Anatomy Test

Carnivores

Carnivores

meat eaters

Omnivores

eat both plants and animals

gastrovascular cavity

a cavity that has a single opening through which food is ingested and waste is excreted

alimentary canal

digestive tube that extends from the mouth to the anus

4 functions of the digestive system

ingestion, digestion, absorption, elimination

Ingestion

taking in food

Propulsion

movement of food

Digestion and absorption

breaking down food and taking in nutrients

Egestion

elimination of waste

Alimentary canal

mouth pharynx esophagus stomach small intestine large intestine

mouth's role in digestion

moistening of food, bolus formation, chemical digestion of starch (not protein)

Accessory organs

teeth tongue salivary glands liver gall bladder pancreas

Teeth

-accessory digestive organs -They are responsible for beginning the mechanical digestion process

Deglutition (swallowing) 2 major phases

•The buccal phase •The pharyngeal-esophageal phase

buccal phase

•After chewing (mastication) and being mixed with saliva, the food lump is called a bolus. •It is forced into the pharynx by the tongue.

The pharyngeal-esophageal phase

a rapid phase of muscle contraction to propel the bolus through the upper esophageal sphincter and into the esophagus

deglutition

swallowing

epiglottis

a flap of cartilage that covers the windpipe while swallowing prevents food from entering the trachea

esophagus

Tube connecting the mouth to the stomach

peristalsis

Involuntary waves of muscle contraction that keep food moving along in one direction through the digestive system.

Stomach

muscular sac with thick walls

4 main regions of stomach

Cardiac region Fundus Body Pyloric region

The digestive system has thick rings of muscle at certain points called _____________. These serve as gatekeepers to allow food to enter and leave at appropriate times

sphincters

The stomach allows food to enter through the_____________ and leave through the _________________.

cardiac sphincter, pyloric sphincter

Cardiac sphincter

separates esophagus from stomach

Pyloric sphincter

separates stomach from small intestine

serosa

slippery outermost layer of stomach

3 layers of muscle in stomach

longitudinal, circular, oblique

What do the 3 layers of muscle in the stomach do

They help churn food and propel it towards the small intestine. The churning process is known as maceration

The innermost layers of the stomach are made of the __________ and ______________

submucosa, mucosa

The folds of the mucosa are called

rugae ("wrinkles") that stretch when the stomach is full.

The mucosa layer contains several specialized gastric gland cells

Mucous cells, Chief cells, Parietal cells

Mucous cells

produce bicarbonate-rich mucus to protect the stomach

Chief cells

secrete pepsinogen

Parietal cells

secrete HCl to kill microbes in food and convert pepsinogen into the digestive enzyme pepsin, which breaks down food proteins

The soupy mixture formed from the squeezing of the stomach and the addition of these gastric juices is known as

chyme

Small intestine

the location of most digestion and nutrient absorption

The small intestine has 3 sections

duodenum, jejunum, ileum

After the ileum, it joins the large intestine at the

ileocecal sphincter

Because the small intestine needs time to absorb nutrients, the chyme must be

slowed down

Circular muscles in the intestinal wall cause ______________ of the chyme

segmentation

This is in contrast to ___________ contractions which involve _______________

peristaltic , longitudinal muscles

After food leaves the small intestine, it enters the ____________

large intestine

The large intestine has 3 major sections

Cecum Colon (broken into ascending colon, transverse colon, and descending colon) Rectum

2 major functions of the large intestine

absorption of water back into the body removal of waste through rectum and anus

haustra

pouches of the large intestine that allow expansion and elongation

Haustral contractions

slow, segmenting movements that last only about 30 minutes after food moves into the large intestine.

Mass movements

• Slow, powerful movements that move waste

• Occur three to four times per day

The rectum collects and stores

undigested waste and bacteria

As the rectum fills, pressure is placed on the ________________, causing it to relax

internal anal sphincter

The external anal sphincter

needs to be voluntarily relaxed to release the built up feces through the anus

ecological costs of food

a measure to express the amount of environmental burden of a product on the basis of prevention of that burden

economical cost of food

Food prices affect people being able to afford healthy food .Supply and demand affect how much food costs

Why do highly process foods persist in the American diet

The accessibility, affordability and convenience of ultra-processed foods have made them more common

carbohydrate

compound made up of carbon, hydrogen, and oxygen atoms; type of nutrient that is the major source of energy for the body(4 calories per gram)

Lipids(fats)

Energy-rich organic compounds, such as fats, oils, and waxes, that are made of carbon, hydrogen, and oxygen(9 calories per gram)

Protiens

nutrients that help build and maintain body cells and tissues(4 calories per gram)

Calorie and calorie

c: Amount of energy needed to raise 1g of water 1 degree C C: Amount of energy needed to raise 1000g of water 1 degree

What is the difference between a gastrovascular cavity and an alimentary canal?

The gastrovascular cavity is a type of tract that comprises a two-way digestive tract and is marked with only one opening. The alimentary canal is considered a type of one-way digestive tract and it is marked with two openings.

animal with gastrovascular cavity

jelly fish

animal with alimentary canal

Earth Worm

Pharynx role in digestion

swallows

esophagus role in digestion

peristalsis and gravity move food along

stomach role in digestion

secrete acid and enzymes that digest food

small intestine role in digestion

prepares food for absorption

large intestine role in digestion

absorbs water and some nutrients

tongue role in digestion

facilitating the movement of food during mastication and assisting swallowing

salivary glands role in digestion

begin chemical digestion

liver role in digestion

produce bile

gall bladder role in digestion

store bile

pancreas role in digestion

production and secretion of digestive juices

function of bile

break down fats

What structure releases bicarbonate

the pancreas

What is the role of the hormone's secretin

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

________ in the saliva begins to break down food in chemical digestion

amalayse

Normal stage of the stomach has __________

low pH due to hydrochloric acid

Main method by which food is moved thru the alimentary canal

Peristalsis

Epiglottis prevents food from entering the ________

Trachea

Mucus prevents stomach acid from damaging the ______

Stomach linings

Stomach churning food is called __________

Maceration

What are the different regions/sphincters of the small intestine?

The small intestine helps further digest food

Duodenum

Jejunum

Ileum

Iloceceal Sphincter

What is the function of duodenum?

The first segment of the small intestine that is responsible for receiving partially digested food from the stomach and breaking it down further using enzymes from the pancreas and bile from the liver and gallbladder. Also responsible for regulating the release of digestive juices from these accessory organs.

What is the function of the jejunum?

The middle segment of the small intestine where most of the nutrient absorption takes place.

What is the function of the ileum?

The final segment of the small intestine that connects to the large intestine at the ileocecal valve. Absorbs any remaining nutrients and water that were not absorbed by the jejunum.

digestion of proteins begins in the __ where __ mix with food to break down protein into __

stomach, HCl and pepsin, amino acids

Amino acids are needed to ?

build new proteins

Amino acids are a ? bonded by ?

monomer of proteins, peptide bonds

What do chief cells do to amino acids?

Hydrolyze (break the bonds)