Anatomy 1 Flashcards
6 key digestive processes
Ingestion Secretion Mixing/propulsion Digestion Absorption Elimination
8 components of alimentary/digestive/ gastrointestinal tract
Mouth Oropharynx Oesophagus Stomach Small intestine Large intestine Rectum Anal canal
What substances are secreted during the digestion process
Digestive juices Water Acid Emulsifiers Buffers Enzymes
What is the mixing and propulsion of food through digestive tract known as
Peristalsis
Two types digestion in digestive tract
Mechanical
Chemical
During absorption in the digestive process, substances pass through the walls in alimentary canal into
Blood
Lymph
3 salivary glands
parotid
sublingual
submandular
what does food change into
bolus, chyme, faeces
passage from mouth to epiglottis called
pharynx
two parts of peritoneum
parietal - lines abdominal wall
visceral - suspends organs within abdomen
visceral peritoneum also known as
mesenteries
specialised double fold of fatty peritoneum hanging from the staomach
omentum
endocrine/exocrine gland difference
endocrine > blood
exocrine > tissues
3 parts small intestine
duodenum
jejenum
ilium
1st place for carb breakdown
mouth
1st place for protein breakdown
stomach
endo/exocrine functions of pancreas
endocrine - insulin into blood
exocrine - enzymes into duodenum
5 layers comprise structure alimentary canal
peritoneum longitudinal muscle layer circular muscle layer submucosa mucosa
2 plexus in alimentary canal structure are where
submucosal plexus in submucosa
myenteric plexus in longitudinal muscle layer
inner most layer of the GIT
Mucosa layer
3 layers of mucosa layer of GIT
Mucous epithelium
lamina propria
muscularis mucosae
2 kinds mucous epithelium in GIT
mouth, pharynx, oesophagus, anus - non-keratinised epithelium
stomach, intestines - epthithelium with MICROVILLI
and GOBLET CELLS
function of goblet cells
secrete mucous
lubricates
protects agains digestive juice erosion
what are enteroendocrine cells - located in epithelium with Microvilli and goblet cells
specialised endocrine cells that secrete hormones into blood
what are serotonin, gastrin, motilin, cholecystokinin (cck)
hormones secreted into blood by enteroendocrine cells
what does lamina propria support
blood vessels - providing routes for nutrients to reach tissues
what is MALT and GALT
Mucosa Associted Lymphoid Tissue
Gut associated Lymphoid tissues
where is gut associated lymphoid tissue found
tonsils, oesophagus, small intestine, appendix, large intestine
what do children rely heavily upon while their immune systems develop (has malt)
tonsils & adenoids
serotonin is both a - and a -
hormone and neuro-transmitter
about 70% of the body’s immune system is found in the
GIT
What is GALT in the Lamina Propria made up of
several types lymphoid tissue containing immune cells - e.g. lymphocytes for protection
and Peyers patches
where are peyers patches located
aggregations of GALT in lamina propria of ileum extending into submucosa
what are peters patches comprised of
GALT
WBCs, B&T Lymphocytes
dendritic cells
Describe muscularis mucosae
v thin layer of smooth muscle tissue
function of muscularis mucosae
creates small folds which increase surface area for absorption/assimilation
where is submucosa layer in GIT
between mucosa and circular muscle layers
submucosa layer is connective tissue containing -
blood vessels, lymph vessels, nerves and some have lymphoid tissues
Muscle layers of GIT known as
Muscularis
2 layers of muscularis
inner circular muscle
outer longitudinal muscle
muscularis in GIT is mostly
SMOOTH INVOLUNTARY
where are voluntary muscles in GIT
mouth, pharynx, upper oesophagus & anal sphincter
involuntary contractions of smooth muscle in GIT aids
mixing food with digestive juices
peristalsis
between muscle layers are -
NEURONS - MYENTERIC PLEXUS
which is the largest serous membrane of the body
peritoneum
the peritoneum is supplied with many vessels of which type
blood
lymph
what does the peritoneum act as a barrier to
local spread of infection
what is ascites
accumulation of fluid in peritoneum (can be a few litres)
what is peritonitis
acute inflammation of peritoneum
how does ascites occur
insufficient protein (albumin) to maintain osmotic pressure in BVs
how many layers does greater momentum have
2, fold over each other to form 4
