A1.2 - A.1.3 Flashcards
homeostasis
the condition in which the body’s internal environment remains relatively constant.
what can extreme temps do for sports
can limit performance, increase the risk of heat illness or cold injury, and can pose life-threatening situations.
Stressors
come from within the body (e.g low blood glucose levels) or outside the body (e.g intense cold, low oxygen etc).
overall What is the hypothalamus responsible for
maintaining homeostasis by regulating most processes that affect the body’s internal environment
What does a negative feedback mechanism include
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)
Intrinsic
internal (regulation of the heart by the heart it takes care of itself)
What is the hypothalamus more specifcally responsible for that are the bodies processes effecting its internal enviroment
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
What do negative feedback loops work to do
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)
The sinoatrial (SA) node
generates electrical impulse and Causes contraction of atria then stimulation of AV node
explain the negative feedback loop of the regulation of ph in the blood
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.
The atrioventricular (AV) node
generates secondary impulse and
Causes contraction of ventricles
regulation/negative feedback loop of the heart in excersise
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
regulation of blood glucose
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.
what can happen to insulin sensitivity with increased exercise
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.
what is insulin resistance
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.
metabolic rate
The amount of energy required to complete regular, daily activities
what factors effect metabolic rate
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 gradient
heat being transferred from a hot area to an area not as hot as where its being transferred from. Like climbing down the ladder.
Conduction
A heat transfer method that involves direct contact between surfaces and depends on the heat gradient e.g running on a hot track
Convection
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
Radiation
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
how does humidity affect evaporation
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.
how does Evaporation work in maintaining homeostasis and sports in general
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.
What are Three factors influence the total amount of sweat vaporized from the skin
SURFACES EXPOSED TO THE ENVIRONMENT - the more exposed, the more sweat is produced
HUMIDITY - more humidity less evaporation
TEMPERATURE - sweat rates increase with increasing temperatures
how does the body maintain homeostasis when its really cold
- The SNS stimulates increased metabolism, increased metabolism produces heat.
- brown fat is activated which increases heat, uses glucose.
Shivering - the body starts to shiver in response to cold, which uses muscular contractions to generate heat.
Vasodilation - the widening of the blood vessels to allow more heat to be transported to the peripheries
Vasoconstriction - the narrowing of the blood vessels to keep the heat closer to the core and maintain body temperature during the cold
What sex has a higher sweat rate
males so they can disapate heat quicker
who has a higher surface mass ratio
females normally have a higher surface mass ratio which can be better for better heat dissipation, especially in endurance events. But it can be a disadvantage as the body will absorb more of the heat from the environment due to the larger surface area leading to the body being unable to stay cool enough to perform well
How does hormonal fluctuation affect thermoregulation
Increased progesterone in the luteal phase causes delayed onset of sweating, which decreases skin blood flow and a small increase in internal body temperatures - none of which are good when trying to keep cool.
Higher S/M Ratio (small body size, lean build) in thermoregulation
More surface area relative to mass → Faster heat exchange.
Greater heat loss in cold environments → Harder to retain body heat.
Better heat dissipation in hot environments → Advantageous in warm climates.
Lower S/M Ratio (large body size, broad thick build)
Less surface area relative to mass → Slower heat exchange.
More heat retention in cold environments → Helps conserve warmth.
Reduced heat loss in hot environments → Higher risk of overheating.
Advantages and disadvantages for a women in a hot dry climate
Advantage: Producing less sweat per gland may help reduce overall water loss, so less dehydration. Less sweat also means the body retains more fluids, which could help sustain endurance
Disadvantage: in a hot, dry environment, where sweat can evaporate quickly to cool the body efficiently, producing less sweat might limit cooling potential. This could lead to higher core temperatures compared to those who sweat more, increasing the risk of overheating.
Advantages and disadvantages for a female in hot humid climates
Advantage: sweat evaporation is limited due to the high moisture content in the air. Because the cooling effect is reduced, producing less sweat per gland can help prevent excessive water loss without sacrificing much in terms of effective cooling. This could be beneficial for managing hydration levels
Disadvantage: less sweat production may still make it harder to maintain a stable body temperature, increasing the risk of overheating in prolonged, intense activities.
process of breathing
Air is initially breathed in through the nose and mouth and it is warmed and moistened. It continues through the larger airways such as the trachea and bronchi.
The bronchi continue to get smaller and branch into bronchioles which then end in alveoli.
Alveoli are 1 cell thick and this is where gas exchange takes place with oxygen and carbon dioxide moving across the very thin barrier that separates the alveoli from the passing blood for further transport.
what pressure needs to occur for inhalation
he pressure inside the lungs needs to be less than the pressure in the atmosphere. The diaphragm contracts and pulls downwards, which makes the thoracic cavity larger and decreases the pressure, causing air to flow into the lungs along the pressure gradient.
what pressure needs to occur for exhalation
In exhalation at rest, the breathing out process is passive, the diaphragm relaxes and recoils back to its original position, making the thoracic cavity smaller and increasing the pressure, causing air to flow back out again.
in exercise how is respiration maximized
More muscles including the intercostals, abdomen and even shoulders contribute by increasing the lung volume during inhalation.
