XI Chap 16 Digestion and Absorption Flashcards
Alfonso Corti, Italian anatomist, was born in ______
1822
Alfonso Corti’s began his scientific career studying cardiovascular systems of _______
reptiles
_________ published a paper on the mammalian auditory system and had an organ named after him
Alfonso Corti
Major components of our food are __________
carbohydrates, proteins and fats
__________ and __________ (food) are required in small quantities
Vitamins and minerals
__________ plays an important role in metabolic processes and prevents dehydration of the body
Water
What is digestion?
Conversion of complex food substances to simple absorbable forms
Digestion is carried out based on _______ and __________ methods
biochemical - pressurized - hormonal - mechanical - metaphysical
biochemical, mechanical
Classify into intracellular and extracellular digestion:
Protozoa Coelenterata Free-living platyhelminthes Platyhelminthes to Chordata Porifera
Protozoa - intracellular
Coelenterata - intracellular and extracellular
Free-living platyhelminthes - intracellular
Platyhelminthes to Chordata - extra-cellular
Porifera - intracellular
Teeth is an example of _____________ type of digestion while digestive enzymes are an example of _____________
mechanical,
biochemical
All digestive enzymes are hydrolases. T or F?
True
Macromolecules are not absorbable by blood. T or F?
True
Micronutrients provide protection whereas macronutrients provide energy. T or F?
False, reverse
Alimentary canal is how long? _____________
6-9 meters
State the germ layer from which foregut, midgut and hindgut of human alimentary canal have originated
Foregut & Hindgut - ectodermal
Midgut - endodermal
Alimentary canal begins with __________ and opens posteriorly through ________
mouth, anus
Mouth of alimentary canal leads to _________
buccal/oral cavity
Oral cavity has _____ and _______
teeth and (muscular) tongue
Each tooth in the oral cavity is embedded in a socket of _________. This type of attachment is called ________
jaw bone, thecodont
Majority of mammals, except human beings, form two sets of teeth during their life. T or F?
False, including human beings
A set of ________ teeth are replaced by a set of ________ teeth aka _____ type of dentition.
milk/deciduous,
permanent/adult,
diphyodont
An adult human has ___ (how many?) permanent teeth of 4 different types, namely:
32, incisors, canine, pre-molars, molars
Arrangement of teeth in each jaw is in the order ________ and represented by the formula _________
I, C, PM, M
2123 / 2123
Hard chewing surface of the teeth made up of ______ helps in the _______ of food
enamel, mastication
What is the primary dentition formula?
2102 / 2102
Formula of monophycodont human teeth?
0021 / 0021
_____________ and _____________ teeth are monophycodont
Pre-molars and last molar
How many I, C, PM and M do adults have?
2 I
1 C
2 premolars
3 molars
How many I, C, PM and M do children have?
2 I
1 C
NO premolars
2 molars
Crown is made up of _____________ whereas root is made up of _____________
crown - enamel and dentine
root - dentine only
Match teeth to their functions
- Biting and holding
- Grinding
- Cutting
- Shearing
- Chewing
- Tearing
- Mastication / crushing
- Biting and holding - I
- Grinding - PM and M
- Cutting - I
- Shearing - C
- Chewing - M
- Tearing - C
- Mastication / crushing - M
____________ is the part of the tooth that is visible
Crown
Enamel is made by ____________ cells, composed of ____________ and its origin is _______derm
ameloblast,
Ca3(PO4)2 and CaCO3,
ectoderm
Dentine is made by ____________ cells and made up of ____________ and its origin is _______derm
odontoblast,
calcified connective tissue,
mesoderm
____________ in tooth has everything a cell requires (lymph vessels, vein, artery, nerve, etc.)
Pulp cavity
____________ is the part of the tooth embedded in the socket
Root
Pulp cavity of tooth has ameloblasts that make dentine throughout life. T or F?
