The digestive system Flashcards
(91 cards)
1
Q
what is the digestive system?
A
the collective name for the alimentary. canal, some accessory organs and digestive processes
2
Q
what are some functions of the digestive system?
A
- prehension
- mechanical breakdown of food
- deglutition
- peristalsis
- chemical digestion of food
- absorption of nutrients and water
- elimination of waste
3
Q
what is prehension?
A
gasping food with lips or mouth
4
Q
what is deglutition?
A
swallowing
5
Q
what is peristalsis?
A
wave contraction to move contents along
6
Q
what are the main parts of thee digestive system?
A
- the mouth
- the pharynx
- the oesophagus
- the stomach
- small intestine
- large intestine
7
Q
what are accessory organs?
A
- organs that secrete enzymes and assimilate food stuffs
8
Q
what are the four accessory organs?
A
- four pairs of salivary glands
- the pancreas
- the liver
- the gall bladder
9
Q
where is the buccal cavity?
A
between teeth and cheeks
10
Q
where is the central cavity?
A
between hard palate, teeth, gums and tongue
11
Q
what is included in the hard palate?
A
- incisive, palatine maxilla bone
- upper surface = floor of nasal cavity
- folds on surface to assist the tongue to direct food to pharynx
12
Q
what is included in the soft palate?
A
- soft tissue extension of hard palate
- no bones
- hangs freely between the oral and nasal cavities (creating the oropharynx and the nasopharynx)
13
Q
what is included in the floor of the oral cavity?
A
- mandible
- mucosa which covers mandible, tongue, and forms part of gingiva
14
Q
what is the crown of a tooth?
A
portion above the gum line
14
Q
what is included in the sides of the oral cavity?
A
- cheeks
- covered with skin on outside
- lined with mucous membranes
- muscular
15
Q
what is the root of a tooth?
A
portion below the gum line
16
Q
what is the neck of a tooth?
A
where crown meets the root
17
Q
what is the enamel of a tooth?
A
the hardest substance in the body,
covers the crown
18
Q
what is the dentine of a tooh?
A
makes up majority of the tooth
19
Q
what is the pulp cavity of a tooth?
A
the centre of the tooth containing nerves and blood vessels
20
Q
what is the cement of a tooth?
A
lines the root to hold tooth in place
21
Q
what is the alveolus of a tooth?
A
tooth socket
22
Q
what is gingiva?
A
gum
23
Q
what is the peridontal ligament?
A
holds the tooth into the socket
24
what are incisors used for?
more important in rabbits
nibbling of food and grooming
25
what are canines used for?
Piercing of food,
holding onto prey
26
what are pre-molars used for?
shearing of food
27
what are molars used for?
shearing and grinding of food
28
how many deciduous and permanent teeth does a dog have?
deciduous - 28 teeth
permanent - 42 teeth
29
how many deciduous and permanent teeth does a cat have?
deciduous - 26 teeth
permanent - 30 teeth
30
how many deciduous and permanent teeth does a rabbit have?
deciduous - 16 teeth
permanent - 28 teeth
31
how many permanent teeth does a guinea pig have?
20 teeth
32
what are the functions of the tongue?
- manipulation of food
- tasting food via the taste buds
- grooming
- lapping liquids
33
what is the tongue?
- muscular organ
- body has a median groove
- root attached to the pharynx
- covered in thick mucous membrane
34
what artery and vein runs along the ventral surface of the tongue?
lingual
35
what is the pharynx?
- opening to the resp and diges system
36
what is the nasopharynx?
internal openings of the nostrils
37
what folds are on the sides of the base of the tongue?
glossopharyngeal folds
38
what happens to the epiglottis during swollowing?
epiglottis closes and covers the trachea
39
what are the four pairs of salivary glands?
- zygomatic (ventral to orbit)
- parotid (base of ear)
- mandibular (angle of jaw)
- sublingual (medial mandible)
40
what is saliva stimulated by?
sight, smell and anticipation of food
41
what is saliva composed of?
90% water, mucous, salt, ptyalin (enzyme)
42
what are the functions of saliva?
- lubricate and soften food
- moisten mouth
- temperature control when animal pants
43
what is the oesophagus?
a narrow muscular tube that aids in digestion
44
what are the four layers of the walls of the digestive tract?
- serous coat (outer)
- muscular layer (2 layers - outer longitudinal and inner)
- submucosa - connective tissue
- mucosa - stratified squamous epithelium
45
what is the stomach?
