Digestion Flashcards
1
Q
What are nutrients?
A
- chemical substances found in foods that are used in human body
2
Q
Why are some nutrients essential?
A
- essential nutrient = ones that cannot be synthesised
- obtained from food only
- water (is synthesised however, not sufficient amount)
3
Q
What are two groups of vitamins?
A
- water-soluble and lipid-soluble
- water-soluble are easily excreted
- lipid-soluble = A D E K (rest is water-sol.)
- vitamins do not have a common structure
4
Q
What is malnutrition?
A
- imbalance of nutrients that causes health problems
- deficiency, imbalance or excess
5
Q
What are minerals?
A
- essential chemical elements found in food (ions)
6
Q
What are different minerals and their function?
A
- Ca2+ — secondary messenger in signalling (muscle contraction. synapse); component of bones
- Fe2+ — part of heme
- Zn2+ — zinc fingers (found in proteins, enzymes)
- Na+, K+ — membrane potential; signalling
- I- — thyroid hormones (growth); nervous system development; metabolic processes
7
Q
Are vitamins universal for all organisms?
A
- no
- some substances which are synthesized by human body may be vitamins for other animals
8
Q
What is the role of vitamin C?
A
- antioxidant
- reduces molecules (electron donor)
- during immunological response
- synthesis of collagen
- deficiency = scurvy
- leads to bleeding gums and under skin
- found in: veggies and fruits
- unstable – amount lowers with time, temp increase, exposure to metals (iron and copper)
9
Q
Do rats synthesise vitamin C?
A
- yes
- experiments with vitamin C deficiency could not be performed on rats
- rats produce their own ascorbic acid (not a vitamin for them)
10
Q
What are the consequences of scurvy?
A
- pain in joints (lack of collagen)
- haemorrhages (bleeding) from gums, under skin, disintegration of blood vessel walls
- teeth loss
- even death
- anaemia
- osteoporosis
11
Q
What is the role of vitamin D?
A
- produced in skin irradiated with UV
- risk of skin cancer
- instead of vitamin it should be prohormone
- turned into calcitriol
- transcription regulator for genes connected to calcium
- Ca homeostasis
- bone mineralisation, muscle contraction, nervous and cellular signalling,
- immune response
12
Q
What are the consequences of overdosage of vitamin D?
A
- toxicity symptoms and hypercalemia
13
Q
What is RDA (recommended daily amount) of vitamin D?
A
- 30 min exposure to sunlight UV (or more)
- depends on latitude, ageing, season, skin pigmentation, clothing
- dietary supplementing needed
- 5 μg/day
14
Q
What are the consequences of vitamin D deficiency?
A
- rickets
- impeded growth, long bones deformation
- osteomalacia
- impaired calcium deposition in bones
- lower mineral density
- posture abnormalities
15
Q
What are essential fatty acids?
A
- omega 3 and 6
- unsaturated
16
Q
What are essential amino acids?
A
- Phenylalanine
- Threonine (if no Phe)
- Valine
- Tryptophan
- Methionine
- Leucine
- Isoleucine
- Lysine
- Histidine
- Arginine (in infants)
17
Q
What are the consequences of starvation?
A
- scarcity of food leading to deficiencies
- lack of protein
- breakdown of muscle tissue and other
- instead essential amino acid are produced
- cardiac muscle can be destroyed
- anorexia = reduced appetite
- anorexia nervous = psychiatric illness, voluntary starvation
- weight, hair loss
- loss of energy
- skin bruises
- suspension of menstrual cycle and ovulation
- reduced blood pressure, slower heart rate
- anorexia nervous = psychiatric illness, voluntary starvation
18
Q
What are the consequences of plasma protein deficiency?
A
- lack of amino acids —> lack of important blood plasma proteins (albumins)
- maintain colloid osmotic pressure
- tissue fluid doesn’t come back to circulatory system
- retended in tissues
- tissue swelling (in abdomen) = edema
19
Q
What is phenylketonuria?
A
- autosomal recessive genetic disorder
- diagnosed in infants
20
Q
What are the causes and consequences of phenylketonuria (PKU)?
A
- caused by lack of enzyme converting phenylalanine —> tyrosine
- phenylalanine converted into phenylpyruvate
- later in urine
- impairment of brain development
- mental retardation
- brain damage
- seizures
21
Q
What is PKU treatment?
A
- incurable
- low-phenylalanine diet
- meat, nuts, cheese, dairy, legumes —> a lot
- controlled amounts: bread, pasta, corn, potatoes
- diet not enough
- medication (BH4)
- removal of phenylalanine
- supplementing of tyrosine
- medication (BH4)
22
Q
How is appetite controlled?
A
- Appetite Control Centre (ACC) in brain (hypothalamus)
- sugar levels
- insulin
- adipose tissue
- leptin
- stomach filling state
- ghrelin
- smell (tasty or disgusting)
23
Q
What are the risks of obesity?
A
- diabetes II
- high blood pressure
- arteriosclerosis (atherosclerosis)
- joint damage
- impotence
- self-esteem issues
- thyroid dysfunctions
- cancer
24
Q
What are exocrine glands?
A
- substances sent out of body
- release them to ducts
- not to blood stream (like endocrine glands)
- examples: sweat, moll, mammary, sebaceous
25
Q
What are parts of alimentary canal?
A
- mouth, large intestine, small intestine, oesophagus, stomach, duodenum, rectum
26
Q
What are digestive glands?
A
- salivary glands
- pyloric glands
- stomach
- pancreatic exocrine and endocrine glands
- goblet cells
- small intestine
27
Q
What are accessory organs?
A
- teeth, liver, gall bladder, bile duct, salivary glands, tongue, pancreas
28
Q
What is digestion?
A
- enzymatic breakdown into monomers
29
Q
Which molecules are digested?
A
- lipids —> fatty acids and glycerol
- lipase + bile
- proteins —> amino acids
- pepsin
- polysaccharides —> monosaccharides
- amylase
- beta-D-glycosidic bond no digested (cellulose)
- nucleic acids —> nucleotides
