Thermoregulation
Peripheral thermoreceptors in skin and mucous membranes
Why is glucose an important substance in the body
Used to generate energy through cell respiration.
Does an increased osmotic pressure indicate too much or too little water in the blood plasma
Where are the peripheral chemoreceptors for gas concentrations located?
In the aorta and carotid arteries
What does hyperglycemia mean?
Higher than normal blood glucose levels.
Outline the methods of heat transfer that result in heat loss from the body.
Conduction
Convection
Radiation
Evaporation
What is the storage molecule for glucose?
Glycogen
What two hormones are involved in the regulation of body fluids?
ADH and Aldosterone
During intense exercise -- > when oxygen levels drop drastically.
Why is iodine important for thyroid function?
How does vasodilation of skin arterioles assist in thermoregulation. When would it occur?
More blood travelling to skin - increases heat loss through radiation and convection.
When body temp is increased.
What are the two main hormones involved in glucose regulation and where are they produced
Insulin - beta cells in IoL in pancreas
Glucagon - alpha cells in IoL in pancreas
What are the main ways of water gain and water loss in the body?
Gain -- (1600ml) drinking, (700ml) food, (200ml) metabolic water
Loss -- Urine (1500ml), Skin (500ml), Lungs (300ml), Faeces (200ml)
What is the relationship between carbon dioxide concentration and pH?
List 5 symptoms of hyperthyroidism
Weight loss, intolerance to cold, rapid heart rate, increased appetite, anxiety, fatigue, sweating, protruding eyeballs
Why would high humidity affect thermoregulation?
In humid conditions - evaporation can't occur, therefore reducing possible heat loss from the body in hot conditions.
What is the term for creating glucose from amino acids or fats. Where does it occur? Which hormone (s) can triggers this?
Gluconeogenesis
Liver
Glucagon, Adrenaline, Cortisol
How does ADH decrease osmotic pressure
It increases the permeability of the DCT and CD to water -- meaning more water is reasborbed into the bloodstream at the nephron.
Why is hyperventilation potentially dangerous prior to swimming underwater?
Name three (3) causes of hypothyroidism
Inadequate iodine in diet
Hashimoto's disease
Cancer - requiring removal of the thyroid
What causes dizziness and feinting when a person has heat exhaustion?
Excessive sweating and vasodilation -- loss of blood volume and wider blood vessels, decreases the blood pressure. Low blood pressure means less blood reaching brain.
What are the four (4) main ways in which insulin reduces blood glucose levels?
Promote uptake of glucose into body cells
Promote glycogenesis in liver and skeletal muscle
Promote lipogenesis
Promote protein synthesis
Provide the full feedback loop for someone who has drunk a 2 litre bottle of water over an hour.
Stimulus: Low osmotic pressure
Receptor: Osmoreceptors in the hypothalamus
Modulator: Hypothalamus
Effector: DCT and CD
Response: Decrease permeability to water - more water excreted
Feedback: increased osmotic pressure.
When people with anxiety hyperventilate -- it is sometimes suggested they breathe in and out of a paper bag. Why?
Why do both hypo and hyperthyroidism cause fatigue?
Hypo -- low metabolic rate -- little energy production through cell respiration
Hyper -- high metabolic rate -- glucose stores used up quickly -- reducing energy available for cell respiration
Provide a full physiological feedback loop for a person during a heat wave.
Stimulus: Increase body temp
Receptors: Central thermos in hypo & peripheral in skin and MM
Modulator: Hypothalamus
Effectors: Sweat glands, blood vessels in skin, thyroid gland
Response: Increase sweat production, vasodilation (increasing heat loss through evap, radiation, convection)
Reduce production of thyroxine -- reducing heat production
Feedback: Reduce body temp.
Provide the full feedback loop for a person who has been fasting for 24 hours ahead of a surgey.
Stimulus: Low blood glucose
Receptor: Chemoreceptor (alpha cells)
modulator: alpha cells in pancreas
Effector: Liver & Skeletal muscle
Response: Glycogenolysis, Gluconeogenesis, Lipolysis
Feedback: Increase blood glucose
Alcohol and caffeine are diuretic agents. Why would they then cause dehydration in the body?
They counteract the action of antidiuretic hormone. This makes the DCT and CD less permeable to water - meaning more is excreted through the kidney -- more lost as urine -- causing dehydration.
Give a full feedback loop for a person who has been holding their breath under water
Stimulus: Increase in CO2, H ions, decrease pH
Receptor: Peripheral chemoreceptors in aortic and carotid bodies. Central chemoreceptors in medulla oblongata
Modulator: Medulla oblongata (respiratory centre)
Effector: Respiratory muscles (diaphragm and intercostals)
Response: Increase rate and depth of breathing
Feedback: Decrease CO2, H ions, increase pH
Compare and contrast Type 1 and Type 2 diabetes in terms of:
Cause:
When it develops:
How it causes high BGL:
Treatment:
Why do both cause excessive thirst?:
Type 1: Immune system attacks beta cells, Develops in childhood, No insulin produced, Insulin injections
Type 2: Lifestyle factors (obesity, high sugar/fat diet, high blood pressure etc.) Adult onset, Cells are resistance to insulin, Low fat/sugar diet, regular exercise, maintainance of healthy weight
Thirst -- high sugar concentration in filtrate -- water follows -- increasing volume and frequency of urination -- causes dehydration -- thirst reflex trigger by hypothalamus.