IB SEHS HL Option D.1-D.7

antioxidants

molecules that can prevent/limit damaging effects of free radicals

how antioxidants fight free radicals

they turn free radicals into far less reactive substances

examples of antioxidants

vitamin A,C,E

enzymes which also fight free radicals

enzymes at least partially composed of copper, manganese, lutein, beta-carotene

foods which contain antioxidants

berries

red grapes

kale

broccoli

free radicals

particle that possesses at least one unpaired electron

examples of free radicals

superoxide

hydroxyl (OH)

nitric oxide (NO)

how free radicals cause damage

remove electrons from parts of cell --> create paired electrons in their own structures

parts of cells that free radicals remove electrons from

cell + mitochondrial membranes

enzymes + DNA

effect of electron removal from cell + mitochondrial membranes

increased/decreased permeability

effect of electron removal from enzymes + DNA

impairment of function --> contributes to development of cancer

free radical production

produced as by-product of normal cell function

antioxidant production

produced naturally to counteract free radicals

effect of exhaustive exercise on free radical + antioxidant balance

oxidative stress

exhaustive exercise --> high levels of free radicals --> natural antioxidants cannot control free radical damage

training effect on antioxidant + free radicals

training partially reduces free radical build-up from exhaustive exercise

athlete consumption of antioxidants

many athletes consume antioxidants in dietary supplements for extra defense against free radical damage

antioxidant supplement effectiveness

evidence supports that antioxidant supplements reduce oxidative stress / have positive impacts on training/performance in the absence of a pre-existing dietary deficiency

excess antioxidant intake may have detrimental effects

normal blood glucose levels at rest

1-4.5 mmol / L

human body keeps them stable

when blood glucose levels change drastically

post-exercise, post-carb-ingestion

pre-exercise vs. post-exercise glucose levels

blood glucose levels decrease as exercise begins --> pre > post

pre-ingestion vs. post-ingestion glucose levels

blood glucose levels increase immediately post-glucose-ingestion --> post > pre

more glucose ingested in a shorter amount of time --> sharper blood-glucose increase post-ingestion-->greater insulin release

hypoglycemia

lower than normal blood glucose

hyperglycemia

higher than normal blood glucose

causes of hypoglycemia

insufficient food intake

excessive exercise

high insulin levels among diabetics

how insufficient food intake causes hypoglycemia

food = ultimate source of all glucose --> insufficient food = insufficient blood glucose

how excessive exercise causes hypoglycemia

exercise depletes blood glucose + body glycogen

how high insulin causes hypoglycemia

insulin stimulates all body cells to absorb blood glucose

diabetics take insulin because they don't produce enough

taking too much insulin --> high insulin concentration --> low blood glucose

causes of hyperglycemia

infections

low insulin levels in diapetics

how infections cause hyperglycemia

mineralocorticoids (aldosterone) + glucocorticoids (cortisol), produced to combat illness, can also cause blood glucose to rise

how low insulin causes hyperglycemia

insulin stimulates all body cells to absorb glucose

diabetics take insulin because they don't produce enough

taking too little insulin --> low insulin --> high blood glucose

rate of hyperglycemia + hypoglycemia development

develop slowly, over several hours or days

glucose concentration gradient

created by constant cell consumption of glucose to create ATP

low inside cell, high outside cell

effect of glucose concentration gradient

promotes diffusion of glucose molecules into cell

problem with glucose size

glucose molecules are too large to diffuse through the cell membrane --> use transporter proteins = facilitated diffusion

glucose transporter proteins

GLUT1

GLUT4

GLUT1

always embedded in cell membrane

used by most glucose during rest

GLUT4

usually stored in intracellular vesicles

translocated to cell membrane when needed for greater/faster glucose movement into cell

at rest, can be stimulated to translocate via raised insulin levels

during exercise, can be stimulated to translocate by calcium ion release

how glucose concentration gradient is maintained

glucose taken into muscle cells quickly converted to glucose-6-phosphate

effect of training on ability to take in glucose

increased training = increased cellular glucose uptake ability

effect of exercise on GLUT4

exercise increases GLUT4 protein production --> increased max rate of glucose uptake

effect of increased cellular glucose uptake ability on performance

increased glucose uptake capabilities --> increased availability of glucose as fuel --> more ATP --> more endurance + power

5.5 - 7.5

pH of mouth

1-4

pH of stomach

6-8

pH of pancreas

6-8

pH of small intestine

increase the rate of digestion whilst maintaining a stable body temperature

the function of enzymes in the context of macronutrient digestion

break down food so that the organism can absorb it.

the need for enzymes in the context of macronutrient digestion

salivary amylase

breaks down carbohydrates (oral cavity)

pancreatic amylase

breaks down carbohydrates and fats (small intestine)

pancreatic lipase

breaks down fats (small intestine)

bile

breaks down fats (small intestine (not pancreatic lipase))

pepsin

breaks down proteins (stomach)

trypsin

breaks down proteins (small intestine)

water

Medium in which metabolic processes occur

Regulates body temperature

Enables movement of substance around body

Allows for exchange of nutrients and products

interstitial (between cells but in tissue), plasma, saliva, lymph, tears, digestive tract, CSF (brain, nerve cord fluid), sweat, urine, exhale

where extracellular fluid can be located in the body

Athletic training causes a loss in water weight and body fat (muscle tissues are more watery)

water distribution in trained individuals

Thirst

Urine color (pale apple juice)

