Digestive System Flashcards
Learn the digestive system part 1
1
Q
what are the main functions of the digestive system?
A
- Take in food (ingestion)
- break it into absorbalbe nutrient molecules (digestion)
- absorb molecules into the blood stream (absorption)
- rid body of indigestible remains (excretion)
2
Q
Organs of the digestive system fall into 2 groups. What are the names of those groups?
A
- Alimentary canal (GI tract)
- Accessory organs
3
Q
Alimentary Canal
A
- continuous muscular tube that runs from mouth to anus
- digests food
- absorbs fragments through lining in blood
- excretes waste
4
Q
What are the Accessory organs?
A
- Teeth
- tongue
- gallbladder
- Digestive glands: produce secretions that break down food (salivary glands, liver, pancreas)
5
Q
- Ingestion
A
taking food into mouth
6
Q
- Mastication
A
chewing food and mixing it with saliva
7
Q
- Peristalsis (Motility)
A
rhythmic wave-like contractions that move food through GI tract
7
Q
- Deglutition
A
swallowing food
8
Q
- Digestion
A
Mechanical or chemical breakdown of foods
9
Q
- Secretion
A
release enzymes, water, and buffers into GI tract
10
Q
- Absorption
A
moving nutrients (monomers) into the body
11
Q
- Defecation
A
excretion of waste products
12
Q
Give a good breakdown of Peristalsis
A
- coordinated muscle contraction and relaxation
- wavelike movements
- food bolus moves forward
13
Q
Give a good breakdown of segmentation
A
- simultaneous muscle contractions
- back and forth movements
- food bolus gets mixed with digestive secretions
14
Q
Mechanical Digestion
A
- begins in the oral cavity
- doesn’t break chemical bonds
- increases surface area for chemical digestion
15
Q
Chemical digestion
A
- Begins in oral cavity but peaks in the stomach and small intestine
- carried out by enzymes
- breaks chemical bonds to generate small molecules from large molecules
16
Q
________ and _________ are the last of the major digestive processes
A
secretion and absorption
17
Q
Secretion
A
- movement of substance from cells into the lumen
- secretion of HCl into stomach to promote digestion
18
Q
Absorption
A
- movement of substance from the lumen to cells
- Highly selective process, specific substances absorbed in different G.I. regions
19
Q
Histological Organization (4 tissue layers)
A
- Mucosa (epithelium)
- Submucosa (connective tissue, nerves, blood vessels)
- muscularis externa (circular layer and longitudinal layer of smooth muscle)
- serosa (connective tissue, continuous with mesentery)
20
Q
Study the digestive tract four layers slide
A
don’t rate this a 5 actually go look at it.
21
Q
- Mucosa
A
- layer that lines lumen
- functions: different layers perform one or all three
: secretes mucus, digestive enzymes and hormones
: absorbs end products of digestion
: protects against infectious disease
22
Q
- Submucosa
A
- consists of areolar connective tissue
- contains blood and lymphatic vessels, lymph nodes
-secretions
23
Q
- Muscularis externa
A
- smooth muscle layer responsible for peristalsis and movement of bolus through GI tract
- contains inner circular muscle layer and outer longitudinal layers (circular layer thickens in some areas to form sphincters)
24
Enteric Nervous System
- the GI tract's own nervous system (gut brain)
- contains more neurons than the spinal cord
- major nerve supply to muscularis externa that controls motility
25
4. Serosa
- outermost layer, made up of visceral peritoneum
- formed from connective tissue
- replaced by fibrous adventitia in esophagus (dense CT that hods esophagus to surrounding structures)
26
Functions of the oral cavity
- protection against physical and chemical abrasions, pathogens
- mechanical digestion: increases surface area using teeth, tongue, and palate
- Lubricating food with saliva
- chemical digestion begins with enzymes in saliva
27
The palate forms the roof of the mouth and has two distinct parts:
1. hard palate: formed by maxillae bone
2. Soft Palate: soft tissue formed by mostly of skeletal muscle
28
What does the soft palate do?
- closes off nasopharynx during swallowing
29
Uvula
fingerlike projection that faces downward from free edge of soft palate
30
The tongue
- composed of interlacing buncles of skeletal muscle
- Functions:
- gripping, repositiong, mixing of food
- formation of bolus, (food and salive)
- initiation of swallowing
- speech
- taste reception
31
What are the features of mastication
- mechanical digestion
- increases surface area
- mixes food with saliva
32
There are three paired ______ _______ _______ located outside the oral cavity that produce saliva
major salivary glands
33
What are the major salivary glands
Parotid, submandibular, and sublingual
34
Parotid gland
- anterior to ear
- parotid duct opens into oral cavity next to 2nd upper molar
35
Submandibular gland
- medial to body of mandible
- duct opens at base of lingual frenulum
36
Sublingual
- anterior to submandibular gland under tongue
- opens via 10-12 ducts into floor of mouth
37
Saliva
- 1-1.5 liters produces each day
- 99.4 percent water and mucus
- secretion stimulation by facial and glossopharyngeal nerves (autonomic cranial nerves) in response to varied stimuli
- cleanses mouth, contains lysozyme (antimicrobial)
- dissolves food chemicals for taste
- begins chemical digestion of starch with enzyme amylase
38
Mumps
inflammation of parotid glands caused by the mumps virus (myxovirus)
- common children's disease
39
How do the mumps spread?
via saliva
40
What are the symptoms of mumps?
- pain upon trying to open mouth or chew
- moderate fever
- pain when swallowing
41
Mumps in adult males carries>>>
a 25% chance of infecting testicles which leads to reduced fertility
42
Pharynx
tube connecting the oral cavity to the larynx
- provides passageway for food, liquid, and air into the esophagus or trachea
43
The esophagus
- flat muscular tube
- runs from laryngopharynx to stomach
- moves through diaphragm at esophageal hiatus
- posses upper and lower esophageal sphincters
44
What is collapsed when not involved in food propulsion?
the esophagus
45
What is the major function of both the esophagus and the pharynx?
Deglutition (swallowing)
46
What are the two phases of deglutition?
Buccal phase: voluntary contraction of tongue forcing bolus into oropharynx
Pharyngeal-esophageal phase: involuntary phase that involves autonomic nervous system
47
Study the pharyngeal-esophogeal phase slide
48
GERD
backflow of acid stomach contents into the esophagus
- lower esophageal sphincter doesn't clost properly causing heartburn feeling