Contraction of these same muscles during exhalation, compresses the lungs faster and more forcefully to expel more air.
Vital Capacity
volume of air forced out after maximum inhalation; the sum of ERV, VT, and IRV.
Expiratory Reserve Volume
the amount of air you can breathe out above a normal breath
Tidal Volume
the volume of air moving in and out of the lungs during regular breathing
Inspiratory Reserve Volume
the amount of air you can breath in above a normal breath
Residual Volume
the amount of air left in the lungs after maximal breathing out
Total Lung Capacity
maximal volume of gas in the lungs after a maximal inhalation; the sum of the RV, ERV, VT, and IRV. NOT INCLUDING the amount of air in the lungs thats always there just incase
How can lung volume change
Lung volume increases with age, Biological females have typically lower lung volume and capacity compared to males
Vital capacity is generally higher in taller people than short people
concentration gradient
Gas will move from an area of concentration to an area of lower concentration
how does concentration gradient work in the body
In the lungs, the air breathed in is high in oxygen and low in carbon dioxide. The blood coming back to the lungs from the tissues is low in oxygen and high in carbon dioxide. Therefore, the oxygen will diffuse from the alveoli to the capillaries and be pumped to the tissues via the heart. The carbon dioxide will diffuse into the alveoli and be breathed out.
Minute Ventilation
amount of air being expelled in 1 minute.
determined by the amount of air breathed in in one breath (tidal volume) multiplied by the number of breaths per minute/ respiration rate
Primary function of the blood
to transfer gasses, nutrients, waste products, hormones and heat to and from various tissues.
Components of blood
Plasma - Mixture of water and electrolytes and transports
Platelets - assist in clotting
White Blood Cells - involved in immune function
Red Blood Cells - carry oxygen to tissues and carbon dioxide back to the lungs for exhalation
what is hemoglobin responsible for
Carrying oxygen and delivering to tissues its also rich in iron
how does altitude training work
If haemoglobin concentration can be increased, more oxygen can be transported and aerobic performance will improve.
In altitude training, an athlete lives and/or trains at high altitudes (where oxygen availability is lower) and the body naturally adapts by producing more haemoglobin and they perform better when they return to sea level with more oxygen availability .
What is blood doping
its an illegal way, where athletes inject previously extracted blood back into their bodies which allows more oxygen to be transported and improves performance. So the red blood cells are put back into them carrying a lot of hemoglobin boosting there oxygen transportation.
Arteries
large diameter, thick muscular walls there is significant pressure as the oxygen rich blood is pumped around the body. They are responsible for taking oxygenated blood to the tissues away from the heart.
Capillaries
narrow vessels with very thin walls. They are the sites of exchange between blood vessels and tissues.
Veins
Veins are responsible for delivering deoxygenated blood back to the heart. They are less muscular as pressure is lower and have valves to stop backflow.
Pulmonary circulation
delivers deoxygenated blood from the right side of the heart to the lungs for reoxygenation and then back to the left side of the heart to be pumped around the body.
Systemic circulation
delivers oxygenated blood from the left side of the heart to body tissues where the oxygen is used up. It then takes deoxygenated blood back to the right side of the heart to continue the cycle
how is blood pressure measured
pressure of the walls of the artery
how does blood travel around the heart
Atrium receives blood first, then pushes it into a larger and thicker walled ventricle. From the ventricle, it is ejected out of the heart.
Systolic Blood Pressure
the pressure during the contraction of the ventricles
Diastolic blood pressure
pressure during the relaxation of the ventricles
normal blood rpessure
around 120/80
what does static and dynamic excersise do for blood pressure
causes increase in stysolic and dyolic blood pressure due to sustained muscle contractions. over time static excersise and dynamic excersise can lead to a lower resting blood pressure
Why is high blood pressure bad
It puts extra strain pon the heart and blood vessels which can create damage overtime, leading to heart disease, stroke, kidney disease, and eye damge
Cardiac output
The amount of blood ejected from the heart in liters per minute. Cardiac output = stroke volume x heart rate
cardiac drift
Over time, heart rate increases to maintain this output due to stroke volume decreasing due to sweating and therefore less blood coming back to the heart.
Stroke Volum
amount of blood being ejected with each contraction (in milliliters/mi)
Maximal Oxygen Uptake (VO2 Max)
maximum rate at which an individual can take in and use oxygen.
nonshivering Thermogenesis
Nonshivering thermogenesis is heat production through metabolic activity, primarily in brown adipose tissue (BAT). It occurs when the body releases norepinephrine, stimulating mitochondria in BAT to generate heat instead of ATP. This is common in infants and hibernating animals but also occurs in adults to a lesser extent.
