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nutrition in humans Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

ingestion

A

food is taken into the body

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2
Q

digestion

A

large, insoluble, complex food molecules are broken down into simpler smaller soluble molecules that can be absorbed into the body cells

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3
Q

assimilation

A

some of the absorbed food are converted into new protoplasm and to release energy

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4
Q

abosrption

A

digested food substances are absorbed into the body cells

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5
Q

egestion

A

removal of undigested matter from body

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6
Q

mouth processes

A

phys digestion: chewing-> phys breaks down food particles into smaller particles -> increase SA to volume ratio of particles for faster rate of chemical digestion
chemi digestion: fod is chemically digested through action of salivary amylase -> hydrolyses starch into maltose
salivary amylase in saliva is secreted by slivary glands

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7
Q

oesophagus func

A

transport food particles from mouth to stomach cia peristalsis

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8
Q

peristalsis def + muscles involved

A

def: rhythmic wavelike contractions of muscles of gut
circular muscles: inner wall
longitudeinal muscles: outer wall
circ mus contract, long mus relax, lumen of gut narrow, gut lobnger, food pushed froward
circ mus relax, long mus con, lumen of gut wider, gut shorter, food enters

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9
Q

stomach process

A

when bolus enters stomach, gastric glands on walls of stomach is stimulated to secrete gastric juices

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10
Q

what do gastric juice scontain

A

HCL and pepsin

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11
Q

func of HCL (4)

A
  1. converts inactive pepsinogen into active pepsin
  2. kills hamrful microorganisms in food
  3. provides optimum PH for actin of enzymes
  4. denatures salivary amylase
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12
Q

func of pepsin

A

chemically digests proteins by hydrolysis into polypeptide (partial digestion)

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13
Q

what happens after everything in stomach

A

liquefied food is called chyme after partial dogestiom

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14
Q

pancreas

A
  1. produces and secretes pancreatic juices itno duodenum via pancreatic duct
  2. a organ or gland
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15
Q

pancreatic juices

A
  1. pancreatic amylase (starch -> maltose)
  2. pancreatic lipase (fats -> fatty acids and glycerol)
  3. pancreatic protease (protein -> polypeptides)
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16
Q

liver and gall bladder

A
  1. liver produces bile
  2. bile is stored in gall bladder
  3. bile is secreted into duodenum via bile duct by gall bladder
17
Q

characteristics of bile

A

greenish yellow liquid
alkaline
not a enzyme -> not affected by temp or PH
contains bile pigments and salts

18
Q

func of bile

A
  1. creates optimal alkaline environemtn for action of enzymes
  2. emulsifies fats into tiny fat droplets that increase surface area to volume ratio of fats for faster rate of digestion of fats by hydrolysis into fatty acids and glycerol by lipase
  3. reduces acidity of chyme from stomach
19
Q

digestion in teh intestine

A

Intestinal maltase
Maltose -> glucose
Pancreatic amylase
Starch -> maltose
Intestinal sucrase, lactase
Digestion of disaccharides
Intestinal protease
Polypeptides -> amino acids
Pancreatic protease
Protein -> polypeptides
Intestinal lipase
Fats -> fatty acids + glycerol
Pancreatic lipase
Fats -> fatty acids + glycerol

20
Q

adaptations o fSI

A
  1. Inner walls of SI is highly folded
    Numerous villi present on the folds
    Numerous microvilli present on epithelial cells of villi
    Increase SA of SI for faster rate of absorption of digested nutrients
  2. Epithelium of villus is one cell thick
    Decrease diffusion distance between lumen of small intestine and capillary/lacteal in villus
    Faster absorption of digested nutrients from lumen of SI into villus
  3. Dense blood capillary network in villus
    To continuously transport digested nutrients away from SI quickly
    To maintain steep concentration gradient of digested nutrients between lumen of SI and blood capillaries in villus
    Faster absorption of digested nutrients into villi of SI
  4. long
    Aloow for sufficient time to absorb the digested nutrients into the villus
  5. Epithelial cells have numerous mitochondria
    increase rate of respiration to release more energy for active transport of nutrients into the villi
21
Q

duodenum

A

Where juices are stimulated to be secreted into once bolus enters SI
Has more epithelial cells in duodenum walls than ileum and jejunum bc digestion mainly occurs in the SI hence the need for intestinal juices to be produced by epithelial cells in walls of the duodenum
Lower concentration of villi than in ileum and jejunum bc absorption mainly occurs in jejunum and ileum

