sports science - option d(2)

2.1: State the reasons why humans cannot live without water for a prolonged period of time

Water is the basic substance for all metabolic processes in the body.

• Provides a medium which is essential for all metabolic processes/reactions in the body

• Helps to regulate body temperature/homeostasis as water can absorb/release a relatively large amount of heat

• Enables cell to cell communication

• Helps give structure and form to the body

2.2: State where extracellular fluid can be located throughout the body

• Blood plasma

• Lymph

• Saliva

• Fluid in the eyes (aqueous humour and vitreous humour)

• Fluid surrounding nerves/spinal cord/cerebrospinal fluid

• Synovial fluid

2.3: Compare water distribution in trained and untrained individuals

• Greater water content in their body both intra and extracellularly due to increased lean muscle mass compared to untrained who have more fat

• Improved temperature regulatory process

• Training increases blood plasma and extracellular fluid content

2.4: Explain that homeostasis involved monitoring levels of variables and correcting changes in levels by negative feedback mechanisms - Homeostasis & Feedback

Homeostasis is a state where the body’s internal environment remains relatively constant (within physiological limits)

Feedback systems are a cycle of events in which the status of a body condition is continually monitored, evaluated and changed.

2.4: Explain that homeostasis involved monitoring levels of variables and correcting changes in levels by negative feedback mechanisms - Negative Feedback

Negative feedback is a mechanism of response in which a stimulus initiates actions that reverse/reduce the stimulus.

• Explanation: Receptors/Sensors in the feedback system detect the change and send input to the control centre. An effector then produces a physiological response that is able to return the controlled condition to its normal state.

• e.g. Insulin and glucose

2.5: Explain the role of the loop of Henle, medulla, collecting duct and ADH in maintaining the water balance of the blood - Kidneys

Kidneys are the urinary organs

• produce urine

• dispose of metabolic waste

• helps regulate the internal environment of the body

2.5: Explain the role of the loop of Henle, medulla, collecting duct and ADH in maintaining the water balance of the blood - Medulla

Inner part of the kidney

• regulates concentration of urine by filtering water, salts and acid

2.5: Explain the role of the loop of Henle, medulla, collecting duct and ADH in maintaining the water balance of the blood - Loop of Henle

In the kidneys

• main function is to reabsorb water and ions from the urine

2.5: Explain the role of the loop of Henle, medulla, collecting duct and ADH in maintaining the water balance of the blood - Collecting Duct

• Collects all material that has not returned to the blood through the tubular membranes

• This material exits the kidney as urine

2.5: Explain the role of the loop of Henle, medulla, collecting duct and ADH in maintaining the water balance of the blood - ADH

Anti-diuretic hormone

• function is to hold water and increase water uptake

• e.g. when body fluid levels are low, receptors in the hypothalamus are stimulated. Hypothalamus then stimulates the pituitary gland to release ADH, which acts on the kidney.

2.6: Describe how the hydration status of athletes can be monitored

• Urine colour (volume)

• Urine osmolarity

• Body mass loss

• Hydrometer

2.6: Describe how the hydration status of athletes can be monitored - Urine Colour

• used as a subjective indicator of dehydration, the darker the colour suggests greater dehydration

2.6: Describe how the hydration status of athletes can be monitored - Urine Osmolarity

• measure the freezing point in urine

2.6: Describe how the hydration status of athletes can be monitored - Hydrometer

• measures the specific gravity of the urine and assesses its concentration

2.7: Explain why endurance athletes require a greater water intake

• Water intake helps to maintain hydration/avoid dehydration, as well as maintaining thermoregulation

• Water loss during prolonged exercise may lead to a decline in athletic performance or serious medical problems (heat exhaustion or heat stroke)

2.8: Discuss the regulation of electrolyte balance during acute and chronic exercise - During exercise

During exercise:

• Osmotic pressure and blood pressure increase during exercise

• Can be a large loss of sweat (water) which leads to a loss of electrolytes

• Electrolyte loss depends on sweat rate, physical condition, training status and state of heat acclimitisation

2.8: Discuss the regulation of electrolyte balance during acute and chronic exercise - Body responds by

Body responds by:

• The endocrine system monitoring fluid levels and electrolyte concentrations and corrects these imbalances

• ADH causes the walls of DCT (distal convoluted tubule) and collecting dust to become permeable to water which then drastically increases the amount of water that is reabsorbed

• ADH also has a vasoconstrictive response on the cardiovascular system