowman’s space which filters out components of the blood and forces them into the bowman’s space via starlings forces

Question 30

What is filtrate ?

Answer 30

The name of the stuff that gets filtered out of the glomerulus and into the bowman’s space is known as filtrate and eventually becomes urine.

Question 31

What happens to the filtrate when it reaches the proximal convoluted tubule?

Answer 31

The PCT is the first site of reabsorption of things the body wants to keep such as water, amino acids, salts, and vitamins

Question 32

What are the 4 main things that need to be retained in the filtrate as is moves through the nephron to become urine

Answer 32

HUNK
H+ ions
Urea
NH3 ammonia
K+

These are the main things being excreted, there are a lot more.

Question 33

What happens at the descending loop of Henle

Answer 33

at the DLOH aquaporins allow water to move back into the blood and not any ions so only water is reabsorbed into the blood as it moves down.

Question 34

What is the vasa recta?

Answer 34

a network of blood capillaries running through the medulla of the kidneys and is responsible for reabsorbing water from the filtrate.

Question 35

What happens at the thick and thin portions of the ascending loop of Henle

Answer 35

the thin ALOH passively reabsorbs salt into the body while the thick portion requires active transport as it is now working against a concentration gradient for the filtrate to reach the desired osmolarity level.

Question 36

What happens at the distal convoluted tubule of the nephron?

Answer 36

The DCT mainly functions to finetune salt levels according to the needs of the body. aldosterone works on the DCT to increase salt absorption in the blood also causing water to follow.

Question 37

What happens at the collecting duct?

Answer 37

Final area for water and sodium absorption back into the body. Aldosterone and ADH/vasopressin can both work on the collecting duct.

Question 38

Difference between ADH/vasopressin and aldosterone

Answer 38

ADH/vasopressin works primarily on the collecting duct by inserting aquaporins which increases water in the body. ADH will dilute the blood because it is only increases water in the body.

Aldosterone works on the collecting duct as well as the DCT and it increases sodium absportion and potassium excretion which also functions to increase water levels in the body as water follows salt. Aldosterone will not dilute the blood because it increases salt as well as water content in the body.

Question 39

How does aldosterone get released?

Answer 39

juxtaglomerular cells near glomerulus snese hypovolemia (not enough blood volume) and release —>renin which releases angiotensin 1 —>which uses ACE (angiotenisn converting enzyme) to convert into —> angiotensin 2 which finally releases aldosterone

Question 40

How does ADH/vasopressin get released

Answer 40

when the blood is hypernatremic, the hypothalamus stimulates the posterior pituitary to release ADH

Question 41

What does Atrial natriuretic peptide do

Answer 41

ANP does the opposite of aldosterone, it increases salt and water in urine and causes more urination. ANP lowers BP and is released by the heart when it is working too hard.