Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

bio ! > digestion ! > Flashcards

digestion ! Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

ingestion !

A

intake of food into our body via the mouth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

digestion !

A

process whereby large, complex, indiffusible, insoluble food molecules are broken down into small, simple, diffusible, soluble molecules that can be absorbed into body cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

physical digestion

A

physical process of breaking up food into smaller molecules through chewing & peristalsis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

chemical digestion

A

process of hydrolysing (breaking down) food into simpler, soluble, diffusible molecules via enzyme action

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

importance of digestion

A

food must be digested to break down the large, complex, insoluble, indiffusible into smaller, simple, soluble and diffusible molecules

  • can pass through the walls of the small intestine & into the blood vessels
  • blood plasma can then transport the simple food molecules (glucose, amino acids) to other parts of the body for use of various processes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

digestive tract

A 
mouth & buccal cavity 
pharynx 
oesphagus 
stomach 
small intestine 
large intestine 
anus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

mouth !

A

site of ingestion

physical : teeth
- chewing action breaks up solid food into smaller pieces -> increases surface area to volume ratio for salivary amylase to act on it more efficiently

chemical : salivary glands

  • secrete saliva containing salivary amylase into food
  • moistens food + breakdown starch -> maltose
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

tongue

A
  1. rolls food particles into bolus
    - easier for food particles to be swallowed via the pharynx into the oesophagus
  2. mix food with saliva
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

pharynx !

A

connects buccal cavity to oesophagus & larynx

common passageway for air and food

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

epiglottis

A

swallowing : food prevented from entering trachea

  • larynx : moves upwards
  • epiglottis covers glottis

breathing : air passes into trachea

  • larynx : moves downwards
  • glottis is open

if food gets into trachea : person will cough to force the food out

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

oesophagus !

A

transports food from pharynx to stomach

- gravity + peristalsis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

peristalsis in oesophagus pt 1 !

A

enables food to be mixed with digestive juices
caused by the actions of antagonistic muscles
- circular & longitudinal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

peristalsis in oesophagus p2 !

A

circular contract - longitudinal relax
- wall of gut : contracts -> becomes narrower & longer -> food is pushed forward

circular relaxes - longitudinal contract
- wall of gut : dialtes -> becomes wider & shorter -> widens lumen for food to enter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

stomach !

A

secretes gastric juice : contains hydrochloric acid, pepsin, renin

distensible muscular bag with thick & well developed muscular wall
- can expand

stomach wall : has numerous pits
- secretes gastric juice into stomach cavity

presence of food in stomach : stimulates gastric glands to secrete gastric juice into stomach cavity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

pyloric sphincter

A

muscular valve found at the end of stomach

contracts : entrance to small intestine (duodenum) closes

relaxes : entrance to small intestine (duodenum) opens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

peristalsis in stomach !

A

churns + breaks up food substances from big particles to small particles

  • increases surface area to volume ratio for protease to act on
  • mixes food substances well with gastric juice
17
Q

hydrochloric acid in gastric juice / stomach’s acidic conditions !

A

stops action of salivary amylase by denaturaing it
changes inactive form of pepsinogen to active form pepsin
provides an acidic pH condition for gastric enzymes
kills potentially harmful microorganisms in food

18
Q

renin

A

curdles milk proteins : converts soluble caseinogen in milk -> insoluble caesin
- requires Ca2+ : allows insoluble caesin to remain in the stomach long enough for digestion by pepsin

19
Q

chyme

A

partly digested food that has been liquified

enters duodenum in small amounts when pyloric sphincter relaxes & opens

20
Q

small intestine parts !

A

duodenum : (from stomach ) + digestion
jejunum : more digestion + assimilation
ileum : absorption + digestion complete

21
Q

duodenum !

A

pancreatic juice

  • inactive trypsinogen -> active trypsin by enterokinase
  • pancreatic lipase
  • pancreatic amylase : starch -> maltose

intestinal juice
- erepsin : hydrplyses polypeptides -> amino acids
proteins -> polypeptides by trypsin
polypeptides -> peptidases by erepsin -> amino acids

  • intestinal lipase

fat digestion : bile
emulsifies fat into minute fat globules : increase surface area to volume ratio for digestion by lipase

22
Q

jejunum !

A

lactose : lactose -> galactose + glucose

sucrose : sucrose -> glucose + fructose

23
Q

absorption !

A

process whereby digested food substances are taken in by the body cells

  1. diffusion
    - glucose + amino acids into blood capillaries of villi
    - glycerol + fatty acids into epithelium -> combine to form minute fat globules -> enter lymphatic capillary
  2. active transport
    - glucose + amino acids : when there is a low conc of digested food substances in lumen of small intestine than blood capillaries
24
Q

small intestine features !

A

inner walls : extensively folded
- provides a large surface area to volume ratio -> increased efficiency for absorption

bears numerous villi : providing a large surface area for absorption

long & coiled : provide sufficient time for absorption

25
Q

villi features !

A

walls : one cell thick
- shorter diffusion distance -> faster rate of absorption

microvilli in epithelium of villi : increases surface area to volume ratio -> faster rate of absorption

lacteal / lymphatic capillary + rich network of blood capillaries
- help transport amino acids & glucose away quickly -> maintain diffusion gradient -> maintain high rate of absorption

26
Q

hepatic portal vein !

A

transports blood rich in glucose & amino acids absorbed from small intestine -> liver

27
Q

assimilation !

A

process whereby absorbed food substances are converted into new protoplasm or used to provide energy

28
Q

assimilation : glucose !

A

used by cells in respiration to release energy

  • most glucose : converted to glycogen for storage in liver
  • some glucose : transported by hepatic vein to diff parts of body
29
Q

assimilation : amino acids !

A

used by cells to make proteins, enzymes, hormones & new protoplasm

excess amino acids : converted to urea by deamination
- remains of deaminated amino acids : converted back to glucose

30
Q

assimilation : fats !

A

used to build protoplasm
stored in adipose tissues : protect vital organs from shock
broken down : to release energy when there is a lack of glucose
used as an insulating material against heat loss

31
Q

liver : carbohydrate metabolism !

A

regulates concentration of blood glucose

after meals : too much glucose in blood

  • insulin secreted (pancreas)
  • excess glucose -> glycogen for storage in liver
  • blood glucose level decreases

fasting / in between meals : too little glucose in blood

  • glucagon secreted (pancreas)
  • glycogen -> glucose to replenish glucose used in respiration by cells
  • blood glucose increases
32
Q

liver : fat digestion !

A

produces bile : stored in gall bladder + discharged into duodenum by bile duct
- emulsification of fats…

33
Q

liver : iron storage !

A

worn out RBC : destroyed in spleen

  • haemoglobin from RBC : transported to liver to be broken down
  • iron released from haemoglobin : stored in liver for synthesis of new RBC
34
Q

liver : deamination of amino acids !

A

excess amino acids deaminated in liver : amino groups removed

converts amino groups -> urea
- removed from body as an excretory product

converts remains of amino acids -> glucose
- excess glucose -> glycogen

35
Q

liver : detoxification !

A

converts toxins & harmful substances into harmless substances

  • alcohol
  • hydrogen peroxide
36
Q

liver : heat production !

A

numerous metabolic activities take place in the liver : large amt of heat produced
- heat generated : distributed to rest of body -> maintain body temperature -> opt temp for enzymes

37
Q

effects of alcohol !

A

slower reaction time
reduces self control
increases risk of liver failure, gastric ulcers, cirrhosis (formation of fibrous tissue in liver), haemorrhage (bleeding in liver) & death

bio ! (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions