Integrated Organ Phys- Exam 3 review material

Where does Chemical and mechanical digestion begin?

In the mouth

What is deglutition?

swallowing

What is the function of the gallbladder?

store and concentrate bile in the hepatic duct and the common bile duct

What makes up the gastrin family?

Gastrin and CCK

What signals GI Peptides?

Hormones or paracrine signals

What is the GI tract the active site of?

Immune reactions

Where are goblet cells located?

in the intestine

How does swallowing work?

1) tongue pushes bolus against soft palate and back of mouth which triggers the swallowing reflex

2) breathing is inhibited as bolus passes the closed airway

3) food moves down into the esophagus

How is surface area increased?

by invaginations called gastric glands

what solution is in the intestine?

isotonic NaCl solution

What is the function of liver hepatocytes?

secrete bile, bile salts, bile pigments, and cholesterol

What is mastication?

chewing

What does mediated transport help with?

absorption of water soluble vitamins

What are the water soluble vitamins?

All B and C vitamins

What do mucins include?

Mucous cells, serous cells, and goblet cells

Where are mucous cells found?

stomach

Muscularais externa

consist of 2 layers of smooth muscle and contain myenteric plexus of the enteric nervous system

Phasic contractions

-last a few seconds

- occur in the posterior region of stomach and small intestine

Saliva is an ____ secretion

exocrine

What does the secretin family include?

Secretin

VIP

GIP

GLP-1

What is the function of secretin?

regulation of gastric acid, regulation of pancreatic bicarbonate, and osmoregulation

What are the major physiological effects of secretin?

Stimulation of pancreatic fluid and bicarbonate secretion

What is the function of VIP?

Vasodilator- a neuromodulator and neurotransmitter

What are the major physiological effects of VIP?

regulates smooth muscle activity, epithelial cell secretion, and blood flow in GI Tract

What is the function of GIP?

- plays a vital role in lipid metabolism and the development of obesity

- Fat stimulates GIP secretion

what are the major physiological effects of GIP?

anabolic hormone that inhibits lipolysis and stimulates lipogenesis

What is the function of GLP-1?

- stimulate release of insulin secretion by binding to pancreatic B cells

- inhibit glucagon secretion

- Reduce gastric emptying

What are the major physiological effects of GLP-1?

enhances satiety and reduces food intake and has beneficial effects on cardiovascular function and endothelial dysfunction

What is serose?

Continuation of peritoneal membrane which forms sheets of mesentery

Where are serous cells found?

salivary glands

slow wave potentials

originate from the interstitial cells of Cajal

What is the submucosa?

Connective tissue that contains submucosal plexus of the enteric nervous system

Vomiting is a ____ reflex

protective

What are carbohydrates and proteins absorbed as?

monosaccharides and short peptides

What are extrinsic neurons?

autonomic neurons that bring signals from CNS to digestive system

What are Kupffer cells?

resident macrophages in the liver that fight bacteria and other materials from the portal blood

What are M cells?

-Found above the Peyer's patches

-M cells are flat APCs that bring antigens into the Peyer's patches.

- involved with immune functions of the GI Tract

What are nucleic acids digested into?

nitrogenous bases and monosaccharides

What are responsible for mixing?

Segmental contractions

What are the challenges within the digestive system?

-Avoiding autodigestion

-mass balance

- fluid loss through diarrhea and vomiting

-defense from pathogens

What are coagulation factors?

fibrinogen i, prothrombin ii, factors, protein C, protein S, antithrombin

What are the digestive hormones?

GI peptides, gastrin family, secretin family, and motilin

What are the 4 basic processes of the digestive system?

digestion, absorption, secretion, and motility

What are the functions of the liver?

-metabolic regulation

-hematological regulation -bile production

- storage

-excretory/secretory

-protective circulatory

- coagulation

What are the hepatocytes of the liver organized into?

lobules

What are the liver enzymes?

-transaminases

-cholestatic enzymes

What are the metabolic functions of the kidney?

- Carbohydrate metabolism: gluconeogenesis. glycogenolysis, and glycogenesis

- Synthesis of lipids

-ketogenesis

- protein metabolism

-synthesis of plasm proteins

- urea synthesis

- hormone metabolism

-RBC production

What are the protective function of the kidneys?

