Flashcards in *Physiology (1) Deck (74)
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1
What is the alimentary canal?
series of hollow organs running from the mouth to the anus (oral to aboral) that are separated by sphincters controlling movement
2
4 functions of the mouth and oropharynx
chop food
lubricate it
start carbohydrate (and limited fat) digestion
propel food to oesophagus
3
Purpose of oesophagus
Propels food to the stomach
4
3 functions of stomach
stores and churns food
continues carbohydrate and initiates protein diffusions
regulates delivery of chyme (semifluid mass of partly digested food) to the duodenum
5
3 parts of the small intestine
Duodenum
Jejunum
ileum
6
Purpose of small intestine
Principle site of digestion and absorption of nutrietns
7
3 main parts of the large intestine
Appendix
Cecum
Colon (ascending, transverse, descending, sigmoid)
8
2 functions of large intestine
colon reabsorbs fluids and electrolytes
Stores faecal matter before delivery of faeces
9
Purpose of rectum and anus
Storage and regulated expulsion of faeces
10
Accessory glands of the GI tract?
Salivary gland
pancreas
liver and gallbladder
11
What are sphincters
sphincters are reinforced circles of smooth muscle which act as unidirectional valves creating movement in one direction
12
4 activities of the alimentary canal
Motility
secretion
digestion
absorption
13
What is motility
Mechanical activity mainly involving smooth muscle
14
4 places skeletal muscle is present
Mouth, pharynx, upper oesophagus and external anal sphincter
15
What does secretion occur due to
the presence of food, hormonal and neural signals
16
what are the 3 things secretion is required for
Digestion
protection
lubrication
17
what is digestion?
chemical breakdown by enzymatic hydrolysis of complex foodstuffs to smaller, absorbable units
18
Where does physical digestion occur (3)
Mouth
stomach
small intestine
19
What is absorption
transfer of the absorbable products of digestion (with water, electrolytes and vitamins) from the digestive tract to the blood, or lymph
20
overal length of the digestive tract
7-10m
21
What are the 4 generalised layers of the digestive tract
Mucosa
Submucosa
Muscularis externa
Serosa
22
What is the 5 things the mucosa is made up from
epithelial cells
exocrine cells
endocrine gland cells
lamina propria (capillaries, enteric neurones, immune cells)
muscularis mucosae (thin layer of muscle that can regulate the surface area of the mucosa)
23
What is the 4 things the submucosa is made of
connective tissue
larger blood and lymph vessels
glands
nerve network (sub-mucous plexus)
24
What are the 3 things the muscularis externa is made up of
circular muscle layer
nerve network (myenteric plexus)
longitudinal muscle layer
25
What is the serosa made up from
Connective tissue
releases a sticky fluid that can help the intestines slide across each other and the peritoneum
26
What are the 3 types of smooth muscle in the GI tract
Circular
longitudinal
muscularis mucosae
27
What is the name of the 3 bands of longitudinal layers that are present in the colon
Taeniea coli
28
Where is an extra oblique layer of muscularis mucosae present
Stomach
29
What happens when circular muscle contracts
The lumen becomes narrower and longer
30
