HUMAN DIGESTIVE SYSTEM Made Easy- Gastrointestinal System
Summary
TLDRThis video delves into the human digestive system, highlighting its two main parts: the digestive tract and digestive organs. It explains how enzymes from these organs transform food into absorbable molecules. The video covers the mouth's role in initial digestion, the esophagus's function in food transport, and the stomach's role in mechanical and chemical digestion. It then focuses on the small intestine's critical job in nutrient absorption, aided by villi and microvilli, and ends with the large intestine's function in water absorption and waste formation. The video also poses a question about liver regeneration, engaging viewers with an interesting fact.
Takeaways
- 📏 The small intestine is approximately five meters long and one inch in diameter, with a surface area of around 2700 square feet, similar to the size of a tennis court.
- ⏱️ The liver can regenerate completely if more than half of it is removed, taking about four to six months to do so.
- 🍲 The human digestive system is composed of the digestive tract and digestive organs, which work together to break down food into absorbable nutrients.
- 🦷 The mouth initiates digestion through chewing and the action of enzymes like amylase and lipase found in saliva.
- 🔄 The esophagus uses peristaltic contractions to move food to the stomach, and the lower esophageal sphincter prevents backflow.
- 🍽️ The stomach stores food, mixes it with gastric juices, and churns it into a semi-liquid form called chyme.
- 🥗 The small intestine is divided into the duodenum, jejunum, and ileum, and is responsible for the majority of digestion and absorption of nutrients.
- 🧬 The liver produces bile, which emulsifies fats, and the pancreas secretes enzymes that aid in the digestion of proteins, carbohydrates, and fats.
- 🌡️ The duodenum neutralizes stomach acid with bicarbonate-rich alkaline secretions to protect its walls and facilitate digestion.
- 🔎 The small intestine's surface is covered with villi and microvilli, which greatly increase the surface area for efficient absorption of nutrients.
- 💩 The large intestine absorbs water and remaining nutrients, and houses bacteria that contribute to digestion and produce important compounds and vitamins.
Q & A
How long is the small intestine and what is its approximate surface area?
-The small intestine is about five meters long and approximately one inch in diameter. Its surface area is not just about six square feet as one might expect from its linear measurements, but it is actually around 2700 square feet, roughly the size of a tennis court.
What is the liver's regeneration time if more than half of it is removed?
-If more than half of your liver is removed, it can regenerate completely in about four to six months.
What are the two main parts of the human digestive system?
-The human digestive system essentially consists of two parts: the digestive tract and the organs of digestion.
What is the role of the mouth in the digestive process?
-The mouth performs the first step of digestion where the teeth, tongue, and palate help to chew the food, dividing it into several hundred pieces. This increases the surface area for enzyme action and makes swallowing easier. The mouth also receives saliva containing enzymes that start the digestion of starch and fat.
What is the function of the epiglottis during eating?
-The epiglottis is a piece of cartilage that covers the opening of the larynx when we eat, preventing food from entering the respiratory tract and ensuring it is passed down into the esophagus.
How does the esophagus move food towards the stomach?
-The esophagus contains smooth muscles that propel food forward through muscular contractions known as peristalsis.
What is the role of the stomach in digestion?
-The stomach has a vital role in digestion as it has a large volume to accommodate large amounts of food at one time, which is digested slowly. It churns the food mechanically and releases powerful chemicals and enzymes like hydrochloric acid and pepsinogen to digest proteins.
How does the small intestine contribute to digestion and absorption?
-The small intestine is responsible for the main job of digestion and absorption of food. It contains abundant enzymes from the liver, pancreas, gallbladder, and its own wall to break down complex food into simple molecules that are easy to absorb.
What is the function of bile produced by the liver?
-Bile produced by the liver helps to emulsify fats in the chyme, leading to the formation of micelles, which are easy to digest and absorb.
What are villi and microvilli, and how do they increase the effectiveness of the small intestine?
-Villi are small projections on the surface of the small intestine, and microvilli are even smaller projections on the surface of villi. Their presence increases the surface area tremendously, making the small intestine super effective in absorbing digested simple food materials.
What is the primary function of the large intestine?
-The large intestine absorbs water and any remaining nutrients from the food before sending the indigestible matter to the rectum. It also contains bacteria that perform important functions in digestion and produce compounds like propionate and butyrate.