Urine osmolarity (more solutes, lower freezing point)

Specific gravity (hydrometer)

Change in body mass (not more than 2%)

how athlete hydration can be monitored.

water used for thermoregulation during exercise → higher need for water replenishment

why endurance athletes require greater water intake

basal metabolic rate (BMR)

Minimum amount of energy needed to survive

Basal metabolic rate

Thermic effect of feeding

Thermic effect of physical activity

components of daily energy expenditure

Intake occurs intermittently during the day, expenditure occurs constantly

Energy balance:

overconsumption of food will lead to storage → weight gain

Insufficient consumption of food will lead to compensation for deficit → weight loss

the relationship between energy expenditure and intake

Obvious differences in body compositions among different sports:

Endurance athletes = slender and small

Strength and power athletes = muscular

association between body composition and athletic performance

Carb Loading

Protein consumption for gaining muscle mass (FFM)

Reduction of energy intake for reducing fat mass

Deliberate restriction of food and fluid to achieve a body mass that allows them to compete in a specific weight class → causes dehydration and low energy stores

Discuss dietary practices employed by athletes to manipulate body composition.

carb loading

reducing training and increasing carbohydrate intake (avoids need for hard exercise to empty muscles of glycogen) → greater energy store, longer performance

low glycogen content

Slow twitch (type I)

medium glycogen content

Fast twitch (type IIa)

high glycogen content

Fast twitch (type IIb)

high intensity exercise (burst of energy needed)

uses fast twitch fibers, anaerobic metabolism, glycolysis will demand high rates of glycogen.

low intensity exercise (endurance)

type 1 (slow twitch) fibers will be used; synthesis of ATP will be aerobic/Krebs cycle.

rate of glycolysis will be low

Continuous moderate exercise (cycling) in slow twitch muscle fibers

rate of glycolysis will be high

High intensity exercise (sprinting) in fast twitch fibers

glycemic index (CI)

a number associated with the carbohydrates in a particular type of food that indicates the effect of these carbohydrates on a person's blood glucose level

High: (sweets) = 100

Medium: (brown rice) = 50

Low: (green vegetables) = > 15

GI

high GI foods

(post-exercise) assist the body in restoring its glycogen stores → re-fueling, or during exercise

low GI foods

may be beneficial prior to exercise; daily diet should be low to medium GI carbohydrates

carbo-loading

high GI foods provide a supply of glycogen (for energy/ATP)

weight reduction

(boxers; jockeys) restrict fluids & food to fit into a weight class → dangerous as it can cause dehydration

Loss of water and salt from sweat

Electrolytes enhance fluid absorption in the gut.

Glucose in drinks provides energy source

the reasons for adding sodium and CHO to water for endurance athletes

sports drinks, bars, and gels

provide a lot of energy but only necessary for extremely intense activity

caffeine

stimulates the nervous system (higher heart rate), can increase blood flow to exercising muscles, increases short-term force, boost mid-event

creatine

gaining muscle, aids the synthesis of creatine phosphate; benefits exercise that uses ATP-PC energy system

bicarbonate

alkaline/base which increases pH of blood which increases tolerance of lactic acid during exercise

0.8 per kg of body weight

the recommended daily intake of protein for adult female and male non-athletes

cheese, eggs, nuts

sources of protein for vegetarians

fish, chicken, red meats

sources of protein for non-vegetarians

1.2 to 1.4 g/kg/day

protein intake for endurance athletes

protein

important for building and repairing cells (muscle) following endurance or shorter events

1.2 to 1.7 g/kg/day

protein intake for strength athletes

weight gain

liver and kidney damage (where excess proteins are processed)

high cholesterol

harmful effects of excessive protein intake

Water: 3-4 days

Food: 30-60 days

How long without food and water (depending on conditions)?

40

During a fast, can lose only __% of body weight without dying

2.5 L

typical daily water loss from urine, sweat, saliva, feces, etc.

hypothalamus

main monitor of fluid level in blood (blood gets thick if without) in brain

Antidiuretic Hormone (ADH)

Causes retention of water in kidneys

Received in the collecting duct of nephron

urine

urea and uric acid; gets rid of nitrogenous waste and salts to keep blood volume correct

urine production

Filtration - capsule

Reabsorption - pct/henle

Secretion - dct

hyponatremia

sodium(NaCl) concentration is too low, water concentration too high; variety of causes possible

mechanical digestion

physical breakdown of big pieces to small (mouth, stomach)

chemical digestion

breakdown at molecular level so that absorption can occur (Mouth (lil), Stomach (lil), Pancreas (producing enzymes), SMALL INTESTINE)

peristalsis

wave movement contraction along gastrointestinal tract (Esophagus → rectum)