False, odondoblasts
_________ teeth are triangular in shape whereas _________ are rectangular
Pre-molar, molar
__________ teeth are chisel-like whereas _________ teeth are sharp and pointed
Incisors, canines
Number of roots in incisor, canine, premolar and molar in upper jaw
Incisor - 1
Canine - 1
Premolar - 2
Molar - 3
Number of roots in incisor, canine, premolar and molar in lower jaw
Incisor - 1
Canine - 1
Premolar - 1
Molar - 2
_________ organisms have homodont teeth (3)
Fishes
Amphibians
Reptiles
The tongue is a freely movable _______ organ of _____dermal origin attached to the _________ of the oral cavity by a _________
muscular,
mesodermal
floor,
frenulum
__________ is the roof of the buccal cavity and has transverse ridges called _______ ______________
Palate,
palatine rugae
Anterior end of the tongue is attached to _________ whereas posterior end is attached to _________
nothing / free,
hyoid bone
_____________ surface of the tongue has papillae whereas _____________ surface is attached to the floor
dorsal, ventral
Frenulum is a ligament. T or F?
True
_______ (upper/lower) surface of the tongue has small projections called _________
Upper, papillae
Tongue is divided into two parts _____________ and _____________. What are their relative sizes?
oral (one-third)
pharangeal (two-thirds)
In the pharangeal part of the tongue lies the lymphoid organ called _____________
lingual tonsil
What are the 4 types of the papillae? Which of these contain taste buds?
Fungiform & Circumvallate - taste buds present
Filliform
Foliate
All papillae bear taste buds. T or F?
False, some
Which papillae are absent in humans?
Foliate
There are in total 3 salivary glands in the human body. T or F?
False, 3 pairs
What are the 3 salivary glands and their positions?
- Parotid - in cheeks, below and anterior to ear
- Submaxillary/submandibular - lower jaw
- Sublingual - below tongue
_____________ are aka cheek teeth
molars
Largest vs smallest gland?
Largest - parotid,
Smallest - sublingual
Percentage release of saliva across the 3 salivary glands?
Submaxillary - 70% most!
Sublingual - 5% least!
Parotid - 20-25%
Ducts of 3 salivary glands?
Parotid - Stenson’s
Submaxillary - Wharton
Sublingual - Rivinus
_____________ gland is affected during mumps
parotid -> swollen
Saliva has pH of ___________
6.8
Humans produce ____L of saliva per day
1.5
Salive is ____% water and _____% ___________
99.5
0.5
solute
What are the solutes in saliva?
Na and K chlorides, bicarbs and phosphates Urea + uric acid Mucus Salivary amylase / ptyalin Lingual lipase Lysozyme - antibacterial Thiocyanate (anti-microbial) IgA
_____ ion in saliva is a co-factor for amylase
Cl
Space between cheek and teeth is called ___________
vestibule
Roof of the buccal cavity is called ________
palate
Oral cavity leads to mouth. T or F?
False, leads to pharynx.
MOUTH leads to oral cavity ;)
Palate is made up of 2 bones: _________ and _________
maxillae
palatine
Accessory digestive organs of humans? (6)
Teeth Tongue Salivary glands Liver Gall bladder Pancreas
Pharynx serves as the common passage for food and air. T or F?
True
______ and _________ (aka __________) open into the pharynx.
Oesophagus, trachea/wind pipe
A ________ flap called ______ prevents the entry of food into the opening of the wind pipe during swallowing
cartilaginous, epiglottis
Opening of the windpipe is aka _________
glottis
Opening of the oesophagus is called ___________
gullet
Epiglottis is part of this ___________ sitting atop the trachea
larynx
_____________ is an extension of the soft palate and and closes off the nasal cavity during swallowing
Uvula
Oesophagus is:
thick/thin?
short/long?
passing through ______, _______ and ______
thin, long tube
passing through neck, thorax and diaphragm
Stomach is a X-shaped bag.
J
A muscular spincter aka __________ regulates the opening of oesophagus into stomach
gastro-oesohageal sphincter
Stomach is located on _________ (upper right / upper left) portion of the abdominal cavity, has ____ (how many?) parts
upper left, 4
What are the 4 major parts of the stomach?
- Cardiac
- Fundic
- Body
- Pyloric
Oesophagus opens into ______ portion of the stomach
Cardiac
______ is the main central region of the stomach and also the largest
Body
Pyloric portion of stomach opens into ____________
first part of the small intestine
___________ region of the stomach is connected to the diaphragm
Fundus
Small intestine is distinguishable into how many regions? What are they?