Outlines
🌟 Introduction to the Human Digestive System
This paragraph introduces the human digestive system, emphasizing the small intestine's surprising surface area of 2700 square feet, akin to a tennis court, despite its physical dimensions. It poses a question about liver regeneration time, offering options for viewers to guess the correct answer. The paragraph outlines the digestive system's two main parts: the digestive tract and the digestive organs, explaining how enzymes from these organs facilitate digestion. It describes the mouth's role in the initial stages of digestion, including the action of teeth, tongue, and saliva, which contains enzymes to start breaking down food. The journey of food from the mouth through the pharynx and esophagus is detailed, highlighting the mechanisms that prevent food from entering the respiratory system.
🍲 The Stomach and Small Intestine's Role in Digestion
The second paragraph delves into the stomach's function as a mixer, facilitated by its muscular layers and secretion of chemicals like hydrochloric acid and enzymes like pepsinogen. It explains how the stomach protects itself from these harsh chemicals with a mucus layer and other mechanisms. The paragraph then describes the small intestine's three sections—duodenum, jejunum, and ileum—and their roles in digestion and absorption. It details how the duodenum neutralizes stomach acid and receives enzymes and bile from the liver and pancreas to further break down food. The functions of the liver in producing bile and the pancreas in secreting enzymes are also covered, along with the process of how these secretions help digest fats, proteins, and carbohydrates.
🌿 The Large Intestine and Final Digestion Processes
The final paragraph discusses the large intestine's role in absorbing water and remaining nutrients from indigestible food matter. It describes the large intestine's structure, including the cecum, ascending, transverse, and descending colon, sigmoid colon, rectum, and anal canal. The paragraph highlights the presence of beneficial bacteria in the large intestine, which contribute to further digestion and produce important compounds and vitamins. It concludes by revealing the answer to the liver regeneration question posed at the beginning of the script, stating that it takes four to six months for the liver to regenerate after more than half has been removed.
Mindmap
Keywords
💡Small intestine
💡Digestive tract
💡Enzymes
💡Villi and microvilli
💡Peristalsis
💡Liver
💡Bile
💡Pancreas
💡Stomach
💡Large intestine
💡Epithelial cells
Highlights
The small intestine is about five meters long and one inch in diameter.
Despite its small diameter, the small intestine has a surface area of around 2700 square feet, similar to a tennis court.
The human digestive system is composed of the digestive tract and organs of digestion.
Digestive enzymes from organs are essential for converting food into absorbable molecules.
The mouth initiates digestion with teeth, tongue, and salivary glands.
Saliva contains enzymes amylase and lipase that start the digestion of starch and fats.
The tongue contains taste buds that detect the four basic tastes.
The pharynx and esophagus control the passage of food to the stomach.
The epiglottis prevents food from entering the respiratory tract.
The stomach's muscular contractions and chemicals aid in digestion and protein breakdown.
The pylorus, at the lower end of the stomach, controls the release of food into the small intestine.
The small intestine is divided into the duodenum, jejunum, and ileum for digestion and absorption.
The duodenum neutralizes stomach acid with bicarbonate-rich alkaline secretions.
The liver produces bile, which emulsifies fats for easier digestion and absorption.
The pancreas secretes enzymes like chymotrypsinogen, trypsinogen, amylase, and lipase for digestion.
Proteins are broken down into peptides and amino acids by enzymes in the stomach and small intestine.
Fats are converted into fatty acids and glycerol by pancreatic and liver enzymes.
Carbohydrates are digested into simple sugars by amylase and brush border enzymes.
The small intestine's villi and microvilli increase the surface area for efficient absorption.
The large intestine absorbs water and remaining nutrients before forming and storing feces.
The large intestine contains bacteria that produce important compounds and vitamins like vitamin K.
It takes about four to six months for the liver to regenerate after more than half is removed.
