Zool 1020 Ch. 15

Protein provides...

4 calories per gram.

What are the forms of digestion

Mechanical, chemical

Complete protein

generally comes form animal sources and contains all the essential amino acids.

What happens to fatty acids and glycerol?

resynthesized into triglycerides, combined with cholesterol and phospholipids, and covered in protein, forming droplets known as chylomicrons, then diffuse into a lymphatic vessel (lacteal) in the core of each villus. They are then delivered to the bloodstream by way of lymphatic vessels.

The primary function of the stomach is to _____.

store and digest food

What are the 3 pairs of salivary glands?

- Sublingual, below tongue - Submandibular, below jaw - Parotid, in front of ears

What does the pancreas contain?

- digestive enzymes including: amylase, tripsin, lipase - bicarbonate ions important in neturalizing acid in chyme - drains from pancreas to pancreatic duct

How does the stomach protect itself from gastric juices?

- mucus - pepsin produced in an inactive form - neural & hormonal mechanisms - food absorbs and dilutes gastric juices - stomach lining is replaced rapidly

What are the digestive activities of the liver?

- produces bile - regulates blood glucose levels - packages lipids with proteins to produce lipoproteins, which aid transport in the blood - removes poisonous substances

What are the 3 regions of the small intestine?

1. Duodenum 2. Jejenum 3. Ileum

`What are the 4 regions of the large intestine

1. cecum 2. colon 3. rectum 4. anal canal

Muscularis

2nd most inner layer (of 4) of GI tract; responsible for movement of materials through the GI tract and for mixing ingested materials with digestive secretions.

Which vitamins are fat soluble?

A, D, E, and K

What is the primary role of the large intestine in digestion?

Absorbs ions, water, and vitamins to maintain homeostasis

What does the large intestine do?

Absorbs water, ions, and vitamins; home to millions of beneficial bacteria

Digestion of starch begins in the mouth with what enzyme?

Amylase

Which vitamins are water-soluble?

C and B

What are proteins?

Chains of amino acids

Which of the following hormones functions to stimulate the release of digestive enzymes from the pancreas?

Cholecystokinin

What do you balance caloric intake with?

Energy expenditure

True or false? Water-soluble nutrients are absorbed into the lacteals, whereas lipid-soluble nutrients are absorbed into the blood capillaries.

False

Pharynx's place in digestive system

Food from mouth through pharynx to espophagus.

What are the hormones that regulate digestive activities?

Gastrin, vasoactive intestinal peptide, secretin, and cholecystokinin.

The substance present in stomach secretions that does the most damage in heartburn is _____.

HCl

What is feces and what does it consist of?

Material left in the large intestine after passing through the colon. Consists of undigested or indigestible material, bacteria, sloughed off cells, and water.

What are the complexes of glycerol, fatty acids, and bile salts formed in the lumen of the small intestine called?

Micelles

What regulates the release of digestive secretions?

Neural and hormonal mechanisms

Lipids

Provide 9 calories per gram; include: fats, oils and cholesterol.

Chemical digestion of proteins is confined to which combination of organs in the digestive system?

Stomach and small intestine

Mouth function in digestive system?

Teeth - tear and grind food Salivary amylase - begins chemical breakdown Taste buds - help monitor quality of food Tongue - manipulates food to be swallowed

What happens to monosaccharides, amino aceds, water, and ions?

They enter the capillary blood network in the center of each villus.

What is the liver's function

To secrete bile that which is then stored in the gallbladder.

What are the fingerlike projections along the surface of the small intestine called?

Villi

High-density lipoproteins (hdl)

a lipoprotein made in the liver and released into the blood that transports cholesterol away from the cells to teh liver. HDLs are often called teh good from of cholesterol.

Lacteal

a lymphatic vessel in an intestinal villus that aids in the absorption of lipids

glycemic response

a measure that describes how quickly a serving of food is converted to blood sugar and how much the level of blood sugar is affected.

Vitamin

a nutrient that is needed in very small amounts and serves as an enzyme or coenzyme.

Cecum

a pouch connected to the junction of the small and large intestines, considered to be the beginning of the large intestine.

Low-density lipoproteins (ldl)

a protein carrier in the blood that transports cholesterol to the cells. LDLs are often called the bad from of cholesterol.

Appendix

a slender closed pouch that extends from the large intestine near the juncture with the small intestine.