22
Q

ileum

A
  1. highly coiled
  2. where most of the absorption of nutrients occur
23
Q

large intestine

A
  1. remianing matter enter - cellulose, bacteria, dead cells lining the intestine walls, water
  2. reabsorption of water back into bloodstream
  3. undigested matter stored in rectum
  4. absorption of ions and vitamins
24
Q

rectum and anus

A

when rectum full, muscles of rectal wall contract to expel the faeces out of body

25
Q

transpoartation of amino acids and glucose out of SI

A
  • by diffusion and active transport
  • absrobed into the capillary of villus
  • blood capillaries form the hepatic portal vein
  • carries glucose and aa to liver
26
Q

transportstio of fats out of SI

A
  • diffuse
  • into epithelium
  • recombien to form minute fat droplets
  • enter the lacteal
  • lacteal form larger lymphatic blood vessel
  • rech thoracic duct
  • fat globules are released into the bloodstream
27
Q

assimilation of glucose

A
  1. oxidiesed during cellular respiration to release energy
  2. excess glucose -> return to the liver -> converted into fats
28
Q

assimilatiom of fats

A
  1. sufficient glucose -> protoplasm
  2. insufficient glucose -> broken down to provode energy
  3. excess fats -> stored in adipose tissues as shocker absorbers around vital organs
29
Q

assimilation of amino acids

A
  1. protoplasm for grwotha nd repair of worn out parts of body
  2. form proteins
  3. synthetise of enzymes and some hormones
30
Q

liver functions (6)

A
  1. regulation of BGC
    - when BGC xxx, islets of pancreas are stimulated to release glucagon/insulin that stimulates the liver cells to convert xxx to xxx, bringing BGC back to norm
  2. deamination of excess aa
    - amino group in aa is broken down and ammonia is formed
    - ammonia is converted into urea that leaves body in teh form of urine
    - carbon residue is cobverted into glucose and oxidised to release energy
    - converted into glycogne if in excess
  3. detoxification
    - alcohol is broken down into acetaldehyde by alcohol dehydrogenase
    - acetaldehyde is further broken down into acetic acid by alcohol dehydrogenase
    - acetic acid is further broken down to releasee energy or converted into glucose for respirationto release energy for cellular activities
  4. production of bile
    - provides optimal alkaline envt fr action of enzymes in SI
    - emulsifies fats into smaller fat droplets to increase SA to vol ratio such that digestion of fats by hydrolysis to fatty acids and glycerol by lipase increases
  5. protein synthesis
    - converts aa into fibrinogen or prothrombin
  6. storage of iron/breaking down of rbc
    - worn out rbc is destroyed in spleen
    - haemoglobin is released
    - haemolglobin in broken down by liver and iron is released
    iron stored in liver
    bile pigments are also produced
31
Q

effects of excessive alcohol consumption (3)

A
  1. digestive system issues
    - stimulatesacid secretion in stomach -> increased risk of getting gastric ulcers
    - prolong abuse -> liver cirrhosis -> liver cells are destroyed and replaced with fibrous tissues
  2. nervous systme issues
    - depressant
    - slows down brain functions
    reduced self control
    social lierties they regret doing
  3. effects n reaction times
    - poor muscle coordination and poor vision
    - underestimate speed + judgement deteriorates
    - traffic accidents

biology (17 decks)

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