Exam 1 – Dr. Eubanks Flashcards
What comes from a reaction between carbohydrates and oxygen?
Glucose
What comes from a reaction between proteins and oxygen?
Amino acids
What comes from a reaction between fat and oxygen?
Fatty acids
Where do oxidative reactions occur?
Within the mitochondria
How is the energy from oxidative reactions released?
In the form of ATP
What makes up ATP?
Adenine
Ribose
Phosphate radicals
What holds ATP together?
2 high energy bonds
What does each 2 high energy bond store?
12,000 calories of energy
If a phosphate bond is lost, what does ATP become?
ADP
What is ATP used for?
Nearly all synthetic reactions (forming bonds) Energizing muscle contractions Active transport across membranes Glandular secretion Energy for nerve conduction
What is glandular secretion?
Synthesis of secreted compound and its concentrations
What is energy for nerve conduction?
Potential energy set up by active ion transport
What happens to energy in foods?
35% becomes heat during ATP production
Another portion becomes heat during transfer energy from ATP to the functional systems of the cells
What happens to 27% of the energy released? What happens to the rest?
It reaches the functional system of the cells
Results in heat production
What is a calorie?
Quantity of heat required to raise the temperature of 1 gram of water 1 degree C
What is a Calorie?
1000 calories or kilocalories (measurement in food)
What is the basal metabolic rate?
The minimum energy expenditure for the body to exist
How much of the daily expenditure of energy is used in a sedentary individual?
50-70%
How is BMR calculated?
From square meter of body surface area
What can raise the metabolic rate?
Exercise/activity Lean body mass Thyroid hormone, growth hormone, testosterone Sympathetic system Fever Cold climate Small body size
Why do proteins cause the body to work harder?
They are difficult to digest
What is hyperthyroidism?
Very high metabolic rate
Mainly in cats
What causes hypothyroidism? What does it occur in?
Too little hormone
Mainly in obese and sedentary dogs
How much energy does purposeful activity use?
25%
How much energy does nonexercise activity use?
7%
How much energy does the thermic effect of food use?
8%
How much energy does arousal, sleeping metabolic rate, and basal metabolic rate use?
60%
What is core temperature?
Temperature of deep tissues is relatively constant, varying less than 1 degree F under normal conditions
What is skin temperature like?
Varies widely, depends on temperature of environment
What is the temperature control center?
Hypothalamus
What is body temp regulated by?
Nervous feedback mechanism
What do skin and deep body temp receptors do?
Mainly detect cold and cool temperatures
Function to prevent hyperthermia
What is the role of the posterior hypothalamus?
Receives input from anterior hypothalamus and peripheral temp receptors to elicit heat producing and heat conserving reactions
What is vasodilation? Vasoconstriction?
When vessels get bigger
When vessels get smaller
What are the mechanisms of heat loss?
Radiation
Conduction/convection
Evaporation
What is radiation?
Infrared heat waves
What does the effectiveness of radiation depend on?
The heat of surrounding objects
What is conduction/convection?
Heat transfer to layer of air at body surface
What is conduction enhanced by?
Convective air flow
What is 70% of dogs and cats cooling mechanisms?
Radiation and convection
When do dogs and cats rely on evaporation?
As ambient temp rises
How do dogs and cats utilize evaporation?
Panting
What happens during panting?
Vasodilation on the tongue and mucosal areas
How does vasodilation work as a temperature decreasing mechanism?
Transfers heat to skin
Cause inhibition of sympathetic centers in posterior hypothalamus that cause vasoconstriction
How does sweating work as a temperature decreasing mechanism?
Evaporative heat loss
Stimulation of preoptic area of hypothalamus which stimulates sweating via sympathetic cholinergic fibers and adrenergic
How does decrease heat production work as a temperature decreasing mechanism?
Shivering and chemical termogenesis are inhibited
What is panting controlled by?
Thermoregulator cells of brain
How does panting work for cooling?
Large quantities of air come in contact with respiratory passages
Water evaporation from respiratory mucosal surfaces and tongue cools blood
What are some temperature increasing mechanisms?
Vasoconstriction
Piloerection
Increased heat production
How does vasoconstriction work as a temperature increasing mechanism?
Impedes heat transfer to skin
Stimulation of sympathetic centers in posterior hypothalamus
What is piloerection?
Hair standing
How does increased heat production work as a temperature increasing mechanism?
Shivering
Sympathetic excitation of heat production
Thyroxine secretion
What does thyroid hormone do?
Cooling of anterior hypothalamic
Preoptic area increases producition of TRH and TSH
Chemical thermogenesis
What does pyrogenic hypothermia lead to?
Fever
Does hyperthermia/pyrexia lead to a fever?
No
What is nonpyrogenic hypothermia?
The inability to release enough heat
What are pyrogens?
Anything that will raise the temperature in the body
How can pyrogens directly reset the set-point temperature?
Bacteria-lipopolysaccharides from the bacterial cell membrane
Pyrogens form degenerating tissues
How can pyrogens indirectly reset the set-point temperature?
IL-1 is released from phagocytes following phagocytosis of blood-borne pyrogens. IL-1 raises set-point by increasing prostaglandin production
What is the body trying to do when you get chills?
Increase its temperature
What is heat stroke due to?
An individual getting heat quicker that they can get rid of it
When does heat stroke occur?
When the body temp rises above 106-108ºF
What does a rising body temp increase?
Metabolism, which generates more heat
When should cooling measures after heat stroke stop?
When the body reaches 103ºF
What is the main organ responsible for thermoregulation?
Anterior portion of hypothalamus
What are changes in temperature detected by?
Peripheral and central thermoreceptors
Peripheral vasodilation and central vasoconstriction
What can heat stroke cause?
Permanent intracellular alterations
Cell membrane instability
Generalized cellular necrosis
Multi-organ dysfunction or failure
What does splanchnic arteriolar vasodilation lead to?
Venous pooling
What does low plasma volume prevent?
Core body heat from dissipating
What are organs commonly affected by heat stroke?
GI tract (splanchnic vasoconstriction) Coagulation (endothelial damage) Renal (dehydration) Cardiac Pulmonary CNS (Neural injury and cell death)
What is frostbite?
Formation of ice crystals in the cells which leads to decreased circulation
What is a final protection against frostbite?
Cold-induced vasodilation
