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Chapter 5: Nutrition in human, muscle and lumen size ratio - Coggle Diagram
Chapter 5: Nutrition in human
What is nutrition in human?
the process in which organisms obtain food and energy for growth, repair and maintenance for the body
What is absorption?
the process whereby digested food substances are absorbed into the body cells
What is digestion?
the process whereby large food molecules are physically and chemically broken down into smaller, soluble food molecules that can be absorbed into the body cells
What is peristalsis?
the rhythmic, wave like muscular contraction in the wall of the alimentary canal
Effects of alcohol consumption on the brain and body
"Wet brain": dementia caused by brain damage
shrinkage of brain volume: affects memory/ reasoning
slurred speech/ blurred vision/ poor muscle coordination
affects fetus' brain: affecting lifelong, physical, mental, behavioral problems
slow down reaction time
reduced self control
cirrhosis (disease in which liver cells are destroyed, leading to liver failure and eventually death)
Social implications on alcohol consumption
exhibit violent behavior (especially towards family)
tend to commit crimes
neglect their work and family
Structure of human digestive system and its functions
Oesophagus
Function
the circular and longitudinal muscles that make up the walls of the oesophagus, stomach, small and large intestines, and rectum. These muscles carry out peristalsis** which will move the food along the alimentary canal
Structural adaptation
the wall of the oesophagus consists of circular and longitudinal muscle
Stomach
Structural adaptation
two rings of muscles (cardiac sphincter and pyloric sphincter) are found at two ends of the stomach
gastric pits consists of cells that produce gastric juice (pepsin and hydrochloric acid)
a bag like organ which consists of a 3rd layer of muscle called oblique muscle in addition to circular and longitudinal muscle
Mouth (buccal cavity)
Structural adaptation
(b) tongue
(c) salivary glands
(a) teeth, which consist of incisors, canine, premolar and molar
Function
(a) used for chewing of food (physical digestion) which will increase surface are to volume ratio for faster rate of chemical digestion by enzymes --> hydrolysis
(b) to roll food into bolus/ boli for easy swallowing
(c) produce saliva which consists mainly of water and salivary amylase
(i) water lubricates the boli for easy swallowing
(ii) salivary amylase speeds up the hydrolysis of starch into maltose
Small intestine
Absorbtion function
structural adaptation
1: S.I is 6-7m long
2: Inner wall is thrown into folds
3: Numerous villi present on inner walls (finger like projection)
4: Presence of microvilli on villi
5: Presence of mitochondria in the epithelial cells
6: Presence of dense network of blood capillaries
function
2,3,4: Increase S.A. for absorbtion for increased rate of aerobic reaspiration
5: Numerous mitochondria = increased rate of aerobic respiration = increased amount of energy for faster rate of active transport
1: Increases time for complete absorbtion and digestion
6: Bring/ transport food substances to and away from the villi at a faster rate creating a steep concentration gradient of food molecules between the blood and villi and the content of the S.I. Hence increasing the rate of absorbtion of food molecules
Digestive function
structural adaptation
(b) intestinal glands found on the epithelium layer of the small intestine inner wall produces intestinal juice
(c) pancreas produces pancreatic juice and transports it to the small intestine via the pancreatic duc
(a) the small intestine is 6-7m long. It consists of duodenum, jejunum, and iluem
(d) liver produces bile. bile stored is in the gall bladder and tranported to the small intestine via bile duct
function
(a) long small intestine increases time for complete digestion and absorbtion
(b) functions of enzymes found in intestinal juice
source: epithelial cells
protease
break down polypeptides to amino acids
maltase
break down maltose to glucose
lipase
break down fats to fatty acid and glycerol
(d)
What is the function of bile?
Bile salts emulsifies fats. They lower the surface tension of the fats, reducing the attractive forces between the fat molecules. This causes the fats to break into tiny fat droplets suspended in water forming an emulsion. Emulsification increases the surface area to volume ratio of the fats, speeding up the digestion by lipase
(c) functions of enzymes found in the pancreatic juice
source: pancreas
protease
break down proteins to polypeptides
pancreatic amylase
break down starch to maltose
lipase
break down fats to fatty acids and glycerol
What is deamination?
(occurs in the liver): the process by which amino acid groups are removed from amino acids and converted to urea
Regulation of blood glucose concentration
When blood glucose rises above normal
Insulin is secreted by pancreas
Liver converts glucose into glycogen for storage
Blood glucose concentration decreases back to normal
When blood glucose falls below normal
glucagon is secreted
Liver converts glycogen into glucose to be released into the bloodstream
Blood glucose concentration increases back to normal
What is the function of liver in assimilation?
the liver produces and secretes bile which is stored in the gall bladder. this helps the physical digestion of fats
muscle and lumen size ratio
circular muscle contract, lumen size decrease
longitudinal muscle contract, lumen size increase