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HUBS EXAM 3 > nutrition, metabolism and body fluids > Flashcards

nutrition, metabolism and body fluids Flashcards

1
Q

what is nutrition

A

the various ways in which foods interact with the human body for the maintenance of health and wellbeing

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2
Q

what is metabolism

A

all the chemical reactions that take place in the body. the substances required for metabolism are transported through body fluids and have an influence on the composition of those fluids

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3
Q

what is cellular metabolism

A

it uses nutrients and oxygen to produce cellular energy necessary for maintaining cellular activities

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4
Q

what are nutrients

A

substances in food used by the body to generate cellular energy and to promote normal growth, functions, maintenance and repair body cells and tissues

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5
Q

what are macronutrients

A

they make up the bulk of the diet, they provide the material sources for ATP and building structures in the body.

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6
Q

what are the types of macronutrients

A

carbohydrates, lipids and proteins

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7
Q

what are the functions of carbohydrates

A
  • obtained from plants, starch provides fiber which aid digestion
  • reduce cholesterol in blood
  • glucose is the carbohydrate fuel used for cellular ATP
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8
Q

what are the functions of lipids

A
  • They provide fuel to generate ATP
  • can be converted into fat molecules for cellular structure and functioning
  • fatty acids are the major fuel source of ATP in hepatocytes and skeletal muscle cells
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9
Q

what are the functions of proteins

A
  • all proteins are broken down into amino acids for absorption in the GI tract
  • used to generate ATP
  • build new protein structures in the body
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10
Q

what are macronutrients and the 2 types

A

nutrients that are only needed in minute amounts

  1. vitamins- used to aid metabolism of macronutrients and maintain homeostasis mostly through coenzymes
  2. minerals- maintain homeostasis, ionized in body fluids to become electrolytes or bound to organic compounds to form phospholipids, hormones and various functional proteins
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11
Q

nutrient pools and storage

A

A certain level of most nutrients are sustained (or stored) within the body. Homeostatic levels of circulating glucose, fatty acids and amino acids are maintained in the blood so that there are always some available for cellular metabolism. In addition, glucose and fatty acids are readily stored in certain body tissues/structures, as are some vitamins and minerals.

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12
Q

what are the 2 types of metabolic (chemical) reactions

A
  1. anabolism- any process in which large molecules or structures are built from smaller ones. these are synthesis or genesis (building) reactions that store heat and energy
  2. catabolism- any process that breaks down complex structures into smaller molecules. these are degenerative reactions which liberate (release) energy and heat
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13
Q

what are the 2 components of cellular metabolism

A
  1. anabolic reactions that facilitate energy storage and structural building repairing or catabolic reactions that lead to step 2 and the generation of ATP which occurs within the cytoplasm of body cells
  2. cellular respiration- a series of catabolic reactions which generate ATP. oxygen is required for this step and it occurs within the mitochondria
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14
Q

what are the steps of cellular respiration

A

pyruvic acid is converted into Acetyl CoA which goes into the krebs cycle and produces 4 reduced co enzymes which go through the electron transport chain and give us ATP

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15
Q

what are the metabolic processes for glucose

A
  1. anabolic- glycogenesis- excess glucose not required for ATP generation is converted into glycogen within the liver and skeletal muscles
  2. catabolic- glycolysis- generates pyruvic acid from glucose to make cellular ATP
    - glycogenolysisis when there isn’t enough glucose supply in the blood, the stored glycogen in the liver can be broken down to release glucose
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16
Q

what are the metabolic processes for lipids (tryglicerides)

A
  1. anabolic- lipogenesis- excess glycerol and fatty acids are taken up by adipose cells and reformed into triglycerides for storage in adipose tissue
  2. catabolic- lipolysis- triglycerides are broken down to glycerol and fatty acids to generate ATP. Glycerol is converted into pyruvic acid and fatty acids are converted into Acetyl CoA
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17
Q

what are the metabolic pathways for proteins (amino acids)

A
  1. anabolic- protein synthesis- most amino acids are taken up by body cells are rebuilt into protein structures that become part of the cell
  2. catabolic- transamination and deamination- when amino acids are used to generate ATP, they are taken up by the liver and is converted into keto acid by taking off the nitrogen which can enter the citric acid cycle (krebs cycle). the nitrogen group is added to a glutamic acid to make urea and water
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18
Q

what are the 2 metabolic states of the body that maintain the blood nutrient pools of the macronutrients and sustain adequate cellular metabolism

