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42 Cards in this Set

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What are the four main functions of Digestive System?
1. Absorption (move food molecules from digestive tract into blood; main goal)
2. Chemical Breakdown
3. Mechanical processing (grinding and mixing)
4. Storage & movement
Label: sublingual and submaxillary glands, small intestine, pharynx, esophagus, trachea, stomach, liver, parotid salivary glands, pancreas, small intestine, and gallbladder
here it is
Give the path of a bolus of food, labeling all components from oral cavity to anus.
Oral Cavity -> Pharynx -> esophagus -> stomach -> small intestine -> large intestine -> anus.
Which part of digestive system is skeletal muscle? Smooth muscle?
Oral cavity, external anal sphincter, and upper esophagus are skeletal muscle.
Lower esophagus, stomach, large intestine, and small intestine are all smooth muscle.
Proportionally, does smooth muscle contain more thin or thick filaments? How much more?
SM contains about 10x to 20x more THIN filament than thick.
Why is smooth muscle referred to as a mesh or network of muscle?
Since SM does not contain any sarcomeres, there is a less orderly arrangement of thin and thick filaments.
Name three things that will stimulate visceral smooth muscle.
1. NeuroXmitter from motor axon.
2. Being stretched
3. Hormones
Starch can be broken down to...
sucrose
What is peristalsis?
Using waves of contraction for Xport.
What is segmenation?
not conracting for movement(as in Peristalsis), but to mix material up while stirring and absorbing.
What is mastication and what purpose does is have in the digesting process?
mastication is chewing, it increases surface area of food, speeding up chemical breakdown.
How many pairs of major salivary glands produce saliva?
three pairs
three functions of Saliva...(produced by Submandibular, sublingual, and Parotid glands)
1. Lubrication - lining of cavity kept moist and food doesn't stick to it.
2. Bolus Formation - tongue forms the off mass into single compact mass(saliva sticky and holds it together)
3. Amylase - enzyme that breaks down polysaccharides(i.e. starch)
Give process of swallow reflex once bolus is formed in oral cavity...
Tongue pushes bolus to back of oral cavity -> stretch receptors stimulated -> swallow reflex.
During the ___(1) phase, the tongue pushes food to back of cavity (voluntary).
(1) Oral Phase
Explain what occurs during Pharyngeal phase of swallowing...
Spinal reflex, larynx rises up -> epiglottis closes off air passage -> Pharynx muscles squeeze bolus thru pharynx to esophagus
Explain what active process occurs in Esophageal phase...
Food is pushed from esophagus down into stomach by peristalsis(active process).
The region above opening at top of stomach is called....
the fundus
This part of digestive system is used for storage, mixing, liquification, and protein breakdown
Stomach
How much volume can stomach hold?
1500mL
Why is storage in stomach important with respect to small intestine?
because small intestine cannot accommodate a large amount of material at once.
Importance of movements and mucus secretion in stomach?(3 things mentioned in class)
1. To reduce particle size even smaller
2. Liquifies solid food (large volume watery mucus)
3. Chyme can now be moved into small intestine.
What is an example of a pacemaker in the stomach and what purpose does this serve?
Self-stimulating; these movements cause slow, powerful peristalsis from body to pylorus(upstream to downstream)
5-20 seconds
How long does it generally take movement of food material from body to pylorus?
What stomach secretion can cause pH to lower from 2 to 1?
HCl
What secretions in stomach (all different secretions):
(a) lower pH
(b) is an inactive enzyme
(c) liquifies food
(d) lines stomach
(a) HCl
(b) Pepsinogen
(c) soluble mucus (huge volume secreted everyday)
(d) insoluble mucus
Kills bacteria, activates pepsinogen(converts into pesin, active from of enzyme pepsinogen)...
HCl
What enzyme...
-Splits particular peptide bonds
-beginning of protein breakdown
-enzymatic (hint: does not entirely breakdown to amino acid)
Pepsin
Why is pepsinogen inactive in the stomach?
(Pepsinogen is the precursor to the protease Pepsin)
So it doesn't digest proteins in lining of the stomach.
What is a weak activator of pepsinogen?
Pepsin
If large amounts water are not recaptured in intestines, ____ occurs
diarrhea
description of ____(1) in the stomach:
-gel-like layer trapped on lining
-physical protection
-little lubricant and cushion
-full of bicarbonate
-protects cell from stomach acid
(1)Insoluble Mucus
Name Three parts of small intestine and give length.
1. Duodenum - about 10 inches.
2. Jejunum - about 8 feet.
3. Ileum - 10 feet (when relaxed)
What part of small intestines is involved in large amount of absorption?
Duodenum
Connected to pylorus of stomach; secretions from liver and pancreas are both dumped into small intestine here.
Duodenum
What is secreted by pancreas; give function? (6 things mentioned in class)
1. Water - further liquifies chyme
2. Bicarbonate (HCO3-) - neutralizes stomach acid.
3. Enzymes- (requires neutral or basic pH)
4. Amylase - breaks down polysaccharides to disaccharides and trisaccharides.
5. Lipase - acts on lipids fat, splits fatty acids off triglycerides.
6. Proteases - breakdown proteins (i.e. Trypsin- secreted as inactive trypsinogen-> trypsinogen activated by enterokinases)
On side of cell wall in small intestine, ____(1) are activated by trypsin
(1) Enterokinases
secrete complex mixture called Bile(2 products)...
Liver
Pigments in bile are...
Waste product from hemoglobin breakdown.
chemicals (not enzymes) involved in digestion of lipids
bile salts
Why are bile salts amphipathic?
Has one polar end and one non-polar end. Dissolves in water-soluble and insoluble, salts emulsify fat, allowing fat molecules to break into smaller droplets.
Why do bile salts have a polar and nonpolar part?
mix partly with fat and water, provides more surface area for the lipase.