Nutrient

a substance in food that provides energy; becomes a part of a structure; or performs a function in growth, maintenance, or repair.

What method are products of digestion absorbed by?

active transport, facilitated diffusion, or simple diffusion.

Hepatic portal vein links.....

capillary beds of the villi in the small intestine with capillary beds in the liver

What does the large intestine consist of?

cecum, colon, rectum, and anal canal

How is the small intestine's surface area for absorption increased?

circular folds in its lining, villi, and microvilli

Complementary proteins

combinations of incomplete proteins that together supply all of the essential amino acids.

Incomplete protein

comes from plant sources and lacks one or more of the essential amino acids.

The primary function of the small intestine is to _____.

digest and absorb nutrients

After leaving the stomach, chyme enters the _____.

duodenum

Simple carbohydrates....

empty calories, they provide only energy.

Bile's function?

emulsifies fat making digestion by water-soluble lipase faster and more complete.

Complex Carbohydrate provides?

energy along with other nutrients?

Where are products of digestion absorbed into?

epithelial cells of villi

Villi

fingerlike projections in the small intestine

Blood flows from the small intestine to the liver through the _____, then from the liver to the inferior vena cava through the _____.

hepatic portal vein; hepatic vein

What do gastric juices consist of?

hydrochloric acid (HCl) and pepsin (protein splitting enzyme)

Mucosa

innermost layer of GI track; mucus secreting

Minerals

inorganic substances needed for a variety of life processes.

Submucosa

layer above mucosa; consists of connective tissue containing blood vessels, lymph vessels, and nerves.

Without bile, one would be unable to digest _____ completely.

lipids, found in butter and fried foods,

Microvilli

microscopic projections that cover the villi.

What does the digestive system consist of?

mouth, pharynx, esophagus, stomach, small intestine, large intestine

Which of the following gives the correct order of the organs that food passes through in the digestive system?

mouth, pharynx, esophagus, stomach, small intestine, large intestine, anus

Mechanical digestion begins in the _____, and chemical digestion begins in the _____.

mouth; mouth

What are the 4 layers of the GI tract (from inside - out)

mucosa, submucosa, muscularis, serosa

How to maintain a stable weight?

number of calories you use in physical activity plus BMR is the number of calories you should consume.

Serosa

outermost layer of GI tract; thin layer of epithelial tiusse supported by connective tissue, wraps around GI tract; secretes fluid to lubricate outside of GI tract to reduce friction with surfaces of other organs.

The tongue functions to _____.

position food for chewing and swallowing

Small intestine

primary site of digestion and absorption

What is "intrinsic factor"

protein necessary for the absorption of vitamin B12 from the small intestine.

Carbohydrate

provides 4 calories per gram; a healthy diet should limit simple carbohydrates and maximize complex carbohydrates.

Elevated blood levels of cholesterol increase _________

risk of heart disease.

What are the accessory organs of the digestive system?

salivary glands, pancrease, liver, and gallbladder

What is the pancreas' function

secretes enzymes to digest most nutrients.

Chyme

semifluid mass created during digestion once the food has been churned and mixed with the gastric juices of the stomach

Gastric glands

several glands in the stomach mucosa that contribute to the gastric juice

Bolus

soft mass of food suitable for swallowing

Stomach's function?

stores food and regulates release of food to small intestine; gastric juices liquefy food; regulates release of chyme into small instestin

Essential Amino Acids

the 9 amino acids out of 20 that the body cannot synthesize and must be obtained in the diet.

Duodenum

the first region of the small intestine. the duodenum receives chyme from the stomach and digestive juices from the pancreas and liver.

Lumen

the inner area of GI tract through which food travels

What is Basal Metabolic Rate (BMR)

the minimal energy needed to keep an awake, resting person alive.

dietary fiber

the non-digestible carbohydrate part of plant foods that forms support structures of stems, seeds, and leaves. Dietary fiber is important for heart and colon health

Peristalsis

the process in which food is propelled along the GI tract

How many layers of smooth muscle does the stomach have and what are they?

three 1. longitudinal 2. circular 3. oblique

What do Neural Reflexes do?

trigger the release of saliva, initiate the secretion of some gastric juice, and are the most important factors of regulating the release of intestinal secretions.

Esophagus function in digestive system?

tube that leads to stomach; food is pushed along through peristalsis

What is a portal system?

vein linking two capillary beds