LONG ANSWER QUESTIONS

Question 1

Explain how oxygen (or vice versa for CO2) in the air around us arrives at the mitochondria (site of Kreb’s Cycle and Electron Transport Chain) in our muscles. (be sure to include: the path O2 or CO2 takes in respiratory tract, a definition of diffusion, diffusion at the lungs, how O2 or CO2 is transported in the blood, diffusion at the muscle).

Answer 1

1. Path in the Respiratory Tract:
   Oxygen enters the body through the nose or mouth and travels down the respiratory tract.
   It passes through the pharynx, larynx, trachea, and then enters the bronchial tree.
   In the bronchial tree, oxygen moves through smaller and smaller air passages, eventually reaching the alveoli in the lungs.
2. Diffusion:
   Diffusion is the process by which molecules move from an area of higher concentration to an area of lower concentration until equilibrium is reached.
   In the lungs, oxygen diffuses from the alveoli (where it is highly concentrated) into the surrounding capillaries (where it is lower in concentration) due to the pressure difference.
3. Diffusion at the Lungs:
   Oxygen diffuses across the thin walls of the alveoli and into the adjacent capillaries, where it binds to hemoglobin molecules in red blood cells.
   Hemoglobin acts as a carrier, allowing oxygen to be transported efficiently through the bloodstream.
4. Transport in the Blood:
   Oxygen is primarily transported in the blood bound to hemoglobin, forming oxyhemoglobin.
   Some oxygen is also transported dissolved in the plasma, but the majority is carried by hemoglobin.
   The oxygenated blood is then pumped by the heart from the lungs to the rest of the body, including the muscles.
5. Diffusion at the Muscles:
   As oxygen-rich blood flows through the capillaries surrounding the muscle cells, oxygen diffuses out of the blood and into the muscle cells.
   Inside the muscle cells, oxygen is used in the mitochondria to support aerobic metabolism, including the Krebs cycle and the electron transport chain.
   Carbon dioxide, a byproduct of cellular respiration, diffuses out of the muscle cells into the bloodstream and is transported back to the lungs for exhalation.

In summary, oxygen in the air around us travels through the respiratory tract, diffuses into the bloodstream at the lungs, is transported by hemoglobin in red blood cells, and then diffuses into muscle cells where it is used in cellular respiration. Conversely, carbon dioxide is produced as a byproduct of cellular respiration, diffuses into the bloodstream, is transported back to the lungs, and then diffuses out of the body during exhalation.

Question 2

Long Answers
1. With reference to conduction, convection, radiation, and evaporation, explain how you can use all these principles to prevent ‘hyperthermia’ of an athlete training during the summer. Use a sport example.

Answer 2

Conduction: Heat transfer through physical contact
ex. wet towel

Convection: cooling via air flow
ex. fan, wind chill

Radiation: heat
ex. avoid/regulate radiation by removing gear or training in the shade

Evaporation: from sweat glands

These can all be used to prevent hyperthermia b/c…
All can be tools to use in game and training to regulate heat and prevent hyperthermia. For example convection and conduction ca be done together as a tool with a cool wind as well as cold towel directly applied to athlete to help cool them, evaporation is a constant mechanism used through the sweat glands to regulate temp, and finally mindfulness f radiation exposure will help limit overheating by being proactive and training in the shade or removing gear when possible.

Exercise Recommendations to Prevent Hyperthermia
1. Be Aware of Humidity
- high humidity is bad
- Location that has airflow (ie. beach)
2. Be Aware of Temperature (Air & Radiant) - Time of day
- Forrest(shade)
3. Ensure Hydration
- ensure sweat response (best water temperature?)
4. Wear proper Clothing
– Sweat soaked clothes inhibits evaporation (humidity high underneath)
– Protective gear prevents heat loss

Question 3

Long Answer
1. Children and adolescents develop at different times/rates. List and explain a specific a) hormonal, b) neurological, c) cardiovascular and d) musculoskeletal factor that may cause one adolescent to improve faster than another in an athletic/sport performance?