3
duodenum, jejunum and ileum
Rank the parts of the small intestine from shortest to longest
Duodenum, Jejunum, Ileum
Opening of the stomach into the __-shaped duodenum is guarded by the ___________
C-shaped, pyloric sphincter
The long coiled portion of the intestine is called the __________, whereas the highly coiled portion is ________
jejunum, ileum
Ileum opens into the _______
large intestine
Large intestine consist of _________, _________ and _________
caecum, colon and rectum
Caecum is a small _____ sac which hosts some _____________
blind, symbiotic micro-organisms
What is the vermiform appendix?
narrow finger-like tubular projection,
vestigial organ,
arises from caecum
Caecum opens into the _______
colon
Parts and order of the colon?
Ascending, transverse, descending, sigmoid
Wall of alimentary canal from ____________ to _________ possesses 4 layers. They are?
oesophagus, rectum
- serosa
- muscularis
- sub-mucosa
- mucosa
Match the following:
- goblet cells
- loose connective tissue
- thin mesothelium
- smooth muscles
mucosa, serosa, muscularis, sub-mucosa
- mucosa
- sub-mucosa
- serosa
- muscularis
________ is the outermost layer of the alimentary wall, and ______ is the innermost.
Serosa, mucosa
Thin mesothelium is the epithelium of visceral organs. T or F?
True
Serosa has some connective tissues. T or F?
True
Serosa is made up of ___________ on inner side and ___________ on outer side in ____________ of the alimentary canal
inner: simple squamous epithelium = mesothelium
outer: loose CT (areolar)
stomach, duodenum, jejunum and ileum
Serosa is made up of mesothelium and areolar CT in the oesophagus. T or F?
False, true for stomach and small intestine
Serosa of the oesophagus is called ___________ and is made up of ___________
tunica adventitia, areolar CT only
Muscularis is arranged into _________
an inner circular and outer longitudinal layer
An oblique may be present in some regions of the _________ e.g. ___________
muscularis, stomach
In the alimentary canal, ___________ has the thickest muscularis
stomach
The sub-mucosal layer is formed of ___________ (type of) tissues containing _____, _____ and _________
loose CT,
nerves, blood and lymph vessels
Blood vessels in the ________ layer perform the function of ___________ except in this part of the alimentary canal ___________
sub-mucosa, absorbing digested food, oesophagus
____________ part of the mucosa comes into contact with food
Mucosal epithelium
Why does lipase not play a major role in digestion in the stomach?
Requires fats to be emulsified => done by bile in the small intestine
In the __________, glands are also present in sub-mucosa
Duodenum
Mucosa forms irregular folds called ______ and small finger-like foldings called ______
rugae, villi
Mucosa can be divided into 3 layers, they are? (from outermost to innermost)
- Muscularis mucosa
- Lamina propria
- Mucosal epithelium
Muscularis mucosa is made up of ____________
smooth muscle
Lamina propria is made up of ____________
areolar CT
Mucosal epithelium is made up of ____________
simple columnar epithelium in stomach, small and large intestines
stratified squamous epithelium in buccal cavity, pharynx and oesophagus
Rugae are in the mucosa of the ______ whereas villi are in the mucosa of lining the _______
stomach, small intestine
Gastric glands are present in the mucosa muscularis of the stomach. T or F?
False, mucosal epithelium
What are the 4 types of cells present in the rugae of the stomach? (From top to bottom)
- Mucus Neck / Goblet cells
- Parietal / oxyntic cells
- Chief / peptic / zymogen cells
- EC cells - G cells
Cells lining the vili produce ______________ giving a _______ appearance
microvilli, brush border
Mucus Neck cells release _-_mm layer of mucus that serves 2 functions, they are?
1-3 mm
- lubrication
- protection from HCl and proteolytic enzymes
____________ cells of the rugae have microvili
Parietal/oxyntic
Oxyntic cells release ____________ which helps to absorb vitamin ____________, the latter aka ____________
Castle Intrinsic factor
B12
extrinsic factor
____________ cells are maximum in number in the rugae
Chief / peptic / zymogen cells
Folds are present in the ____________ of the stomach and in the ____________ of the small intestine
mucosa,
mucosa and sub-mucosa
Chief cells are mainly found in the ________ region of the stomach
fundic
Role of chief cells?
Release inactive protein enzymes (pepsinogen and prorennin) and gastric lipase
Enteroendocrine cells (aka EC cells) and specifically _____ cells release ____________ which causes ____________
G, gastric hormone, release of gastric juice
What are Argentaffin cells?
aka EC cells,
in the intestinal glands
release local hormones secretin and cholecystokinin (CCK)
G cells cause the release of gastrin hormone into the stomach which aids in digestion. T or F?
