Human Digestive System Flashcards
Define peristalsis
ryhtmaic contraction and relaxation of smooth muscle tissue in the digestive tract
Explain the juice present in the stomach
- Gastric juice is secreted by gastric glands.
- Contains hydrochloric acid: neutralise alkaline condition of salivary amylase in bolus // convert pepsinogen into pepsin
- pepsinogen : inactive enzyme
- mucus : protect the inner walls of stomach
explain the digestion of protein in the duodenum
- receives bile secreted from liver
- containing trypsin to hydrolyse polypeptide into dipeptide.
- H20 is added for hydrolisation
Why can’t carbohydrate be digested in the stomach?
- HCL secreted by parietal cell stops the action of salivary amylase in the bolus
What is the function of liver in the digestive tract?
- Produces bile for digestion in the duodenum
What are the contents of intestinal juice?
- erepsin - lipase - maltase - lactase - sucrase
Write the chemical equation for lactose
lactose + water –> galactase + glucose
Benedict’s test added to a piece of food sample has truned from blue to brick red percipitate. What does this indicate、
Protein is present in food sample
What is the expected result when starch, salivary amylase and iodine solution is mixed?
brown (remain unchanged)
define assimilation
utilization of end products of digestion to build complex compounds by body cells
State the adaptations of ileum
Long and has folded layers with a large number of villi
State the adaptations of villus
- One cell thick epithelial wall : easier exchange of gaseous
- surrounded by a large network of blood capillaries: efficient transportation.
- goblet cells: secretes mucus to aid digestion
Explain how amino acid is absorbed for the use in body
- amino acid actively absorbed into blood cappilaries
- transported through hepatic portal vein to liver
- liver to body cells via hepatic vein
- synthesize enzymes and hormones // plasma protein // repair damaged tissues
state 5 substances absorbed into the blood capillaries
- fructose : facillitated diffusion
- glucose: active
- amino acid: active
- vitamin B, C : absorbed with water
- water : osmosis
what happens to excess amino acid in the liver
- deamination occurs
- amino acid is converted into urea
- urea is excreted in urine
what is the use of plasma protein ?
- blood clotting
- osmoregulation
what are the uses of lipid in the body
- excess lipid is stored in adipose tissue as heat insulator
- fat is oxidised to generate energy when there is insufficient glucose
- main component to buil phospholipid and cholesterol in plasma membrane
What happens to excess glucose
- Glucose is converted into glycogen with the help of insulin hormone.
- excess glycogen stored in liver as fats
How is fatty acid and lipid absorbed into lacteals?
- Fatty acid and lacteal recombine (condensation) to form tiny lipid droplets
- lipid droplets diffuse into lacteals
What are the main roles of the large intestine?
- Reabsorb water and minerals
- formation of feaces
where are the exterior and interior sphincter muscles located?
anus
Name 3 intestinal contents in the faeces
water // dead cells // dead bacteria // fibre // toxins (drugs) // cellulose from plant walls // bile pigment // undigested food
Why is reabsorbtion of water and minerals important in the large intestine?
- retain water in the body
- to form a semi-solid feaces
- maintain body health through absorbtion of minerals
Explain the formation of faeces
- undigested food enters the large intestine after absorbtion in the small intestine.
- the intestinal contents are such as dead cells n bacteria, fibres, bile pigments and drugs
- water and minerals are reabsorbed in the colon to form a semi-solid substance that is faeces.
How does gastric bypass surgery help an obese person?
- reduce the size of stomach
What are the side effects of gastric bypass?
- nausea
- acid reflux
- vomiting
- expanded oesophagus
- risk of infection
What is haemorrhoids?
- conditition when hard and dry faeces remains inthe rectum for too long
- increases pressure on blood vessels around anus
- blood vessels stretch and rupture
- causing burning sensation and bleeding
What is the effect of toxic substance in the faeces toward the humans’ body?
- causes uncontrolled mitosis in colon cells
- collon cancer
What is BMR
- Basal Metabollic rate
- the minimum rate of energy used by the body to keep it alive
What food class should pregnant mothers control?
- carbohydrate
- prevents pregnancy diabetes
Why must elderly people reduce red meat intake?
- red meat has purines
- forms excess uric acid deposited in between joints
- causing gout arthritis
Which formula is correct?
A: energy value = 4.2 x mass of water x mass of food / increase in temperature x 1000
B: E = 4.2 x mass of water x increase in temperature / mass of food
C: E = 4.2 x mass of water x increase in temperature / mass of food x 1000
C
Why is a diet rich in fat unhealthy?
- Fat is converted into fatty acid and lipid which makes up cholesterol.
- High level of cholesterol will be deposited in the inner wall of blood vessels –> atherosclerosis
- The blocked arteries increase blood pressure
- Lack of oxygenated blood to cardiac muscles causes heart attack
- excess cholesterl lead to gallstone formation