greater omentum contains considerable amount of what tissue
adipose
what is momentum full of (immune related)
lymph nodes containing macrphages and plasma cells - produce antibodies - combat/contain infections of GIT
brain of gut known as
Enteric nervous system
how does enteric nervous system function in relation to autonomic nervous system
functions independently but regulated by
2 plexuses of enteric nervous system
myenteric (auerbach’s plexus)
submucosal plexus
myenteric plexus location and function
between circular/longitudinal muscles of muscular is layer
controls mainly GIT motility
submucosa plexus location/function
between muscular is and submucosal layer
controls glandular/digestive SECRETIONS
3 types neurons
motor neurons
sensory neurons
interneurons
function of interneurons
connect 2 plexuses
function of sensory neurons
act as chemoreceptors and stretch receptors
blood supply to alimentary canal
via arteries from aorta
function of motor neurons
control motility in myenteric and secretions in submucosal
blood return to heart from alimentary canal via which veins
portal
iliac
portal vein serves which parts of GIT
lower oesophagus stomach pancreas small & large intestine part of rectum & spleen
iliac veins serves which part of GIT
lower part of rectum
anal canal
which are the fat soluble vitamins
A D E K
water soluble vitamins
C B
Which organ is the storage place for fat soluble vitamins
Liver
inner surface of mouth are
mucous membranes
what is the tongue attached to
hyoid bone
Surface of tongue covered with what
papillae - contain taste buds
what is pharynx reflex action
bolus is pushed by tongue into pharynx closing nasopharynx
how many teeth
32 (20 temporary)
3 parts of tooth
crown, neck, root
how is saliva produced
via reflex controlled by autonomic nervous system
how much saliva do we produce a day
1.5 litres - lubricates mouth/mucous membranes
what happens to saliva once it is swallowed
components reabsorbed
what happens during dehydration
saliva is stopped - thirst sensation
sympathetic nervous system has what effect on saliva
reduces salivation - thicker saliva, dry mouth
which nervous system controls continuos salivation
parasympathetic
which 2 main enzymes are present in saliva
salivary amylase,
lysozyme
pH of saliva -
6.35 - 6.85
mildly acidic
constituents of saliva
water - 99/5% mineral salts enzymes mucous immunoglobulins blood clotting factors
7 functions of saliva
digestion - chemical breakdown of polysaccharides
lubricating & dissolving food
cleansing of oral cavity & teeth
defence (immunoglobulins & lysozymes)
taste
buffer for acidic foods
waste removal - urea/uric acid from the body
urea is a byproduct of what
breakdown of ammonia
ibuprofen cuts off what
mucous supply in gut. - protection against stomach ulcers
oesophagus passes through what on it’s way to the stomach
diaphragm
skin fold which occludes the trachea
epiglottis
what acts as a seal on the stomach to prevent reflux into oesophagus
lower oesophageal sphincter
lower oesophageal relaxants
spicy food caffeine mint tomatoes alcohol acidic food fatty food citrus
4 main regions of stomach
cardia
fundus
body
pyloric
what is the cephalic phase of digestion
brain-linked -
taste/smell/sound of food stimulates gastric juice production in stomach before food arrives in it
3 exocrine glands in stomach
parietal cells
chief cells
goblet cells
function of goblet cells
secrete mucous
function of chief cells
secrete pepsinogen & lipase enzymes into stomach for digestion of proteins & lipids
what is pepsinogen converted into in the stomach
the enzyme pepsin for protein digestion
what do parietal cells produce
intrinsic factor and hydrochloric acid in the stomach
IF & HCI
IF is necessary for what
B12 absorption
3 functions of HCI
activates enzymes for digestion
antimicrobial agent for ingested microbes
denatures proteins
total daily secretions of stomach (mucous and gastric juices)
2-3L per day
pH of stomach
1.5-2 extremely acidic
take what to increase stomach acid
ACV
6 functions of stomach
mixing chamber - mechanical digestion
holding reservoir
defence
absorption (limited) water, alcohol, lipid soluble drugs
digestion - limited chemical digestion proteins & lipids
iron - solubilised
2 hormones produced in stomach
Ghrelin
Gastrin
role of Ghrelin
hormone.