False, hormones always released into blood
Mucosa and submucosa folds in the small intestine are called ____________ or ____________
plicae circulares
valve of kerkrings
Mucosa of small intestine contain folds which contain villi which contain cells with microvili (i.e. “brush bordered cells”). T or F?
True
Microvilli are microscopic projections on stomach cells that are few in number. T or F?
False, microscopic yes but numerous
How do the modifications of the mucosa in the small intestine help?
Increases surface area
Villi are supplied with a network of _________
capillaries
What is the lacteal?
large lymph vessel in villi of small intestinal mucosa
Mucosal epithelium has goblet cells which ___________ that help in ___________
secrete mucus, lubrication
Mucosa forms ______ in the stomach and ____________ in between the bases of the villi in intestine,
gastric glands, crypts
Both duodenum sub-mucosa and mucosa of stomach have glands. T or F?
True
_________ are present in between the bases of villi in intestinal mucosa
Crypts of Lieberkuhn
Intestinal glands are called ___________
crypts of Lieberkuhn
What are the 4 types of cells in intestinal gland?
- Paneth cell
- Other cells that secrete enzymatic content
- Goblet cells
- EC cells
What do paneth cells produce? (2)
Enzymatic part of succus entericus (intestinal juice)
Lysozyme / antibacterial compound
Brunner’s glands are present in the _________ of the duodenum
sub-mucosa
Brunner’s glands produce _________
non-enzymatic part of intestinal juice
How much intestinal juice is produced by humans per day? What is its pH?
1L per day
ph 7.8
Intestinal juice is aka _________ and it is released by _________ and _________
succus entericus,
Brunner’s gland
Crypt of Lieberkuhn
Success entericus contains salts like _________ to _________
sodium bicarbonate.
maintain alkaline pH of duodenum
What is the full-form of MALT? it is also known as?
Mucosa associated lymphoid tissue,
GALT - Gut associated ….
Where in the mucosa is malt found?
In the lamina propria of mucosa
Malt of ileum is found in the form of ___________
Peyer’s patches
What are the 2 nerve plexuses present in alimentary canal?
Auerbach and Meissners
Where is Auerbach Nerve Plexus present and what does it do?
ACT - between circular and longitudinal muscles
responsible for peristalsis
Where is Meissner’s nerve plexus and what does it do?
MSC - between sub-mucosa and inner circular muscles
induces secretions of glands (digestive juices)
Three of the four layers of alimentary wall show modifications in different parts of the alimentary canal. T or F?
False, all 4
What are the (accessory) digestive glands associated with the alimentary canal?
salivary glands,
liver (with gall bladder),
pancreas
Saliva is produced by how many PAIRS of salivary glands. What are they?
3
parotids
sub-maxillary/sub-mandibular
sub-lingual
Salivary glands are situated just outside the ___________
buccal cavity
Locations of the 3 PAIRS of salivary glands?
Parotids - cheek
Sub-maxillary/sub-mandibular - lower jaw
Sub-linguals - below tongue
___________ is the largest gland of the body
Liver
Liver weighs about ______ in adult human?
1.2 to 1.5 kg
Liver is situated in the ____ cavity just below the _________
abdominal, diaphragm
Liver has how many lobes?
2
The ________ are the structural and functional units of liver
hepatic lobules
Hepatic lobules contain hepatic cells arranged in the form of _________
hepatic cords
What is Glisson’s capsule?
thin connective tissue sheath covering each hepatic lobule as well as the entire liver
_____ is secreted by hepatic cells, passes through the hepatic ducts and is stored and concentrated in the __________
Bile, gall baldder
Glisson’s capsule is made up of ____________ tissue
white fibrous connective tissue
What are hepatocytes?
Hepatic cells - main cells of the liver that produce bile
Hepatic lobules are in the form of ____________ rings
benzene
____________ lobe of the liver is larger than the ____________
Right, left
Liver is situated in the ____________ cavity just below the ____________
abdominal, diaphragm
Gall bladder is
thick/thin?
muscular/bony?
sac/tube?
thin, muscular, sac
Common hepatic duct is made up of ____________ and ____________
left and right hepatic ducts
What is the cystic duct?