Transcripts
the small intestine is about five meters
long and about one inch in diameter
based on these measurements you would
expect the surface area of the small
intestine to be about six square feet
but it's actually around 2700 square
feet or about the size of a tennis court
in this video we will discuss the human
digestive system watch to the end for
some more amazing facts like this I want
to start this video by asking a simple
question if you remove more than half of
your liver what is the time taken to
regenerate it completely is it a one
week B 1 month C 6 months or D 1 year
write your answers in the comments below
let's see who gets it right at the end
of the video so the human digestive
system essentially consists of two parts
the digestive tract and organs of
digestion without the organs the
digestive tract is just a tube and
probably the same stuff will come out
that you will put in without the action
of the enzymes from these organs the
digestive organs release several
chemicals that turn this 30 feet long
tube into a powerful digesting factory
that converts complex food materials
into simple easy to absorb small
molecules that are then utilized by the
body for various purposes
the human digestive system starts with
the mouth the mouth consists of several
structures that perform the first step
of digestion the teeth tongue palate
help to chew the food which divides the
food into several hundred pieces this
serves two important purposes it makes
swallowing of the food much easier and
it increases the surface area of the
food making the action of enzymes much
faster the mouth also receives the
cretians from salivary glands the
parotid gland the submandibular gland
the sublingual gland and also many -
lavery glands
the saliva contains two important
enzymes in the Emil ace and the lipase
which helped to start the digestion of
starch by breaking it into smaller
sugars and fats into simple lipids the
tongue also contains thousands of taste
receptors contained in structures known
as taste buds these give the information
about the four basic tastes so after the
food has been chewed and mixed with the
saliva it then passes into the pharynx
and then into the esophagus through a
series of controlled muscle contractions
known as a deglutition reflex the
pharynx is a conducting zone that is a
part of both of the respiratory tract as
well as the digestive system the pharynx
continues down as esophagus but it also
receives the opening of larynx
anteriorly
the epiglottis is a piece of cartilage
that covers the opening of larynx when
we are breathing the epiglottis is open
like it is in this situation the
esophagus is collapsed and the air
passes forward into the larynx when we
eat the larynx opening is closed and
this prevents the food from entering
into the respiratory tract and it is
passed down into the esophagus instead
the next part of the digestive system is
the east of Vegas which is a 25
centimeter long muscular tube through
which the food passes into the stomach
it passes through the posterior
mediastinum and enters the abdomen
through a hole in the diaphragm and
joins the stomach the whole length of
the esophagus contains smooth muscles
which propel the food forward through
muscular contractions known as
peristalsis these muscles are very
strong at the lower end to form the
lower esophageal sphincter which has a
valve like function
it remains constricted at all times to
prevent the contents of stomach from
entering into the esophagus except when
we eat and drink to allow one-way
movement of food when this muscle loses
its tone it leads to many diseases like
the gastroesophageal reflux disease
the next organ in the digestive tract is
the stomach stomach is a Jay
shaped organ and it is connected to the
ESO Vegas at the upper end and the
duodenum at the lower end it has a vital
role in digestion it has large volume so
you can eat large amounts of food at one
time which is digested slowly by
controlling its release through the
stomach although it's true you can live
without your stomach but the patients in
which the stomach has been removed have
to eat very small quantities of food
frequently the stomach has layers of
smooth muscles in its walls which turn
the stomach into a literal mixer the
layers of the stomach wall are mucosa
submucosa muscular layer and the
outermost coating the serosa
the smooth muscles caused waves of
muscular contractions known as
peristalsis which cause mechanical
churning of the food the stomach
releases powerful strong chemicals like
the hydrochloric acid sodium chloride
and powerful enzymes like pepsinogen
which digests proteins
since these chemicals can damage the
stomach wall mucus which is secreted by
the gastric glands forms a protective
layer on the inner wall of the stomach
the wall also secretes bicarbonate ions
and has tight cell junctions to prevent
damage from HCL all these factors
prevent the damage to the wall and allow
maintenance of a low pH which is
required for the action of pepsin which
is the active enzyme the lower part of
the stomach is called pylorus and it
also has a strong smooth muscle
sphincter which opens usually after one
hour of taking a meal till then the food
has been converted into a semi-liquid
form known as time which is slowly
released forward next the food passes
into the small intestine which is a 5
meter long tube divided into 3 parts
duodenum jejunum and ileum the small