A
  1. absorptive (fed) state- the time during and for a few hours after the meal when digested food is being absorbed into the bloodstream and body cells are able to use the recently absorbed nutrients for cellular respiration
  2. postabsorptive (fasting) state- the time that occurs between meals, when cellular energy is being supplied from the existing energy in the body
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19
Q

what is the setpoint range for blood glucose

A

3-8mmol/L. the homeostatic feedback mechanisms regulating each metabolic state work towards trying to keep blood glucose levels within this set point range

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20
Q

what are the metabolic activities that occur more readily in an absorptive state

A
  • lipogenesis (storing lipids)
  • insulin regulates the metabolic processes
  • anabolism exceeds catabolism (more are being built than broken down)
  • increased protein synthesis
  • glucose main food fuel supply
  • glycogenesis (stored glucose)
  • increased glycolysis (breaking down glucose)
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21
Q

what are the metabolic activities that occur more readily in a postabsorptive state

A
  • decreased glycolysis
  • glycogenolysis (breaking down glucose)
  • lipolysis (breaking down lipids)
  • decrease in protein synthesis and transamination and deamination
  • gluconeogenesis
  • catabolism exceeds anabolism (more breaking down reactions)
  • fatty acids are the main source
  • glucagon regulates
  • SNS activated
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22
Q

the absorptive state is regulated by insulin whose effects include:

A

insulin is released when the blood glucose levels rise and facilitate the immediate use of glucose for ATP generation in the body cells and for energy storage

  • uptake of glucose by body cells for cellular respiration (glycolysis)
  • uptake of glucose by liver and skeletal muscle for glycogenesis
  • uptake of glycerol, fatty acids and glucose by adipose tissue for lipogenesis
  • uptake of amino acids by body cells for protein synthesis
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23
Q

the postabsorptive state is regulated by glucagon and sympathetic nervous system activity whose effects are: glucagon is released in response to reduced blood glucose levels and stimulates:

A

glucagon is released in response to reduced blood glucose levels and stimulates:
- glycogenolysis and gluconeogenesis in the liver, increasing the amount of glucose in the blood
- lipolysis, increasing the availability of fatty acids (and glycerol) for ATP generation
sympathetic nervous system activity complements the actions of glucagon by:
- enhancing lipolysis
- releasing adrenaline and noradrenaline from the adrenal glands which promote glycogenolysis and gluconeogenesis

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24
Q

the body strives for balance between energy inputs and energy outputs to be able to maintain an adequate metabolic rate, what are energy inputs and outputs

A
  • energy inputs- energy obtained from food fuels (nutrients)
  • energy outputs- energy lost as heat from the body, energy used to do cellular work, energy stored as glycogen or fat
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25
Q

what is total metabolic rate

A

rate of energy output due to all body activities at any given time. the total metabolic rate fluctuates regularly, with the most dramatic changes occurring due to increases in skeletal muscle activity and the ingestion/ digestion of food

26
Q

what is the basal metabolic rate

A

base, or minimum, rate of metabolic reactions (energy output) required to maintain/ perform only the body’s most essential functions

27
Q

what factors influence a person’s basal metabolic rate

A
  • surface area to body mass ratio
  • stress
  • age
  • body temperature
  • sex
  • thyroid hormone
28
Q

relate energy balance, appetite and basal rate

A

ensuring there is a balance between energy inputs and energy outputs is necessary for an individual to be able to maintain their basal metabolic rate and to support their total metabolic rate. appetite is the mechanism by which the body tries to regulate energy balance

29
Q

what are stimuli that decrease appetite

A
  • stomach distension (stretching)
  • hormones released during the absorptive state
  • increased blood glucose levels
  • rising leptin levels
30
Q

what are stimuli that increase appetite

A
  • hormones released from an empty stomach
  • reduced blood glucose levels
  • certain neurotransmitters
  • falling leptin levels
31
Q

what is glycogenolysis

A

breakdown of glycogen (releasing stored glucose)

32
Q

what is glycolysis

A

conversion of glucose to pyruvic acid

33
Q

what is glycogenesis

A

creation of glycogen (storing glucose)

34
Q

what is gluconeogenesis

A

creation of glucose from non-carbohydrate sources (e.g. lipids & proteins)