Duct of the gall bladder
Common bile duct is made of hepatic duct and the pancreatic duct. T or F?
False, hepatic duct and cystic duct
____________ duct is aka ductus choledocus
Common bile duct
Common bile duct contains the sphincter of ____________
Boyden
What is the role of sphincter of Boyden?
controls secretion of bile;
if food absent in duodenum, sphincter is closed => bile stored in gall bladder
Hepatic duct and bile duct together open into the duodenum. T or F?
False, pancreatic duct and bile duct
Common bile duct vs hepato-pancreatic duct?
Bile duct - cystic + hepatic ducts
Hepato-pancreatic duct - bile + pancreatic duct
Hepato-pancreatic duct is guarded by a sphincter called ____________
sphincter of Oddi
What is the role of sphincter of Oddi?
controls secretion of bile + pancreatic juice
Duct of ____________ is the main pancreatic duct that secretes 95% of juice
Wirsung
____________ is the accessory pancreatic duct
Duct of Santorini
Hepato pancreatic duct opens into the ____________ of the duodenum
Ampulla of Valer
____________ is considered as complete digestive juice
Pancreatic juice
Buccal cavity performs 2 major functions:
- mastication of food
2. facilitation of swallowing
Which three parts of alimentary canal work together to masticate and mix up the food?
Teeth, tongue and saliva
Mucus in saliva helps in ____________
lubricating and adhering the masticated food particles into a “bolus”
What is deglutition?
Bolus from buccal cavity is conveyed from buccal cavity into pharynx and then into oesophagus and stomach by swallowing
___________ regulates deglutition
medulla oblongata
What is peristalsis? Where does it occur?
Successive waves of coordinated muscular contractions and relaxations that help the bolus pass down the OESOPHAGUS
Saliva secreted in oral cavity contains ?
electrolytes: Na+, K+, Cl-, HCO3-
enzymes: salivary amylase & lysozyme
Chemical process of digestion is initiated in the oral cavity by _______
hydrolytic action of salivary amylase
Salivary amylase is an enzyme that catalyzes splitting of _________
carbohydrate
What percent of starch is hydrolysed by amylase? What does it form?
30%
disaccharide, maltose
Role of lysozyme in saliva?
antibacterial agent => prevents infections
What is the optimum pH for salivary amylase?
6.8
Three major types of cells in gastric glands and their roles?
- Mucus neck cells - secrete mucus
- Peptic/Chief cells - secrete pepsinogen (proenzyme)
- Parietal/Oxyntic cells - secrete HCl and intrinsic factor
Intrinsic factor is essential for absorption of _____
B12
Stomach stores food for ______ hours
4-5
What is chyme?
Food mixed thoroughly with acidic gastric stomach juices
Chyme is produced by the _____ movements of the stomach wall
churning
Proenzyme pepsinogen on exposure to _______ gets converted into ______
HCl, pepsin
Pepsin is the proteolytic enzyme of the _______
stomach
Pepsin converts _____ into ________
proteins into proteoses and peptones (peptides)
Mucus and bicarbonates in gastric juice play an important role in ______ and ________
lubrication and protection of mucosal epithelium
HCl provides the ______ (acidic / alkaline) pH optimal for pepsins. What is the optimal pH? (numerically)
acidic, 1.8
______ is a proteolytic enzyme found in gastric juices of infants which helps in digestion of __________
Rennin, milk proteins
Small amounts of ligases are also secreted by gastric glands. T or F?
False, lipases
Movements are generated by the muscularis layer of small intestine that help with mixing up of the food and secretions. T or F?
True
What are the secretions in the small intestine?
Bile, pancreatic juice and intestinal juice
_____ and _______ are released through the hepato-pancreatic duct.
Bile and pancreatic juice
Pancreatic juice contains?
inactive enzymes, protein digesting - trypsinogen, chymotrypsinogen, procarboxypeptidases
pancreatic amylase (amylopsin)
steapsin (fat digestive enzyme cluster) - which contains pancreatic lipases
nucleases
sodium bicarbonate
pH of pancreatic juice?
Proportion of water to solutes?
7.1 to 8.2
98% H2O, 2% solutes
Trypsinogen is activated by an enzyme ________ secreted by the _____________
enterokinase, intestinal mucosa
Activated form of typsinogen is called _______ and it in turn activates _________
trypsin, other enzymes in pancreatic juice
Bile released into duodenum contains ?