stimulates hunger, gastric motility,
growth hormone secretion
role of gastrin
hormone
produced by G cells
promotes gastric juice secretion
increases gastric motility
what are hiccups
air cuaght in fundus
how long after eating does the body know its full
20 mins
most of what happens in the small intestine
digestion
absorption
what extra muscular layer does the stomach have
an inner oblique layer
2 sphincters at either end of stomach
lower oesophageal sphincter
pyloric sphincter
folds in the stomach are called
rugae
inner membrane of stomach known as
serosa
how long is small intestine
6 metres approx
folds of small intestine called
villi
function of villi in small intestine
maximise surface area,
optimise digestion & absorption
3 regions of small intestine top > bottom
duodenum
jejunum
ilium
what happens in duodenum
most emulsification and digestion happens here
what happens in jejunum
most absorption happens here
what happens in ilium
Vit B12 is absorbed
ph of small intestine
8 - mildly basic
5 cells found in small intestine
aborptive goblet paneth endocrine duodenal (brunners) glands
function absorptive cells small intestine
digest/absorb nutrients
function paneth cells small intestine
secrete lysozyme - antimicrobial enzyme
types of endocrine cells small inyestine
s cells, ccl cells, k cells - secrete hormones
function of duodenal (brunner’s glands) small intestine
secrete alkaline mucous to neutralise stomach acidity
2 types capillaries in villi
blood capillaries
lacteals - lymph capillaries
functions of blood capillaries and lacteals in villi
absorb nutrients into blood & lymph
total secretions of small intestine
approx 1.5l daily
11 enzymes found in small intestines
pancreatic amylase trypsin chymotrypsin dipeptidase aminopeptidase pancreatic liipase ribonuclease deoxyribonuclease nucleosidases phosphatases
two types of enzyme found in small intestine
pancreatic
brush border
definition of brush border enzyme
enzymes attached to the lining of the intestine not free in the lumen
4 brush border enzymes in small intestine and functions
dipeptidase - digests protein
aminopeptidase - digests protein
nucleosidaeses - digests RNA/DNA
phosphateses - digests RNA/DNA
pancreatic enzymes in small intestine & functions
pancreatic amylase - breakdown starches
trypsin - protein digestion
chymotrypsin - protein digestion
carboxypeptidase - protein digestion
pancreatic lipase - lipid digestion
ribonuclease - digests RNA
deoxyribonuclease - digests RNA
7 hormones found in small intestine
S cells - secretin CCk cells - cck K cells - Peptide YY (PYY) Gastric inhibitory polypeptide Glucagon-like peptide 1 (GLP-1) Gastrin releaseing peptide (GRP) (bombesin)
Role of S cells
secretes secretin - stimulates pancreatic juice and bile production
role of CCK cells
secretes hormone CCK (cholocystokonin
stimulates pancreatic juice/bile production, decreases gastric juice & motility.
stimulates pyloric sphincter closure and sateity
K cells role
produces hormone which stimulates insulin production by pancreas
role of Peptide YY PYY
reduces appetite, inhibits insulin production by pancreas
role of Gastric inhibitory peptide
stimulates insulin production
role of Glucagon-like peptide 1 (GLP-1)
stimulates insulin secretion
inhibits glucagon secretion
role of Gastrin releasing pap tide (GRP) (Bombesin)
potent stimulant of gastrin/pancreatic secretions
triggers CCK release
supresses appetite
length of large intesine
1.5 m
are enzymes produced in large intesine
no just mucous
4 regions of large intestine
Cecum
colon - ascending, transverse, descending
rectum
anal canal
where is the appendix located
attached to Cecum - twisted coiled tube
what does the large intestine absorb
water
minerals
vitamins
some drugs
why could you not use oral drugs as suppositories
they are much stronger than suppositories as are designed to survive hepatic 1st pass
Large intestine contains 100 trillion ?
microbes (bacteria)
how much bacteria in faeces
30-50%
what happens to remaining carbs in large intestine
fermented, producing hydrogen and amino acids
what happens to some toxic products of bacterial fermentation in the large intestine
some are absorbed, transported to liver
then exreted in urine
what vitamins are produced in large intestine
Vit B12, Vit K
fatty acids
describe defecation
mass peristaltic movements push feacal matter into rectum
stimulates stretch receptors and defaction reflex
bowel movements vary depending on
diet health stress exercise emotions hydration
3 accessory organs of alimentary canal
liver
gallbladder
pancreas
how does liver compare to other glands/organs in body
heaviest gland
2nd largest organ after skin
how much blood does the liver filter
1.4 litres per MINUTE!
