Module 12 Wk 1 Flashcards
(PM - why and how?)
Describe how to perform and record a basic postmortem examination
- skin to open up hips and axillae
- then fully skin apart from limbs
- open up abdomen and thoracic cavities
- observe all
- External examination
(ID/Age/ breed/ sex/ Body condition/ weight) - Internal examination
(dissection - skin to open up hips and axillae, then fully skin apart from limbs, open up the abdomen and thoracic cavities - Dorsal OR Lateral approach) - Observation in situ
- Organ removal for visual inspection, palpation, and incision
Demonstrate safe working practices in the PM room
- white wellies
- lab coat
- apron
- blue gloves
- long arm gloves
- long white protective apron
- disinfect boots
Describe how you would collect suitable samples for ancillary testing
Histopathology -1cm thick
bacteriology/ virology - 1 cm by 1cm cube
toxicology - 50g feces
parasitology - 100g feces
(Thermoreg, pyrexia and hypthermia)
Define Poikilotherms
Their temperature fluctuates with the enviro and their activity level is related to body/enviro temp
Define Homeotherms
They are animals that maintain a ‘steady’ body temp, either increasing or decreasing it. They remain active in all temps.
Define an Endotherm
Internal heat production, can change their metabolic rate.
Are ecto or endotherms broadly homeotherms
Endotherms
Define Ectotherm
They rely upon external heat sources. Have low metabolic rate
Are ecto or endotherms broadly Poikiolotherms
Ectotherms
If there is an excess increase or decrease in body temp it will lead to death, so what has to happen when there is an excess increase in temp? Decrease in temp?
- heat loss must increase
- heat production must increase
Why is the core body temp most important to regulate?
Due to all main important organs in the cranium, thoracic and abdominal cavity being there
In a healthy individual should the temperature range be narrow?
Yes
Why is skin temp not always representative of core temp?
Use skin to regulate core temp
What is a circadian rhythm?
Rhythm with approx 24hr period - inherent rhythm of body temp
Describe seasonal variations in body temp
In winter body temp will be slightly lower than in summer
describe how digestion effets body temp
If you have just had a meal body temp will increase slightly due to specific dynamic actions where we take food into the body and process it, we burn ATP as we do resulting in some energy coming out in the form of heat.
What are the ways heat can be transferred?
Radiation
Conduction
Evaporation
Describe radiation
Energy, in the infrared portion of the spectrum given off or absorbed by an object
Describe Conduction
Energy is transferred between an object and the material next to the object by direct passage
what are conductive losses increased by?
air
Describe Evaporation
loss of water from an organism in the form of water vapor requires significant heat input
T/F anaimals can maintain body temp despite ambient?
True
Describe the control of thermogenesis?
- Its is regulated at the level of the preoptic area of the hypothalamus
- peripheral and central temp centers send info to the POA
- POA acts as an integrating center and sends info about the error to heat promoting or losing center
What does a decrease in ambient temperatures necessitate effect?
It increases the rate of heat production which compensates hear loss to the enviro
Describe behavioral to decrease heat loss
Animals take a closed position decreasing the radiant heat loss to the environment by making themselves as small as possible - tail over nose as it’s not insulated, closed off armpits.
What are the 5 physiological changes that increase heat production/promotion?
- cutaneous vasoconstriction
- countercurrent exchange system
- piloerection
- Shivering Thermogenesis
- Non-shivering thermogenesis
Describe how cutaneous vasoconstriction impacts heat production/promotion
- peripheral vaso diverts blood to the core
- periodic vaso pushes blood out to skin
What are the complications of vasoconstriction?
- Hypovolemia - a condition that occurs when your body loses fluid, like blood or water
- Frostbite - don’t have enough blood going out to the skin so it will die
What is the countercurrent exchange systems?
Where main arteries and adjacent veins deeo within tissue exchange heat so that blood out is also still warm
What is piloerection?
The contraction of small muscles at the base of hair follicles resulting in visible erection of hair.
Describe shivering thermogenesis
It is a spinal reflex causing small muscle movements building up ATP which releases heat
Describe non-shivering thermogenesis
Where SNS via beta-adrenoreceptors and T4 stimulate the sodium-potassium ATPase which in return increases metabolic rate and therefore heat production.
What are behavioral chnages that increase heat loss?
- open posture
- expose areas with low insulation
- minimal touching
- go to a cool loaction
What are the two physiological changes that increase heat loss
- altering conductance
- evaporative heat loss
Describe how altering conductance increases heat loss and what is the problem with it?
- Cutaneous vasodilation increase skin temp
- The problem with it is the effectiveness of conduction and convection decreases as ambient temp increases
Describe the different ways to increase heat loss via evaporation
- sweating - not all animals have sweat glands
- panting
- the spread of saliva on the fur (pretty ineffective)
Describe Panting and the side effects (good and bad)
- Movement of air in the ‘non-respiratory zone’ of airways ‘forced convection’
- Bad side effects such as loss of CO2, more work, loss of salt and good as cools blood going to brain
In response to adverse environmental conditions there are a number of responses depending on temporal characteristics and magnitude of change, what are these?
Phenotypic Adaptation during lifetime
Genotypic Adaptation
Acclimatization in response to natural forces
Acclimation in laboratory
Describe adjustments to chronic cold temperatures
- Increase thermal gradients
- increase metabolic rate
- decrease core temp ie hibernation
Describe adjustments to chronic hot temperature?
- decrease thermal gradient
- increase in core temp
- decrease the metabolic rate