S1 Flashcards
What are the 3 signalling molecule classifications?
Endogenous
Exogenous 1- natural
Exogenous 2-synthetic
What is homeostasis?
Maintaining the optimal environment for cells to function.
What is thermoregulation?
A regulation of temperature.
What should the temperature be?
36.5-37.5
Why is a high temperature bad?
Proteins denature , pH disrupt relatively weak electrostatic bonds between chains, loss of tertiary structure and active site
What are the two sets of thermoreceptors?
Skin- external ambient temperature
Central Hypothalamus- core body temp
What is in place if you get hot?
Vasodilation
Increased sweat from sweat glands
Decrease tonic vasoconstriction
What are the mechanisms involved in increasing temperature?
Decreased cutaneous blood flow
Instigate shivering reflex, increased heat generation
Skeletal muscle contraction
What is the difference between positive feedback and negative feedback?
Positive feedback is when the point diverts away from a set point.
Negative is when an effect goes further away from a set point.
What are the two groups at risk of thermoregulation defects?
Above 60-65 Gradual decline in whole body function Decrease in sweat response The metabolic fat reserves decrease Atrophy of skeletal muscle Disease state affects body systems.
Why are neonates at risk from lack of thermoregulation?
Immature bodysystems
Cannot thermoregulation independent of care
They have no shiver reflex
Can’t sweat
Have a large SA: body volume ratio so get rapid heat loss.
Give an example of two diseases which affect thermoregulation and why…
MS
You get demyelination in CNS which affects thermoregulation pathways, the thermoregulation has reduces or totally blocks nerve impulse conduction and you can experience both heat stress due to the lack of sweat response or cold stress due to vasoconstriction and shivering being adversely affected.
Diabetes
Heat stress: reduced blood flow and sweating response
Cold stress: blunted response of shivering and vasoconstriction leads to I’m
Aired regulation of core temp.
Givesome extracellular signalling molecules…
Endocrine- atravels through blood to other cells
Paracrine- acts on nearby cells
Autocrine- acts on itself
What are the 4 types of hormones and give examples of each…
Amine (amino acid) hormones for example: thyroid hormones are tyrosine based, they are triiodothyronine (T3) and thyroxine (T4)
Peptide hormones ie: oxytocin
Protein hormones: Human growth hormone
Steroid hormones: testosterone and progesterone (derived from the lipid cholesterol)
What is the mechanism of action for: catecholamines, peptides and proteins and steroids?
Catecholamines- causes a change in the membrane potential which triggers the synthesis of cystolic second messengers
Peptides and proteins- triggers synthesis of cystolic second messengers, triggers PROTEIN KINASE ACTIVITY
Steroids- receptor-hormone come,ex controls the transcription and stability of mRNAS (translated into DNA)