how does the liver receive it’s oxygenated blood
via hepatic artery
what does the portal vein bring into the liver
nutrient and toxin rich blood
describe hepatic first pass
ALL BLOOD from GIT is transported to liver (via portal vein) to be filtered/metabolised before going into systemic circulation
where does blood from portal vein and hepatic artery mix
in sinusoids
what are sinusoids
columns/capillaries between hepatocytes
which phagocytic cells are found in liver which remove foreign bodies from blood
Kupffer cells
where does the filtered blood from the liver go
enters the central vein then hepatic vein and into systemic circulation
describe gallbladder
pear shaped 7-10cm sac in liver
what is bile
emulsifying agent
emulsifies fats/oils
function of bile ducts
collect bile produced by liver cells - hepatocytes - which pools in gallbladder
where does bile go and via what
enters small intestine via common bile duct
composition of bile - 3
bile salts from bile acids
cholesterol
Bilirubin from RBC breakdown
how much bile to we produce daily
500-1000ml
pH bile
7.6 - 8.6 - mildly basic
describe enterohepatic circulation (bile)
bile salts in ileum are absorbed & transported back to liver for recycling
How does liver cleanse blood
of particles and microbes via Kupffer cells
How does liver detoxify blood
metabolises/neutralises drugs, toxins, alcohol
what happens o erythrocytes in liver
heamolysis
what happens to plasma proteins in liver
clotting and coagulation factors like fibrinogen are synthesised
how does liver contribute to hormone homeostasis
makes
regulates
detoxifies hormones
what does the liver do to glucose, fats and amino acids
metabolises them
how does liver contribute to heat production - thermogenisi
warmest organ
what does liver synthesise
Vit A, Co-Q10, activation Vit D
What nutrients does Liver store
Vits A, D, E, K, B12
iron, copper, glycogen
How does liver metabolise carbohydrate
excess glucose converted into glycogen for storage
glycogen converted to glucose as required
How does liver metabolise fat
metabolises fat from storage as required
synthesises cholesterol & triglycerides
how does liver metabolise protein
converts essential amino acids into non-essential amino acids
removes nitrogen groups from amino acids to form urea to be excreted
breaks down nucleotides to form uric acid for excretion
how does liver metabolise hormones
insulin & glycogen are deactivated/broken down by liver
liver cells known as
hepatocytes
in how many phases does the liver detox the blood
2
what enzyme complexes does phase 1 involve
cytochrome p450 enzyme complexes
what 5 reactions occur in phase 1 of liver blood detoxification
oxidation reduction hydrolysis dehydration dehalogenation
what happens to water insoluble toxins during phase 1 of liver blood detoxification
converted to water soluble toxins to be extorted by kidneys
when is coffee metabolised by the liver
during phase 1 as water soluble - if client has problem check phase 1
during phase 1 detoxification of liver toxins are converted into what
intermediate metabolites - more toxic than toxins!
to be metabolised in phase 2
what are metabolites also known as
free radicals
name for 2 types of toxins
endogenous - created in body
external -
phrase to help remember 2 phases of liver detoxification
phase 1 chops
phase 2 mops
what can go wrong with the liver during detoxification
produces too many intermediate metabolites - need to speed up phase 1 and slow down phase 2
what supplements does the body require to help mop up the metabolites/free radicals
antioxidants
what happens during phase 2 liver detoxification
CONJUGATION REACTIONS molecules attached to toxins neutralised made stable (non-reactive) made water soluble to be excreted
7 reactions during liver phase 2 detoxification
glucoronidation sulphation glutathione conjugation amino acid conjugation acetylation methylation
what macro-nutrient does the liver rely heavily upon to function properly
protein
waste from liver eliminated via -
gall bladder
kidneys
how is pancreas connected to the duodenum
via 2 ducts
pancreas exocrine function
pancreatic juice into small intestines - 1.5l approx
Pancreatic juice contains
alkalising bicarbonate ions protease enzymes lipase amylase water
endocrine function of pancreas - 4 substances into blood
insulin
glucagon
somatostatin
pancreatic polypeptide
cells of adipose tissue called
adipocytes
what hormone does adipose tissue produce that is related to digestion
LEPTIN
reduces apetite and regulates fat storage
