Liver Functions Part II 3E1 From where we left off…
-
Upload
xavier-campbell -
Category
Documents
-
view
219 -
download
0
Transcript of Liver Functions Part II 3E1 From where we left off…
Liver Functions Part II
3E1
From where we left off…
In the small intestines• Complete digestion occurs in the small intestines
• End products (glucose, amino acids, fatty acids, glycerol) diffuse into the blood vessels lining the small intestines.
• This process is called Absorption.
Some animal samples
• Guess what is the organ shown!
• From which animal?
Adaptation of the small intestine for
absorption
Structure of small intestine
What do you see in the intestinal walls?
How do the folds and villi help in absorption?
• The presence of folds and villi in the intestinal wall increase surface area
More adaptations from the small intestine
• the epithelial cell of the intestinal wall
• One-celled thick epithelial wall and microvilli further increases surface areasurface area
The small intestines• What makes the small intestines suitable for Absorption?
1) Elongated ileum, Inner surface of the ileum is folded
These features provide large surface area:vol for absorption
2) Villi and microvilli
The small intestines• What makes the small intestines suitable for Absorption?
3) Many blood vessels lining the small intestines
Absorption• Absorption occurs by:
– Diffusion– Active transport
• After absorption,
Glucose and amino acids enter the blood capilliaries
Glycerol and fatty acids enter the lacteals
How does absorption takes place in the intestines
Absorption of fatty acids and glycerol
• Glycerol and fatty acids diffuse into the epithelium where they combined to form minute fat globules and enters the lacteals
• Fat globules mix with lymph in the lacteals to form chyle
• Liver is not involved *
Assimilation and
function of the liver
Overview
Role of Digestion Mouth & Oesophagus
Gall Bladder &Pancreas
Stomach
Large Intestine & Others Small Intestine
Overview – 4 Stages Ingestion Digestion
AbsorptionAssimilation
Lesson objectives:
• Describe the fate of glucose, amino acids and fats in the blood that leaves the intestines, after a meal.
• Describe the 5 major roles that the liver plays in the human body
– Regulation of blood glucose concentration– Deamination of amino acids– Production of bile– Detoxication– Iron storage
Fate of glucose and amino acids
Transport and utilization of absorbed foods
In the Liver!Types of absorbed food products
Glucose
Amino acids
Fats
From the small intestines to the liver! How??
Connected by a vein called Hepatic Portal Vein!
Guess which part the vein connects to the intestine?
A
B
C
D
Carbohydrate metabolism
Hepatic portal vein
transports sugars like glucose from the intestines to the liver
Question!
Receives 5 glucose molecules from the intestines
Requires only 3 glucose molecules for breathing
how many molecules of glucose do you think the liver would transport to the
lungs?
Receives 5 glucose molecules from the intestines
Requires only 3 glucose molecules for breathing
Liver in Glucose metabolism
Hepatic portal vein
In the liver….
1. Some glucose carried in the blood to be distributed to the rest of the body
- Tissue respiration
Carbohydrate metabolism
In the liver….
-Glucose (excess) Glycogen (stored)Hormone : Insulin
- If the glucose level is too low in the bloodGlycogen (stored) GlucoseHormone: Glucagon
Insulin and glucagon
What about the amino acids absorbed by the small intestines?
Similar route as sugars:
Intestines hepatic portal vein liver general blood circulation
Liver in Protein metabolism
Hepatic portal vein
Fate of amino acids
Amino acid metabolism
•Converted into protoplasm•Used for growth & repair of worn-out parts•Formation of enzymes & hormones
•Excess amino acids cannot be stored : Deamination
Deamination
—N—H
HC—OH
||O
R
|—C— |
H
Amino group Carbon residue
Ammonia (toxic)
Urea (non-toxic)
glucose
glycogen
Intestines lacteal lymphatic vessels blood rest of the body
Fat metabolism
Fate of Fats
• maintenance of cell membranes•Production of hormones
• Excess fats stored in adipose tissues
When glucose supply is low, fats will be oxidised in the liver to provide energy
(Liver not involved)
Summary: 5 major roles that the liver plays
– Regulation of blood glucose concentration
– Deamination of amino acids
– Iron storage
– Production of bile
– Detoxication
True/False
• Liver is part of the alimentary canal
True/False
• Carbohydrates are digested in the liver
True/False
• Excess amino acids are deaminated
True/False
• Fats are absorbed in the liver and transport to other parts of the body for usage.