A1.2 - A.1.3

the condition in which the body’s internal environment remains relatively constant.

can limit performance, increase the risk of heat illness or cold injury, and can pose life-threatening situations.

come from within the body (e.g low blood glucose levels) or outside the body (e.g intense cold, low oxygen etc).

maintaining homeostasis by regulating most processes that affect the body’s internal environment

A receptor (such as nerve endings in the skin that sense temperature) A control center (such as the hypothalamus) An effector (such as shivering if your body temperature drops)

internal (regulation of the heart by the heart it takes care of itself)

Blood pressure Heart rate Strength of contraction of the heart Respiration Digestion Body temperature Thirst and fluid balance Interaction between the nervous and endocrine systems Appetite and food intake Sleep-wake cycles

they work to reverse the effects of the stimulus and return the body to a state of homeostasis (like making the body warmer when its really cold)

generates electrical impulse and Causes contraction of atria then stimulation of AV node

To maintain homeostasis, the respiratory control center in the brain and chemoreceptors throughout the body monitor the blood acidity. If CO2 levels rise and the blood becomes acidic (this can harm organs and is more common in exercise), the respiratory control center increases the rate and depth of breathing which speeds up the removal of CO2 from the blood and body, returning the blood to it’s normal ph levels.

generates secondary impulse and Causes contraction of ventricles

when exercise begins, the sympathetic nervous system stimulation increases to have the heart beat faster and more powerfully to supply the required blood and oxygen to working muscles. in general controlled by the autonomic nervous system which uses the sympathetic nervous system to increase heart rate and force of contraction and the parasympathetic nervous system to slow it down and do the opposite

When blood glucose levels are high (e.g after a meal), the pancreas releases insulin into the bloodstream Insulin signals the liver and muscle cells to take up glucose and convert it into glycogen for storage and stimulates the adipose tissue to take up the glucose and store it as fat When blood glucose levels are low (during exercise or fasting), the pancreas releases glucagon Glucagon signals the liver to break down glycogen into glucose and release it into the bloodstream, raising blood glucose levels The endocrine and energy systems work together to maintain appropriate blood glucose levels by using hormones to regulate glucose metabolism in the body

During exercise lasting >30 min, insulin levels drop but even though there is less insulin in the blood, the insulin that is there in excersise is more effective at allowing the glucose into the muscle and liver cells.

exercise also increases insulin sensitivity so the body needs less insulin to transport glucose over time. This effect occurs because muscle contractions stimulate glucose transport proteins to move to the cell surface, allowing glucose to enter the cell directly.

Insulin resistance is when the body’s cells become less sensitive to insulin and do not uptake the glucose from the blood, leaving blood sugar levels high. This can lead to serious health problems including Type II Diabetes. Insulin resistance results in the pancreas producing MORE insulin to regulate the blood sugar levels and, over time, the body becomes less sensitive to it.

The amount of energy required to complete regular, daily activities

Exercise (↑ metabolic rate) Hormones (thyroid hormone ↑ metabolic rate) Nervous System (SNS activity ↑ metabolic rate) Body temperature (higher body temp ↑ metabolic rate) Ingestion of food (↑ metabolic rate) Age (children have higher metabolic rate than adults) Sex differences (metabolic rate is lower in biological females, except during pregnancy)

heat being transferred from a hot area to an area not as hot as where its being transferred from. Like climbing down the ladder.

A heat transfer method that involves direct contact between surfaces and depends on the heat gradient e.g running on a hot track

moving heat from one place to another via air or water e.g the human body loses heat to water if the water is cooler, body loses heat to the environment if the air is cooler than the body

energy waves that are sent from the sun and are absorbed by the body e.g sunbathing when the air is warmer than the body

maximal evaporative cooling is affected by the humidity (amount of water particles in the air). If the air is already laden with moisture, there is no gradient for the sweat to evaporate into as the air is already moist. The sweat just rolls off the skin and provides no cooling effect at all and more acts as a warm blanket.

The body detects that there is an increase in core body temperature and vasodilates the blood vessels which allows more blood (and heat) to flow to the peripheries and skin to lower the core temperature and be evaporated and release that heat.