Nutritions in Humans Flashcards

1
Q

Why is digestion important?

A
  1. breaks down larger molecules into smaller, simpler soluble and diffusible molecules
  2. can be absorbed into the blood stream and transported to body cells to be utilised
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2
Q

Define physical digestion, its purpose, where in the alimentary canal it can be found.

A
  1. mechanical breakdown of food into smaller pieces
  2. increases the SA:V ration for digestive enzymes to act on food efficiently

Mouth and Stomach

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3
Q

Define chemical digestion

A
  1. enzymatuc reaction that breaks down large molecules to smaller, diffusible ones.

*digestive enzymes are released in mouth, stomach and SI

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4
Q

Tell me the pathway of food! (Hint: its not the pathway of the alimentary canal)

A

Ingestion - Digestion - Absorption - Assimilation - Egestion

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5
Q

What is digestion

A

the process where food is broken down from larger molecules into smaller, simpler soluble and diffusible molecules that can be absorbed by bodily cells

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5
Q

What is ingestion?

A

the intake of food

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6
Q

What is assimiliation?

A

digested food is converted into new protoplasm/used to provide energy

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7
Q

What is absorption

A

digested food diffuses into cells

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8
Q

3 enzymes and what reactions they catalyse:
1. lipases
2. amylase
3. proteases

A
  1. (fat digesting) Fat –(lipase)–> glycerol+fatty acid
  2. (starch digesting). starch – (amylase) –>sugars/maltose
  3. (protein digesting). Protein – (proteases)–> amino acids
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8
Q

What is egestion?

A

discharge of undigested materual

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9
Q

What occurs in moth/buccal cavity?

A

Physical digestion:
- When food enters the moth, teeth breaks up food into smaller pieces
- increase in SA:V ration for enzymatic action on food chewing
- muscular tongue mixes food with saliva and rolls it into compact masses called bolus
- push bolus to back of the moth where its swallowed

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10
Q

What is the purpose of salivary glands?

A

produces saliva which contains enzymes. flows into buccal cavity via sulivary duct.

SALIVARY AMYLASE:
hydrolyses starch -> maltose

LYSOZYME
1. kills bacteria, microorganism
2. is present in mucus - soften and lubricates food making swallowing easier

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11
Q

talk about the swallong process.

A
  1. food is pushed into the pharnyx (connects moth or gullet and larynx -> voice box)
  2. Epiglottis (small flap) is bent down because weight of food. windpipe is closed.
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12
Q

Function of oesaphagus

A

Movement through peristalsis.

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13
Q

define peristalsis and its functions.

A

Peristalsis is the rhythmic contractions of circular and longitudinal muscles along the digestive system that propels food in a wave-like, unidirectional motion that is independent of gravity. involves a pair of antagonistic muscles which alternate in contraction.

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