* Chapter 39 Flashcards
Difference between incomplete and complete digestive system?
Incomplete: has one opening and is bidirectional (For example a flatworm)
Complete: a tube with two openings, allowing food to move in one direction through lumen, unidirectional-> travels to specialized regions and whatever not absorbed leaves butt.
the digestive tube is how long…?
30 ft long, 20 ft of it consists of small intestine
function of the esophagus
connects mouth to stomach
what makes up the alimentary canal?
the mouth, esophagus, stomach, small intestine, large intestine
What are the accessory organs and their functions?
- Salivary glands: secrete liquid that contains digestive enzyme amylase, to aid digestion & neutralize acids
This accessory organ secretes saliva into mouth (enzymes), that moisten food for easier swallowing, initiate chemical break down of food, and dissolves food components enabling you to taste food - pancreas: regulates blood sugar (insulin - & glycogen +),
secretes enzymes to break down carbohydrates +fats +protein - Liver: largest internal organ we have, produces bile
- Gallbladder: Stores and releases bile
Complete digestion of proteins=
Complete digestion of carbohydrates=
Complete digestion of DNA=
- amino acids
- monossacchraids
- Nucleotides
What does saliva contain and what are their functions?
- Salivary amylase: catalyzes the hydrolysis of starch into disacchrides. Begins carbohydrates digestion. break carb polyssaccarides
- Bicarbonate: neutralizes acids and protects inner lining of mouth mouth from acidic food
- mucins: lubricate and stick substances that bind food together into a ball to swallow with ease
Functions of the tongue?
- tongue exerts initial force on ball of food to go to the esophagus
- mix food with saliva
- tastebuds help us chose food to ingest
- taste buds also help us compare normal foods so we dont get food poisoning
- taste= happiness, so system wants
food moves down esophagus by _______
rhythmic peristaltic contractions
What type of muscle tissue lines the entire digestive tube?
smooth muscle tissue
What is the Sphincter?
ring of smooth muscle tissue that can contract, close junction and open junction to determine how much food goes down stomach
The stomach is a muscular sac that …..
stores and mixes food, secretes substances that dissolve and degrade food, and controls the rate at which food enters the small intestine
Gastric fluid consists of …?
hydrochloric acid, pepsinogen (inactive) and mucus
what is HCI
dissolves bits of food to form a soupy chyme (dissolved food)
it also converts pepsinogen (inactive) to pepsin (active)
pepsin begins the digestion of ____
proteins
What protects the stomach lining. What happens if these are blocked?
Mucus and Bicarbonate. If these are blocked, a peptic ulcer may be resulted (holes in lining of stomach)
Peristaltic contractions churn the chyme and keep the sphincter of the stomach’s exit ____, but small amounts are released at regular intervals into the ____
closed; small intestine
The small intestine is composed of three regions? what are they?
- Duodenum: (beginning of small intestine) where most digestion occurs (complete digestion)
- Jejunum: Central section, place where food is absorbed (longest section), it is the longest so food has more opportunities to be absorbed
- ileum: whatever is left behind will be brought to the large intestine for elimination
Secretions from the small intestine contain digestive enzymes such as…?
intestinal peptidase (carbohydrates), lactase (lactose), lipase (lipase) and sucrase (sucrose/sugar).
The pancreas secrete digestive enzymes including :
pancreatic amylase: *oolgiossacchrides will be broken down into monosacchrides (saliva amylase does this too)
lipases, nucleases and trypsin and chymotrysin that digest proteins into peptide fragments and carboxypeptidase and aminopeptidase.
These enzymes are taken into duodenum for complete digestion
Pancreas consist of exocrine and endocrine glands, describe their functions
Exocrine glands: produce fluids that travel through ducts and most of their fluids go to outside of your body
Endocrine glands: produce and release hormones directly into the blood stream
_____ from the pancreas buffers the acid from the stomach
bicarbonate
Function of liver
- liver destroys old blood cells,
- stores glycogen
- and adds glucose to the bloodstream when levels drop
- it produces biles salts which are stored as bile in the gallbladder
- the liver also stores and synthesizes certain nutrients and detoxifies alcohol and other poisons
function of bile
Bile breaks up fat droplets in the small intestine
What is emulsification?
break down of lipase into smaller molecules of lipid
What are the layers of the small intestinal wall and what are their function?
- The mucosa: the epithelial lining that faces the lumen of the gut; connective tissue underlies it
- The submucosa: contains blood and lymph vessels plus nerve networks
- A muscle layer (longitudinal and circular): is covered with the outermost serosa
How is absorptive surface area increased?
by finger-like projections of the intestinal lining called villi, the cells of which bear smaller microvilli
what are the absorption mechanisms
- repeated segmentation contractions create an oscillating movement that mixes the food
- monosaccharides (glucose) and amino acids cross the gut libing by active transport and enter the bloodstream
- Triglycerides leave the cells by exocytosis to enter the lymph vessels
The large intestine (colon) stores and concentrates feces…. what are feces?
undigested and unabsorbed material, water and bacteria
The large intestine begins as a cup-shaped pouch called ____. ____ is at the junction of colon with the small intestine (appendix attached here)
cecum
function of pharynx
the pharynx (or throat) is lined with sensory receptors that can detect pressure. The pharynx permits the passage of swallowed solids and liquids into the esophagus and conducts air to and from the trachea, or windpipe, during respiration.
Mucosa are richly ____
folded
villus is made up of
simple columnar
function of lymph vessels
carries lipids to adipose tissue to be stored
The rectum stores ___
feces
sodium is actively transported out of the _____ and water follows
colon
what system controls the progression of the material through the colon and its eventual expulsion at the anus?
the nervous system
What favors growth of bacteria in the colon?
the slow movement of materials through the colon
What are the functions of bacteria residing in the human intestine ?
to break down nutrients and produce vitamins such as vitamin K
non-pathogenic bacteria create?
vitamin B
Co-enzymes (NADand FAD)–> ATP
^^^^ derived by vitamin B
Feces contain pathogenic bacteria that can _____ if it stays in the intestine too long
infect
H20 from large intestine go to ____
hypertonic solution
–> water conservation is very important
From feces… H2O is reabsobered by….
osmosis