- purification

-transformation

-clearance

-endogenous: hormones and ammonia

-exogenous: drugs and chemicals

What are the secretory glands in the GI?

oxyntic glands and pyloric glands

What are the 3 functions of the stomach?

storage, digestion, defense against swallowed pathogens

What are tonic contractions?

- Last minutes to hours

- occur in some smooth muscle sphincters and anterior portion of stomach

-prevent bolus from moving backwards

What control is salivary secretion under?

Autonomic control

What do chief cells secrete?

pepsinogen

How does pepsinogen become pepsin?

When pepsinogen comes in contact with HCl it breaks down into pepsin (active form)

What is gluconeogenesis?

process of synthesizing glucose

What is glycolysis?

The process by which glucose is metabolically used

What is glycogenesis?

synthesis of glycogen from glucose

What is glycogenolysis?

breaking down glycogen into glucose

What do D cells secrete?

somatostatin (inhibits acid secretion)

What do ECL cells secrete?

histamine

What do G cells secrete?

Gastrin (stimulates acid secretion)

What do goblet cells do?

secrete mucus to lubricate and protect the intestine

What do immune cells secrete?

Cytokines which trigger the inflammatory response

What do mucous cells secrete?

mucus, bicarbonate (protects stomach from autodigestion)

What do parietal cells secrete?

HCl and intrinsic factor (Ca 2+ absorption)

What do alpha cells secrete?

glucagon

What do beta cells secrete?

insulin

What do F cells secrete?

pancreatic polypeptide

What do enteroendocrine cells secrete?

GLP-1, GLP-2, PYY, CCK, and seratonin

What is the function of GLP-2?

-act on the hypothalamus to stop appetite and food intake

-regulates gastric motility -gastric acid secretion -intestinal hexose transport

-increases the barrier function of the gut epithelium

what is the function of PYY?

regulates body weight by reducing food intake and by increasing energy expenditure

- decreases appetite

What is the function of CCK?

- cause gallbladder to secrete bile

- pancreas to secrete pancreatic juice

-inhibits gastrin secretion

- increases appetite

- stimulate emulsification of fat and protein

what is the function of serotonin?

-inhibits gastric acid secretion

-stimulate the production and release of gastric and colonic mucus

-stimulate motility

what does lipid digestion depend on?

bile salts and lipases absorbed by lacteal ducts

What does saliva do?

-soften and lubricates food

- Chemical digestion

-protective function

what does the antechamber of the heart do?

collects portal blood from the GI tract

What does the digestive activity in the stomach begin with?

long vagal reflex of the cephalic phase

What does the entrance of some amino acids require?

active transport and energy

What does the intestine absorb?

vitamins and minerals

What does the large intestine do?

-concentrates waste for excretion

- digestion

-absorption

What does the liver excrete/secrete?

-bile

-water

-cholesterol

-bile pigments

-anions of bile acids

-phospholipids

-bicarbonate and other ions

- IGF-1 and most blood proteins

-cholesterol and other fatty acids

What does the liver store?

-Glycogen

-Vitamins A, D, E, K, B12

-minerals: iron and Copper

What is bile used for?

fat digestion

What is mucosa?

-created from mucosal epithelium, lamina propria, and muscularis mucosae

-inner lining

What is peptide absorption?

-form where majority of protein is absorbed more rapidly than free amino acids

-active transport

-only free amino acids are absorbed into blood

What is responsible for forward movement?

peristaltic contractions

What is the dual role of pancreas?

endocrine and exocrine functions

What is the endocrine function of the pancreas?

secrete insulin and glucagon

What is the exocrine function of the pancreas?

secrete bicarbonate and digestive enzymes (secreted as zymogens and activated in the small intestine)

what is the largest of the internal organs?

the liver

What is the motility of the large intestine?

mass movement moves bolus forward and triggers defecation

What moves bolus forward?

peristalsis

What neutralizes gastric acid?

Bicarbonate

what occurs by active transport?

mineral absorption

what organs are part of the digestive system?

-oral cavity (with salivary glands)

-esophagus

-stomach

- pylorus (with pyloric valve)

- small intestine

- pancreas

- liver

-large intestine

- anus (with external anal sphincter)

What regulates the GI functions?

-intrinsic and extrinsic neurons

-neurotransmitters and neuromodulators

-glial support cells

-diffusion barrier

Where are digestive enzymes secreted?

mouth, stomach, intestines

where are long reflexes integrated

CNS

Where are short reflexes integrated?

ENS

Where does most digestion occur?

small intestine