Unit 3 SEHS IB HL

The hypothalamus is responsible for..

most of the body's processes

three parts of a feedback mechanism

receptor, control centre and an effector

negative feedback loop

reduces or reverses a change

positive feedback loop

amplifies change's effects

negative feedback example

when body temp rises, thermoreceptors detect the change and hypothalamus activates sweating to increase heat loss, making the body temp return to normal

positive feedback example

continous release of oxytocin during childbirth to increace contractions

Steroid Hormones solubility and binding

fat-soluble and bind to intracellular receptors

non steroid hormones solubility and binding

not fat soluble and binds to surface receptors

steroid hormone examples

testosterone, estrogen, progesterone, cortisol

non steroid hormone examples

insulin, glucagon, adrenaline

prostaglandins

local hormone that triggers swelling in inflammatory responses

hormone secretion patterns

cyclical, in situations or in waves

growth hormone is more released at...

night

cortisol spikes in the...

morning

neural regulation

signals from nervous system, eg adrenaline

humoral regulation

changes in blood chemistry eg blood glucose levels

hormonal regulation

changes in other hormone levels eg ghrelin signaling appetite

Gluconeogenesis

formation of glucose from noncarbohydrate sources

glycogenolysis

liver glycogen breaking down into glucose

conduction

heat transfer through direct contact eg sitting on a bench

convection

heat transfer through air or water eg running on a windy day

radiation

heat transfer through energy waves eg sunlight

evaporation

removing heat from the skins surface eg sweating

humid air impact on sweating

slows sweating making cooling less effective

acclimation

adapting in artificial environments

heat acclimatization 4 benefits

better thirst regulation, progression in exercise, lower heart rate and body temp, increased sweating

5 chronic adaptations to heat acclimatization

increased plasma volume, earlier onset of sweating, diluted sweat, exercise feels easier, less glycogen use

3 performance improvements after heat acclimatization

increased vo2 max, lactate threshold, and thermotolerance

Hyperthermia

high body temperature

Hypothermia

low body temperature

at high altitude, pressure is...

low

Hypoxemia

Low oxygen levels in the blood.

immediate adjustments to altitude

hyperventilation, increased cardiac output, reduced saturation of hemoglobin

effects of altitude on fluid balance

humidity is low, dehydration occurs

macronutrients

carbohydrates, proteins, fats and water

carbohydrate food source

sweets, grains, fruits and veggies

fat food source

meat, dairy and eggs

water source

drinks, fruits and veggies

micronutrients

vitamins, minerals and trace elements

simple carbs

monosaccharides and disaccharides

complex carbs

polysaccharides

monosaccharides examples

glucose fructose galactose

Disaccharides examples

maltose lactose sucrose

polysaccharides examples

starches glycogen fibres

lipids aka

triglycerides

roles of lipids

longterm energy source, insulation with adipose tissue

roles of carbs

main energy source

roles of protein

growth, repair, enzymes and muscle tissue

roles of water

transport, thermoregulation

roles of vitamins

helps metabolism and energy release

roles of minerals

bone density, oxygen transport and muscle function

why carbs matter in sport

carbs break down into ATP during aerobic and anaerobic systems during exercise

unsaturated fats bond and source

double bonds from plants

saturated fats bond and source

no double bonds from animals

glycaemic index

measures how quickly a food raises blood sugar

fats are mainly used during ______ exercise

low to moderate intensity

condensation

molecules join together and water is removed

hydrolysis

large molecules are broken down by adding water

Low Energy Availability (LEA)

insufficient energy to support physiological functions needed for optimal health

which 4 body functions does LEA effect

hormone production, immune function and recovery

RED-S

Relative Energy Deficiency in Sport (longterm LEA)

effects of RED-S

weakens bones, cardiovascular health and immunity

which sport type is most at risk of RED-S

sports where low body mass is valued

Iron

important for oxygen transport (hemoglobin and myoglobin)

Calcium

important for bones and muscle contraction

sodium and potassium

important for water balance and muscle-nerve functioning

Gut microbiome

community of microorganisms living in the large intestine

3 ways to improve the gut microbiome

fibre, fruits and veggies, exercise

3 hards to the gut microbiome

stress, poor diet and high sugar

why the gut microbiome matters

important in digestion, nutrient absorption and immunity

big 4 functions of water in the body

solvent for metabolic transport, thermoregulation, lubrication and enabling biochemical reactions

where water is lost

sweat/breathing evaporation, urine

negative feedback loop of water balance

hypothalamus detects dehydration, pituitary gland releases ADH and the kidneys start absorbing more water

water loss impact on cardiac output

during exercise, sweating reduces blood volume, decreasing stroke volume and therefore heart rate increases to maintain cadiac output resulting in cardiovascular drift

main effect of progesterone

increasing core body temperature, harder to get rid of heat

main role of oestrogen in performance

helps spare glycogen, meaning the body relies more on fat for energy

Why is glycogen sparing beneficial

delays fatigue during prolonged exercise by preserving carbohydrate stores

How does oestrogen affect joints

Oestrogen can influence joint laxity (stiffness/flexibility), which may increase injury risk or affect movement stability

How does testosterone affect bone health

It increases bone density and strength, reducing injury risk

How does testosterone affect oxygen transport

stimulates erythropoietin (EPO), increasing red blood cell production and improving oxygen delivery

metabolism

all chemical reactions in the body

anabolism

reactions that build and use energy

catabolism

reactions that break and release energy

ATP-PC system

uses creatine phosphate to generate ATP

Anaerobic/Glycolytic system

Through glycolysis, ATP is produced quickly but lactate and hydrogen ions are produced

Aerobic system

uses carbs and fats for fuel but produces ATP slowly

ATP-PC system type of exercise and eg

explosive exercise, 100m sprint

Anaerobic/glycolytic system type of exercise and eg

high intensity, 400m sprint

Aerobic system type of exercise and eg

endurance, marathon

training impacting VO2 MAX

SV increases, capillarization

Oxygen deficit

body requiring more oxygen than consumed in the beginning of exercise

EPOC stands for

excess post-exercise oxygen consumption

EPOC explanation

after exercise, the body needs extra oxygen to restore ATP/PC stores, remove lactate and reoxygenate myoglobin