95% H2O
5% solutes -
Bile pigments (bilirubin and bili-verdin)
Inorganic bile salts - NaCl, sodium carbonate, sodium bicarbonate
Organic bile salts - Na glycocholate, Na taurocholate
Cholesterol & Phospholipids (lecithin)
NO ENZYMES
What part of bile helps in emulsification of fats?
Organic bile salts - Na glycocholate/taurocholate
Bile pigments are made from breakdown of __________
Hb
pH of bile is ?
8.0
Enzymes in bile help in emulsification of fats and also activates lipases. T or F?
False, Not enzymes, but rest is true
Secretions of ______ cells of mucosa alongwith secretions of goblet cells constitute the intestinal juice aka ___________
brush border cells, succus entericus
Succus entericus contains enzymes including ______
disaccharidases (e.g. maltase)
dipeptidases
lipases
nucleosidases
There are no starch digesting enzymes or nucleic acid digesting enzymes in intestinal juice. T or F?
True, hence it is not a complete digestive juice
Mucus and bicarbonates from pancreas provide a _________(acidic or alkaline) medium for enzymatic activities. pH ____
alkaline, 7.8
What are Brunner’s glands?
Sub-mucosal glands that also help provide an alkaline medium and protect intestinal mucosa
Name the enzymes that catalyze the following in the stomach: Nucleotides Polysaccharides/starch Nucleic acids Peptones/Proteoses Fats Proteins Nucleosides
Nucleotides - Nucleotidase
Polysaccharides/starch - Amylase
Nucleic acids - Nuclease
Peptones/Proteoses - Trypsin/Chymotrypsin/Carboxypeptidase
Fats - Lipase
Proteins - Trypsin/Chymotrypsin/Carboxypeptidase
Nucleosides - Nucleosidase
Name the enzymes that catalyze the following in the stomach: Maltose Sucrose Di/Monoglycerides Dipeptides Lactose
Maltose - Maltase Sucrose - Sucrase Di/Monoglycerides - Lipases Dipeptides - Dipeptidase Lactose - Lactase
Match the following: Fats Carbohydrates Proteins Nucleic acid
Proteolytic enzymes of pancreas - pancreatic amylase - lipase in bile - pancreatic juice
Fats - Lipase in bile
Carbohydrates - Pancreatic amylase
Proteins - Proteolytic enzymes of pancreas
Nucleic acid - pancreatic juice
Enzymes in the succus entericus act on end products of ___________
reactions of carbs/fats/proteins/nucleic acid by enzymes of bile / pancreatic juices
The final steps in digestion occur very close to the ______ epithelial cells of _________
mucosal, duodenum region of small intestine
Simple substances formed at the end of digestion are absorbed in the ______ and _____ regions of the small intestine
jejunum, ileum
Pick the simple substances formed at the end of digestion?
Nucleosides, Amino acids, Glucose, Di/Monoglycerides, Galactose, Fructose, Sugars, Amylase, Bases, Lipase, Fatty acids, Glycerol
Amino acids, Glucose, Galactose, Fructose, Sugars, Bases, Fatty acids, Glycerol
Match the end products of breakdown of following:
Maltose
Sucrose
Lactose
Fructose, Glucose, Galactose, Di/Monoglycerides, Starch
Maltose - Glucose + Glucose
Sucrose - Glucose + Fructose
Lactose - Glucose + Galactose
Undigested and unabsorbed substances (faeces) are passed on to ___________
large intestine
No significant digestive activity occurs in the large intestine. T or F?
True
Functions of large intestine? (2)
- Absorption of some water, minerals and certain drugs
2. Secretion of mucus - adhering waste together and lubrication
Faeces enter the caecum of large intestine through ________ valve and is temporarily stored in ________ until defaecation
ileo-caecal valve, rectum
Sight, smell or presence of food in oral cavity can stimulate secretion of saliva. T or F?
True
Gastric and intestinal secretions are stimulated by neural signals. T or F?
True
Muscular activities of different parts of alimentary canals are moderated only by local neural mechanisms. T or F?
