Physiological Indicators Flashcards
True or false
Behavioural changes happen before physiological welfare indicators
True
Behavioural changes happen before physiological welfare indicators however we still need physiological indicators because of what 4 things?
1) It’s essential to have an additional set of welfare indicators that can be used to assess welfare
2) Physiological indicators provide a different perspective than behavioural measures
3) Some limitations are seen with behavioural measures, but there are also limitations with physiological ones
4) physiology, neurology and behaviour are interrelated
Give some examples of physiological indicators
Cardiovascular and respiratory measurements Hormones Neurotransmitters Biochemical parameters Immune function Pheromones and secretions Gene expression Organ/tissue composition and pathology Anatomical indicators
Define homeostasis
Homeostasis = It’s the dynamic maintenance of a constraint internal environment within the body
Constraint = a limitation or restriction
The body's internal environment remains generally fairly constant despite significant changes in the environment This is due to the body's dynamic internal maintenance mechanisms
Any challenge to an individual’s homeostasis is known as what?
Stress
Any challenge to an individual’s homeostasis is known as stress
What is the physiological definition of stress?
Physiological stress = response of the body to a demand that tends to disturb homeostasis
Due to the definition of physiological stress what 3 things can be said about it?
Stress responses are an adaptive mechanism
Stress responses are innate to the individual
Stress responses promote survival
How does stress responses promote survival?
Stress hormones are usually catabolic hormones
Catabolic hormones break down other molecules to release energy
Stress hormones break down molecules to release the energy needed at that time to perform an action necessary for the individual to survive
An example of this would be generating energy to run from a predator
What are stress hormones?
Stress hormones are an adaptive mechanism to generate energy to allow the animal to perform an action that ensures it’s survival in a stressful situation
What is the hypothalamic-pituitary-adrenal axis known as?
HPA Axis
The hypothalamic-pituitary-adrenal axis is a feedback loop responsible for what?
Promoting/controling stress responses
The hypothalamic-pituitary-adrenal axis is a feedback loop responsible for promoting/controlling stress responses
How does the HPA axis work?
First a signal is sent to the anterior pituitary lobe
Then the signal causes the anterior pituitary lobe to produce adrenocorticotropic hormones (ACTH)
Then the ACTH hormones travel to the adrenal cortex
ACTH then triggers the adrenal cortex to produce glucocorticoids
The glucocorticoids then travel through the blood to produce negative feedback once they reach either the hypothalamus or the posterior pituitary lobe
This then stops the stress response
What are glucocorticoids referred to as?
Stress hormones
Glucocorticoids are referred to as stress hormones
True or false
Different species produce different types of glucocorticoids
True
Give examples of different glucocorticoids produced by different species
Cortisol is produced by:
- humans - ruminants - most mammals
Corticosterone is produced by:
- birds - rodents - reptiles
Where are glucocorticoids produced?
Adrenal cortex’s medulla
Glucocorticoids are produced in the adrenal cortex’s medulla
What is the adrenal cortex’s medulla responsible for producing?
Glucocorticoids
Adrenaline
Noradrenaline
What types of hormone are glucocorticoids?
Glucocorticoids are steroid hormones
Glucocorticoids are also catabolic hormones
True or false
Glucocorticoids are at a constant level within an individual
False
Glucocorticoids levels show constant variation within the individual
How can you measure glucocorticoids?
From the:
- Blood - Metabolites in: - faeces - urine - Saliva - Hair - Milk
Where are glucocorticoids released into?
The blood
What kind of action is the effect on the body after the glucocorticoid hormones are released into the bloodstream?
Delayed action
The effect on the body after the glucocorticoid hormones are released into the bloodstream is a delayed action
What are the 3 benefits of having access to the Hypothalamic-pituitary-adrenal axis activity?
1) Glucocorticoids help us to deal with stress, as it maintains a steady state of fuel to the body
2) Glucocorticoids help to deal with stress invoking situations by helping to:
- Conserve glucose and energy molecules
- Elevate or stabilise glucose concentrations depending on the individuals need in a given situation
- Mobilise protein and lipid reserves
- Conserve salts and water
- have anti-inflammatory effects
3) Glucocorticoids are responsible for returning the body to a normal pre-stress state
This helps return the body to a normal homeostatic state
What are the 5 disadvantages of HPA activity as a welfare indicator?
There are only a limited number of steroid hormones in the brain, meaning that once the glucocorticoid brain receptors are saturated the excess glucocorticoids remain in the bloodstream
Due to this the excess glucocorticoids will travel around the body and bind to steriod receptors on other organs causing damage
Glucocorticoids maintain the organism in an alert state
Glucocorticoids have anti-inflammatory properties that slow down healing
Glucocorticoids suppress the immune system leaving the organism open to infection and disease
Glucocorticoids can also suppress the reproductive system
Due to these negative effects we can use glucocorticoids as a welfare indicator
What are glucocorticoids used to assess?
Stress and pain induced distress
Glucocorticoids are used in the assessment of stress and pain induced distress
Glucocorticoids are the most widely used assessment indicator of stress and pain induced distress
Why are glucocorticoids used in the assessment of stress and pain induced distress?
This is because glucocorticoid hormones are 1 of the easiest measures you can get non-invasively
What do glucocorticoids measure?
Glucocorticoids measure arousal rather than valence
Because glucocorticoid measure arousal rather than valence you need to do what 2 things in your welfare assessment?
1) Rule out interfering factors
2) Use another indicator to determine valence alongside glucocorticoids
Because glucocorticoid measure arousal rather than valence you need to do what 2 things in your welfare assessment?
1) Rule out interfering factors
2) Use another indicator to determine valence alongside glucocorticoids
What is important about species differences when it comes to glucocorticoids?
Across species the type of glucocorticoids varies and so do the glucocorticoid metabolites
Each species also varies in how the glucocorticoid metabolites are excreted and the proportion of glucocorticoid metabolites in each excretion type also varies
This is important to note when designing your experiments