- large muscular and glandular organ with curved appearance
46
where does the stomach lie when its empty and when it is full?
empty - lies against the liver
full - extends beyond the liver and to the left
47
where does the spleen sit?
within the greater ometum
48
what is the cardiac sphincter?
a muscular ring of tissue that stops food and liquid returning to that oesophagus from the stomach
49
what does the pyloric sphincter prevent?
- prevent entry of food into duodenum
- prevents reflux in stomach
50
what do rugae do?
- increase surface area
- flatten when full
51
what 4 layers with modifications does the stomach have?
- serous coat (outer)
- muscular layer (3 layers - oblique, circular, longitudinal)
- submucosa - connective tissue
- mucosa - deep pits into which gastric juices are secreted from gastric glands
52
what are the functions of the stomach?
- digestion
- storage of food
- churning of food
- antiseptic/bactericidal
53
what are the three cells in relation to gastric juices?
- goblet cell
- chief cells
- parietal/oxyntic cells
54
what stimulates gastric juices?
hormone gastric which is produced as food enters the stomach
55
what are goblet cells?
- lie amongst epithelial cells
- secrete protective mucus
56
what are chief cells?
-found in fundus
- secrete enzyme precursors (pepsinogen and prorennin)
57
what are pariental/oxyntic cells?
- found in fundus
- secrete hydrochloric acid and converts enzymes into active form (pepsinogen into pepsin)
58
what do juices contain?
water and salt
59
what is chyme?
juices and food create a semi fluid substance called chyme
60
what is vomiting?
expulsion of stomach contents
61
what is the mechanism of vomiting?
- deep inspiration
- closure of the glottis
- elevation of soft palate
- close resp tract
- contraction of abdo and thoracic muscles
- opening of sphincter
- food forced up the oesophagus to the mouth
62
what does excessive vomiting cause?
- acid-base balance
- dehydration
- electrolyte imbalances
63
what are the small intestines' 4 layers?
- mucosa
- submucosa
- muscularus mucosa
- serosa
64
what are Peyers patches and what do they do?
- aggregations of lymphatic tissue that deal with bacteria
65
what are the three parts of the small intestine?
- duodenum
- jejunum
- ileum
66
what is the duodenum?
- widest part of the small intestine
- three ducts lead into it - two pancreatic and one bile
67
what is the jejunum?
- 2nd part of the SI
- faster movement of food than ileum
68
what is the ileum?
- remainder of small intestine
- modifications to 4 layer structure
- submucosa - Brunner's glands which produce alkaline fluid and mucous
- mucosa - modified into villi which contain crypts of Lieberkuhn which produce digestive enzyme
69
what is the pancreas?
- mixed gland
- between stomach and duodenum
70
what is the largest portion of the pancreas and what does it produce?
exocrine which produces pancreatic juices
71
what is produced in response to hormones in the pancreas?
pancreatic juice
72
Gastrin is produced by what?
G-cells in the stomach
73
where is cholecystokinin produced?
the duodenum
74
what is in pancreatic juices?
- bicarbonate
- trypsinogen
- trypsin
- lipase
- amylase
75
what do pancreatic juices digest?
carbs and fat
76
where is bile produced and stored?
produced in liver
stored in gallbladder
77
where do bile pigments come from?
waste from liver (breakdown of blood pigments)
78
what does delayed defacation cause?
constipation due to too much water absorption
79
what does maltose convert into?
glucose
80
what does sucrose convert into?
glucose and fructose
81
what does lactose concert into?
glucose and galactose
82
what does trypsinogen convert into?
tryspin
83
what does disaccharides convert into?
monosaccharides
84
what cell structure are the outer layer of villi cells in the SI?
ciliated columnar cells
85
what are some functions of the large intestine?
- absorb water, salt and other secretions
- excrete and store faeces
- digestion in herbivores
86
what is included in the large intestine?
- caecum
- colon
- rectum
- anal canal
87
what is the caecum?
blind ending sac that breaks down veg matter in small animals
88
what is the colon?
three parts
- ascending
- transverse
- descending
89
what is the rectum?
- short and wide
- secured with muscle and soft tissue
- first part covered with peritoneum
90
what is the anal canal?
2 sets of sphincter muscles
- inner circular smooth muscle (involuntary)
- outer striated muscle (voluntary)