intestine has the main job of digestion
and absorption of food this is performed
by abundant enzymes through the liver
pancreas gallbladder and a small
intestinal wall itself the first part
the duodenum is the shortest which is
about 25 centimetres in length since it
is connected to stomach at the upper end
it
receive strong acidic chyme which can
potentially damage its wall so it
produces bicarbonate rich alkaline
secretions that neutralize the acid so
you can see in this diagram the duodenum
receives secretions from gall bladder
pancreas and liver these secretions
contain numerous enzymes that digest the
food and convert it into simple
molecules that are easy to absorb and
utilize by the body
the liver which is a vital organ of
digestive system produces bile which
consists of water
97% bile salts bile pigments and mucus
these secretions are delivered to the
duodenum via the common bile duct the
gall bladder is used to store bile and
concentrated since we eat a lot of fat
in our diet which is not water-soluble
and cannot be absorbed as such bile
helps to emulsify the fats in the chyme
and leads to the formation of micelles
which are easy to digest and absorb the
pancreas which lies behind the stomach
has both an exocrine as well as an
endocrine part the endocrine portion
produces insulin and glucagon click on
the card above to learn more about the
endocrine system the exocrine part
however secretes important digestive
enzymes like the chymotrypsinogen and
trypsinogen also amylase and lipase
chymotrypsinogen is converted into
chymotrypsin and trypsinogen is
converted into trypsin which are the
active form of these enzymes and these
enzymes digest proteins amylase digests
carbohydrates
whereas lipase digests fats
now approximately 1r after you take a
meal the food starts to enter the
duodenum where all these enzymes and
bile start their action the food then
passes slowly from duodenum to jejunum
and then to ilium most of the digestion
of food takes place in the small
intestine the wall of the small
intestine contains layers of smooth
muscles which cause segmental
contractions that move the food forward
slowly the carbohydrates fats and
proteins and other nutrients are
completely digested slowly over a period
of many ARS now if we talk about
proteins these proteins are converted
into peptides and simple amino acids by
the action of many enzymes from the
stomach and small intestine the main
enzyme which act on proteins are the
chymotrypsin and trypsin which are
pancreatic enzymes the fat in our diet
is converted into simple molecules like
fatty acids and glycerol from the
enzymes from pancreas and liver the
pancreatic enzyme lipase is the main fat
digesting enzyme whereas the bile from
the liver helps to digest the fats the
main enzymes that digest carbohydrates
are amylase from the pancreas which
convert complex carbohydrates into
simple ones and also enzymes from the
small intestinal wall which are known as
brush border enzymes these enzymes
include extra neighs glucoamylase
maltese sucrase and lactase so all of
these complex food is broken down into
simple molecules which are easy to
absorb now if you look at the
microscopic structure of the wall or
small intestine you can see that it
consists of small projections on the
surface which are known as villi these
villi in turn have more smaller
projections on their surface which are
known as micro villi the presence of
villi and microvilli on the surface of
small indesign increases the surface
area of the small indesign tremendously
which makes it super effective to absorb
these digested simple food materials
these molecules cross the cells of these
micro villi and are then taken up into
the bloodstream and lymphatics in the
vessels present in the center of these
villi
so after most of the
digested and absorbed in the small
intestine the rest of the food passes
into the large intestine the large and
Stein begins with the cecum which marks
a distinction between the small and the
large colon the large intestine is
divided into ascending transverse and
descending colon the descending colon
then leads into the sigmoid colon which
then leads into the rectum and that
finally leads into the annal canal
overall the length of large in Stein is
about 1.5 meters which is about
one-fifth the length of whole GI tract
the large intestine absorbs water and
any remaining and probable nutrients
from the food before sending the
indigestible matter to the rectum the
large intestine contains over 700
species of bacteria that perform various
important functions in digestion and can
you believe the bacteria in our large
gut is about 200 grams in weight in the
large intestine the microbes act on the
remaining food and produce important
compounds like propionate butyrate etc
these compounds are used by the large
intestine cells for their nourishment
important vitamins like vitamin K are
also produced after this the remaining
material turns almost solid which is
compacted in stools and stored in the
rectum till it's excreted through the
anus so this was a brief review of the
human digestive system now coming back
to the question we asked in the
beginning that was if you remove more
than half of your liver how much time
will it take to regenerate it completely
and the answer to this question is four
to six months yes in about six months
you will have a brand new liver
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