35
Q

what are the 2 subdivisions of extracellular fluid

A
  • interstitial fluid: makes up 4/5 of the ECF. this is fluid found outside body cells, mostly found within connective tissue, except blood
  • plasma: the ECF of blood, making up the remaining 1/5 of the ECF
36
Q

what are electrolytes

A
  • sodium
  • acids and bases
  • chloride
  • calcium
  • potassium
37
Q

what are non-electrolytes

A
  • glucose
  • fatty acids
  • amino acids
38
Q

which electrolyte is found in the greatest concentration within the ICF ( and therefore contributes the most to ICF osmolarity)

A

potassium

39
Q

what electrolyte is found in the greatest concentration within the ECF (and therefore contributes the most to ECF osmolarity)

A

sodium

40
Q

what is osmolarity

A

the total concentration of all solutes in either fluid compartment. they must be the same.

41
Q

how is osmolarity maintained between body fluid compartments

A

The osmolarity of the fluid compartments influences the movement of water. If there is an imbalance of osmolarity, water will move between the ICF and ECF. water will always move from low to high osmolarity.

42
Q

what is the thirst mechanism (regulating water levels)

A

this regulates water via drinking. When plasma osmolarity increases, it triggers a thirst mechanism, resulting in the desire to drink water and therefore reducing plasma osmolarity. It is also triggered by losses in plasma volume, as water consumption will increase blood volume. This mechanism is controlled by the hypothalamus. This mechanism does not regulate water gains via metabolism or food

43
Q

what is the antidiuretic hormone (regulating water levels)

A

ADH regulates water loss via urinary output. It increases water reabsorption at the kidneys, returning more water to the blood which decreases the volume of urine and increases the concentration of urine. ADH is the main regulator of water levels in the ECF. This mechanism does not regulate water losses of evaporation via the lungs and skin, water loss in feces, or the minimum amount of water required to excrete kidney solutes.

44
Q

what are sources of water gained

A

food, beverages, cellular metabolism

45
Q

What are sources of water loss

A

Urine, sweat, evaporation via skin and lungs, feces

46
Q

what are sources of electrolyte gain

A

food, beverages

47
Q

what are sources of electrolyte loss

A

urine, feces, sweat

48
Q

regulating electrolyte/ salt levels

A
  • Sodium is the most abundant electrolyte in the ECF and therefore the most important one to regulate. It is regulated through urinary output via aldosterone which increases sodium reabsorption at the kidneys. When there is increased sodium reabsorption, water will follow therefore increasing blood volume and blood pressure.
  • Potassium is regulated by aldosterone which increases potassium excretion at the kidneys to keep levels low in the ECF
  • Calcium is regulated by parathyroid hormone which has a number of effects to increase blood calcium levels.
49
Q

what are acids and bases

A

specific types of electrolytes whose concentrations within the body fluids influence nearly all biochemical reactions in the body

50
Q

what are acids

A

hydrogen containing compounds that release H+ ions when dissolved in water

51
Q

what are bases

A

compounds that picked up/ bind H+ ions. Most bases contain hydroxides which release OH- ions in water which then pick up the H+ ions.

52
Q

what is the pH set point range for ECF?

A

7.35-7.45

53
Q

what are the pH scales in relation to hydrogen

A

The greater the concentration of H+, the lower the pH and the more acidic the fluid will be. The lower the concentration of H+, the higher the pH and the more basic (alkaline) the fluid will be. A pH of 7 is considered neutral because the concentration of H+ is roughly equal to the concentration of available bases.

54
Q

what is a buffer system

A

allow metabolic acids to go through the blood without affecting the PH

55
Q

what is the bicarbonate buffer system

A

the most important buffering system in the ECF and begins with the movement of CO2 generated by cellular metabolism reacting with water to form carbonic acid which disassociates into a hydrogen ion and a bicarbonate ion. This system picks up most of the metabolic acids and neutralises them

56
Q

what is the protein buffer system

A

includes hemoglobin in red blood cells which can buffer the H+ that comes off the CO2.

57
Q

what is the phosphate buffer system

A

buffers acids within the intracellular fluid and within urine

58
Q

what is acid-base excretion

A

Buffering is only a temporary solution to reducing changes in body fluid pH. buffers can not eliminate H+ ions and there is a limited amount of buffers. So the H+ that is produced must be eliminated from the body.

59
Q

how do the lungs do acid-base excretion

A

they excrete H+ ions that were buffered by the protein buffer system by breathing out

60
Q

how does the kidneys do acid-base excretion

A

excrete acids or bases as required to be expelled in urine.

HUBS EXAM 3 (9 decks)

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