False, local and CNS
Hormonal control of secretion of digestive juices is carried out by __________ hormones produced by _______
local,
gastric and intestinal mucosa
______ is the ultimate form of all energy
Heat
1 calorie or Joule is amount of heat required to raise the temperature of ______ of water by ______
1g, 1°C
Gross calorific & physiological values of:
a. carbohydrates
b. proteins
c. fats
a. 4.1 & 4.0 kcal/g
b. 5.65 & 4.0 kcal/g
c. 9.4 & 90 kcal/g
What is absorption?
Process by which end products of digestion pass through intestinal mucosa into the blood or lymph
Absorption is carried out by what 3 mechanisms?
Passive, active or facilitated transport
What is absorbed in digestion by simple diffusion?
Small amounts of monosaccharides (e.g. glucose), amino acids, some electrolytes (e.g. Cl ions)
Some substances like _____ and ________ are absorbed after digestion with the help of carrier proteins. This process is called _________.
glucose, amino acids, facilitated transport
Transport of water depends on _________ gradient
osmotic
Active transport occurs against concentration gradient hence requires energy. T or F?
True
What are the nutrients absorbed into blood by active transport?
Amino acids, monosaccharides (glucose), electrolytes like Na+
Fatty acids and glycerol being soluble cannot be absorbed by the blood. T or F?
False, insoluble!! => cannot be absorbed
How are fatty acids and glycerol absorbed by blood?
- incorporated into micelles (small droplets)
- micelles move into the intestinal mucosa
- micelles are re-formed into chylomicrons (very small protein coated fat globules)
- Chylomicrons are transported into lymph vessels (lacteals) in the villi
- Lymph vessels release into blood stream
Absorption of substances takes place only in small intestine. T or F?
False, different parts of the alimentary canal but most absorption occurs in the small intestine
Match substance to relevant point of absorption (mouth, stomach, small or large intestine): minerals, alcohol drugs, nutrients, water, simple sugars, medicine
minerals - large intestine alcohol - stomach drugs - mouth, large intestine nutrients - small intestine water - stomach, large intestine simple sugars - stomach medicine - stomach
Drugs coming in contact with mucosa of moth and lower side of tongue are absorbed into the __________ lining them
blood capillaries
What is assimilation?
Process by which absorbed substances finally reach tissues which utilise them
Faeces in rectum initiates a ________ causing an urge or desire for removal
neural reflex
Egestion is a _______ process (involuntary or voluntary) and carried out by a ______ movement
voluntary, mass peristaltic
_________________ is the most common ailment related to the digestive system due to ______ or _______ infections
Inflammation of the intestinal tract, bacterial, viral
Name parasites of the intestine
Tapeworm, roundworm, threadworm, hookworm, pinworm
Name the following digestive system disorders:
a. abnormal frequency of bowel movement leading to reduced absorption of food
b. reflexive ejection of stomach contents through mouth
c. feeling of fullness
d. deficiency of protein and calories
e. liver affected, deposit of bile in skin and eyes
f. abnormal frequency of bowel movement due to faeces retained in colon
a. Diarrhoea
b. vomiting
c. indigestion
d. PEM
e. jaundice
f. constipation
Vomiting is controlled by the _______
vomit centre in the medulla
A feeling of _______ precedes vomitting
nausea
What are the causes of indigestion?
inadequate enzyme secretion, anxiety, food poisoning, overeating, spicy food
What does PEM stand for?
Protein-energy malnutrition
Marasmus vs. Kwashiorkar?
Marasmus - simultaneous deficiency of protein and food calories, infants < 1 yr, mother’s milk replaced too early
Kwashiorkar - protein deficiency only, infants > 1 yr, replacement of mother’s milk by high calorie but low protein diet
Symptoms of Marasmus and Kwashiorkar?
Common - wasting of muscles, thinning of limbs, failure of growth and brain development
Marasmus - skin is dry, thin and wrinkled; body weight decline
Kwashiorkar - some fat still left under skin; extensive oedema and swelling of body parts
In stomach, mainly protein digestion takes place. T or F?
True
The digested end products are absorbed into the body through the epithelial lining of the __________
intestinal villi
Mastication and churning is an example of _____________ type of digestion while digestive enzymes are an example of _____________
mechanical,
biochemical
State the germ layer from which foregut, midgut and hindgut of human alimentary canal have originated
Foregut & Hindgut - ectodermal
Midgut - endodermal
Intestinal glands are called ____________
crypts of Lieberkuhn