Answer 3

1. Musculoskeletal
   - Some kids (boys or girls) will grow taller faster or earlier than others
   - Elevated GH
   - Height is Due to Early Accelerated Bone Development

Muscle (Strength)
- Some kids will get stronger faster/earlier than others
– 10-fold increase in testosterone levels in boys from childhood to adolescence

2. Hormonal

Adipose Tissue
* Girls will begin to store more body fat then boys
– Estrogen increases fat deposition
– Lipoprotein lipase dictates location

3. Cardiovascular
   * Maximum heart rate
   – Kids have higher max heart rates
   * Smaller chambers can fill quickly
   * Smaller stroke volume (SV) – Less myocardium
   – Lower testosterone
   * Higher a-vO2 difference
   – Naturally high capillary to muscle ratio (Why?)
   – Low glycogen stores
   * Fatigue quickly when pushed anaerobically
   ** some kids genetics and physical activity Cavan have them mow advance for their age.
4. Neurological
   Myelination of neurons continues into adolescence
   – In the brain and in nerves throughout body
   – Kids who complete myelination before others could be because of genetics or physical activity levels

Question 4

Long Answers
1. An athlete may dehydrate during an endurance event causing blood pressure to drop. Explain why blood pressure drops and what the body can do to raise blood pressure once it drops below homeostatic levels (be sure to include multiple hormones in your answer).

Answer 4

When an athlete becomes dehydrated during an endurance event, blood pressure may drop due to several physiological mechanisms. Dehydration reduces blood volume, which in turn decreases cardiac output—the amount of blood pumped by the heart per minute. As a result, less blood is available to circulate throughout the body, leading to a decrease in blood pressure. Additionally, dehydration can cause electrolyte imbalances, such as low sodium levels, which can impair the body’s ability to regulate blood pressure and fluid balance.

Once blood pressure drops below homeostatic levels, the body initiates several compensatory mechanisms to raise blood pressure and restore circulation. These mechanisms involve the activation of hormonal and neural pathways to increase vascular tone, cardiac output, and fluid retention. Here’s how the body can raise blood pressure in response to dehydration:

Activation of the Renin-Angiotensin-Aldosterone System (RAAS):
Dehydration triggers the release of renin from the kidneys into the bloodstream. Renin acts on angiotensinogen (produced by the liver) to convert it into angiotensin I, which is then converted to angiotensin II by the angiotensin-converting enzyme (ACE) in the lungs.
Angiotensin II is a potent vasoconstrictor that constricts blood vessels, increasing peripheral vascular resistance and raising blood pressure.
Angiotensin II also stimulates the secretion of aldosterone from the adrenal glands. Aldosterone acts on the kidneys to increase the reabsorption of sodium and water, leading to expansion of blood volume and restoration of blood pressure.
Sympathetic Nervous System Activation:
Dehydration activates the sympathetic nervous system, leading to the release of catecholamines (epinephrine and norepinephrine) from the adrenal glands and sympathetic nerve terminals.
Catecholamines stimulate the heart to increase heart rate (positive chronotropic effect) and contractility (positive inotropic effect), resulting in an increase in cardiac output.
Catecholamines also cause vasoconstriction of peripheral blood vessels, redistributing blood flow to vital organs and tissues and raising blood pressure.
Antidiuretic Hormone (ADH) Release:
Dehydration stimulates the release of antidiuretic hormone (ADH), also known as vasopressin, from the posterior pituitary gland.
ADH acts on the kidneys to increase water reabsorption, reducing urine output and conserving body fluids.
By increasing water retention, ADH helps to expand blood volume and raise blood pressure.
In summary, when an athlete becomes dehydrated during an endurance event, blood pressure may drop due to reduced blood volume and electrolyte imbalances. To counteract this drop in blood pressure and restore circulation, the body activates compensatory mechanisms, including the renin-angiotensin-aldosterone system (RAAS), sympathetic nervous system, and release of antidiuretic hormone (ADH). These mechanisms work together to increase vascular tone, cardiac output, and fluid retention, thereby raising blood pressure and maintaining perfusion to vital organs and tissues during exercise.